Transcript Physical color propria

PowerPoint® Lecture Slides
prepared by
Janice Meeking,
Mount Royal College
CHAPTER
1
The Human
Body: An
Orientation:
Part A
Copyright © 2010 Pearson Education, Inc.
How to use this study guide
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principles you must know
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Overview of Anatomy and Physiology
• Anatomy: The study of structure
• Subdivisions:
• Gross or macroscopic (e.g., regional, surface,
and systemic anatomy)
• Microscopic (e.g., cytology – study of cells
and histology –study of tissues)
• Developmental (e.g., embryology)
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Overview of Anatomy and Physiology
• Physiology: The study of function at many
levels
• Subdivisions are based on organ systems
(e.g., renal or cardiovascular physiology)
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Principle of Complementarity
• Anatomy and physiology are inseparable.
• Function always reflects structure
• What a structure can do depends on its
specific form
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Must Know!
Atoms
Organelle
Smooth muscle cell
Molecule
1 Chemical level
Atoms combine to form molecules.
Cardiovascular
system
Heart
Blood
vessels
2 Cellular level
Cells are made up of
molecules.
Smooth muscle tissue
3 Tissue level
Tissues consist of similar
types of cells.
Blood vessel (organ)
Smooth muscle tissue
Connective tissue
Epithelial
tissue
4 Organ level
Organs are made up of different types
of tissues.
6 Organismal level
The human organism is made up
of many organ systems.
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5 Organ system level
Organ systems consist of different
organs that work together closely.
Figure 1.1
Overview of Organ Systems
• Note major organs and functions of the 11
organ systems (Fig. 1.3)
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Hair
Skin
Nails
(a) Integumentary System
Forms the external body covering, and
protects deeper tissues from injury.
Synthesizes vitamin D, and houses
cutaneous (pain, pressure, etc.)
receptors and sweat and oil glands.
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Figure 1.3a
Bones
Joint
(b) Skeletal System
Protects and supports body organs,
and provides a framework the muscles
use to cause movement. Blood cells
are formed within bones. Bones store
minerals.
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Figure 1.3b
Skeletal
muscles
(c) Muscular System
Allows manipulation of the environment,
locomotion, and facial expression. Maintains posture, and produces heat.
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Figure 1.3c
Brain
Spinal
cord
(d)
Nerves
Nervous System
As the fast-acting control system of
the body, it responds to internal and
external changes by activating
appropriate muscles and glands.
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Figure 1.3d
Pineal gland
Pituitary
gland
Thyroid
gland
Thymus
Adrenal
gland
Pancreas
Testis
Ovary
(e) Endocrine System
Glands secrete hormones that regulate
processes such as growth, reproduction,
and nutrient use (metabolism) by body
cells.
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Figure 1.3e
Heart
Blood
vessels
(f) Cardiovascular System
Blood vessels transport blood,
which carries oxygen, carbon
dioxide, nutrients, wastes, etc.
The heart pumps blood.
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Figure 1.3f
Red bone
marrow
Thymus
Lymphatic
vessels
Thoracic
duct
Spleen
Lymph
nodes
(g) Lymphatic System/Immunity
Picks up fluid leaked from blood vessels
and returns it to blood. Disposes of debris
in the lymphatic stream. Houses white
blood cells (lymphocytes) involved in
immunity. The immune response mounts
the attack against foreign substances
within the body.
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Figure 1.3g
Nasal
cavity
Pharynx
Larynx
Trachea
Bronchus
Lung
(h) Respiratory System
Keeps blood constantly supplied with
oxygen and removes carbon dioxide.
The gaseous exchanges occur through
the walls of the air sacs of the lungs.
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Figure 1.3h
Oral cavity
Esophagus
Liver
Stomach
Small
intestine
Large
intestine
Rectum
Anus
(i) Digestive System
Breaks down food into absorbable
units that enter the blood for
distribution to body cells. Indigestible
foodstuffs are eliminated as feces.
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Figure 1.3i
Kidney
Ureter
Urinary
bladder
Urethra
(j) Urinary System
Eliminates nitrogenous wastes from the
body. Regulates water, electrolyte and
acid-base balance of the blood.
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Figure 1.3j
Mammary
glands (in
breasts)
Prostate
gland
Ovary
Penis
Testis
Scrotum
Ductus
deferens
Uterus
Vagina
(k) Male Reproductive System
Uterine
tube
(l) Female Reproductive System
Overall function is production of offspring. Testes produce sperm and male sex
hormone, and male ducts and glands aid in delivery of sperm to the female
reproductive tract. Ovaries produce eggs and female sex hormones. The remaining
female structures serve as sites for fertilization and development of the fetus.
Mammary glands of female breasts produce milk to nourish the newborn.
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Figure 1.3k-l
Homeostasis
• Maintenance of a relatively stable internal
environment despite continuous outside
changes
• A dynamic state of equilibrium
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Homeostatic Control Mechanisms
• Involve continuous monitoring and
regulation of many factors (variables)
• Nervous and endocrine systems
accomplish the communication via nerve
impulses and hormones
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Components of a Control Mechanism
1. Receptor (sensor)
•
Monitors the environment
•
Responds to stimuli (changes in controlled variables)
2. Control center
•
Determines the set point at which the variable is
maintained
•
Receives input from receptor
•
Determines appropriate response
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Components of a Control Mechanism
3. Effector
•
Receives output from control center
•
Provides the means to respond
•
Response acts to reduce or enhance the
stimulus (feedback)
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3 Input: Information
sent along afferent
pathway to control
center.
2
Receptor
detects
change.
Receptor
4 Output:
Control
Center
Afferent
Efferent
pathway
pathway
1
Stimulus
produces
change in
variable.
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BALANCE
Information sent along
efferent pathway to
effector.
Effector
5
Response
of effector
feeds back
to reduce
the effect of
stimulus
and returns
variable to
homeostatic
level.
Figure 1.4
Negative Feedback
• The response reduces or shuts off the
original stimulus
• Examples:
• Regulation of body temperature (a nervous
mechanism)
• Regulation of blood volume by ADH (an
endocrine mechanism)
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Negative Feedback: Regulation of Blood
Volume by ADH
• Receptors sense decreased blood volume
• Control center in hypothalamus stimulates
pituitary gland to release antidiuretic
hormone (ADH)
• ADH causes the kidneys (effectors) to return
more water to the blood
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Positive Feedback
• The response enhances or exaggerates
the original stimulus
• May exhibit a cascade or amplifying effect
• Usually controls infrequent events e.g.:
• Enhancement of labor contractions by
oxytocin (Chapter 28)
• Platelet plug formation and blood clotting
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Homeostatic Imbalance
• Disturbance of homeostasis
• Increases risk of disease
• Contributes to changes associated with aging
• May allow destructive positive feedback
mechanisms to take over (e.g., heart failure)
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PowerPoint® Lecture Slides
prepared by
Janice Meeking,
Mount Royal College
CHAPTER
1
The Human
Body: An
Orientation:
Part B
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Anatomical Position
• Standard anatomical body position:
• Body erect
• Feet slightly apart
• Palms facing forward
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Table 1.1
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Table 1.1
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Table 1.1
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Table 1.1
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Table 1.1
Regional Terms
• Two major divisions of body:
• Axial
• Head, neck, and trunk
• Appendicular
• Limbs
• Regional terms designate specific areas
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Cephalic
Frontal
Orbital
Nasal
Oral
Mental
Cervical
Thoracic
Axillary
Mammary
Sternal
Abdominal
Umbilical
Pelvic
Inguinal
(groin)
Pubic
(genital)
Thorax
Abdomen
Back (Dorsum)
(a) Anterior/Ventral
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Upper limb
Acromial
Brachial (arm)
Antecubital
Antebrachial
(forearm)
Carpal (wrist)
Manus (hand)
Palmar
Pollex
Digital
Lower limb
Coxal (hip)
Femoral (thigh)
Patellar
Crural (leg)
Fibular or peroneal
Pedal (foot)
Tarsal (ankle)
Metatarsal
Digital
Hallux
Figure 1.7a
Body Cavities
• Dorsal cavity
• Protects nervous system
• Two subdivisions:
• Cranial cavity
• Encases brain
• Vertebral cavity
• Encases spinal cord
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Body Cavities
• Ventral cavity
• Houses internal organs (viscera)
• Two subdivisions (separated by diaphragm):
• Thoracic cavity
• Abdominopelvic cavity
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Cranial
cavity
Cranial
cavity
(contains
brain)
Dorsal
body
cavity
Dorsal body cavity
Ventral body cavity
Vertebral
cavity
Superior
mediastinum
Pleural
cavity
Pericardial
cavity within
the mediastinum
Diaphragm
Thoracic
cavity
(contains
heart and
lungs)
Vertebral
cavity
(contains
spinal
cord)
(a) Lateral view
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Ventral body
cavity
(thoracic and
Abdomino- abdominopelvic
pelvic
cavities)
cavity
Abdominal cavity
(contains digestive
viscera)
Pelvic cavity
(contains urinary
bladder, reproductive
organs, and rectum)
(b) Anterior view
Figure 1.9a-b
Serous Membrane (Serosa)
• Thin, double-layered membrane separated
by serous fluid
• Parietal serosa lines internal body walls
• Visceral serosa covers the internal organs
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PowerPoint® Lecture Slides
prepared by
Janice Meeking,
Mount Royal College
CHAPTER
2
Chemistry
Comes Alive:
Part A
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Major Elements of the Human Body
• Oxygen (O)
• Carbon (C)
• Hydrogen (H)
• Nitrogen (N)
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About 96% of body mass –
“bulk elements”
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Atomic Structure
• Determined by numbers of subatomic
particles
• Nucleus consists of neutrons and protons
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Atomic Structure
• Electrons: dictate chemical properties
• Orbit nucleus
• Equal in number to protons in atom
• Negative charge
• 1/2000 the mass of a proton (0 amu)
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Identifying Elements
• Atomic number = number of protons in
nucleus
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Identifying Elements
• Mass number = mass of the protons and
neutrons
• Mass numbers of atoms of an element are not
all identical
• Isotopes are structural variations of elements
that differ in the number of neutrons they
contain
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Identifying Elements
• Atomic weight = average of mass numbers
of all isotopes
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Molecules and Compounds
• Most atoms combine chemically with other
atoms to form molecules and compounds
• Molecule—two or more atoms bonded
together (e.g., H2 or C6H12O6)
• Compound—two or more different kinds of
atoms bonded together (e.g., C6H12O6)
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Types of Chemical Bonds
• Ionic
• Covalent
• Hydrogen
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Ionic Bonds
• Ions are formed by transfer of valence shell
electrons between atoms
• Anions (– charge) have gained one or more
electrons
• Cations (+ charge) have lost one or more
electrons
• Attraction of opposite charges results in
an ionic bond
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Covalent Bonds
• Formed by sharing of two or more valence
shell electrons
• Allows each atom to fill its valence shell at
least part of the time
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Reacting atoms
Resulting molecules
+
Molecule of
Hydrogen
Carbon
methane gas (CH4)
atoms
atom
(a) Formation of four single covalent bonds:
carbon shares four electron pairs with four
hydrogen atoms.
