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361 Cards in this Set

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  • Back
What nerves are responsible for light touch, touch, vibration/pressure, and temperature?
Light touch: Meissner's corpuscles
Touch: Merkle's corpuscles
Vibration/pressure: Pacinian corpuscles
Temperature: Ruffini corpuscles
What is the New Head Hypothesis?Early radiations of vertebrates was about predators
Early readiations of veretebrates was about predators to find prey or escape ~ neural crest cells primitive chordates developed into noses, eyes, ears, and tongues
What is responsible for the color and brightness of light?
Color: wavelength
Brightness: amplitude
Describe the evolution of complex eyes.
Evolved from pigmented cells that changed as a result of photons hitting them; the eye is mostly an outgrowth of the forebrain - a little stalk sticking out from the diencephalon, interacting with thickened tissue on the ectoderm called placode (ectoderm that organizes signaling); the lens placode stimulates the optic stlak to form multiple layers, which curl around; the remaining lens placode forms the lens; evolved more than once (evolved differently in gastropods and humans)
What are the 3 layers of the 3-layered capsule?
Sclera ("hard"), choroid (vessels), and retina
What layer of hte capsule is the iris a part of?
Pigmented choroid
What are the stages of object perception by the eye?
1. Focusing by the cornea (aqueous humor in the cornea has a refractive index that is different from water and influences the convexity of the cornea)
2. Focusing by the lens
3. Photoreception
What drainsk the aqueous humor?
Canals of Schlemm
Describe how the lens focuses on near objects and far objects.
Near: Contraction of ciliary muscles relaxes zonules, permitting focus on near objects

Far: Relaxation of ciliary muscles allows zonules to tense lens, flatting it for focus on far objects
Describe the lens.
5 mm thick; 9 mm diameter; naturally convex; thousands of layers of flexible transparent protein (crystallin)
What is the lens suspended by?
1000s of filaments, called zonules, that attach to ciliar muslces; muscle contractions slacken the zonules
What happens to the lens as we age?
Lens mineralizes (stiffens) so relaxation of zonules fails to allow lens to regain convexity
What is another name for nearsighted and what is another name for farsighted?
Nearsighted = myopic
Farsighted = hyperopic
How are objects focused in nearsightedness and farsightedness?
Nearsightedness - objects are focused before the retina

Farsightedness - objects are focused behind the retina
How can diet influence myopi?
High starch causes high insulin, which causes high IGF1 and the sclera is sensitive to IGF1 when growing, causing long eyeballs ~ nearsightedness
Describe the order of cells in photoreception.
Rods/cones to bipolar to ganglion cells; horizontal cells are between rods/cones and bipolar cels; amacrine cells are between bipolar cells and ganglion cells
Are there more rod or cone inputs to biplar cells?
6-600 rod cell inputs; single cone cell input

120 million rods pre eye; 6 million cones per eye
What are the pigments in rods and cones?
Rods: rhodopsin
Cones: opsin
Describe the acuity, sensitivity and color perception in rods and cones
Rods: low acuity/high sensitivity; little color perception

