Transcript Bio 211 Lecture 5

Exam 3 Review Slides
Lectures 9-12
Chapters 5, 6, and 7
Types/Functions of Epithelial Tissue
• Types of epithelium
• Covering and Lining Epithelium
– External Surfaces, e.g., skin, Internal surfaces
• Glandular Epithelium
• Functions of Epithelial Tissue
– Physical protection
– Control of permeability
• Secretion, Absorption, Filtration
– Provide sensation
– Provide specialized secretions (glands)
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Characteristics of Epithelial Tissue
• Specialized contacts with other cells
• Polarity (different ends of cell do different
things)
• Avascularity (no blood supply)
• Regeneration (can divide to make new
cells)
• Cellularity (lots of cells in close contact)
Remember: Epithelial tissues always have a
free surface and a basement membrane
3
Basal Lamina
Formerly called: Basement membrane
Two components:
Lamina Lucida
- glycoproteins and fine protein filaments
- Barrier for passage of substances from
underlying tissue into epithelium
Lamina Densa
Lamina = thin layer
- bundles of coarse protein fibers
- gives basal lamina its strength
Figure from: Martini, Fundamentals of Anatomy & Physiology, Benjamin Cummings, 2004
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Classification of Epithelial Tissues
Epithelial tissues are classified according to
both their:
• Shape
– Squamous (Thin, flat, irregular in shape)
– Cuboidal (Square or cuboidal)
– Columnar (Rectangular, tall)
• Type of layering (stratification)
– Simple (one layer)
– Stratified (two or more layers)
– Note that classification of stratified
epithelium is based on the shape of the
superficial, not deep, layers
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Characteristics of Epithelial Tissue
Specialized Contacts
Tight junction – forces
substances to go
through cells, rather
than being able to pass
between them
Gap junction – allow
rapid passage of small
molecules/ions
between cells
Figure from: Martini,
Anatomy & Physiology,
Prentice Hall, 2001
Desmosome – binds
cells together firmly so
they stay connected
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Review
NAME OF ET
DESCRIPTION
STRUCTURE
LOCATION
FUNCTION
SIMPLE
SQUAMOUS
a single layer of
flattened cells
linings of air sacs,
capillaries, lymph
vessels, body
cavities; covering
ventral organs
diffusion, reduction of
friction
SIMPLE
CUBOIDAL
a single layer of cubeshaped cells with
large centrally
located nuclei
linings of kidney
tubules, ducts of
glands
absorption,
secretion
SIMPLE
COLUMNAR
a single layer of tall
cells with basally
located nuclei,
goblet cells, &
mucrovilli
lining of intestine
protection,
absorption,
secretion
PSEUDOSTRATIFIED
COLUMNAR
a single layer of tall
cells with scattered
nuclei, cilia, &
goblet cells
lining of trachea,
lining of fallopian tube
protection, secretion
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Review
NAME OF ET
DESCRIPTION
STRUCTURE
LOCATION
FUNCTION
STRATIFIED
SQUAMOUS
many layers of
flattened cells
keratinized =
epidermis;
non-keratinized =
lining of vagina,
anus, throat, mouth
protection
TRANSITIONAL
several layers of
cells that change
shape under
pressure
lining of urinary
bladder and ureters
Distensibility (able
to stretch)
GLANDULAR
simple cuboidal
lining the ducts of
glands
secretion
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Review of Epithelial Tissues
• Glands are specialized epithelium
– Secrete on to a surface (exocrine)
– Secrete into a duct (exocrine)
– Secrete into the blood (endocrine)
• Exocrine glands have several different mechanisms of secretion
– Merocrine
• Release of product from vesicles by exocytosis
– Apocrine
• Loss of cytoplasm containing secretion; Apical portion of
cytoplasm is shed
– Holocrine
• Entire cell is packed with secretion and then bursts
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Membranes
A membrane is a combination of epithelium and
connective tissue that covers and protects other structures
and tissues. Technically, then, a membrane is an organ.
Serous
• line body cavities that
lack openings to outside
• reduce friction
• inner lining of thorax and
abdomen
• cover organs of thorax
and abdomen
• secrete serous fluid
Mucous
• line tubes and organs
that open to outside world
• lining of mouth, nose,
throat, digestive tract, etc.