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or
Structural
formula
shows
single
bonds.
Figure 2.7a
Covalent Bonds
• Sharing of electrons may be equal or
unequal
• Equal sharing produces electrically balanced
nonpolar molecules
• CO2
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Figure 2.8a
Covalent Bonds
• Unequal sharing by atoms with different
electron-attracting abilities produces polar
molecules
• H2O
• Atoms with six or seven valence shell
electrons are electronegative, e.g., oxygen
• Atoms with one or two valence shell
electrons are electropositive, e.g., sodium
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Figure 2.8b
Hydrogen Bonds
• Attractive force between electropositive
hydrogen of one molecule and an
electronegative atom of another molecule
• Common between dipoles such as water
• Act as inter- and intramolecular bonds,
holding a large molecule in a threedimensional shape
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+
–
Hydrogen bond
(indicated by
dotted line)
+
+
–
–
–
+
+
+
–
(a) The slightly positive ends (+) of the water
molecules become aligned with the slightly
negative ends (–) of other water molecules.
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Figure 2.10a
Patterns of Chemical Reactions
• Synthesis (combination) reactions
• Decomposition reactions
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Synthesis Reactions
• A + B  AB
• Always involve bond formation
• Dehydration
• Anabolic
• Endergonic
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(a) Synthesis reactions
Smaller particles are bonded
together to form larger,
more complex molecules.
Example
Amino acids are joined together to
form a protein molecule.
Amino acid
molecules
Protein
molecule
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Figure 2.11a
Decomposition Reactions
• AB  A + B
• Reverse synthesis reactions
• Hydrolysis
• Involve breaking of bonds
• Catabolic
• Exergonic
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(b) Decomposition reactions
Bonds are broken in larger
molecules, resulting in smaller,
less complex molecules.
Example
Glycogen is broken down to release
glucose units.
Glycogen
Glucose
molecules
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Figure 2.11b
Chemical Reactions
• All chemical reactions are either exergonic or
endergonic
• Exergonic reactions—release energy
• Catabolic reactions
• Endergonic reactions—products contain
more potential energy than did reactants
• Anabolic reactions
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Rate of Chemical Reactions
• Rate of reaction is influenced by:
•  temperature   rate
•  particle size   rate
•  concentration of reactant   rate
• Catalysts:  rate without being chemically
changed
• Enzymes are biological catalysts
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PowerPoint® Lecture Slides
prepared by
Janice Meeking,
Mount Royal College
CHAPTER
2
Chemistry
Comes Alive:
Part B
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Classes of Compounds
• Inorganic compounds
• Water, salts, and many acids and bases
• Do not contain carbon
• Organic compounds
• Carbohydrates, fats, proteins, and nucleic
acids
• Contain carbon, usually large, and are
covalently bonded
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Water
• 60%–80% of the volume of living cells
• Most important inorganic compound in living
organisms because of its properties
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Properties of Water
• High heat capacity
• Absorbs and releases heat with little
temperature change
• Prevents sudden changes in temperature
• High heat of vaporization
• Evaporation requires large amounts of heat
• Useful cooling mechanism
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Properties of Water
• Polar solvent properties
• Dissolves and dissociates ionic substances
• Forms hydration layers around large charged
molecules, e.g., proteins (colloid formation)
• Body’s major transport medium
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+
–
+
Water molecule
Salt crystal
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Ions in solution
Figure 2.12
Properties of Water
• Reactivity
• A necessary part of hydrolysis and dehydration
synthesis reactions
• Cushioning
• Protects certain organs from physical trauma,
e.g., cerebrospinal fluid
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Salts
• Ionic compounds that dissociate in water
• Contain cations other than H+ and anions
other than OH–
• Ions (electrolytes) conduct electrical currents
in solution
• Ions play specialized roles in body
functions (e.g., sodium, potassium, calcium,
and iron)
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Acids and Bases
• Both are electrolytes
• Acids are proton (hydrogen ion) donors
(release H+ in solution)
• HCl  H+ + Cl–
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Acids and Bases
• Bases are proton acceptors (take up H+
from solution)
• NaOH  Na+ + OH–
• OH– accepts an available proton (H+)
• OH– + H+  H2O
• Bicarbonate ion (HCO3–) and ammonia
(NH3) are important bases in the body
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Acid-Base Concentration
• Acid solutions contain [H+]
• As [H+] increases, acidity increases
• Alkaline solutions contain bases [OH–]
• As [H+] decreases (or as [OH–] increases),
alkalinity increases
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pH: Acid-Base Concentration
• pH = the negative logarithm of [H+] in moles
per liter
• Neutral solutions:
• Pure water is pH neutral (contains equal
numbers of H+ and OH–)
• pH of pure water = pH 7: [H+] = 10 –7 M
• All neutral solutions are pH 7
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pH: Acid-Base Concentration
• Acidic solutions
•  [H+],  pH
• Acidic pH: 0–6.99
• pH scale is logarithmic: a pH 5 solution has 10
times more H+ than a pH 6 solution
• Alkaline solutions
•  [H+],  pH
• Alkaline (basic) pH: 7.01–14
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Concentration
(moles/liter)
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Examples
[OH–]
[H+]
pH
100
10–14
14
1M Sodium
hydroxide (pH=14)
10–1
10–13
13
Oven cleaner, lye
(pH=13.5)
10–2
10–12
12
10–3
10–11
11
10–4
10–10
10
10–5
10–9
9
10–6
10–8
8
10–7
10–7
7 Neutral
10–8
10–6
6
10–9
10–5
5
10–10
10–4
4
10–11
10–3
3
10–12
10–2
2
10–13
10–1
1
10–14
100
0
Household ammonia
(pH=10.5–11.5)
Household bleach
(pH=9.5)
Egg white (pH=8)
Blood (pH=7.4)
Milk (pH=6.3–6.6)
Black coffee (pH=5)
Wine (pH=2.5–3.5)
Lemon juice; gastric
juice (pH=2)
1M Hydrochloric
acid (pH=0)
Figure 2.13
Acid-Base Homeostasis
• pH change interferes with cell function and
may damage living tissue
• Slight change in pH can be fatal
• pH is regulated by kidneys – secrete
hydrogen ions, lungs – excrete carbon
dioxide, and buffers
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Buffers
• Mixture of compounds that resist pH
changes
• Convert strong (completely dissociated) acids
or bases into weak (slightly dissociated) ones
• Carbonic acid-bicarbonate system
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Organic Compounds
• Contain carbon (except CO2 and CO, which
are inorganic)
• Unique to living systems
• Include carbohydrates, lipids, proteins, and
nucleic acids
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Organic Compounds
• Many are polymers—chains of similar units
(monomers or building blocks)
• Synthesized by dehydration synthesis
• Broken down by hydrolysis reactions
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(a)
Dehydration synthesis
Monomers are joined by removal of OH from one monomer
and removal of H from the other at the site of bond formation.