Bones: high acuity/low sensitivity; color perception
Where are the rods and cones located?
ROd=s are distributed all over the retina; cones are mostly in macula (derived feature of monkeys), especially in fovea (small pit in center of macula w/o vessels)
What opsins do humans have?
Red, green, and blue
How many opsins do most mammals have?
2
What did trichromatic vision and macula and fovea evolve?
Trichromatic vision useful for selecting ripe fruits and tender leaves; macula and fovea useful for seeing detail and rich color
What is steroscopy?
Ability to perceive depth
What are monocular cues for steroscopy?
Relative size (more distant things are smaller), clarity (more distant things are fuzzier), parallax (more distant objects appear to move less when we change position)
What is true stereoscopy?
Binocular vision; eyes form about a 70-80 degree angle (80 in humans) with the midline of the head, providing narraower range but more stereoscopy
In most mammlals, sclera is pigmented like the iris; why is the sclera visible in humans?
You can tell where people are looking
How many taste buds do humans have?
10,000
What are buds?
Groups of cells, arranged like orange segments around a central pore
What are the 3 steps of taste?
1. Food particles dissolve in liquid (salive, ingested)
2. Enter pore
3. Bind to receptor, causing depolarization
Is there a "tongue map"
No, contrary to common belief
What percent of flavor is from smell?
80%
What is the MW of odorants?
<300
What are the steps of olfaction?
1. Odorant dissolves in mucous
2. Binds to recpeotr on olfactory nerve dendrie
3. Action potentials travel to synapse in olfacotry bulb (glomerulus 10-100 neurons)
4. About 12-36 glomeruli synapse per mitral cell
5. Olfactory nerve carries stimulus to various parts of the brain
Draw the anatomic feature associated with olfaction.
(In lecture 24: cilia of olfactory receptor neurons in mucosa on olfactory epithelium; axons of the neruons pass through cribiform bone, past olfactory nerve filaments, and form glomeruli in olfactory bulb; mitral cell synapse on glomeruli and lead to olfactory tract
What is are words for good smeller and bad smeller.
Good smeller: macrosmat
Bad smeller: microsmat
What are 3 reasons humans are poor smellers?
1. Relatively small olfactory bulbs (30% volume relative to brain size)
2. Fewer olfactory neurons (humans have 5-10 million whereas rodents have 15-20 million and dogs have about 200 million)
3. Fewer functioning olfactory receptors (humans have 300 functional OR genes out of 1000, rordents have 1000 functional OR genes out of 1300 and chimps have 500 functional OR genes out of 1000); each olfactory nerve has one gene coding for its receptor
Are humans good at perceiving odorants when we try?
Yes
Why is the human nose especially turbulent?
Air has to go through a right angle, causing turbulence, so a lot of contact with olfactory receptors
What are the two pathways for odorants in humans?
1. Orthonasal (10% of air hits olfactory epithelium coming in)
2. Retronasal (odorants come back from mouth)
Where is much of flavor perception?
Neocortex
What is sound?
Pressurized wave of molecules (usually air)
Describe the 3 stages of hearing in humans.
Stage 1: Outer ear
1. Sound is reflected by earlobe (pinna) into ear canal
2. Sound is amplified/filtered in ear canal (resonator) - longer tubes amplify lower frequencies, narrow tubes filter lower frequencies
3. Sounds cause vibrations of tympanic membrane

Stage 2: Middle ear
4. Ear ossicles (malleus, incus, stapes) amplify sound amplification
5. Movements of ossicles vibrate oval window of inner ear

Stage 3a: Inner ear (liquid)
6. Vibrations pass up cochlea
7. Vibrations of basilar membrane within the cochlea displaces hair cells in the Organ of Corti

Stage 3b: Organ of Corti
8. Organ of Corti hair cells end in sterocilia which touch stationary tectorial membrane. Bent by vibrations.
9. Vibratoins open K+ channels which depolarize cell, opening voltage-gated Ca2+ channels that trigger neurotransmitter (glutamate) release to cochlear nerve
How do the ear ossicles amplify sound and why is this amplification important?
Incus and sapes form bent lever amlifier (moment arm) with 10-20 times amplification; important because inner ear is filled with fluid, so it requires more energy to propagate waves
Describe the cochlea.
Spiral-shaped tube of bone with 3 "tubes" (scala tympani, cala vestibuli, and chochlear duct); vibrations go up the scala tympani and down the scala vestibuli; lower frequencies travel farther; vibrations in scala tympani cause vibrations of basilar membrane that separates the central cochlear duct
Draw the parts of the cochlea.
Lecture 24
What regulates the frequency and amplitude of sound?
Frequency: Which hair cells are activated (distal = lower)

