Transcript Animal Form and Function Notes

Today’s Plan: 4/21/10
 Tests/Graded Work/Housekeeping
(20 mins)
 AP Lab 10 (the rest of class)Remember, we’re on early release!
Today’s Plan: 4/26/2010
 Go over week (5 mins)
 Histology lab (55 mins)-Due today!
 Notes (the rest of class)
Today’s Plan: 4/27/2010
 Set-up for dissection (5 mins)
 Begin Rat Dissection (50 mins)
 Animal Anatomy Notes (the rest of
class)
Today’s Plan: 4/29/2010
 Finish Rat Dissection Questions (20
mins)
 Rat Dissection Suppliment (40 mins)
 Continue Notes (the rest of class)
Today’s Plan: 4/30/2010
 Finish Rat Dissection suppliment (50
mins)
 Notes (the rest of class)
Today’s Plan: 12/1/09
 AP Lab 10
 Notes, continued
Today’s Plan: 12/2/09
 Bellwork: AP Statistics Survey (5
mins)
 Finish AP Lab 10 (20 mins)
 Finish Notes (the rest of class)
Today’s Plan: 12/3/09
 Bellwork: Test Q&A (10 mins)
 Animal Anatomy Test (as needed)
 If you finish early, finish up AP Lab 10
and turn in today!
Animal Form and Function Notes
 Anatomy-how the body is put together
 Physiology-how the organs and tissues operate
 Animal Systems:
 Integumentary
 Respiratory
 Skeletal
 Circulatory
 Excretory
 Digestive
 Nervous
 Muscular
 Immune
 Endocrine
 Reproductive
Figure 41-7
Tissues are organized into organs.
Organs are organized into systems.
Digestive system:
Salivary glands secrete enzymes
that begin to digest food.
Tissues:
The esophagus is a long,
muscular tube that transports
food to the stomach.
Epithelia
Connective
tissue
The stomach is a thick,
muscular sac whose contractions
help break up food.
Smooth
muscle
Nerves
Organ:
Small
intestine
The liver and pancreas contain
cells that secrete enzymes and
other molecules that aid digestion.
The small intestine is a long,
coiled tube where enzymes digest
food and nutrients are absorbed.
The large intestine is a large
tube where water is resorbed and
wastes are compacted.
Animal Tissue Types





Recall:cellstissuesorgansorgan systems
Epithelial tissue-most common tissue in the body (skin and protective coverings)

Cuboidal-cube-shaped

Columnar-rectangular

Squamous-flat

Transitional-changes shape (ex: lining of bladder)
Connective tissue-bind and support the body parts

Loose-Binds and cushions tissues to one another

Cartilage-cushions and supports

Fibrous-tendons (muscle to bone) and ligaments (bone to bone)

Bone

Adipose-fat

Blood
Muscle tissue-Responsible for movement

Skeletal-voluntary movements

Smooth-involuntary movements

Cardiac-special muscle that’s striated like skeletal, but involuntary like
smooth
Nervous tissue-Regulates body functions, connects parts of body to brain

Nerves

Glial cells-insulate and bind nervous cells
Figure 41-6
Epithelium forms a surface layer
Epithelium
Cells in epithelial tissues are joined tightly
and have polarity.
Faces internal or
Apical surface of epithelium
external environment
Tight junction
Epithelial cells
Basolateral surface of epithelium
Connects to other
tissues
Figure 41-3
Loose connective tissue has a soft
extracellular matrix; it provides padding.
Soft
extracellular
matrix
Cells
Protein fibers
Bone and cartilage have a hard (bone) or stiff
(cartilage) extracellular matrix; they support the body.
Hard
extracellular
matrix
Bone cells
Stiff
extracellular
matrix
Cartilage cells
Blood has a liquid extracellular matrix;
it functions in transport.
Liquid
extracellular
matrix
(plasma)
White blood cells
Red blood cells
Figure 41-19
A cell in normal adipose tissue
A cell in brown adipose tissue
Mitochondria
Lipid droplets
Nuclei
Homeostatic Control
 Involves nervous system and endocrine system
 Feedback mechanisms
 Animals mostly rely on negative feedback, where the
stimulus is reduced (ex: exercise raises body temp,
which makes you sweat for evaporative cooling)
 Occasionally, responses are controlled by positive
feedback, where the stimulus is intensified (ex:
childbirth)
 Temperature regulation
 Endotherms-”warm blooded” maintain a constant
internal body temp (usually homeothermic)
 Ectotherms-”cold blooded” body temp is same as
environment (usually poikilothermic)
 Remember, animal surface area (ex: African elephant
ears), metabolism, and evaporation are involved in
temperature regulation
Figure 41-16
External stimuli
Heat
or
Cold
Temperature receptors
(skin, spinal cord,
anterior hypothalamus)
SENSORS
If body temp is
above set point:
If body temp is
below set point:
Heat-loss centers activated:
Heat-gain centers activated:
1. Blood vessels near skin dilate;
1. Blood vessels near skin
blood flow increases, heat loss
from skin surface increases.
constrict; blood flow lessens, heat
loss from skin surface decreases.
2. Sweat glands stimulated;
2. Shivering generates heat in
evaporation results in heat loss
from skin.
muscles.
panting results in heat loss.
respiration and heat production.
3. Chemical signals arrive at cells,
3. Respiratory centers stimulated; stimulate increase in cellular
Record temperature
NEGATIVE
FEEDBACK
Temperature control
(centers in hypothalamus)
Is body temp
above or below
set point?
EFFECTORS
INTEGRATOR
Change body temp
to return it to set point
Compares sensor input with set
point, then instructs effectors
Figure 41-17
Endotherms
Some small
birds and
mammals
Heterotherms
Mole-rats
Most
terrestrial
invertebrates
Freshwater
invertebrates
Bees and
some other
insects
A few fish
Homeotherms
Many insects
Amphibians, lizards, snakes,
turtles, crocodiles
Most
freshwater
fish
Most birds
and mammals
Polar
marine
fish and
invertebrates
Most
marine
fish
Marine
invertebrates
Ectotherms
Animal Nutrition
 Since animals are consumers, they need to
eat others to survive
 As with plants and other organisms, some
nutrients are “essential,” meaning that the
animal can’t make them itself
 Essential amino acids-without these, the animal
can’t grow
 Essential fatty acids-it’s rare that animals are
deficient in these b/c most organisms that
animals eat have them.
 Essential vitamins-organic molecules required in
small amounts for an animal’s metabolism
 Minerals are also necessary for many metabolic
processes but are inorganic
Figure 43-00-Table 43-2
Figure 43-00-Table 43-1
Dietary deficiencies
 Undernourishment-organisms not eating
enough, and therefore not having enough
energy or essential nutrients
 Malnourishment-long-term absence of
essential nutrients from a diet
 Yes, if you eat at McDonald’s every day,
you’ll be malnourished AND obese!
 Obesity and overnourishment (usually b/c
of excess calories)-studies show that a
restricted calorie diet leads to increased
longevity
Stages of Nutrition
 Ingesting-Done by the oral cavity, which
passes food through the pharynx, past the
epiglotis, through the esophagus to the
stomach (peristalic contractions of the
smooth muscle that lines the esophagus)
 Digesting-Done by the stomach, glands,
and intestines
 Extracellular digestion in compartments
 Compartment can be stomach or gastrovascular
cavity
 Absorbing-Done by the intestines, kidneys
and stomach
 Eliminating-Done by kidneys, large
intestine
Figure 43-5
The digestive tract:
Accessory organs:
1. Mouth
Mechanical and chemical processing
(chewing reduces size of food; saliva
digests carbohydrates)
2. Esophagus
Salivary glands
Secrete enzymes that
digest carbohydrates;
supply lubricating
mucus
Transports food
Liver
3. Stomach
Mechanical and chemical processing
(digestion of proteins)
Secretes molecules
required for
digestion of fats
4. Small intestine
Chemical processing and absorption
(digestion of proteins, fats, carbohydrates;
absorption of nutrients and water)
Gallbladder
Stores secretions
from liver; empties
into small intestine
5. Large intestine
Water absorption and feces
formation
6. Rectum
Holds feces
7. Anus
Feces elimination
Pancreas
Secretes enzymes
and other materials
into small intestine
Figure 43-6
Carbohydrates
Lipids
Salivary
amylase
1. Mouth
Proteins
Lingual
lipase
2. Esophagus
Pepsin
3. Stomach
Polypeptides
Pancreatic
-amylase
4. Small intestine
Lumen
of small
intestine
Monosaccharides
(simple sugars)
Disaccharides
Trisaccharides
Bile salts
and pancreatic
lipase
Monoglycerides
Fatty acids
Trypsin
Chymotrypsin
Elastase
Carboxypepitidase
Short peptides
Amino acids
DIFFUSION
Cell membrane of epithelial cell
FACILITATED
DIFFUSION AND
COTRANSPORT
Epithelium of
small intestine
Monoglycerides
Fatty acids
FACILITATED
DIFFUSION AND
COTRANSPORT
Triglycerides
Amino acids
Monosaccharides
Chylomicron (proteincoated globules)
FACILITATED
DIFFUSION
To bloodstream
EXOCYTOSIS
To lymph vessels,
then bloodstream
FACILITATED
DIFFUSION AND
COTRANSPORT
To bloodstream
Mouth and Stomach Digestion
 A bolus, or ball of chewed food is first worked on by
amylase produced in the salivary glands, which
breaks down carbohydrates
 Gastric Juice in the stomach contains the following,
and mainly breaks down small polypeptides:
 HCl
 Pepsin (an enzyme)
 Cells that produce the pepsin, parietal cells, synthesize
pepsin as pepsinogen which isn’t active until it comes
into contact with the HCl in the stomach lumen
 The stomach lining is also protected by mucus, and
regenerates new epithelials every 3 days to prevent
ulcers
 Digestion is also physical, since the stomach contracts
to mix and break down the chyme (food and gastric
juice)
 The release of food to the small intestine is controled
by the pyloric sphincter
Figure 43-9
Secretory cells in the stomach lining
Canal empties into
lumen of stomach
Stomach
Goblet cells
(secrete mucus)
Parietal cells
(secrete HCl)
Secretion of HCl by parietal cells
Chief cells
(secrete
pepsinogen)
HCl
to lumen
Proton pump
Chloride channel
Blood
vessel
Parietal cell
Canal empties
to lumen
Intestinal Digestion