Monomer 1
+
Monomer 2
Monomers linked by covalent bond
(b)
Hydrolysis
Monomers are released by the addition of a water molecule, adding OH to one monomer and H to the other.
+
Monomer 1
Monomer 2
Monomers linked by covalent bond
(c)
Example reactions
Dehydration synthesis of sucrose and its breakdown by hydrolysis
Water is
released
+
Water is
consumed
Glucose
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Fructose
Sucrose
Figure 2.14
Carbohydrates
• Sugars and starches
• Contain C, H, and O [(CH20)n]
• Three classes
• Monosaccharides
• Disaccharides
• Polysaccharides
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Carbohydrates
• Functions
• Major source of cellular fuel (e.g., glucose)
• Structural molecules (e.g., ribose sugar in
RNA)
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Monosaccharides
• Simple sugars containing three to seven C
atoms
• (CH20)n
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(a) Monosaccharides
Monomers of carbohydrates
Example
Example
Hexose sugars (the hexoses shown
Pentose sugars
here are isomers)
Glucose
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Fructose
Galactose
Deoxyribose
Ribose
Figure 2.15a
Disaccharides
• Double sugars
• Too large to pass through cell membranes
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(b) Disaccharides
Consist of two linked monosaccharides
Example
Sucrose, maltose, and lactose
(these disaccharides are isomers)
Glucose
Fructose
Sucrose
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Glucose
Maltose
Glucose
Galactose
Glucose
Lactose
Figure 2.15b
Polysaccharides
• Polymers of simple sugars, e.g., starch
and glycogen
• Not very soluble
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(c) Polysaccharides
Long branching chains (polymers) of linked monosaccharides
Example
This polysaccharide is a simplified representation of
glycogen, a polysaccharide formed from glucose units.
Glycogen
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Figure 2.15c
Lipids
• Contain C, H, O (less than in carbohydrates),
and sometimes P
• Insoluble in water
• Main types:
• Neutral fats or triglycerides
• Phospholipids
• Steroids
• Eicosanoids
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Triglycerides
• Neutral fats—solid fats and liquid oils
• Composed of three fatty acids bonded to a
glycerol molecule
• Main functions
• Energy storage
• Insulation
• Protection
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(a) Triglyceride formation
Three fatty acid chains are bound to glycerol by
dehydration synthesis
+
Glycerol
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3 fatty acid chains
Triglyceride,
or neutral fat
3 water
molecules
Figure 2.16a
Saturation of Fatty Acids
• Saturated fatty acids
• Single bonds between C atoms; maximum
number of H
• Solid animal fats, e.g., butter
• Unsaturated fatty acids
• One or more double bonds between C
atoms
• Reduced number of H atoms
• Plant oils, e.g., olive oil
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Phospholipids
• Modified triglycerides:
• Glycerol + two fatty acids and a
phosphorus (P)-containing group
• “Head” and “tail” regions have different
properties
• Predominate and important in cell
membrane structure
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(b) “Typical” structure of a phospholipid molecule
Two fatty acid chains and a phosphorus-containing group are
attached to the glycerol backbone.
Example
Phosphatidylcholine
Polar
“head”
Nonpolar
“tail”
(schematic
phospholipid)
Phosphoruscontaining
group (polar
“head”)
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Glycerol
backbone
2 fatty acid chains
(nonpolar “tail”)
Figure 2.16b
Steroids
• Steroids—interlocking four-ring structure
• Cholesterol, vitamin D, steroid hormones,
and bile salts
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(c)
Simplified structure of a steroid
Four interlocking hydrocarbon rings form a steroid.
Example
Cholesterol (cholesterol is the
basis for all steroids formed in the body)
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Figure 2.16c
Eicosanoids
• Many different ones
• Derived from a fatty acid (arachidonic acid)
in cell membranes
• Prostaglandins
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Other Lipids in the Body
• Other fat-soluble vitamins
• Vitamins A, E, and K
• Lipoproteins
• Transport fats in the blood
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Proteins
• Polymers of amino acids (20 types)
• Joined by peptide bonds
• polypeptides
• Contain C, H, O, N, and sometimes S and P
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Amine
group
Acid
group
(a) Generalized
structure of all
amino acids.
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(b) Glycine
is the simplest
amino acid.
(c) Aspartic acid
(d) Lysine
(an acidic amino acid)
(a basic amino acid)
has an acid group
has an amine group
(—COOH) in the
(–NH2) in the R group.
R group.
(e) Cysteine
(a basic amino acid)
has a sulfhydryl (–SH)
group in the R group,
which suggests that
this amino acid is likely
to participate in
intramolecular bonding.
Figure 2.17
Dehydration synthesis:
The acid group of one
amino acid is bonded to
the amine group of the
next, with loss of a water
molecule.
Peptide
bond
+
Amino acid
Amino acid
Dipeptide
Hydrolysis: Peptide
bonds linking amino
acids together are
broken when water is
added to the bond.
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Figure 2.18
Amino acid
Amino acid
Amino acid
Amino acid
Amino acid
(a) Primary structure:
The sequence of amino acids forms the polypeptide chain.
Copyright © 2010 Pearson Education, Inc.
Figure 2.19a
a-Helix: The primary chain is coiled
b-Sheet: The primary chain “zig-zags” back
to form a spiral structure, which is
and forth forming a “pleated” sheet. Adjacent
stabilized by hydrogen bonds.
strands are held together by hydrogen bonds.
(b) Secondary structure:
The primary chain forms spirals (a-helices) and sheets (b-sheets).
Copyright © 2010 Pearson Education, Inc.
Figure 2.19b
Tertiary structure of prealbumin
(transthyretin), a protein that
transports the thyroid hormone
thyroxine in serum and cerebrospinal fluid.
(c) Tertiary structure:
Superimposed on secondary structure. a-Helices and/or b-sheets are
folded up to form a compact globular molecule held together by
intramolecular (e.g. disulfide) bonds.
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Figure 2.19c
Quaternary structure of
a functional prealbumin
molecule. Two identical
prealbumin subunits
join head to tail to form
the dimer.
(d) Quaternary structure:
Two or more polypeptide chains, each with its own tertiary structure,
combine to form a functional protein.
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Figure 2.19d
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Protein Denaturation
• Shape change and disruption of active
sites due to environmental changes (e.g.,
decreased pH or increased temperature)
• Reversible in most cases, if normal conditions
are restored
• Irreversible if extreme changes damage the
structure beyond repair (e.g., cooking an egg)
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Enzymes
• Biological catalysts
• Lower the activation energy, increase the
speed of a reaction (millions of reactions per
minute!)
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Enzymes
• Speed reaction time
• Lower energy of activation
• Not used up in reaction
• Reusable
• Specific active site(s)
• Specific substrate
• Usually globular proteins
• Readily denatured under extreme
environmental conditions
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WITHOUT ENZYME
WITH ENZYME
Activation
energy
required
Less activation
energy required
Reactants
Reactants
Product
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Product
Figure 2.20
Characteristics of Enzymes
• Often named for the reaction they catalyze;
usually end in -ase (e.g., hydrolases,
oxidases)
• Some functional enzymes (holoenzymes)
consist of:
• Apoenzyme (protein)
• Cofactor (metal ion) or coenzyme (a
vitamin)
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Substrates (S)
e.g., amino acids
+
Product (P)
e.g., dipeptide
Energy is
absorbed;
bond is
formed.
Water is
released.
H2O
Peptide
bond
Active site
Enzyme (E)
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Enzyme-substrate
complex (E-S)
1 Substrates bind
2 Internal
at active site.
rearrangements
Enzyme changes
leading to
shape to hold
catalysis occur.
substrates in
proper position.
Enzyme (E)
3
Product is
released. Enzyme
returns to original
shape and is
available to catalyze
another reaction.