Amplitude: Rate at which given hair cell vibrates
Give the hertz for human year, best perception, human speech, elephant hearing, and mouse hearing.
Human hearing: 20-17000
Best perception: 2000--4000
Human speech: 100-7000
Elephant: 1-21000
Mouse: 100-91000
How is sound localized?
Interaural level difference; interaural timing difference
BEsides hearing, what else are the hair cells in the ear used for?
Vestibular system (balance)
Do humans have positive or negative allometry for tooth size compared to body size?
Negative allometry - we have very small teeth for our body size
Besides small teeth/body size, what is another human peculiarity of eating?
High risk of choking (4thl eading cause of accidental death)
Why is human diet odd?
We eat soft, tender, and highly processed food; we don't even actually need to chew our food; we are biologically constrained to eating cooked and processed food
How do our eating tendencies compare with chimps and hunter/gatherers?
We spend about 1% of our time feeding, whereas hunters/gatherers spend 5% and chimps spend 50%; we eat less ripe fruit fibrous plants, more meat and insects than chimps, and much more refined sugars and carbs
What does chewing do to the surface area/volume ratio?
Increases it
Do humans get a higher or lower metabolic rate becuase we chew our food.
HIgher; similar to the way snakes get more metabolic energy from a ground up rat because there is more SA for enzymes to act on)
List the number of the different types of teeth per quadrant in babies and adults.
Baby (deciduous): 2 incisors, 1 canine, 2 molars
Permanent: 2 incisors, 1 canine, 2 premolars, 3 molars
Describ ethe 3 dental tissues
1. Enamel crown: 99% mineral; very hard and stiff
2. Dentine root: 60% mineral; like bone
3. Cementum (covers root): 60% mineral; holds tooth into gum
Describe the evolution of teeth.
First teeth were cone-shaped enamel cusps on an enamel shelf; early synapsides (reptiles that mammals evolved from) evolved serial arrays of cusps; the earliest species of mammal-like reptiles were triconodonts, which had a reptile-like row of teeth; docodonts had cusps folded into triangles; marsupials and placentals have trisophenic molars, that evolved by adding oan extra basin to the tooth
What is beneficial about tribsophenic molars?
Have both cutting edges and grinding basins
What aspect of mastication was a key factor in the mammalian radiation?
Tribosphenic molar, becuase could eat wide ragne of foods and more efficient mastication (higher BMRs)
What are 6 other features unique to mammalian teeth?
1. Dentition = 2 sets of teeth (deciduous and permanent)
2. Precise, complex occlusion (with vertical and sideways movements)
3. Complex chewing muscles
4. PLaint, muscular cheeks
5. Large, complex, muscle tongue
6. Prolonged preparation of food in oral cavity; formation of a bolus
What is stiffness?
Stress/Strain; slope on curve of stress vs. strain
What is strength?
Energy tofracture of matieral
What is toughness (R) in terms of the stress/strain graph for teeth?
Area under curve divided by thickness of food
What is the formula for "stuff"ness?
(R/E)^0.5 = (toughness/stiffness)^0.5
What foods have low "stuff"ness and how does mastication deal with them?
Stiff foods ~ stress limited; cusps for fracturing
What foods have high "stuff"ness and how does mastication deal with them?
Tough foods ~ displacement limited; crests and cones for slicing, shearing, and piercing
What type of mastication do premolars and molars do?
Fracturing/grinding and shearing
What type of mastication do incisors and canines do?
Slicing/tearing and piercing
What are the four major jaw elevators (adductors)
- Temporalis on front choronoid process
- Lateral pterygoid on back choronoid process
- Masseter at outer base of jaw
- Medial pterygoid on inner base of jaw (mirrors masseter on the inside)
What muscles depress the mandible (abduction)?
Digastric and infrahyoid muscles; attached to the hyoid bone at the base of the tongue
Where does the jaw movement occur?
Temporomandibular joint (TMJ)
How does jaw movement occur at the TMJ?
Lateral pterygoid pulls the articular disc
What are the three opposing types of movements at the TMJ?
- Abduction/adduction
- Anterior translation (protraction) vs. Posterior translation (retraction)
- Lateral rotation (teeth away from midline) vs. medial rotation (teeth towards the midline)
Describe the two phases of incision.
1. Opening phase (mandible is depressed (abducted) by jaw depressors and simultaneously translated forward by lateral pterygoid to make incisors meet up)
2. Closing phase (mandible elevated (adducted) by jaw adductors; remains anteriorly translated by lateral pterygoid)
What is mastication?
Grinding, fracturing, etc...not incision
Why do mammals masticate on one side at a time?
Use much force on one area to increase stress
Why does mastication require very precise movements?
To make the cusps of hte lower teeth precisely fit the basins between cusps of upper teeth and vice versa
Describe the two phases of mastication.
1. Opening stroke (abduct mandible; anteriorly translate both TMJs)
2. Closing stroke
A. Fast close (adduct mandible at both TMJs; position working side lower teeth just lateral to uppers by laterally rotatin gand retracting WS condyl at TMJ)
B. Slow close/occlusion (adduct and medially rotate mandible by retracting and rotating BS condyle, pulling teeth up and into centric occlusion under high force
What are timing differences necessary between the EMG signals of jaw muscles on the working vs. the balancing side?
Necessary for precise and forceful occlusion
What is one reason humans don't have a snout?
We have smaller teeth
What are the implications of not having a snout (write out the equations for torque, etc.)?
Gives our chewing muscles higher efficiency.