Large complex carbs, most fats, and larger polypeptides have
to be broken down in the small intestine (both in the lumen
and epithelials)
The 1st 25 cm of the sm. Intestine, the duodenum, does most
of this digestion




Pancreas produces pancreatic amylase and lipase, as well as
several proteases (trypsin and chymotrypsin) in an alkaline
solution that is transferred to the duodenum via the pancreatic
duct
The liver produces bile that emulsifies fats (breaks them into
smaller droplets) so there’s more fat surface area for lipases to
work. This bile is stored in the gall bladder and flows through the
bile duct in as well.
Villi and Microvilli in the wall of the small intestine increase the
surface area for absorption
Once food passes through the small intestine, it goes to the
large intestine, where beneficial bacteria break down what we
can’t and release vitamins for absorbtion



Water is also absorbed, forming solid feces
There are 3 parts of the colon, or large intestine, beginning with
the ascending colon, which has a blind end called a caecum
Hanging from the caecum is the appendix
Figure 43-11
The lining of the small intestine has extensive folds.
Fold
Villi
Cross section
of small
intestine
Muscle
Three-dimensional view of fold
Fold
Villi
Blood
vessels
Muscle
Microvilli are extensions of epithelial cells in villi.
Villus
Epithelial
cells
Blood
vessels
Lacteal
(lymph
system)
Microvilli of epithelial
cells
Figure 43-13
DIGESTION OF LIPIDS IN SMALL INTESTINE
Monoglycerides
Lipase

Fatty
acids
1. Large fat globules
2. Bile salts (produced
3. Small fat
4. Lipase digests the small fat
are not digested
efficiently by lipase.
in liver) act as
emulsifying agents.
droplets result from
emulsification.
droplets into monoglycerides
and free fatty acids.
Hormonal Control of Digestion
 Gastrin is produced in the cells of the
stomach lining as soon as the animal
detects food and stimulates cells to produce
gastric juices
 Secretin is produced in the cells lining the
duodenum when food leaves the stomach.
It stimulates the pancreas to produce the
alkaline solution for it’s secretions
 Cholecystokinin is produced by the small
intestine when fats are present, and
stimulates the gallbladder to release bile.
Digestion Adaptations
 Ruminants have chambers in their
stomachs and often re-chew their food
multiple times
 Herbivorous animals often have longer
small intestines in order to break down the
tough plant fibers that they eat. They also
have a larger caecum with lots more
bacteria. (Rabbits eat their dung to
recapture these bacteria)
Figure 43-10
Newly eaten food
(green arrows)
Four-chambered
stomach:
1. Rumen
Intestine
3. Omasum
Regurgitated
cud
(black arrow)
2. Reticulum
4. Abomasum
Re-swallowed cud
(red arrows)
Osmoregulation and Excretion
 Water balance is obviously important to maintain
(cells die if they dehydrate, or burst if overhydrated)
 Marine fish constantly drink salt water and secrete
urea or other salty solutions in their bodies since
they’re hypoosmotic (live in a hypertonic soln)
 Freshwater fish constantly urinate and absorb salt
through their gills because they’re hyperosmotic
 Other animal adaptations for osmoregulation:
 Flame cells (protonephridia)in planaria (a flat worm)cilliated cells
 Nephridia (metanephridia) in annelids-paired organs
that collect urine, reabsorb what’s needed, and
secrete excess water
 Malpighian tubes in spiders contain high
concentrations of potassium ion, so that the
surrounding cells reabsorb water and conserve it
Figure 42-2
Freshwater
Seawater
Gain some
electrolytes
in food and
water
Gain some
electrolytes
in food
Gain
metabolic
water
Gill
Replace
water by
drinking
Gill tissue
(lower
osmolarity)
Seawater
(higher
osmolarity)
Gain many
electrolytes
by diffusion
Lose large
amounts of
water by
osmosis
Lose electrolytes
through active
transport out
Lose some
electrolytes
in urine
Lose water
in urine
formation
Gill tissue
(higher
osmolarity)
Freshwater
(lower
osmolarity)
Gill
Gain
metabolic
water
Gain electrolytes
Gain
water by through active
osmosis transport in
Lose
electrolytes
by diffusion
Lose some
electrolytes
in urine
Lose water
in urine
formation
Nitrogenous Wastes
 As proteins and nucleic acids are broken down, lots of
nitrogenous wastes are produced.
 The form that this waste takes reflects the animal’s
phylogeny
 Ammonia-can’t be tolerated in large amounts, so
must be constantly diluted. Aquatic animals have
this type of waste, and mostly across their gills
 Urea-This is safer for land animals and is produced in
the liver, however this is energetically expensive
since the organism has to convert ammonia into urea
 Uric Acid-Insects, reptiles, and land snails. This is a
semisolid, non-water soluble waste, and is also
nontoxic. It’s also energetically expensive
The Excretory Process
 Filtration-excretory tube collects filtrate
from the blood. Filtration is accomplished
by pressure and selectively permeable
membranes
 Reabsorption-reclamation of valuable
substances
 Secretion-toxins, etc are are added to the
filtrate
 Excretion-removal of the altered filtrate
(urine)
The Kidney