Figure 2.21
Nucleic Acids
• DNA and RNA
• Largest molecules in the body
• Contain C, O, H, N, and P
• Building block = nucleotide, composed of
N-containing base,
• Backbone – a pentose sugar, and a
phosphate group
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Deoxyribonucleic Acid (DNA)
• Four bases:
• adenine (A), guanine (G), cytosine (C), and
thymine (T)
• A – T, G – C
• Double-stranded helical molecule in the
cell nucleus
• Provides instructions for protein synthesis
• Replicates before cell division, ensuring
genetic continuity
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Phosphate
Sugar:
Deoxyribose
Base:
Adenine (A)
Thymine (T)
Adenine nucleotide
Sugar
Phosphate
Thymine nucleotide
Hydrogen
bond
(a)
Sugar-phosphate
backbone
Deoxyribose
sugar
Phosphate
Adenine (A)
Thymine (T)
Cytosine (C)
Guanine (G)
(b)
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(c) Computer-generated image of a DNA molecule
Figure 2.22
Ribonucleic Acid (RNA)
• Four bases:
• adenine (A), guanine (G), cytosine (C), and
uracil (U)
• Uracil instead of guanine
• Single-stranded molecule mostly active
outside the nucleus
• Three varieties of RNA carry out the DNA
orders for protein synthesis
• messenger RNA, transfer RNA, and
ribosomal RNA
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Adenosine Triphosphate (ATP)
• Adenine-containing RNA nucleotide with two
additional phosphate groups
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High-energy phosphate
bonds can be hydrolyzed
to release energy.
Adenine
Phosphate groups
Ribose
Adenosine
Adenosine monophosphate (AMP)
Adenosine diphosphate (ADP)
Adenosine triphosphate (ATP)
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Figure 2.23
Function of ATP
• Phosphorylation:
• Terminal phosphates are enzymatically
transferred to and energize other molecules
• Such “primed” molecules perform cellular
work (life processes) using the phosphate
bond energy
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Solute
+
Membrane
protein
(a) Transport work: ATP phosphorylates transport
proteins, activating them to transport solutes
(ions, for example) across cell membranes.
+
Relaxed smooth
muscle cell
Contracted smooth
muscle cell
(b) Mechanical work: ATP phosphorylates
contractile proteins in muscle cells so the
cells can shorten.
+
(c) Chemical work: ATP phosphorylates key
reactants, providing energy to drive
energy-absorbing chemical reactions.
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Figure 2.24
PowerPoint® Lecture Slides
prepared by
Janice Meeking,
Mount Royal College
CHAPTER
3
Cells: The
Living Units:
Part A
Copyright © 2010 Pearson Education, Inc.
Cell Theory
• The cell is the smallest structural and
functional living unit
• Organismal functions depend on
individual and collective cell functions
• Biochemical activities of cells are dictated
by their specific subcellular structures
• Continuity of life has a cellular basis
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Generalized Cell
• All cells have some common structures and
functions
• Human cells have three basic parts:
• Plasma membrane—flexible outer boundary
• Cytoplasm—intracellular fluid containing
organelles
• Nucleus—control center
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Plasma Membrane
• Bimolecular layer of lipids and proteins in
a constantly changing – fluid mosaic
• Function: molecular transport
• Plays a dynamic role in cellular activity
• Separates intracellular fluid (ICF) from
extracellular fluid (ECF)
• Interstitial fluid (IF) = ECF that surrounds cells
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Extracellular fluid
(watery environment)
Polar head of
phospholipid
molecule
Cholesterol
Glycolipid
Glycoprotein
Carbohydrate
of glycocalyx
Outwardfacing
layer of
phospholipids
Integral
proteins
Filament of
cytoskeleton
Peripheral
Bimolecular
Inward-facing
proteins
lipid layer
layer of
containing
phospholipids
Nonpolar
proteins
tail of
phospholipid
Cytoplasm
molecule
(watery environment)
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Figure 3.3
Membrane Lipids
• 75% phospholipids (lipid bilayer)
• Phosphate heads: polar and hydrophilic
• Fatty acid tails: nonpolar and hydrophobic (Review
Fig. 2.16b)
• Amphipathic
• 5% glycolipids
• Lipids with polar sugar groups on outer membrane
surface
• 20% cholesterol
• Increases membrane stability and fluidity
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Membrane Proteins
• Integral proteins
• Firmly inserted into the membrane (most are
transmembrane)
• Functions:
• Transport proteins (channels and
carriers), enzymes, or receptors
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Membrane Proteins
• Peripheral proteins
• Loosely attached to integral proteins
• Include filaments on intracellular surface and
glycoproteins on extracellular surface
• Functions:
• Enzymes, motor proteins, cell-to-cell
links, provide support on intracellular
surface, and form part of glycocalyx
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Functions of Membrane Proteins
1. Transport
2. Receptors for signal transduction
3. Attachment to cytoskeleton and
extracellular matrix
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(a) Transport
A protein (left) that spans the membrane
may provide a hydrophilic channel across
the membrane that is selective for a
particular solute. Some transport proteins
(right) hydrolyze ATP as an energy source
to actively pump substances across the
membrane.
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Figure 3.4a
Signal
Receptor
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(b) Receptors for signal transduction
A membrane protein exposed to the
outside of the cell may have a binding
site with a specific shape that fits the
shape of a chemical messenger, such
as a hormone. The external signal may
cause a change in shape in the protein
that initiates a chain of chemical
reactions in the cell.
Figure 3.4b
(c) Attachment to the cytoskeleton
and extracellular matrix (ECM)
Elements of the cytoskeleton (cell’s
internal supports) and the extracellular
matrix (fibers and other substances
outside the cell) may be anchored to
membrane proteins, which help maintain
cell shape and fix the location of certain
membrane proteins. Others play a role in
cell movement or bind adjacent cells
together.
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Figure 3.4c
Functions of Membrane Proteins
4. Enzymatic activity
5. Intercellular joining
6. Cell-cell recognition
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(d) Enzymatic activity
Enzymes
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A protein built into the membrane may
be an enzyme with its active site
exposed to substances in the adjacent
solution. In some cases, several
enzymes in a membrane act as a team
that catalyzes sequential steps of a
metabolic pathway as indicated (left to
right) here.
Figure 3.4d
(e) Intercellular joining
Membrane proteins of adjacent cells
may be hooked together in various
kinds of intercellular junctions. Some
membrane proteins (CAMs) of this
group provide temporary binding sites
that guide cell migration and other
cell-to-cell interactions.
CAMs
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Figure 3.4e
(f) Cell-cell recognition
Some glycoproteins (proteins bonded
to short chains of sugars) serve as
identification tags that are specifically
recognized by other cells.
Glycoprotein
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Figure 3.4f
Membrane Transport
• Plasma membranes are selectively
permeable
• Some molecules easily pass through the
membrane; others do not
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Types of Membrane Transport
• Passive processes
• No cellular energy (ATP) required
• Substance moves down its concentration
gradient
• Active processes
• Energy (ATP) required
• Occurs only in living cell membranes
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Passive Processes
•
What determines whether or not a
substance can passively permeate a
membrane?
1. Lipid solubility of substance
2. Channels of appropriate size
3. Carrier proteins
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Passive Processes
1. Simple diffusion
2. Carrier-mediated facilitated diffusion
3. Channel-mediated facilitated diffusion
4. Osmosis
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Passive Processes: Simple Diffusion
• Nonpolar lipid-soluble (hydrophobic)
substances diffuse directly through the
phospholipid bilayer
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Extracellular fluid
Lipidsoluble
solutes
Cytoplasm
(a) Simple diffusion of fat-soluble molecules
directly through the phospholipid bilayer
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Figure 3.7a
Passive Processes: Facilitated Diffusion
• Certain lipophobic molecules (e.g., glucose,
amino acids, and ions) use carrier proteins or
channel proteins, both of which:
• Exhibit specificity (selectivity)
• Are saturable; rate is determined by
number of carriers or channels
• Can be regulated in terms of activity and
quantity
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Facilitated Diffusion Using Carrier Proteins
• Transmembrane integral proteins
transport specific polar molecules (e.g.,
sugars and amino acids)
• Binding of substrate causes shape change in
carrier
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Lipid-insoluble
solutes (such as
sugars or amino
acids)
(b) Carrier-mediated facilitated diffusion via a protein
carrier specific for one chemical; binding of substrate
causes shape change in transport protein
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Figure 3.7b
Facilitated Diffusion Using Channel Proteins
• Aqueous channels formed by
transmembrane proteins selectively
transport ions or water
• Two types:
• Leakage channels
• Always open
• Gated channels
• Controlled by chemical or electrical signals
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Small lipidinsoluble
solutes
(c) Channel-mediated facilitated diffusion
through a channel protein; mostly ions
selected on basis of size and charge
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Figure 3.7c
Passive Processes: Osmosis
• Movement of solvent (water) across a
selectively permeable membrane
• Water diffuses through plasma
membranes:
• Through the lipid bilayer
• Through water channels called aquaporins
(AQPs)
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Water
molecules
Lipid
billayer
Aquaporin
(d) Osmosis, diffusion of a solvent such as
water through a specific channel protein
(aquaporin) or through the lipid bilayer
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Figure 3.7d
Passive Processes: Osmosis
• Water concentration is determined by
solute concentration because solute
particles displace water molecules
• Osmolarity: The measure of total
concentration of solute particles
• When solutions of different osmolarity are
separated by a membrane, osmosis occurs
until equilibrium is reached
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(a)
Membrane permeable to both solutes and water
Solute and water molecules move down their concentration gradients
in opposite directions. Fluid volume remains the same in both compartments.