• secrete mucus
Synovial
• surround joint cavities
Cutaneous
• covers body
• skin
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Review
NAME OF CT
DESCRIPTION
MESENCHYME
LOCATION
FUNCTION
Embryo
gives rise to all other
CT’s
AREOLAR
gel-like matrix with
fibroblasts, collagen
and elastic fibers
beneath ET (serous
membranes around
organs & lining
cavities)
diffusion, cushioning
organs
ADIPOSE
closely packed
adipocytes with
nuclei pushed to one
side by fats
beneath skin, breasts,
around kidneys &
eyeballs
insulation, energy
store, protection
RETICULAR
network of reticular
fibers in loose matrix
basement
membranes,
lymphatic organs
support
DENSE
REGULAR
dense matrix of
collagen fibers
tendons, ligaments
attachment (high
tensile strength)
DENSE
IRREGULAR
loose matrix of
collagen fibers
dermis of skin
strength in several
directions
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Review
NAME OF CT
DESCRIPTION
LOCATION
FUNCTION
ELASTIC CT
matrix of elastic
fibers
lung tissue, wall of
aorta
durability with
stretch
HYALINE
CARTILAGE
chondrocytes in
lacunae in
amorphous
matrix
embryonic. skeleton,
costal cart, tip of
nose, trachea,
larynx
support
FIBROCARTILAGE
less firm than above
intervertebral discs,
pubic symphysis
tensile strength,
shock absorber
ELASTIC
CARTILAGE
above plus elastic
fibers
external ear,
epiglottis
shape maintenance
plus flexibility
BONE
concentric circles of
calcified matrix
Bones
support, protection,
movement, Ca ++
storage,
hematopoiesis
BLOOD
red cells, white cells
and platelets in
liquid plasma
in heart and blood
vessels
transport of nutrients,
wastes & gases
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Connective Tissue (CT) Summary Table
Three main components of ALL CT: cell, fibers, ground substance
Name of
CT
CT Proper
Cartilage
Bone
Different types of
this CT
Main types of
fibers present
1) Areolar (Loose)
2) Dense regular
3) Dense irregular
4) Adipose
5) Reticular
6) Elastic
1) Fibroblasts
2) Fibroblasts
3) Fibroblasts
4) Adipocytes
5) Fibroblasts
6) Fibroblasts
1) Hyaline
2) Fibrocartilage
3) Elastic
1) Collagen (sparse)
(All) Chondrocytes 2) Collagen (dense)
3) Elastic
1) Dense
2) Spongy
Blood
--
Lymph
Main types of cells
present
--
(All) Osteocytes
1) RBCs
2) WBCs
3) Platelets (cell
fragments)
Lymphocytes
1) Collagen, Elastic
2) Collagen
3) Collagen
4) Reticular
5) Reticular
6) Elastic
Consistency of
matrix
Semi-liquid
Examples of Locations
1) Skin, between muscles
2) Tendons, ligaments
3) Dermis
4) Body fat areas
5) Stroma of liver, spleen
6) Lungs, airways,
arteries/heart
Semi-solid,
gelatinous
1) Ribs, ends of bones
2) Intervertebral disks
3) Pinna of ear, epiglottis
Collagen
Solid
(hydroxyapatite)
1) Outer portions of bone
2) Inner portions of bone
Fibrinogen (soluble)
Liquid
Blood vessels, heart
Reticular (in stroma
of lymphoid organs)
Liquid
Lymph vessels
-cyte = fully differentiated; -blast = young, actively synthesizing cell
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Connective Tissue - Major Cell Types
Fibroblasts
• fixed cell
• most common cell; always
in CT proper
• large, star-shaped
• produce fibers
• produce ground substance
Macrophages
• wandering cell
• phagocytic
• important in defense
• derived from circulating
monocytes
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Connective Tissue Fibers
Collagenous fibers
• thick
• composed of collagen
• great tensile strength
• hold structures together
• abundant in dense CT
• tendons, ligaments
Elastic fibers
• bundles of
microfibrils embedded
in elastin
• fibers branch
• elasticity
• vocal cords, air
passages
Reticular fibers
• very thin collagenous
fibers
• highly branched
• form supportive
networks
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The “Ground Substance” of CT
glucosamine
VERY hydrophilic!