Is part of the excretory system that produces urine, sends
it through the ureters to the urinary bladder, and out
through the urethra
Kidney parts include:
 Medulla
 Cortex
 Pelvis-collecting area for urine once it’s made
 Renal arteries (in) and renal veins (out) carry blood for
filtration
Functional unit of the kidney is the nephron
 Bowman’s capsule= (glomerulus) blood is forced here
first for filtration and into the proximal convoluted tube
 Convoluted tubule=Proximal portion is closest to
Bowman’s capsule, is followed by the loop of Henle, and
the distal convoluted tubule
 Collecting ducts=lead to the renal pelvis
 Afferent arterioles feed Bowman’s capsule and efferent
arterioles take blood away
Figure 42-10
Urinary system
Kidney
Cortex
Kidney
Nephron structure
Nephron
Nephron
Medulla
Renal
vein
Renal
artery
Ureter
Ureter
Bladder
Urethra
In some nephrons
the loop of Henle
is long and plunges
into the medulla
In most nephrons,
the loop of Henle
is relatively short
and is located in
the cortex
Processes in the Nephron
 The afferent arteriole brings blood to Bowman’s
capsule, where it’s Filtered by pressure that forces the
solutes like glucose, salts, vitamins, and nitrogen
wastes through fenestrations just small enough to
pass. Blood components stay in the blood vessels
 As the filtrate passes through the proximal convoluted
tubule, nitrogenous wastes, water and salts are
Secreted into the filtrate
 As the filtrate moves down the loop of Henle, water is
Reabsorbed, and the urine becomes more
concentrated. However, as it moves up the loop of
Henle, salts move out and the urine becomes less
concentrated
Figure 42-12
Anatomy of the renal corpuscle
Blood leaves
glomerulus
Bowman’s capsule
Glomerulus
Pre-urine
leaves
Bowman’s
capsule.
Blood enters
glomerulus.
Filtration
Pores in blood vessel
Filtration slits
in cells that
wrap around
vessel
Direction of
blood movement
Large molecules
and cells remain
in bloodstream.
Fluid and small
solutes are pushed
through the pores
and the filtration
slits into Bowman’s
capsule.
Figure 42-15b
Permeability
100
Passive
transport 300
300
Active
transport
600
600
900
Passive
transport
1200
Descending limb is highly
permeable to water but
impermeable to solutes
Ascending limb is impermeable
to water but highly permeable to
Na+ and Cl–
Figure 42-16
Distal tubule
Loop of
Henle
Solutes
(electrolytes,
urea)
Cortex
Collecting
duct
Medulla
Hormonal Control of Excretion
 Antidiuretic Hormone (ADH)-causes
the reabsorption of water as the urine
moves through the collecting duct,
which re-concentrates the urine
 Aldosterone-causes the reabsorption
of water and Na+ by altering the
permeability of the distal convoluted
tubule
Figure 42-18a
ADH present
Distal tubule
Loop of
Henle
Cortex
Collecting
duct
Aquaporins
Solutes
Medulla
Circulation and Gas Exchange
 In animals without a circulatory system (cnidarians),
there’s a gastrovascular cavity with fluid. The walls of
the cavity are only a couple of cell layers thick.
 Open circulation occurs in organisms like insects,
where blood (hemolymph)is pumped into an internal
cavity (hemocoel or sinus), so that it can wash over
the organs of the cavity. Ostia collect the hemolymph
and return it to the heart
 Closed circulation occurs in most organisms and is
where blood is confined to vessels.
 Arteries move away from the heart
 These branch into arterioles and then capillaries
 Veins move toward the heart
 Venules collect deoxygenated blood from the capillaries
and move it to the veins
Figure 44-3
Closed system: Blood never leaves vessels.
Lymph travels
through closed
lymph vessels
Blood travels
through closed
blood vessels
Single heart
Open system: Hemolymph leaves vessels and comes into
direct contact with tissues.
Tubular heart
Hemolymph
(“blood-lymph”)
flows throughout
body cavity
Figure 44-22
Capillaries are small and extremely thin walled.
Veins and arteries differ in structure.
Red
blood
cells
Capillary
Artery
(Medium-sized)
Vein
(Medium-sized)
Nucleus
Fibrous tissue
Endothelial cells
Muscle tissue
Basement membrane
Elastic tissue
Endothelium
Single vs. Double Circulation
 In fishes, rays and sharks, the heart only contains 2
chambers (1 atrium, 1 ventricle).
 The blood goes into the atrium, ventricle, and then to
the gills and the rest of the body. This is single
circulation(1 loop)
 In other animals, there’s a 3 or 4 chambered heart (2
atria, 1 or 2 ventricles)
 The blood goes into the right atrium and right
ventricle. The pulmonary artery then takes the blood
to the lungs (1st circulation, pulmonary curcuit) for
oxygenation.
 When the blood is oxygenated, it returns to the left
atrium, where it’s pumped into the left ventricle and
out through the aorta (2nd circulation, systemic
circuit)
 In animals with 3 chambered hearts, blood returns from
the lungs into the ventricle, which has a divider that
keeps 90% of the oxygenated and deoxygenated blood
from mixing.
Figure 44-24
Fish
1 circuit
2-chambered heart
Gills
V
A
Frogs
2 circuits
3-chambered heart
2 circuits
“5-chambered” heart
Lung
Lung
A
A
A
V
Body
Turtles, lizards
Body
A
V
Body
Crocodiles
2 circuits
4-chambered heart
Birds
2 circuits
2 circuits
4-chambered heart 4-chambered heart
Lung
A
Mammals
A
V V
Body
Lung
Lung
A
A
A
A
V V
V V
Body
Body
A  Atrium
V  Ventricle
Ventricle divided into chambers
Three-chambered heart
Two circulatory loops
Figure 44-25
Pulmonary circulation
1. Blood returns to heart
from body, enters right
atrium.
Aorta
Superior
vena cava
Pulmonary
artery
6
3
2. Blood enters
right ventricle.
Pulmonary
vein
3. Blood is pumped
from right ventricle
to lungs.
4
Right
atrium
Left
atrium
1
Systemic circulation
Atrioventricular
valve
Atrioventricular
4. Blood returns to left valve
atrium from lungs.
5
5. Blood enters left
ventricle.
Inferior
vena cava
2
6. Blood is pumped from
left ventricle to body.
Right
ventricle
Left
ventricle
Semilunar
valves
The Cardiac Cycle
 This is the rhythmic contraction of the heart muscles.
 This is regulated by autorhythmic cells that contract
without being iniated by nerve cells
 Within the right atrium is the SA (sinoatrial)node, or
pacemaker, on the top atrial wall, which contracts
both atria simultaneously, and sends a delayed
impulse to the AV (arterioventricular)node in the
lower wall of the right atrium.
 The AV node is responsible for ventricular
contractions (systole-top number on blood pressure),
forcing blood into the pulmonary arteries and aorta
 When the ventricles relax (diastole-bottom number
on blood pressure), blood flows back on the AV
valves, closing them and the semilunar valves in the
aorta and pulmonary artery (this is responsible for
the heart sound)
Figure 44-28
Sinoatrial node
Atrioventricular node
Right
atrium
Right
ventricle
Conducting fibers
Left
atrium
Left
ventricle
Figure 44-29
SA node
activates
atria
AV
node
delay
Electrical Electrical activity
in ventricles
activity
in atria
Ventricles recover
About the Mammalian Heart
 Cardiac output=heart rate and stroke
volume
 Heart rate=number of bpm
 Stroke volume=amount of blood pumped by a
ventricle on a contraction (70mL is average for
an adult human)
 For the avg individual at rest, cardiac
output=72bpm(70mL)=5L/min, which is about
equal to the total blood volume
 Heart murmurs occur when a valve is faulty
and is allowing backflow
Blood Vessels and Pressure
 Blood pressure is highest in the aorta and pulmonary
artery, closest to the contraction that caused the
pressure
 When blood reaches the capillaries and venules, it’s
pressure is virtually 0. Contractions of nearby
skeletal muscles keep the blood flowing.
 Blood constantly moves toward the heart b/c veins
have valves that prevent backflow.
 Blood pressure is regulated over the long term by
changes in the smooth muscles in arteriole walls
 Vasoconstriction is caused by contractions of the
smooth muscle in response to tension, physical stress
 Vasodilation is caused by the relaxation of the
smooth muscle
Figure 44-30
From heart
Velocity
Total area
Capillaries
Return to heart
The Lymphatic System
 This is a network of vessels amongst the
capillaries of the circulatory system.
 Approximately 4L of fluid per day leaves the
capillaries and goes through the lymphatic
system
 Lymph is that lost fluid, and it returns to the
circulatory system at the base of the neck in the
large veins there
 Lymph nodes filter lymph and attack any
viruses and bacteria that may be traveling
in the blood stream.
 Lymph nodes also produce and send out
immune cells to fight infections in other body
parts.
Blood
 Blood contains:
 Red Blood Cells (RBCs or erythrocytes)biconcave disc-shaped cells that carry
oxygen using hemoglobin
 White Blood Cells (WBCs or leucocytes)disease-fighting cells
 Platelets-cell fragments that help with
blood clotting
 Plasma-liquid portion of the blood
Figure 44-15
Hemoglobin
Each hemoglobin
molecule can
bind up to four
molecules of
oxygen
O2 from
lung
98.5% of oxygen
loads to hemoglobin
in red blood cells
1.5% of
oxygen
loads to blood
plasma
The rate of unloading depends on the
partial pressure of oxygen in the tissue
O2 to tissues
Blood Clotting
 Blood vessel breaks expose proteins
(like collagen) that attract platelets,
which are sticky. Platelets release
clotting factors.
 Fibrinogen is an inactive component
of blood, but is converted to fibrin,
which forms a net-like set of threads
across the break. This traps blood
cells that finish the clot
Gas Exchange
 Is based on partial pressure (recall from
chemistry the total pressure of a mixture of
gasses=the sums of the pressures of each
gas within it, the partial pressures)
 Oxygen diffuses out of the air into the
blood not because it’s less concentrated
there, but because it has a lower pressure
there.
 This gas exchange for the entire organism
is respiration. What cells do with the
oxygen to break down sgars is cellular
respiration
Respiratory challenges and
mechanisms