Left
compartment:
Solution with
lower osmolarity
Right
compartment:
Solution with
greater osmolarity
Both solutions have the
same osmolarity: volume
unchanged
H2O
Solute
Membrane
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Solute
molecules
(sugar)
Figure 3.8a
(b)
Membrane permeable to water, impermeable to solutes
Solute molecules are prevented from moving but water moves by osmosis.
Volume increases in the compartment with the higher osmolarity.
Left
compartment
Right
compartment
Both solutions have identical
osmolarity, but volume of the
solution on the right is greater
because only water is
free to move
H2O
Membrane
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Solute
molecules
(sugar)
Figure 3.8b
Importance of Osmosis
• When osmosis occurs, water enters or leaves
a cell
• Change in cell volume disrupts cell function
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Tonicity
• Tonicity: The ability of a solution to cause a cell
to shrink or swell (concentration of solute).
Water moves to area of higher solute
concentration across a semipermeable
membrane
• Isotonic: A solution with the same solute
concentration as that of the cytosol
• Hypertonic: A solution having greater solute
concentration than that of the cytosol
• Hypotonic: A solution having lesser solute
concentration than that of the cytosol
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(a) Isotonic solutions
Cells retain their normal size and
shape in isotonic solutions (same
solute/water concentration as inside
cells; water moves in and out).
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(b) Hypertonic solutions
Cells lose water by osmosis and
shrink in a hypertonic solution
(contains a higher concentration
of solutes than are present inside
the cells).
(c) Hypotonic solutions
Cells take on water by osmosis until
they become bloated and burst (lyse)
in a hypotonic solution (contains a
lower concentration of solutes than
are present in cells).
Figure 3.9
Summary of Passive Processes
Process
Simple
diffusion
Facilitated
diffusion
Osmosis
Energy
Source
Kinetic
energy
Kinetic
energy
Kinetic
energy
• Also see Table 3.1
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Example
Movement of O2 through
phospholipid bilayer
Movement of glucose into
cells
Movement of H2O through
phospholipid bilayer or
AQPs
PowerPoint® Lecture Slides
prepared by
Janice Meeking,
Mount Royal College
CHAPTER
3
Cells: The
Living Units:
Part B
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Membrane Transport: Active Processes
• Two types of active processes:
• Active transport
• Vesicular transport
• Both use ATP to move solutes across a living
plasma membrane
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Active Transport
• Requires carrier proteins (solute pumps)
• Moves solutes against a concentration
gradient
• Types of active transport:
• Primary active transport
• Secondary active transport
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Primary Active Transport
• Energy from hydrolysis of ATP causes
shape change in transport protein so that
bound solutes (ions) are “pumped” across
the membrane
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Primary Active Transport
• Sodium-potassium pump (Na+-K+ ATPase)
• Located in all plasma membranes
• Involved in primary and secondary active transport of
nutrients and ions
• Maintains electrochemical gradients essential for
functions of muscle and nerve tissues
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Extracellular fluid
Na+
Na+-K+ pump
Na+ bound
K+
ATP-binding site
Cytoplasm
1 Cytoplasmic Na+ binds to pump protein.
P
ATP
K+ released
ADP
6 K+ is released from the pump protein
and Na+ sites are ready to bind Na+ again.
The cycle repeats.
2 Binding of Na+ promotes
phosphorylation of the protein by ATP.
Na+ released
K+ bound
P
Pi
K+
5 K+ binding triggers release of the
phosphate. Pump protein returns to its
original conformation.
3 Phosphorylation causes the protein to
change shape, expelling Na+ to the outside.
P
4 Extracellular K+ binds to pump protein.
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Figure 3.10
Secondary Active Transport
• Depends on an ion gradient created by
primary active transport
• Energy stored in ionic gradients is used
indirectly to drive transport of other
solutes
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Vesicular Transport
• Transport of large particles,
macromolecules, and fluids across plasma
membranes
• Requires cellular energy (e.g., ATP)
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Vesicular Transport
• Functions:
• Exocytosis—transport out of cell
• Endocytosis—transport into cell
• Transcytosis—transport into, across, and
then out of cell
• Substance (vesicular) trafficking—transport
from one area or organelle in cell to another
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Endocytosis and Transcytosis
• Involve formation of protein-coated
vesicles
• Often receptor mediated, therefore very
selective
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1 Coated pit ingests
substance.
Extracellular fluid
Protein coat
(typically
clathrin)
2 Proteincoated
vesicle
detaches.
Plasma
membrane
Cytoplasm
3 Coat proteins detach
and are recycled to
plasma membrane.
Transport
vesicle
Endosome
Uncoated
endocytic vesicle
4 Uncoated vesicle fuses
with a sorting vesicle
called an endosome.
Lysosome
5 Transport
vesicle containing
membrane components
moves to the plasma
membrane for recycling.
6 Fused vesicle may (a) fuse
(a)
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with lysosome for digestion
of its contents, or (b) deliver
its contents to the plasma
membrane on the
opposite side of the cell
(transcytosis).
(b)
Figure 3.12
Endocytosis
• Phagocytosis — pseudopods engulf solids
and bring them into cell’s interior
• Macrophages and some white blood cells
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(a)
Phagocytosis
The cell engulfs a large particle
by forming projecting pseudopods (“false
feet”) around it and enclosing it within a membrane
sac called a phagosome.
The phagosome is
combined with a lysosome.
Undigested contents remain
in the vesicle (now called a
residual body) or are ejected
by exocytosis. Vesicle may
or may not be proteincoated but has receptors
capable of binding to
Phagosome
microorganisms or solid
particles.
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Figure 3.13a
Endocytosis
• Fluid-phase endocytosis (pinocytosis)—
plasma membrane infolds, bringing
extracellular fluid and solutes into interior of
the cell
• Nutrient absorption in the small intestine
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(b)
Pinocytosis
The cell “gulps” drops of
extracellular fluid containing
solutes into tiny vesicles. No
receptors are used, so the
process is nonspecific. Most
vesicles are protein-coated.
Vesicle
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Figure 3.13b
Endocytosis
• Receptor-mediated endocytosis — clathrincoated pits provide main route for
endocytosis and transcytosis
• Uptake of enzymes, low-density lipoproteins,
iron, and insulin
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(c)
Receptor-mediated
endocytosis
Extracellular substances
bind to specific receptor
proteins in regions of coated
pits, enabling the cell to
ingest and concentrate
specific substances
(ligands) in protein-coated
vesicles. Ligands may
Vesicle
simply be released inside
the cell, or combined with a
lysosome to digest contents.
Receptors are recycled to
Receptor recycled
to plasma membrane
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the plasma membrane in
vesicles.
Figure 3.13c
Exocytosis
• Examples:
• Hormone secretion
• Neurotransmitter release
• Mucus secretion
• Ejection of wastes
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Plasma membrane The process
Extracellular
of exocytosis
SNARE (t-SNARE)
fluid
Secretory
vesicle
Vesicle
SNARE
(v-SNARE)
Molecule to
be secreted
Cytoplasm
1 The membrane-
bound vesicle
migrates to the
plasma membrane.
2 There, proteins
at the vesicle
Fused surface (v-SNAREs)
v- and bind with t-SNAREs
t-SNAREs (plasma membrane
proteins).
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Fusion pore formed
3 The vesicle
and plasma
membrane fuse
and a pore
opens up.
4 Vesicle
contents are
released to the
cell exterior.