Very active in controlling
passage of substances through
this portion of the matrix and
keeping CT hydrated
GAGs = glycosaminoglycans (negatively charged
polysaccharides); a major molecule in ground
substance
Figures from: Alberts et al., Essential Cell Biology, Garland Press, 1998
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Tendons and Ligaments
Tendons:
Connect muscle to bone
Ligaments: Connect bone to bone
Aponeuroses: Broad, fibrous sheets; usually attach muscle to muscle (or bone)
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CT Framework of the Body
Fascia connects the
organs of the dorsal
and ventral cavities
with the rest of the
body
Figure from: Martini, Anatomy & Physiology, Prentice Hall, 2001
Provide:
- Strength
- Stability
- Organ position
- Conduits
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Muscle – Overview
• General characteristics
–
–
–
–
Elongated cells with special properties
Muscle cells (myocytes) = muscle fibers
Contractile (major property of all muscle)
Use actin (thin) and myosin (thick) for contraction
• Three types of muscle tissue
– Cardiac (involuntary)
– Skeletal
– Smooth
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Review of Muscle Types
NAME OF
MUSCLE
TISSUE
DESCRIPTION OF
STRUCTURE
TYPE OF
CONTROL
LOCATION
FUNCTION
SKELETAL
MUSCLE
long, thin fibers with
many nuclei and
striations
Voluntary
attached to bones
to move bones
SMOOTH
MUSCLE
spindle shaped cells with
one centrally
located nucleus,
lacking striations
Involuntary
walls of visceral
hollow organs,
irises of eyes,
walls of blood
vessels
to move substances
through
passageways (i.e.
food, urine,
semen),
constrict blood
vessels, etc
CARDIAC
MUSCLE
a network of striated
cells with one
centrally located
nucleus attached by
intercalated discs
- Intercalated disks
consist of gap
junctions and
desmosomes
Involuntary
heart
pump blood to lungs
and body
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Nervous Tissue
• found in brain, spinal cord, and peripheral nerves
• conduction of nerve impulses
• basic cells are neurons
• sensory reception
• neuroglial cells are supporting cells
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Introduction to Inflammation
Restoration of homeostasis after tissue injury or infections involves two processes:
1) inflammation and 2) repair.
Hallmarks of inflammation: Redness, heat, pain, swelling, and loss of function
(Inflammation = ‘-itis’)
Figure from: Martini, Anatomy & Physiology, Prentice Hall, 2001
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Functions of the Integumentary System
• Functions of the integument
– Protection (from mechanical/chemical/bacterial
damage, UV radiation)
– Temperature regulation (extreme heat, extreme
cold) and Fluid conservation
– Excretion
– Vitamin D production
– Sensation (touch, pressure)
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Layers of the Epidermis - Overview
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Thick and Thin Skin
Thin (0.07-0.12 mm)
(epidermal thickness)
Thick (0.8-1.4 mm)
(epidermal thickness)
Thick skin - palms of hands, soles of feet; five epidermal layers
Thin skin - everywhere else; four epidermal layers (no s. lucidum)
Figure from: Martini, Anatomy & Physiology, Prentice Hall, 2001
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Cells of the Epidermis
• Epidermis of the skin is classified as a keratinized
stratified squamous epithelium
• Cells of the epidermis include
– Keratinocytes (90%)
• Keratin – a tough, fibrous intracellular protein (protection)
• Lamellar granules (waterproofing, extracellular)
– Melanocytes (8%)
• Produce melanin (protection from UV radiation)
– Langerhans cells (1-2%)
• Migrate to skin from bone marrow
• Participate in skin’s immune response (dendritic cells)
– Merkel cells (< 1%)
• Least numerous; specialized epithelial cells
• Function in sensation of touch
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Skin Color
Genetic Factors
• varying amounts and
type of melanin
• varying size/number of
melanin granules
• albinos lack melanin
(but not melanocytes!)