Marine organisms have to cope with less oxygen in their
surrounding fluid than land-living organisms b/c oxygen is
less soluble in water than in air.
There are 3 main respiratory mechanisms that organisms
employ:
 Direct contact with Oxygen from the environment(Flatworms, sponges, etc) use diffusion through the skin
 Gills-These are outgrowths from the body that can be
covered or exposed to water. Covered gills require
active water movement over them and they have
countercurrent exchange between the capillaries in the
gills and the water since they flow in opposite directions
which is efficient (oxygen-poor blood is always in
contact with water)
 Tracheae-These are a series of tubes that run through
the bodies of insects. Spiracles are openings of the
trachae on the outside of the body
 Lungs-these are closely connected with the circulatory
system (as discussed before) since they’re not
connected to the rest of the organs of the body.
Figure 44-6
External gills are in direct contact with water.
External
gills
Internal gills must have water brought to them.
Carapace removed
Internal gills
(each contains many
small filaments)
Figure 44-7
Gill arches hold
many gill filaments
Water IN
Water OUT
Detail of gill filament:
To body
From
heart
Water flow
Gill lamella
Blood flow
Capillaries
Figure 44-10
Muscles
contract
Muscles Muscle
relax
contracts
Wing
up
Air
in
Trachea
Tracheae expand,
air enters.
Muscle
relaxes
Wing
down
Air
out
Trachea
Tracheae are squeezed,
air is pushed out.
Figure 44-2
Air
Tubing conducts
air to and from…
… gas exchange
surfaces in the lung
Lungs
Figure 44-11
Airways into the lung
Alveoli
The alveolar gas-exchange surface
Smallest
bronchiole
Air
Air
Trachea
Oxygenated
blood out
Deoxygenated
blood in
Bronchi
0.2
m
Bronchioles
Oxygen
Aqueous film
Epithelium of alveolus
Wall of capillary
Blood
Lung
Alveolus
Capillaries
ECM
How lung-breathing occurs
 Amphibians-positive pressure breathing (air
is forced into the lungs). Buccopharyngeal
respiration
 Birds-1-way flow of air through air sacs
that act as billows, moving air through the
lungs. Parabronchi (air tubes) do gas
exchange
 Mammals-negative pressure breathing (a
vacuum is created by the diaphragm)
Figure 44-14
Anatomy of the avian respiratory system
Lung
Parabronchi
Trachea
Posterior
air sacs
Anterior
air sacs
One-way airflow through the avian lung
Lungs empty.
Posterior air
sacs fill with
outside air
Anterior air
sacs fill with air
from lungs
Lungs fill with air
from posterior sacs.
Posterior air
sacs empty
Anterior air
sacs empty
Figure 44-12
Lungs expand and contract is response to changes in
pressure inside the chest cavity.
INHALATION
EXHALATION
Diaphragm
Ventilatory forces can be modeled by a balloon in a jar.
Pressure
more
negative
When the diaphragm is pulled
down, the balloon inflates.
Pressure
less
negative
When the diaphragm is
released, the balloon deflates.
Breathing control
 CO2 is transported through the blood as
bicarbonate (HCO3-). This is carried within
the plasma, but made in the RBCs
 CO2+H20H2CO3H+ and HCO3- (acidic)
 Breathing control centers in the brain
establish the breathing rhythm
 Chemoreceptors in the carotid arteries
monitor the pH of the blood and send this
information to the diaphragm to increase
respiration rate (negative feedback)
The Immune System
 Pathogen-infectious agent (virus, bacteria,
protist, fungus)
 Antigen-any molecule that can be
recognized as foreign
 The immune system protects against
pathogens using barriers as well as many
specific and non-specific responses
 First-line of defense-barriers (innate
defenses)
 Second-line of defense-general fighting of
infection (non-specific, innate defenses)
 Third-line of defense-cells built to fight
specific infections (acquired immunity)
Figure 49-4
Components of the
immune system
Lymphocyte origin:
Bone marrow
Lymphocyte maturation:
Bone marrow (B cells)
Thymus (T cells)
Lymphocyte activation:
Spleen
Lymph nodes
Lymphocyte transport:
Lymphatic ducts
Blood vessels
First Line of Defense
 Skin-covered in oily and acidic secretions
from sweat glands
 Antimicrobial proteins (lysozymes) that
break down the walls of bacteria and are
contained insaliva, tears, and other mucus
 Cillia-beat to sweep invaders out of the
respiratory tract
 Gastric Juice-kills most microbes that make
it to the stomach
 Symbiotic Bacteria-outcompete harmful
bacteria in the gut and vagina
Figure 49-1
Eyes
Blinking wipes tears across
the eye. Tears contain the
antibacterial enzyme lysozyme.
Ears
Hairs and ear wax trap
pathogens in the passageway
of the external ear.
Nose
The nasal passages are lined
with mucus secretions and
hairs that trap pathogens.
Digestive tract
Pathogens are trapped in saliva
and mucus, then swallowed.
Most are destroyed by the low
pH of the stomach.
Airways (lining of trachea)
Ciliated
cells
Mucus-secreting
cells
Instead of reaching the
lungs, most pathogens are
trapped in mucus and swept
up and out of the airway via
the beating of cilia.
Second Line Defenses