Figure 3.14a
Summary of Active Processes
Process
Energy Source
Example
Primary active
transport
ATP
Pumping of ions across
membranes
Secondary active
transport
Ion gradient
Movement of polar or charged
solutes across membranes
Exocytosis
ATP
Secretion of hormones and
neurotransmitters
Phagocytosis
ATP
White blood cell phagocytosis
Pinocytosis
ATP
Absorption by intestinal cells
Receptor-mediated
endocytosis
ATP
Hormone and cholesterol uptake
• Also see Table 3.2
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Membrane Potential
• Separation of oppositely charged
particles (ions) across a membrane
creates a membrane potential (potential
energy measured as voltage)
• Resting membrane potential (RMP):
Voltage measured in resting state in all cells
• Ranges from –50 to –100 mV in different cells
• Results from diffusion and active transport
of ions (mainly K+)
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Generation and Maintenance of RMP
1. The Na+ -K+ pump continuously ejects
Na+ from cell and carries K+ back in
2. Some K+ continually diffuses down its
concentration gradient out of cell
through K+ leakage channels
3. Membrane interior becomes negative
(relative to exterior) because of large
anions trapped inside cell
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Generation and Maintenance of RMP
4. Electrochemical gradient begins to
attract K+ back into cell
5. RMP is established at the point where
the electrical gradient balances the K+
concentration gradient
6. A steady state is maintained because the
rate of active transport is equal to and
depends on the rate of Na+ diffusion into
cell
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1 K+ diffuse down their steep
Extracellular fluid
concentration gradient (out of the cell)
via leakage channels. Loss of K+ results
in a negative charge on the inner
plasma membrane face.
2 K+ also move into the cell
because they are attracted to the
negative charge established on the
inner plasma membrane face.
3 A negative membrane potential
Potassium
leakage
channels
Cytoplasm
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(–90 mV) is established when the
movement of K+ out of the cell equals
K+ movement into the cell. At this
point, the concentration gradient
promoting K+ exit exactly opposes the
electrical gradient for K+ entry.
Protein anion (unable to
follow K+ through the
membrane)
Figure 3.15
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Copyright © 2010 Pearson Education, Inc.
Copyright © 2010 Pearson Education, Inc.
PowerPoint® Lecture Slides
prepared by
Janice Meeking,
Mount Royal College
CHAPTER
3
Cells: The
Living Units:
Part C
Copyright © 2010 Pearson Education, Inc.
Cytoplasm
• Located between plasma membrane and nucleus
• Cytosol
• Water with solutes (protein, salts, sugars, etc.)
• Cytoplasmic organelles
• Metabolic machinery of cell
• Inclusions
• Granules of glycogen or pigments, lipid droplets,
vacuoles, and crystals
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Cytoplasmic Organelles
• Membranous
• Nonmembranous
• Mitochondria
• Cytoskeleton
• Peroxisomes
• Centrioles
• Lysosomes
• Ribosomes
• Endoplasmic
reticulum
• Golgi apparatus
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Mitochondria
• Double-membrane structure with shelflike
cristae
• Provide most of cell’s ATP via aerobic
cellular respiration
• Contain their own DNA and RNA
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Ribosomes
• Granules containing protein and rRNA
• Site of protein synthesis
• Free ribosomes synthesize soluble proteins
• Membrane-bound ribosomes (on rough ER)
synthesize proteins to be incorporated into
membranes or exported from the cell
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Endoplasmic Reticulum (ER)
• Interconnected tubes and parallel
membranes enclosing cisternae
• Continuous with nuclear membrane
• Two varieties:
1. Rough ER
2. Smooth ER
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Rough ER
• External surface studded with ribosomes
• Manufactures all secreted proteins
• Synthesizes membrane integral proteins and
phospholipids
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Smooth ER
• Tubules arranged in a looping network
• Enzyme (integral protein) functions:
• In the liver—lipid and cholesterol metabolism,
breakdown of glycogen, and, along with kidneys,
detoxification of drugs, pesticides, and
carcinogens
• Synthesis of steroid-based hormones
• In intestinal cells—absorption, synthesis, and
transport of fats
• In skeletal and cardiac muscle—storage and
release of calcium
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Golgi Apparatus
• Stacked and flattened membranous sacs
• Modifies, concentrates, and packages
proteins and lipids
• Transport vessels from ER fuse with convex
cis face of Golgi apparatus
• Proteins then pass through Golgi apparatus to
trans face
• Secretory vesicles leave trans face of Golgi
stack and move to designated parts of cell
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Lysosomes
• Spherical membranous bags containing
digestive enzymes (acid hydrolases)
• Digest ingested bacteria, viruses, and toxins
• Degrade nonfunctional organelles
• Break down and release glycogen
• Break down bone to release Ca2+
• Destroy cells in injured or non-useful tissue
(autolysis)
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Cellular Extensions
• Microvilli
• Fingerlike extensions of plasma membrane
• Increase surface area for absorption
• Core of actin filaments for stiffening
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PowerPoint® Lecture Slides
prepared by
Janice Meeking,
Mount Royal College
CHAPTER
4
Tissue: The
Living Fabric:
Part A
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Tissues
• Groups of cells similar in structure and
function
• Types of tissues
1. Epithelial tissue
2. Connective tissue
3. Muscle tissue
4. Nerve tissue
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Epithelial Tissue (Epithelium)
•
Two main types (by location):
1. Covering and lining epithelia
•
On external and internal surfaces
2. Glandular epithelia
•
Secretory tissue in glands
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Characteristics of Epithelial Tissue
1. Cells have polarity—apical (upper, free)
and basal (lower, attached) surfaces
•
Apical surfaces may bear microvilli (e.g.,
brush border of intestinal lining) or cilia (e.g.,
lining of trachea)
•
Noncellular basal lamina of glycoprotein
and collagen lies adjacent to basal
surface
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Characteristics of Epithelial Tissue
2. Are composed of closely packed cells
•
Continuous sheets held together by tight
junctions and desmosomes
3. Supported by a connective tissue
reticular lamina (under the basal lamina)
4. Avascular but innervated
5. High rate of regeneration
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Classification of Epithelia
•
Ask two questions:
1. How many layers?
1 = simple epithelium
>1 = stratified epithelium
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Apical surface
Basal surface
Simple
Apical surface
Basal surface
Stratified
(a) Classification based on number of cell layers.
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Figure 4.2a
Classification of Epithelia
2. What type of cell?
1. Squamous
2. Cuboidal
3. Columnar
•
(If stratified, name according to apical layer
of cells)
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Squamous
Cuboidal
Columnar
(b) Classification based on cell shape.
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Figure 4.2b
Overview of Epithelial Tissues
• For each of the following types of epithelia,
note:
• Description
• Function
• Location
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(a) Simple squamous epithelium
Description: Single layer of flattened
cells with disc-shaped central nuclei
and sparse cytoplasm; the simplest
of the epithelia.
Air sacs of
lung tissue
Function: Allows passage of
materials by diffusion and filtration
in sites where protection is not
important; secretes lubricating
substances in serosae.
Nuclei of
squamous
epithelial
cells
Location: Kidney glomeruli; air sacs
of lungs; lining of heart, blood
vessels, and lymphatic vessels; lining
of ventral body cavity (serosae).
Photomicrograph: Simple squamous epithelium
forming part of the alveolar (air sac) walls (125x).
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Figure 4.3a
Epithelia: Simple Squamous
• Two other locations
• Endothelium
• The lining of lymphatic vessels, blood
vessels, and heart
• Mesothelium
• The epithelium of serous membranes in the
ventral body cavity
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(b) Simple cuboidal epithelium
Description: Single layer of
cubelike cells with large,
spherical central nuclei.
Simple
cuboidal
epithelial
cells
Function: Secretion and
absorption.
Basement
membrane
Location: Kidney tubules;
ducts and secretory portions
of small glands; ovary surface.
Connective
tissue
Photomicrograph: Simple cuboidal
epithelium in kidney tubules (430x).
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Figure 4.3b
(c) Simple columnar epithelium
Description: Single layer of tall cells
with round to oval nuclei; some cells
bear cilia; layer may contain mucussecreting unicellular glands (goblet cells).
Simple
columnar
epithelial
cell
Function: Absorption; secretion of
mucus, enzymes, and other substances;
ciliated type propels mucus (or
reproductive cells) by ciliary action.
Location: Nonciliated type lines most of
the digestive tract (stomach to anal canal),
gallbladder, and excretory ducts of some
glands; ciliated variety lines small
bronchi, uterine tubes, and some regions
of the uterus.
Basement
membrane
Photomicrograph: Simple columnar epithelium
of the stomach mucosa (860X).
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Figure 4.3c
(d) Pseudostratified columnar epithelium
Description: Single layer of cells of
differing heights, some not reaching
the free surface; nuclei seen at
different levels; may contain mucussecreting cells and bear cilia.
Cilia
Mucus of
mucous cell
Pseudostratified
epithelial
layer
Function: Secretion, particularly of
mucus; propulsion of mucus by
ciliary action.