Environmental Factors
• sunlight
• UV light from sunlamps
• X rays
Physiological Factors
• dilation of dermal blood vessels
(erythema)
• constriction of dermal blood
vessels (less pink, pale = pallor)
• level of oxygenation of blood
* normal = pink (fair-skinned)
* low = bluish (cyanosis)
• carotene -> Vit A (yellow)
• jaundice (yellow)
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Skin Color and Melanin
Dark-skinned
Fair-skinned
Melanocytes produce melanin
- tyrosine  melanin
- UV radiation up-regulates
production of melanin
- Caucasian vs. dark-skinned
* number vs. activity
* layer of epidermis
Figure from: Martini, Fundamentals of Anatomy & Physiology, Pearson Education, 2004
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Keratin and Vitamin D
• Keratin
– Protection
– Water resistance
• Vitamin D3 (“sunshine vitamin”)
– After UV irradiation epidermal cells in s. spinosum and
s. basale convert a cholesterol-related steroid to Vit D3
(cholecalciferol)
– Vit D3 –  absorption of calcium and phosphorus by
small intestine
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Dermis
Papillary layer
- areolar connective tissue (CT)
- capillaries and sensory neurons
- dermal papillae
- fingerprints (with epi. ridges)
Reticular layer
- dense, irregular CT
- collagen fiber bundles extend
upward and downward
- also contains elastic fibers and
cells of CT proper
- accessory organs of
integumentary system (from epi.)
- cleavage or tension lines
- flexure lines
Figure adapted from: Martini, Anatomy & Physiology, Prentice Hall, 2001
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Subcutaneous Layer
Basal lamina
- Stabilization of dermis
- INSULATION
- Areolar and adipose tissue
- Effect of hormones
- Reservoir of blood
Also called ‘hypodermis’.
This is the superficial fascia.
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Hair (pilo-)
• epidermal cells
• tube-like depression
• extends into dermis
• hair root (in dermis)
• hair shaft (outer 1/3)
• hair papilla
• dead epidermal cells
• melanin
• arrector pili muscle
Basal lamina
(from epidermis)
Nerves in root hair
plexus
A hair in the scalp grows for 2-5 years, about 0.33mm/day
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Hair Follicles
Hair color
Types of hair:
1. Lanugo – long,
blond, fine (fetal,
anorexia nervosa)
2. Vellus – short, blond
(children)
3. Terminal – course,
pigmented (adults)
Some hair color
Figure adapted from: Martini, Anatomy & Physiology, Prentice Hall, 2001
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Sebaceous (Oil) Glands
• usually associated with hair
follicles
• holocrine glands
• secrete sebum, a waxy, oily
material
• inhibits growth of bacteria
• lubricates and protects keratin
of hair shaft, and conditions skin
• absent on palms and soles
Sebaceous follicles – not
associated with hair.
Discharge directly on to
skin. On face, back, chest,
nipples and male sex
organs.
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Sweat Glands
• also called sudoriferous glands
• apocrine (merocrine secr.)
glands
- associated with hair follicles
- thick, odorous secretion
Sweating with wetness = diaphoresis
• eccrine (merocrine secr.) glands
- most numerous
- palms, soles, forehead, neck,
back
- directly on to surface
- watery secretion
- for thermoregulation
• ceruminous glands
• mammary glands
Specialized (apocrine secretion)
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Nails
(Perionychiu
m)
Figure from: Saladin,
Anatomy & Physiology,
McGraw Hill, 2007
Hyponychium
Know these terms
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Regulation of Body Temperature
Hyperthermia – Abnormally high
body temperature
May be caused by
- environment (heat, humidity)
- illness (fever [>=37.20C], pyrexia)
- anesthesia (malignant h.)
Corrected by loss of heat by
radiation, convection, conduction,
evaporation
Heat exhaustion (prostration)
- Fatigue
- Dizziness
- Headache
- Muscle cramps
- Nausea
- May lead to heat stroke
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Regulation of Body Temperature
Hypothermia – Abnormally
low body temperature (at
least 20C below normal body
temp)
May be caused by:
- exposure to cold (primary)
- illness (secondary)
- surgical induction (clinical)
Cardiac arrest is likely if
temperature falls below 28oC
(82oF)
Corrected by mechanisms to
retain body heat (see left) 38
Healing of Cuts
Figure from: Martini,
Anatomy & Physiology,
Prentice Hall, 2001
1. Bleeding/clotting
2. Scab formation
Tissue repair can occur by either:
1) regeneration – healing with tissue that was originally present
2) fibrosis – healing with ‘scar’ tissue (carried out by fibroblasts)
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Healing of Cuts
3. Epidermal cell migration and
collagen production
4. Shedding of scab; covering of
wound with epithelium
Figure from: Martini, Anatomy & Physiology, Prentice Hall, 2001
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