Phagocytes (WBCs)-engulf pathogens by phagocytosis
 Neutrophils-most abundant phagocytic cells that engulf pathogens
 Monocytes-cells that enlarge into macrophages that engulf still
more pathogens and cell debris (large numbers of these in the
spleen and lymph nodes)
 NK or natural killer cells-Destroy cells that play host to viruses and
bacteria
 Eosinophils kill multicellular invaders
 Dendritic cells stimulate acquired immunity
Complement system-about 30 proteins that function together to
stimulate immune response. These attract phagocytes to an infection
and help to break open foreign cells
Interferons-proteins produced by infected cells that stimulate
neighboring cells to produce proteins to defend against infecting
viruses
Inflammatory Response-pain and swelling at an infection site
 Mast cells (basophils) in the area burst open and release histamine
 Histamine cause nearby blood vessels to dilate, biringing more
blood to the infection site.(vasodilation)
 Phagocytes are attracted to that area, and relaease chemical
signals that bring more blood to the area
 The complement system reacts
Figure 49-2
Mast cells secrete signals that increase
blood flow.
Granules
contain signaling
molecules
Nucleus
Neutrophils ingest and kill pathogens.
Multi-lobed
nucleus
Vesicles
containing
signaling
molecules
Macrophages recruit other cells and
ingest and kill pathogens.
Lysosomes
digest
bacteria
Vesicles
secrete cellkilling toxins
Pseudopodia engulf
bacteria
Nucleus
Figure 49-5
Inactive lymphocyte
Nucleus
Activated lymphocyte
Nucleus
Large amount
of rough ER
Figure 49-3
THE INFLAMMATORY RESPONSE
Blood vessel
Red blood cell
Platelet
1. Bacteria and
other pathogens
enter wound.
2. Platelets from
blood release
blood-clotting
proteins at
wound site.
3. Injured tissues
Macrophage
and macrophages
at the site release
chemokines, which
recruit immune
system cells to site.
4. Mast cells at
Mast cell
the site secrete
factors that
constrict blood
vessel at wound
but dilate blood
vessels near
wound.
5. Neutrophils
Neutrophil
arrive, begin
removing
pathogens by
phagocytosis.
6. Some newly
Macrophage
Initiate tissue
repair
arrived leukocytes
mature into
macrophages
that phagocytize
pathogens and
secrete key
cell-cell signals.
Third line of defense (Acquired
Immunity)
 Up until now, the immune response has been general
and not specific to the pathogen.
 Acquired immunity is built specifically to fight a
particular antigen (like a toxin from a bacterium,
protein coat of a virus, or a molecule unique to a
pathogen)
 Major histocompatibility complex (MHC) distinguishes
between “self” cells and “foreign” cells
 This is a collection of glycoproteins on the surfaces of
all body cells
 These are made from about 20 genes (50 alleles) and
each is unique to each person, so it’s unlikely you’ll
have the same proteins as someone else
Acquired Immune Cells
 B Cells-are made and mature in the bone marrow,
and respond to antigens. They make antibodies
(proteins) against the antigen
 Antibodies are specific to the antigen
 There are 5 classes of antibodies (immunoblobulins),
and each is associated with a particular activity
 Each class of antibodies is Y-shaped with constant
regions and variable regions. The variable regions
give the antibodies specificity for the antigen
 Plasma Cells-release antibodies that circulate to an
infection site
 Memory B Cells-stick around after an infection to
make you immune to future attacks from the same
strain of the infection
Figure 49-6a
B-cell receptor
Antigenbinding site
Antigenbinding site
Light
chain
Heavy chain
Heavy chain
Disulfide bridge
Transmembrane domains
Light chains
Antigenbinding
site
Antigenbinding
site
Heavy chain
Heavy chain
Figure 49-6-Table 49-2
Acquired Immune Cells cont.
 T Cells-originate in the bone marrow, but mature in
the thymus (a gland, hence the “T”)
 MHC markers of the T cells distinguish between self
and nonself cells
 A host body cell will display self and non-self
markers, which the Tcells interpret as nonself
 Cancer cells are often recognized as nonself
 Cytotoxic T cells-lyse nonself cells by punctuing them
 Helper T cells-activate inactive macrophages,
stimulate B cell production and stimulate cytotoxic T
cells
 When an antigen binds to T or B cells, they
proliferate, which is called clonal selection, since only
cells that match the antigen will be cloned
Figure 49-6b
T-cell receptor
Antigen-binding site
 Chain
 Chain
Transmembrane domains
Antigen-binding site
 Chain
 Chain
Types of Immune Response
 Cell-mediated response-Mostly T cells respond to
nonself cells via clonal selection
 Tcells produce cytotoxic Tcells
 T cells produce helper Tcells that bind to
macrophages, which carry nonself markers from the
cells they’ve encountered
 Helper T cells produce interleukins to stimulate
proliferation of more T and B cells (these make you
achy)
 Humoral response (antibody-mediated)-response to
antigens or pathogens within the lymph.
 B cells produce plasma cells, which release antibodies
for the antigen
 B cells produce memory cells
 Macrophages and helper T cells stimulate B cell
production
Figure 49-13
CELL-MEDIATED RESPONSE
HUMORAL RESPONSE
1. Cytotoxic T cell
Granules
Cytotoxic T cell
1. Antibodies coat
makes contact with
virus-infected cell and
releases granules
(black dots).
Virus-infected
host cell
free virus particles.
The virus cannot bind
to the host cell’s
plasma membrane.
Uninfected
host cell
Virus particle
Antibody
Virus
Antigen
2. Molecules in the
granules induce
infected cell to selfdestruct, killing he
viral particles inside.
2. The antibody-coated
Neutrophil
virus is recognized,
phagocytized, and
destroyed by a
neutrophil or
macrophage.
Figure 49-11
Antigen fragment
binding site
ANTIGEN PRESENTATION
1. Dendritic cell
Dendritic cell Foreign peptide
ingests peptide.
2. Enzyme complex
inside cell breaks
peptide into pieces.
Major
histocompatibility
(MHC) protein
3. Peptide pieces bind
to MHC Class I protein
inside endoplasmic
reticulum.
ER
4. The MHC-peptide
complex is transported
to the cell surface via
the Golgi apparatus.
Golgi
apparatus
MHC
Piece of
foreign
peptide
5. The MHC Class I
protein presents the
peptide on the surface
of the cell membrane.
T-CELL ACTIVATION (CD8+ T cells)
Dendritic cell
MHC
Antigen
1. T-cell receptor binds
to peptide presented
on MHC protein on
surface of dendritic cell.
Complex activation
process begins,
involving interactions
among many proteins
on the surfaces of the
two cells.
CD8+
T cell
Clonal expansion
2. Activated CD8+
T cells multiply and
differentiate. Effector
T cells that result leave
lymph node and
enter blood.
Cytotoxic T cells
Figure 49-12
B-CELL ACTIVATION
Foreign
peptide
B-cell
receptors
B-cell
1. B cell encounters and
binds to foreign peptide
in lymph or blood. The
peptide is internalized,
processed, and presented
on the surface by an
MHC Class II protein.
MHC
Class II
protein
2. The MHC-peptide
B cell
complex interacts with
complementary receptors
on a helper T cell,
activating it.
3. Cytokines from the
activated helper T cell
activate the B cell.
Cytokines
Helper T cell
4. The activated B cell
Plasma
cells
Antibodies
begins to divide. Some
daughter cells
differentiate into plasma
cells which produce
large quantities of
antibodies.
Antibodies will bind to
antigens and mark
them for destruction
Fighting Infection
 Antibiotics-fight bacteria only
 Vaccines-preventative, containing only
antigen-portions or dead/weak strains of
pathogens in order to stimulate memory
cell production
 Active immunity (everything we’ve
discussed so far)
 Passive immunity-when antibodies are
given to you. Usually via the placenta or
breast milk for babies
Figure 49-14
Initial exposure to antigen
Second exposure to antigen
Secondary
immune
response
Response
is larger
Primary immune
response
Response
is faster
Immune Disorders
 Allergies-hypersensitive responses to
antigens called allergens. IgE class
antibodies are produced
 Autoimmune Diseases-loss of self-tolerance
 Stress and exertion-exercise improves the
immune system, stress supresses it
 Immunodeficiency Diseases
 HIV
 Severe combined immunodeficiency (SCD)lymphocytes are rare or absent
Regulation and Control
 Endocrine System-is a series of
hormone-producing glands
throughout the body which are
circulated through the blood and
influence target cells
 The nervous system also controls the
body’s functions
AP-Pertinent Endocrine Info
 Posterior Pituitary-stores ADH (antidiuretic
hormone) and oxytocin, which are
produced in the hypothalamus
 Anterior Pituitary-produces tropic hormones
(hormones that target other glands)
 Regulated by releasing hormones produced by
the hypothalamus
 Pancreas
 Islets of Langerhans have 2 cell types
(producing antagonistic hormones)
 Alpha cells-secrete glucagon into the blood
when blood sugar drops, stimulating the liver to
release glucose
 Beta cells-secrete insulin, stimulating the liver
to take up glucose and convert it to glycogen or
fat
Figure 47-3-1
Hypothalamus
Growth-hormone-releasing hormone:
stimulates release of GH from pituitary
gland
Corticotropin-releasing hormone (CRH):
stimulates release of ACTH from pituitary
gland
Thyroid-releasing hormone: stimulates
release of TSH from thyroid gland
Gonadotropin-releasing hormone:
stimulates release of FSH and LH from
pituitary gland
Antidiuretic hormone (ADH): promotes
reabsorption of H2O by kidneys
Oxytocin: induces labor and milk release
from mammary glands in females
Polypeptides
Amino acid derivatives
Steroids
Figure 47-3-2
Polypeptides
Amino acid derivatives
Steroids
Thyroid gland
Thyroxine: increases metabolic rate
and heart rate; promotes growth
Adrenal glands
Epinephrine: produces many effects
related to short-term stress response
Cortisol: produces many effects related to
short-term and long-term stress responses
Aldosterone: increases reabsorption of
Na+ by kidneys
Kidneys
Erythropoietin (EPO): increases
synthesis of red blood cells
Vitamin D: decreases blood Ca2+
Testes (in males)
Testosterone: regulates development
and maintenance of secondary sex
characteristics in males; other effects
Figure 47-3-3
Polypeptides
Amino acid derivatives
Steroids
Pituitary gland
Growth hormone (GH): stimulates
growth
Adrenocorticotropic hormone (ACTH):
stimulates adrenal glands to secrete
glucocorticoids
Thyroid-stimulating hormone (TSH):
stimulates thyroid gland to secrete
thyroxine
Follicle-stimulating hormone (FSH)
and luteinizing hormone (LH): involved
in production of sex hormones;
regulate menstrual cycle in females
Prolactin: stimulates mammary gland
growth and milk production in females
Figure 47-3-4
Polypeptides
Amino acid derivatives
Steroids
Parathyroid glands
Parathyroid hormone (PTH):
increases blood Ca2+
Pancreas (islets of Langerhans)
Insulin: decreases blood glucose
Glucagon: increases blood glucose
Ovaries (in females)
Estradiol: regulates development and
maintenance of secondary sex
characteristics in females; other effects
Progesterone: prepares uterus for
pregnancy
Figure 47-16
The posterior pituitary
The anterior pituitary
Hypothalamus
Neurosecretory
cells of the
hypothalamus
Hypothalamic
hormones
Neurosecretory
cells of the
hypothalamus
Hypothalamic
hormones
Blood vessels
Posterior
pituitary
Anterior
pituitary
Blood vessels
Pituitary
hormones
Hormone
Target
Response
ADH
Oxytocin
Kidney
nephrons
Mammary glands,
uterine muscles
Aquaporins Contraction during
activated; H2O labor; ejection of
reabsorbed milk during nursing
Hormone
Target
Response
ACTH
Adrenal
cortex
Follicle-stimulating Growth
hormone (FSH) hormone
and luteinizing
(GH)
hormone (LH)
Testes or
ovaries
Prolactin
(PRL)
Many tissues Mammary
glands
Thyroidstimulating
hormone
(TSH)
Thyroid
Production of Production of sex Growth
Mammary
Production of
glucocorticoids hormones; control
gland growth;
thyroid
of menstrual cycle
milk production
hormones
How hormones work
 Method 1: (for steroid hormones)
 The hormone diffuses through the pm and heads
for the nucleus.
 It binds to a receptor protein in the nucleus,
which activates the DNA to turn on a specific
gene
 Method 2: (for protein hormones)
 The hormone binds to a receptor on the plasma
membrane (receptor-mediated endocytosis),
which stimulates a second messenger
 2nd messengers can be cAMP, which triggers an
enzyme that makes cellular changes, or Inositol
triphosphate (IP3) that triggers the release of
calcium ion from the ER, that triggers enzymes
to make cellular changes
Figure 47-18
STEROID HORMONE ACTION
Nucleus
Hormone
receptor
Steroid
hormone
mRNA
Proteins
DNA
Hormonereceptor
complex
1. Steroid
2. Hormone binds
hormone
enters
target cell.
to receptor, induces
conformational
change.
Hormoneresponse
element
RNA
polymerase
3. Hormone-receptor
4. Many mRNA
complex enters
nucleus and binds
to DNA, induces
start of transcription.
transcripts are
produced,
amplifying
the signal.
Ribosome
5. Each transcript is
translated many times,
further amplifying the
signal.
Figure 47-21
MODEL FOR EPINEPHRINE ACTION
1. Epinephrine
binds to receptor
Epinephrine
Adenylyl
cyclase
Receptor
2. Activation
of G protein
3. Activated
adenylyl cyclase
catalyzes
formation of
cAMP
Transmission of
message from
cell surface
4. Activation of cAMP-dependent protein
kinase A
5. Activation of phosphorylase kinase
6. Activation of phosphorylase
7. Production of glucose from glycogen
Nerves and Impulses
 A Neuron (nerve cell) consists of a cell body,
dendrite(s), and an axon
 Impulses begin at the dentrites, travels through the
cell body, and ends at the axon in a gap called a
synapse
 Synapse is the axon of one nerve and its gap
associated with the dendrite of the next nerve
 Types of neurons
 Sensory (afferent)-receive the initial stimulus (retina
of eye, skin touch receptors, etc)
 Motor (efferent)-stimulate effectors (target cells that
produce a response (neuro-muscular junctins, sweat
gland stimulus, etc)
 Association (interneurons)-in the spinal cord and