Location: Nonciliated type in male’s
sperm-carrying ducts and ducts of
large glands; ciliated variety lines
the trachea, most of the upper
respiratory tract.
Trachea
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Photomicrograph: Pseudostratified ciliated
columnar epithelium lining the human trachea (570x).
Basement
membrane
Figure 4.3d
(e) Stratified squamous epithelium
Description: Thick membrane
composed of several cell layers;
basal cells are cuboidal or columnar
and metabolically active; surface
cells are flattened (squamous); in the
keratinized type, the surface cells are
full of keratin and dead; basal cells
are active in mitosis and produce the
cells of the more superficial layers.
Stratified
squamous
epithelium
Function: Protects underlying
tissues in areas subjected to abrasion.
Nuclei
Location: Nonkeratinized type forms
the moist linings of the esophagus,
mouth, and vagina; keratinized variety
forms the epidermis of the skin, a dry
membrane.
Basement
membrane
Connective
tissue
Photomicrograph: Stratified squamous epithelium
lining the esophagus (285x).
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Figure 4.3e
Epithelia: Stratified Cuboidal
• Quite rare in body
• Found in some sweat and mammary
glands
• Typically two cell layers thick
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Epithelia: Stratified Columnar
• Limited distribution in body
• Small amounts in pharynx, male urethra, and
lining some glandular ducts
• Also occurs at transition areas between two
other types of epithelia
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(f) Transitional epithelium
Description: Resembles both
stratified squamous and stratified
cuboidal; basal cells cuboidal or
columnar; surface cells dome
shaped or squamouslike, depending
on degree of organ stretch.
Transitional
epithelium
Function: Stretches readily and
permits distension of urinary organ
by contained urine.
Location: Lines the ureters, urinary
bladder, and part of the urethra.
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Basement
membrane
Connective
tissue
Photomicrograph: Transitional epithelium lining the urinary
bladder, relaxed state (360X); note the bulbous, or rounded,
appearance of the cells at the surface; these cells flatten and
become elongated when the bladder is filled with urine.
Figure 4.3f
Glandular Epithelia
• A gland is one or more cells that makes
and secretes an aqueous fluid
• Classified by:
• Site of product release—endocrine or
exocrine
• Relative number of cells forming the gland—
unicellular (e.g., goblet cells) or multicellular
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Endocrine Glands
• Ductless glands
• Secrete hormones that travel through
lymph or blood to target organs
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Exocrine Glands
• More numerous than endocrine glands
• Secrete products into ducts
• Secretions released onto body surfaces
(skin) or into body cavities
• Examples include mucous, sweat, oil, and
salivary glands
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Unicellular Exocrine Glands
• The only important unicellular gland is the
goblet cell
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Modes of Secretion
• Merocrine
• Products are secreted by exocytosis (e.g.,
pancreas, sweat and salivary glands)
• Holocrine
• Products are secreted by rupture of gland cells
(e.g., sebaceous glands)
• Apocrine
• Products secreted by pinching off top of cell
(modified sweat glands, mammary, and
ceruminous)
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PowerPoint® Lecture Slides
prepared by
Janice Meeking,
Mount Royal College
CHAPTER
4
Tissue: The
Living Fabric:
Part B
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Connective Tissue
• Most abundant and widely distributed
tissue type
• Four classes
1. Connective tissue proper
2. Cartilage
3. Bone tissue
4. Blood
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Major Functions of Connective Tissue
1. Binding and support
2. Protection
3. Insulation
4. Transportation (blood)
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Characteristics of Connective Tissue
• Connective tissues have:
• Mesenchyme as their common tissue of origin
• Varying degrees of vascularity
• Cells separated by nonliving extracellular
matrix (ground substance and fibers)
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Structural Elements of Connective Tissue
• Ground substance
• Medium through which solutes diffuse between blood
capillaries and cells
• Components:
• Interstitial fluid
• Adhesion proteins (“glue”)
• Proteoglycans (glycosaminoglycans)
• Protein core + large polysaccharides
negatively charged (chrondroitin sulfate and
hyaluronic acid)
• Trap water in varying amounts, affecting the
viscosity of the ground substance
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Structural Elements of Connective Tissue
• Three types of fibers
• Collagen (white fibers)
• Strongest and most abundant type (single most
abundant type of protein in body)
• Provides high tensile strength
• Elastic
• Networks of long, thin, elastin fibers that allow for
stretch
• Reticular
• Short, fine, highly branched collagenous fibers
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Structural Elements of Connective Tissue
• Cells
• Mitotically active and secretory cells = “blasts”
• Mature cells = “cytes”
• Fibroblasts in connective tissue proper
• Chondroblasts and chondrocytes in cartilage
• Osteoblasts and osteocytes in bone (osseous
tissue)
• Hematopoietic stem cells in bone marrow
• Fat cells, white blood cells, mast cells, and
macrophages
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Cell types
Macrophage
Extracellular
matrix
Ground substance
Fibers
• Collagen fiber
• Elastic fiber
• Reticular fiber
Fibroblast
Lymphocyte
Fat cell
Capillary
Mast cell
Neutrophil
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Figure 4.7
Connective Tissue: Embryonic
• Mesenchyme—embryonic connective
tissue
• Gives rise to all other connective tissues
• Gel-like ground substance with fibers and starshaped mesenchymal cells
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Overview of Connective Tissues
• For each of the following examples of
connective tissue, note:
• Description
• Function
• Location
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Connective Tissue Proper
• Types:
• Loose connective
tissue
• Dense
connective tissue
• Areolar
• Dense regular
• Adipose
• Dense irregular
• Reticular
• Elastic
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(a) Connective tissue proper: loose connective tissue, areolar
Description: Gel-like matrix with all
three fiber types; cells: fibroblasts,
macrophages, mast cells, and some
white blood cells.
Elastic
fibers
Function: Wraps and cushions
organs; its macrophages phagocytize
bacteria; plays important role in
inflammation; holds and conveys
tissue fluid.
Collagen
fibers
Location: Widely distributed under
epithelia of body, e.g., forms lamina
propria of mucous membranes;
packages organs; surrounds
capillaries.
Fibroblast
nuclei
Epithelium
Lamina
propria
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Photomicrograph: Areolar connective tissue, a
soft packaging tissue of the body (300x).
Figure 4.8a
(b) Connective tissue proper: loose connective tissue, adipose
Description: Matrix as in areolar,
but very sparse; closely packed
adipocytes, or fat cells, have
nucleus pushed to the side by large
fat droplet.
Function: Provides reserve food
fuel; insulates against heat loss;
supports and protects organs.
Nucleus of
fat cell
Location: Under skin in the
hypodermis; around kidneys and
eyeballs; within abdomen; in breasts.
Vacuole
containing
fat droplet
Adipose
tissue
Mammary
glands
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Photomicrograph: Adipose tissue from the
subcutaneous layer under the skin (350x).
Figure 4.8b
(c) Connective tissue proper: loose connective tissue, reticular
Description: Network of reticular
fibers in a typical loose ground
substance; reticular cells lie on the
network.
Function: Fibers form a soft internal
skeleton (stroma) that supports other
cell types including white blood cells,
mast cells, and macrophages.
Location: Lymphoid organs (lymph
nodes, bone marrow, and spleen).
White blood
cell
(lymphocyte)
Reticular
fibers
Spleen
Photomicrograph: Dark-staining network of reticular
connective tissue fibers forming the internal skeleton
of the spleen (350x).
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Figure 4.8c
(d) Connective tissue proper: dense connective tissue, dense regular
Description: Primarily parallel
collagen fibers; a few elastic fibers;
major cell type is the fibroblast.
Collagen
fibers
Function: Attaches muscles to
bones or to muscles; attaches bones
to bones; withstands great tensile
stress when pulling force is applied
in one direction.
Location: Tendons, most
ligaments, aponeuroses.
Nuclei of
fibroblasts
Shoulder
joint
Ligament
Photomicrograph: Dense regular connective
tissue from a tendon (500x).
Tendon
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Figure 4.8d
(e) Connective tissue proper: dense connective tissue, dense irregular
Description: Primarily
irregularly arranged collagen
fibers; some elastic fibers;
major cell type is the fibroblast.
Nuclei of
fibroblasts
Function: Able to withstand
tension exerted in many
directions; provides structural
strength.
Location: Fibrous capsules of
organs and of joints; dermis of
the skin; submucosa of
digestive tract.
Fibrous
joint
capsule
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Collagen
fibers
Photomicrograph: Dense irregular
connective tissue from the dermis of the
skin (400x).
Figure 4.8e
(f) Connective tissue proper: dense connective tissue, elastic
Description: Dense regular
connective tissue containing a high
proportion of elastic fibers.