brain. These receive sensory info and send impulses
to motor neurons, and are known as integrators that
evaluate appropriate responses to stimuli
Figure 45-3
Information flow through neurons
Neurons form networks for information flow
Nucleus
Dendrites Cell body
Axon
Collect
electrical
signals
Passes electrical signals
to dendrites of another
cell or to an effector cell
Integrates incoming signals
and generates outgoing
signal to axon
Impulse Transmission
 Chemical changes across the membranes of
neurons transmits the impulse.
 An unstimulated neuron is polarized-an
excess of Na+ is on the outside of the cell,
while an excess of K+ is on the outside.
Sodium/potassium pumps maintain this
polarization
 Overall, the inside of the cell is negative b/c
of a large number of negatively charged
molecules and ions inside the cell.
 Transmission of a nerve starts with this
unstimulated resting potential
Figure 45-4
Instrument
records voltage
across membrane
Outside of cell
Microelectrode
0 mV
K channel
– 65 mV
Inside of cell
Figure 45-5
HOW THE SODIUM-POTASSIUM PUMP (Na+/K+-ATPase) WORKS
Outside
cell
Inside
cell
1. Three sodium ions
2. ATP phosphorylates the pump.
3. Two potassium ions
4. The phosphate group drops
(Na+) enter the protein
from within the cell.
It changes shape and releases
3 Na+ to the outside of the cell.
(K+) enter the protein
from outside the cell.
off the pump. The protein
changes shape and releases
2 K+ to the interior of the cell.
Propagating the Impulse
 In response to a stimulus, gated ion
channels open an allow Na+ to rush into
the cell, meaning that the cell depolarizes.
 If the impulse is strong enough to get
above the threshold level, more ion
channels open, causing action potential
(complete depolarization), which stimulates
neighboring channels to open
 In response, other channels open to allow
K+ outside of the cell to repolarize the cell
 This results in hyperpolarization b/c more
K+ moves out than is needed to establish
repolarization
Figure 45-6
1. Depolarization
phase
2. Repolarization
phase
Threshold potential
Resting potential
3. Hyperpolarization phase
Figure 45-11
PROPAGATION OF ACTION POTENTIAL
Axon
Neuron
Action potential spreads as a wave of depolarization.
Electrode
A
1. Na+ enters axon.
Neuron
Electrode
B
Electrode
C
A
B
2. Charge spreads;
membrane
“downstream”
depolarizes.
Depolarization at
next ion channel
3. Voltage-gated
channel opens in
response to
depolarization.
C
Refractory Period
 The neuron cannot now respond to a
new stimulus b/c K+ and Na+ are on
the wrong sides of the membrane
 Sodium/Potassium pumps must now
reestablish resting potential so that
the neuron can react to a new
stimulus
Myelinzation
 Some neurons are myelinized
(covered with a sheath of Schwann
cells), which insulate the nerve’s
impulse
 Breaks in this sheath are called nodes
of Ranvier. Impulses jump from node
to node (saltatory conduction)
Figure 45-12a
Action potentials jump down axon.
Action potential jumps
from node to node
Nodes of Ranvier
Schwann cells (glia)
wrap around axon,
forming myelin sheath
Axon
Schwann cell membrane
wrapped around axon
Figure 45-12b
WHY ACTION POTENTIALS JUMP DOWN MYELINATED AXONS
Schwann cell
1. As charge spreads down
an axon, myelination (via
Schwann cells) prevents
ions from leaking out across
the plasma membrane.
Node of
Ranvier
2. Charge spreads
unimpeded until it reaches
an unmyelinated section of
the axon, called the node
of Ranvier, which is packed
with Na+ channels.
3. In this way, electrical
signals continue to jump
down the axon much faster
than they can move down
an unmyelinated cell.
At the Synapse
 The impules reaches a presynaptic dead-end, but still
needs to be carried to the postsynaptic cell
 Chemicals are needed to bridge that gap and transmit
information between these cells
 Calcium gates open, letting Ca+2 ion into the
presynaptic cell
 Synaptic vessicles on the presynaptic cell release
neurotransmitter substances
 Neurotransmitters bind with postsynaptic cell
receptors
 If its Na+ gates are open, the membrane depolarizes,
resulting in excitatory postsynaptic potential (EPSP)
 If its Na+ gates are closed, the membrane becomes
hyperpolarized and results in inhibitory postsynaptic
potential (IPSP)
 Neurotransmitters are degraded and recycled by
enzymes in the synaptic cleft and picked up by the
presynaptic cell to be re-used
Figure 45-14
Synaptic
vesicles
Synapse
End of axon
Dendrite
Figure 45-15
ACTION POTENTIAL TRIGGERS RELEASE OF NEUROTRANSMITTER
Na+ and K+
channels
Presynaptic
neuron
1. Action potential arrives;
Action
potentials
triggers entry of Ca2+.
2. In response to Ca2+, synaptic
Presynaptic
membrane
(axon)
vesicles fuse with presynaptic
membrane, then release
neurotransmitter.
3. Ion channels open when
Postsynaptic
neuron
neurotransmitter binds; ion
flows cause change in
postsynaptic cell potential.
Postsynaptic
membrane
(dendrite or
cell body)
4. Ion channels will close as
Synaptic
cleft
neurotransmitter is broken
down or taken back up by
presynaptic cell (not shown).
Figure 45-15-Table 45-2
The Nervous System
 In primative organisms, there is a
primitave nervous system, often with no
centralized control center (esp with radially
symmetric animals)
 With bilateral symmetry and cephalization,
nervous systems became ladder-like and
ganglia began taking on a primitive brainlike function
 With vertebrates, there is 1 major nerve
bundle and a brain.
The Vertebrate Nervous system
 Reflex-see following diagram
 CNS (Central Nervous System)-Brain,
spinal cord
 PNS (Peripheral Nervous System)-sensory
neurons that transmit impulses to the CNS,
and back to effectors
 Motor neurons within the PNS:
 Somatic Nervous system-directs skeletal
muscles
 Autonomic Nervous system-directs organ
activities and involuntary muscles (2 divisions);
 Sympathetic nervous system-Prepare the body for
action (increasing heart rate, release of sugar, i.e.
fight or flight)
 Parasympathetic nervous system-tranquil functions
like saliva or digestive enzyme release
Figure 45-1
The brain integrates sensory information and sends signals
to effector cells.
Sensory neuron
When reflexes occur, sensory information bypasses the
brain.
CNS (brain
 spinal cord)
Sensory receptor
Spinal cord
Interneuron
Interneuron
Motor neuron
(part of PNS)
Motor neuron
Sensory
receptor
Effector cells
Effector cells
Sensory neuron
Figure 45-18
Central nervous system (CNS)
Information processing
Peripheral nervous system (PNS)
Sensory
information
travels in
afferent division
Somatic
nervous
system
Most information
travels in
efferent division,
which includes…
Autonomic
nervous system
Sympathetic
division
Parasympathetic
division
Figure 45-19
PARASYMPATHETIC NERVES
SYMPATHETIC NERVES
“Rest and digest”
“Fight or flight”
Constrict pupils
Dilate pupils
Stimulate saliva
Inhibit salivation
Slow heartbeat
Constrict airways
Cranial
nerves
Cervical
nerves
Relax airways
Stimulate activity
of stomach
Inhibit release of
glucose; stimulate
gallbladder
Inhibit activity
of stomach
Thoracic
nerves
Stimulate release
of glucose; inhibit
gallbladder
Stimulate activity
of intestines
Inhibit activity
of intestines
Lumbar
nerves
Secrete
epinephrine and
norepinephrine
(hormones that
stimulate activity;
see Chapter 47)
Sacral
nerves
Contract bladder
Promote erection
of genitals
Increase heartbeat
Sympathetic chain:
bundles of nerves
that synapse with
nerves from spinal
cord, then send
projections to organs
Relax bladder
Promote
ejaculation and
vaginal contraction
Sensation and Perception
 The Brain has different regions for
processing different information, but
the cerebral cortex (outside) of the
brain processes most information
 Various organs function to allow the
organism to get information about
the outside world.
Figure 45-20
The brain is made up of four distinct structures.
The cerebrum has two hemispheres, each of which
has four lobes.
Rear view
Inside view
Cerebrum
Diencephalon
Information
relay and control
of homeostasis
Brain stem Information relay
and center of autonomic control
for heart, lungs, digestive system
Conscious
thought,
memory
Left cerebral
hemisphere
Corpus callosum:
neurons that connect
the two hemispheres
Cerebellum
Coordination
of complex
motor patterns
Right cerebral
hemisphere
Inside view
Frontal lobe
Corpus callosum
Temporal lobe
Parietal lobe
Occipital lobe
Top view of cerebrum
Motor functions
(right side of body)
Top view
Sense of touch
and of temperature
(right side of body)
Hearing (right ear)
Language and
math computation
Sight
(right visual field)
Motor functions
(left side of body)
Sense of touch
and of temperature
(left side of body)
Corpus callosum
Figure 45-21
Left
hemisphere
Hearing (left ear)
Spatial
visualization
and analysis
Right
hemisphere
Sight
(left visual field)
Leg
Hip
Trunk
Cross section through area responsible for sense of touch
and of temperature
Genitals
Teeth
Jaw
Tongue
Intra-abdominal
Left
hemisphere
Figure 46-4
Middle Inner
ear
ear
Outer
ear
Auditory
neurons
(to brain)
Cochlea
Ear canal
Ear ossicles
Oval
window
Sound
waves
(in fluid)
Sound
waves
(in air)
Stapes
Cochlea
Middle
ear cavity
Tympanic membrane
(eardrum)
Figure 46-5
The middle chamber of the fluid-filled cochlea contains hair
cells.
Cochlea
Auditory
nerve
Three
fluidfilled
chambers
Tectorial
membrane
Neurons
(to auditory
nerve)
Hair
cells
Hair cells are sandwiched between membranes.
Stereocilia
Outer
hair cells
Axons of
sensory
neurons
Inner
hair cells
Tectorial
membrane
Basilar
membrane
Figure 46-8
The structure of the vertebrate eye.
In the retina, cells are arranged in layers.
Ganglion cells
Sclera
Iris
Retina
Direction of light
Pupil
Cornea
Fovea
Lens
Optic nerve
(to brain)
Axons to optic nerve
Connecting neurons
Pigmented
Photoreceptor cells epithelium
Figure 46-14
Pit vipers can detect infrared radiation.
Warm animals emit much more infrared radiation than their surroundings do.
Pits
What we see in the light (the top
compartment in the white box contains
a lightbulb wrapped in dark cloth)
What pit vipers “see” in the dark
Figure 46-15
Taste bud
Pore
Taste cells
(salt, acid,
sweet, bitter,
meaty, etc.)
Afferent neuron (to brain)
Figure 46-16
Action potentials
Brain
Glomeruli
Nasal cavity
Olfactory
bulb of
brain
Bone
Olfactory
receptor
neuron
Mucus
Odor molecules
Muscles
 3 types: skeletal, cardiac, and smooth
 Skeletal muscle consists of muscle fibers
 Sarcolemma-plasma membrane of the muscle
cell has many transverse tubules (T tubules) or
invaginations
 Sarcoplasm-cytoplasm of the muscle cell has a
strong sarcoplasmic reticulum
 Cells are multinucleate and the nuclei migrate
outward
 Filled with myofibrils, consisting of:
 Thin filaments-actin (globular protein) in a
double helix, and troponin and tropomyosin that
cover binding sites on the actin
 Thick filaments-myosin (filamentous protein)
with a protruding head
Figure 46-24-Table_46-1
Figure 46-19
Sarcomere
Muscles
Myofibril
Dark band Light band
Bundle of
muscle fibers
(many cells)
Muscle fiber
(one cell)
contains many
myofibrils
Relaxed
Contracted
Muscle tissue
Figure 46-20
Thin filament (actin)
Myofibril
Thick filament (myosin)
Relaxed
Z disk
A
B
C
D
Contracted
A
B
C D
Muscle Contraction
 Is described as a sliding filament model
 ATP binds to the myosin head, forming ADP+P
 Calcium ion binds to troponin, which shifts the
tropomysin, exposing the binding sites on the actin
filaments
 Myosin heads bind to actin at the binding sites,
releasing the ADP+P. This pulls the actin toward the
center of the sarcomere, causing the muscle fiber to
contract
 Addition of new ATP unbinds the cross-brige between
actin and myosin, and the muscle goes back to it’s
unattached position
 Given all of this, why rigor mortis?
Figure 46-22
CHANGES IN THE CONFORMATION OF THE MYOSIN HEAD PRODUCE MOVEMENT.
1. ATP bound to myosin head.
Myosin head
of thick filament
Head releases from thin filament.
Actin in thin filament
4. ADP released.
2. ATP hydrolized.
Cycle is ready to
repeat.
Head pivots, binds to
new actin subunit.
3. Pi released. Head pivots,
moves filament (power stroke).
Figure 46-23
Tropomyosin and troponin work together to block the
myosin binding sites on actin.
Myosin head
Troponin
Myosin binding
sites blocked
Tropomyosin
Actin
Calcium ions
Myosin
binding sites
When a calcium ion binds to troponin, the troponintropomyosin complex moves, exposing myosin binding sites.
Myosin binding
site exposed to
myosin head
Calcium ion
Troponin-tropomyosin complex, moved
Neuromuscular Junctions
 This occurs when the end of an axon
synapes with a muscle.
 Action potential releases acetylcholine
 This generates action potential on the
sarcolemma and T tubules
 Sarcoplasmic reticulum releases
Calcium ion
 Actin/Myosin cross bridges form
Figure 46-24
Motor neuron
Muscle cell
HOW DO ACTION POTENTIALS TRIGGER
MUSCLE CONTRACTION?
Motor neuron
Action
potential
1. Action potential
ACh
arrives; acetylcholine
(Ach) is released.
ACh receptor
Action
potentials
2. ACh binds to ACh
receptors on the muscle
cell, triggering depolarization that leads to
action potential.
3. Action potentials
propagate across muscle
cell’s plasma membrane
and into interior of cell via
T tubules.
4. Proteins in T tubules
open Ca2+ channels in
sarcoplasmic reticulum.
5. Ca2+ is released
from sarcoplasmic
reticulum. Sarcomeres
contract when troponin
and tropomyosin move in
response to Ca2+ and
expose actin binding
sites in the thin filaments
(see Figure 46.23).
Thick filaments
(myosin)
Thin filaments Ca2+
(actin)
ions
Reproduction
 While some animals are capable of
asexual reproduction (budding,
parthenogenesis), most reproduce
sexually
 Humans, as well as some other
animals have both primary and
secondary sex characteristics
 Primary sex characteristics=structures
directly involve with sexual reproduction
 Secondary sex characteristcs=structures
that distinguish male from female, but
aren’t involved in reproduction directly
Human Reproductive Anatomy

Female
Ovaries-produce eggs and hormones
Oviducts (fallopian tubes)-carry eggs to uterus
Uterus-muscular organ for implantation and development of
young. Neck of the uterus is a muscular structure called the cervix
 Vagina-tube-like structure leading out of the body from the uterus
Male
 Testis-produce sperm and are made of seminiferous tubules and
interstitial (stem) cells. These hang below the body in the scrotum
b/c sperm are best produced about 2 degrees below body temp
 Epididymis-coiled tube attached to each testis where sperm
mature
 Vas deferens-tube that transfers sperm from epiddiymis to urethra
 Seminal vesicles-glands that secrete mucus that mixes with the
sperm to make semen. Mucus contains fructose to give the sperm
energy and prostaglandins that stimulate uterine contractions
 Prostate gland-secretes an alkaline fluid into the semen which
helps to neutralize vaginal acidity as well as any acidity from
leftover urine in the urethra
 Bulbourethral (Cowper’s) glands-secrete fluid into the urethra for
lubrication
 Penis-transport structure for semen




Figure 48-9
Side view
Oviduct
Ovary
Uterus
Urinary bladder
Cervix
Vagina
Urethra
Clitoris
Labium
minus
Labium majus
Opening of vagina
Front view
Opening of urethra
Oviduct
Ovary
Uterus
Cervix
Vagina
Figure 48-7
Side view
Vas deferens
Urinary
bladder
Seminal vesicle
Ejaculatory duct
Prostate gland
Bulbourethral gland
Urethra
Epididymis
Erectile
tissue of
penis
Testis
Scrotum
Prepuce
(foreskin)
Vas deferens
Front view
Urinary bladder
Seminal vesicle
Prostate gland
Bulbourethral gland
Urethra
Erectile tissue of penis
Vas deferens
Epididymis
Testis
Scrotum
Figure 48-7-Table 48-1
Gametogenesis in Males
 Spermatogenesis-begins at puberty and ends at
death. Spermatogonia divide mitotically to make
primary spermatocytes, which go through meiosis.
 Cells produced by Meiosis I are called secondary
spermatocytes. Cells produced by meiosis II are
called spermatids.
 Sertoli cells in the seminiferous tubules nourish the
spermatids as they mature. They finish maturing into
sperm in the epididymis where they’re stored until
used.
 Sperm contain a head region, containing the nucleus
and acrosome (with enzymes), the midpiece,
containing mitochondria to power the tail, and the tail
Figure 48-3
Oogenesis
Spermatogenesis
Spermatogonium (2n)
(May divide by mitosis to
form more spermatogonia)
Mitosis and
differentiation
Oogonium (2n)
Mitosis and
differentiation
Primary spermatocyte (2n)
Primary oocyte (2n)
Meiosis I
Meiosis I
Secondary oocyte 
polar body (n)
Secondary
spermatocyte (n)
Meiosis II
Meiosis II
Spermatids (n)
Mature sperm
cells (n)
Ootid  polar body (n)
Mature egg cell (ovum) (n)
Figure 22-2
Acrosome
Head
Neck
Midpiece
Nucleus
Centriole
Plasma
membrane
Vacuole
(not present
in all sperm)
Tail
Mitochondria
Flagellum
Gametogenesis in Females





Oogenesis-begins during embryonic development with
oogonia that divide mitotically to make primary oocytes.
Primary oocytes will undergo meiosis, however the timing is
different than that of the male. Before birth, these proceed
only to Prophase I until the female hits puberty.
At puberty, once per month, 1 primary oocyte will proceed
through meiosis I within a group of cells called a follicle,
that nourishes and protects the cell.
At the end of Mieosis I, cytoplasmic division is uneven,
resulting in 1 secondary oocyte and 1 polar body. This
polar body may go through meiosis II, but eventually
disintegrates and is not used.
The secondary oocyte is what is “ovulated” when the folicle
breaks open on the wall of the ovary If it is fertilized as it
proceeds down the fallopian tube, it undergoes Meiosis II,
but again, cytoplasmic division is uneven so only one
mature ovum is produced
Hormonal Control of Reproduction




The female reproductive cycle is characterized by 2 separate cycles, since
the body needs to prepare both the egg and the uterus for implantation
The hypothalamus releases gonadotropin releasing hormone (GnRH),
because of low levels of estrogen and progesterone in the blood, which
stiumlates the anterior pitutary to release follicle stimulating hormone
(FSH) and luteinizing hormone (LH)
The ovarian cycle