Function: Allows recoil of tissue
following stretching; maintains
pulsatile flow of blood through
arteries; aids passive recoil of lungs
following inspiration.
Elastic fibers
Location: Walls of large arteries;
within certain ligaments associated
with the vertebral column; within the
walls of the bronchial tubes.
Aorta
Heart
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Photomicrograph: Elastic connective tissue in
the wall of the aorta (250x).
Figure 4.8f
Connective Tissue: Cartilage
• Three types of cartilage:
1. Hyaline cartilage
2. Elastic cartilage
3. Fibrocartilage
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(g) Cartilage: hyaline
Description: Amorphous but firm
matrix; collagen fibers form an
imperceptible network; chondroblasts
produce the matrix and when mature
(chondrocytes) lie in lacunae.
Function: Supports and reinforces;
has resilient cushioning properties;
resists compressive stress.
Location: Forms most of the
embryonic skeleton; covers the ends
of long bones in joint cavities; forms
costal cartilages of the ribs; cartilages
of the nose, trachea, and larynx.
Chondrocyte
in lacuna
Matrix
Costal
cartilages
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Photomicrograph: Hyaline cartilage from the
trachea (750x).
Figure 4.8g
(h) Cartilage: elastic
Description: Similar to hyaline
cartilage, but more elastic fibers
in matrix.
Function: Maintains the shape
of a structure while allowing
great flexibility.
Chondrocyte
in lacuna
Location: Supports the external
ear (pinna); epiglottis.
Matrix
Photomicrograph: Elastic cartilage from
the human ear pinna; forms the flexible
skeleton of the ear (800x).
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Figure 4.8h
(i) Cartilage: fibrocartilage
Description: Matrix similar to
but less firm than that in hyaline
cartilage; thick collagen fibers
predominate.
Function: Tensile strength
with the ability to absorb
compressive shock.
Location: Intervertebral discs;
pubic symphysis; discs of knee
joint.
Chondrocytes
in lacunae
Intervertebral
discs
Collagen
fiber
Photomicrograph: Fibrocartilage of an
intervertebral disc (125x). Special staining
produced the blue color seen.
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Figure 4.8i
(j) Others: bone (osseous tissue)
Description: Hard, calcified
matrix containing many collagen
fibers; osteocytes lie in lacunae.
Very well vascularized.
Function: Bone supports and
protects (by enclosing);
provides levers for the muscles
to act on; stores calcium and
other minerals and fat; marrow
inside bones is the site for blood
cell formation (hematopoiesis).
Location: Bones
Central
canal
Lacunae
Lamella
Photomicrograph: Cross-sectional view
of bone (125x).
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Figure 4.8j
(k) Others: blood
Description: Red and white
blood cells in a fluid matrix
(plasma).
Plasma
Function: Transport of
respiratory gases, nutrients,
wastes, and other substances.
Location: Contained within
blood vessels.
Neutrophil
Red blood
cells
Lymphocyte
Photomicrograph: Smear of human blood (1860x); two
white blood cells (neutrophil in upper left and lymphocyte
in lower right) are seen surrounded by red blood cells.
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Figure 4.8k
Nervous Tissue
• Nervous system (more detail with the Nervous
System, Chapter 11)
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Nervous tissue
Description: Neurons are
branching cells; cell processes
that may be quite long extend from
the nucleus-containing cell body;
also contributing to nervous tissue
are nonirritable supporting cells
(not illustrated).
Nuclei of
supporting
cells
Neuron processes Cell body
Axon
Dendrites
Cell body
of a neuron
Function: Transmit electrical
signals from sensory receptors
and to effectors (muscles and
glands) which control their activity.
Location: Brain, spinal
cord, and nerves.
Neuron
processes
Photomicrograph: Neurons (350x)
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Figure 4.9
Muscle Tissue
• Skeletal muscle (more detail with the
Muscular System, Chapter 10)
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(a) Skeletal muscle
Description: Long, cylindrical,
multinucleate cells; obvious
striations.
Striations
Function: Voluntary movement;
locomotion; manipulation of the
environment; facial expression;
voluntary control.
Location: In skeletal muscles
attached to bones or
occasionally to skin.
Nuclei
Part of
muscle
fiber (cell)
Photomicrograph: Skeletal muscle (approx. 460x).
Notice the obvious banding pattern and the
fact that these large cells are multinucleate.
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Figure 4.10a
Muscle Tissue
• Cardiac muscle (more detail with the
Cardiovascular System, Chapters 18 and 19)
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(b) Cardiac muscle
Description: Branching,
striated, generally uninucleate
cells that interdigitate at
specialized junctions
(intercalated discs).
Striations
Intercalated
discs
Function: As it contracts, it
propels blood into the
circulation; involuntary control.
Location: The walls of the
heart.
Nucleus
Photomicrograph: Cardiac muscle (500X);
notice the striations, branching of cells, and
the intercalated discs.
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Figure 4.10b
Muscle Tissue
• Smooth muscle
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(c) Smooth muscle
Description: Spindle-shaped
cells with central nuclei; no
striations; cells arranged
closely to form sheets.
Function: Propels substances
or objects (foodstuffs, urine,
a baby) along internal passageways; involuntary control.
Location: Mostly in the walls
of hollow organs.
Smooth
muscle
cell
Nuclei
Photomicrograph: Sheet of smooth muscle (200x).
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Figure 4.10c
Epithelial Membranes
• Cutaneous membrane (skin) (More detail
with the Integumentary System, Chapter 5)
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Cutaneous
membrane
(skin)
(a) Cutaneous membrane (the skin)
covers the body surface.
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Figure 4.11a
Epithelial Membranes
• Mucous membranes
• Mucosae
• Line body cavities open to the exterior (e.g.,
digestive and respiratory tracts)
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Mucosa of
nasal cavity
Mucosa of
mouth
Esophagus
lining
Mucosa of
lung bronchi
(b) Mucous membranes line body cavities
open to the exterior.
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Figure 4.11b
Epithelial Membranes
• Serous Membranes
• Serosae—membranes (mesothelium + areolar
tissue) in a closed ventral body cavity
• Parietal serosae line internal body walls
• Visceral serosae cover internal organs
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Parietal
peritoneum
Parietal
pleura
Visceral
pleura
Visceral
peritoneum
Parietal
pericardium
Visceral
pericardium
(c) Serous membranes line body cavities
closed to the exterior.
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Figure 4.11c
Steps in Tissue Repair
1. Inflammation
• Release of inflammatory chemicals
• Dilation of blood vessels
• Increase in vessel permeability
• Clotting occurs
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Scab
Epidermis
Blood clot in
incised wound
Inflammatory
chemicals
Vein
Migrating white
blood cell
Artery
1 Inflammation sets the stage:
• Severed blood vessels bleed and inflammatory chemicals are
released.
• Local blood vessels become more permeable, allowing white
blood cells, fluid, clotting proteins and other plasma proteins
to seep into the injured area.
• Clotting occurs; surface dries and forms a scab.
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Figure 4.12, step 1
Steps in Tissue Repair
2. Organization and restored blood supply
•
The blood clot is replaced with
granulation tissue
•
Epithelium begins to regenerate
•
Fibroblasts produce collagen fibers to
bridge the gap
•
Debris is phagocytized
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Regenerating
epithelium
Area of
granulation
tissue
ingrowth
Fibroblast
Macrophage
2 Organization restores the blood supply:
• The clot is replaced by granulation tissue, which restores
the vascular supply.
• Fibroblasts produce collagen fibers that bridge the gap.
• Macrophages phagocytize cell debris.
• Surface epithelial cells multiply and migrate over the
granulation tissue.
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Figure 4.12, step 2
Steps in Tissue Repair
3. Regeneration and fibrosis
• The scab detaches
• Fibrous tissue matures; epithelium
thickens and begins to resemble adjacent
tissue
• Results in a fully regenerated epithelium
with underlying scar tissue
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Regenerated
epithelium
Fibrosed
area
3
Regeneration and fibrosis effect permanent repair:
• The fibrosed area matures and contracts; the epithelium
thickens.
• A fully regenerated epithelium with an underlying area of
scar tissue results.
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Figure 4.12, step 3
Developmental Aspects
• Primary germ layers: ectoderm, mesoderm,
and endoderm
• Formed early in embryonic development
• Specialize to form the four primary tissues
• Nerve tissue arises from ectoderm
• Muscle and connective tissues arise from
mesoderm
• Epithelial tissues arise from all three
germ layers
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16-day-old embryo
(dorsal surface view)
Ectoderm
Mesoderm
Endoderm
Epithelium
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Muscle and connective
tissue (mostly from
mesoderm)
Nervous tissue
(from ectoderm)
Figure 4.13