The follicular phase-development of the egg and estrogen secretion
from the follicle

Ovulation-midcycle release of the egg b/c of positive feedback from the
quick release of LH

Luteal phase-secretion of estrogen and progesterone from the corpus
luteum after ovulation and the corpus luteum thickens
The menstrual cycle

Endometrium thickens as a result of the estrogen and progesterone
from the luteal phase

High levels of estrogen and progesterone cause negative feedback of
the hypothalamus and anterior pituitary which stops producing FSH
and LH

The endometrium disintegrates, causing the flow phase(menstrual
cycle)

If an embryo were to have implanted, it would secrete human chorionic
gonadotropin (HCG), which would sustain the corpus luteum, which
would continue to secrete estrogen and progesterone (pregnancy tests
detect HCG). Later, the placenta would produce progesterone.
Figure 48-12
5. Degeneration of
corpus luteum
Secondary oocyte
to oviduct
4. Ovulation
Oocytes
Follicle
cells
3. Maturation of
follicle
1. Formation of primary
oocytes within follicles
2. Follicle growth
Figure 48-13
FOLLICULAR PHASE
Follicle growth
LUTEAL PHASE
Ovulation
Corpus luteum degeneration
Pituitary
hormone
cycle
Progesterone
Estradiol
Hormone levels
Ovarian
hormone
cycle
Hormone levels
Ovarian
cycle
LH
Menstrual
(uterine)
cycle
Thickness of
uterine lining
FSH
Menstruation
0
7
14
Days
21
28
Figure 48-14
FOLLICULAR PHASE
LUTEAL PHASE
Ovulation
Follicle growth
Corpus luteum degeneration
Progesterone
Follicles and
corpus luteum
secrete
hormones
Estradiol
Negative
feedback
on LH
Positive
feedback
on LH
Negative
feedback
on LH,
FSH
Ovarian hormones and
pituitary hormones exert
feedback on each other
Hormones in the male cycle
 The same hormones that regulate the
female cycle also regulate the male.
 Again, as the hypothalamus releases GnRH,
the anterior pituitary releases FSH and LH
(which stimulates the interstitial cells in
males, so it’s called ICSH in males)
 Interstitial cells release testosterone and
other androgens, which cause the Sertoli
cells to nourish the sperm cells. Hormone
and gamete production are relatively stable
throughout the cycle
Development
 In some animals, there’s
metamorphosis (insects have
complete or incomplete), amphibians
have a different form where they reappropriate the energy and cells from
a tail to the legs
 In humans, development continues
from fertilization until birth, and the
infant resembles the adult
Fertilization
 Occurs when the sperm penetrates the plasma
membrane of the secondary oocyte.
 Recognition-sperm secretes a protein that binds with
receptor molecules in the zona pellucida (surrounding
the plasma membrane of the oocyte)
 Penetration-the plasma membrane of the gametes
fuse so that the sperm nucleus can enter the oocyte
 A fertilization membrane forms-blocking any other
sperm from entering the oocyte
 The secondary oocyte completes meiosis II-the polar
body is discharged
 Nuclear fusion/replication-the gamete nuclei fuse
resulting in a diploid zygote nucleus
Figure 22-1
Haploid (n)
Diploid (2n)
FERTILIZATION
CLEAVAGE
Sperm
Blastula
Fertilized
egg
Egg
Adult
Gastrula
Newborn
Second trimester
First trimester
Early first trimester
Figure 22-9
Day 0
Fertilization
Day 1
Day 2
Day 3
Blastocyst
Day 4
Day 5
Fallopian tube
Inner
cell
mass
Day 6
Ovulation
Uterus
Ovary
Precursor
to placenta
Trophoblast
Days 7–10: Implantation in
uterine wall
Figure 22-7
A WAVE OF Ca2+ SPREADS FROM THE SITE OF SPERM ENTRY.
Sperm enters
egg here
Ca2+
Ca2+
A wave of
calcium ions
starts at the
point of sperm
entry and
propagates
across the egg
THE FERTILIZATION ENVELOPE LIFTS AND BLOCKS EXCESS SPERM.
Sperm enters
egg here
Fertilization
envelope
Excess
sperm
1. Egg is covered with sperm.
2. Fertilization envelope
3. Fertilization envelope expands
One sperm enters.
begins to lift and clear away
excess sperm.
across egg. When complete, all
excess sperm are cleared away.
Cleavage
 This is where the zygote begins to divide mitotically,
rapidly, dividing up the cytoplasm from the zygote
amongst the daughter cells
 Polarity-the egg has an upper animal pole and a
lower vegetal pole. Cells at the vegetal pole form the
yolk
 Cleavage type-early cleavages are polar, dividing the
egg into segments (like and orange). Later, the
cleavages become parallel with the equator
(equatorial cleavage)
 Recall that protostomes exhibit spiral
cleavage(determinate), while deuterostomes exhibit
radial cleavage (indeterminate)
 Indeterminate cleavage happens when a cell is
formed that can complete its normal development if
separated from the embryo
 Determinate cleavage happens when a cell is formed
that cannot complete development on its own, but is
instead a part of a developing tissue
Figure 22-8-1
Radial cleavage: Cells divide at right angles to each other.
Spiral cleavage: Cells divide at oblique angles to each other.
Development continues. . .
 As cleavage continues, a solid ball of
cells called a morula is formed.
 After the morula phase, as cells
continue to divide, the result is a
hollow ball of cells called a blastula
 Gastrulation follows (we’ve discussed
this), forming the germ layers,
archenteron (primordial gut) and
blastopore
Organogenesis
 Recall that the 3 tissue layers give rise to distinct
organs and organ systems
 The Notochord in chordates forms along the dorsal
surface of the mesoderm. If the chordate is a
vertebrate, the vertebrae will form from nearby cells
in the mesoderm
 The Neural tube forms in the ectoderm layer above
the notochord from a layer of cells called the neural
plate. The plate indents, forming the neural groove,
which rolls up into the neural tube, which will develop
into the CNS. Some cells roll off the top of the neural
tube to form the neural crest, which will form many of
the components of the head (teeth, bones, muscles,
pigment cell of the skin, nerves)
Figure 22-10
Ectoderm-derived
Nervous system
Cornea and lens of eye
Epidermis of skin
Epithelial lining of mouth
and rectum
Mesoderm-derived
Skeletal system
Circulatory system
Lymphatic system
Muscular system
Excretory system
Reproductive system
Dermis of skin
Lining of body cavity
Endoderm-derived
Epithelial lining of:
digestive tract
respiratory tract
reproductive tract
urinary tract
Liver
Pancreas
Thyroid
Parathyroids
Thymus
Figure 22-13
FORMATION OF NEURAL TUBE
Dorsal
Notochord
Signaling
molecules
Neural tube
Start of gut
Ectoderm
Mesoderm
Endoderm
Ventral
1. Notochord forms
2. Signals from cells in and
3. Formation of neural
from mesoderm cells
soon after gastrulation
is complete.
near the notochord induce
inward folding of the ectoderm.
tube is complete. Cells of
notochord are fated to die.
Extraembryonic membrane
development (Amniotes)
 These develop outside of the embryo in birds, reptiles,
and humans
 Chorion-outer membrane that in egg-layers is for gas
exchange. This implants into the endometrium and
later forms the placenta in humans
 Allantois-this is a sac that buds from the archenteron.
It encircles the embryo forming a layer below the
chorion. In birds and reptiles, it stores wastes, and
then fuses with the chorion for gas exchange. In
mammals, this transports waste to the placenta, and
finally forms the umbilical cord
 Amnion-encloses the amniotic cavity (fluid-filled) to
cushion and protect the embryo
 Yolk sac-in birds and reptiles, this is a food store for
the embryo. In the placentals, the sac is empty b/c
the embryo gets nourishment through the placenta
Variations on embryonic
development




The stages described are general deuterostome stages. There are
some specific differences between organisms.
Frogs
 Gray crescent forms b/c of the reorganization of the cytoplasm of
the zygote’s cells
 During gastrulation, a dorsal lip is formed when cells migrate over
the top edge of the blastopore, over a region that was formerly the
gray crescent
 Yolk material is more extensive
Birds
 Blastodisc-cleavage in the blastula forms a flattened disc-shaped
region that sits on top of the yolk
 Primitive streak-the blastopore is line-shaped, rather than round
Humans
 Blastocyst consists of 2 parts, the trophoblast and embryonic disc
 Trophoblast-outer ring of cells that is embedded in the
endometrium and that produces the HCG, which maintains the
corpus luteum. This later forms the chorion and placenta
 Embryonic disc- is the inner cell mass (ICM) within the cavity
formed by the trophoblast. This is like the blastodisc of birds, and
forms a primitive streak
Factors Influencing Development
 What causes cells to differentiate along different
lines?
 Egg cytoplasm-unequal distribution forms polar bodies
and oocytes, it also forms the gray crescent in frogs,
and causes poles in embryos
 Embryonic induction-occurs where one cell group
influences the development of its neighboring cells
(these are called organizers) Ex: notochord cells,
dorsal lip cells
 Homeotic (Hox) genes-These turn on and off genes
that affect development. Recall that these tell the
embryo where each segment of the body is