Torque = F * moment arm
Fmasseter * rmasseter = Fbite * rbite
Humans have a higher ratio of rmasseter to rbite, so Fbit is less as Fmass is the same for both species

Efficiency of torque generation rmasseter: rbite, and the ratio is higher in humans
Despite lower mechanical advantage, why is bite force much greater in chimps than humans?
Chimps have more fas-rich muscle fibers
How does soft diet affect the strain on our bones?
Causes lower strain; strain helps bones grow (and the jaw has high strain)
What are wisdom teeth?
3rd molars
Why can't wisdom teeth fit as well in the jaws of contemporary human beings?
Insufficient manidibular and maxillary growth due to less strain
Describe the differences in oral cavities of humans and chimps.
Humans have a short rather than a long oral cavity; a short round tonuge, rather than a long, rectangular tongue, low hyoid and larynx rather than a high hyoid and larynx, and the epiglottis and soft palate are separate rather than overlapped
What is it helpful for humans to have equally long horizontal and vertical proportions of their vocal tract?
Give us very distinct, clear vowels
Describe the steps of swallowing.
Stage I: Voluntary
1. Tongue pushes bolus to back of oral cavity
2. Muscles that attach to hyoid elevate hyoid
3. Tongue pushesbolus into oropharynx
Stage 2: Involuntary
4. Soft palate elevated to seal off nasal cavity
5. Hyoid pulled forward to poen entrance to esophagus
6. Epiglottis pushed down by tongue
Stage 3: Involuntary
7. Trachea closed by closing vocal cods
8. Epiglottis flips down
9. Muscles surrounding oropharynx squeeze bolus towards esophagus
Stage 4: Involuntary
10. Muscles squeeze bolus into esophagus
What is the buccal cavity?
Mouth/place where food is ingested
What is the alimentary canal?
Digestive tract after the pharynx
What are the four main processes carried out by the GI tract?
DIgestion, secretion, absorption, and motility
Describe the hepatic portal vein.
Veinous return goes leaves stomach and intenstines and passes through liver before going to the heart; another portal system in the hypothalamus
What is "specific dynamic action" or "heat increment" of feeding.
Increase in metabolic rate that occurs after feeding; in humans, this increase is typically about 10-20%, whereas in other animals 200+%
The "thermic effect" of food accounts for about what percent of our total energy expenditure per day?
10%
In snakes, what part of hte body has the largest post-prandial increase?
Intestinal mucosa
What are the five digestive processes the liver is involved in?
Deamination, ketogenesis, glycogeneiss, urea production, protein catabolism
What organs have the higehst metabolic rate/mass?
Kidney, liver, and stomach
What cell type is the digestive system mostly derived from?
Endoderm
What are the three parts of a salivary gland?
Mucous cells; serous cells (secrete amylase); duct (squirts saliva into mouth)
What is the omentum?
Major fat store
What is chyme?
The mixture of small food fragments and HCL leaving the stomach
What does the body of the stomach secrete?
Mucus, pepsinogen, and HCL
What does the antrum of the stomach secrete?
Mucus, pepsinogen, and gastrin
What do HCl and pepsinogen do in the stomach?
HCL breaks down connective tissue; HCL also activates pepsinogen to form pepsins, which are protein-digesting enzymes
What are gastric pits?
Open into narrow tubes which are lined with cells that secrete enzymes and acid
What do chief cells do?
Secrete pepsinogen.
What do parietal cells do?
Parietal cells synthesize and secrete the HCL responsible for acidic pH in the gastric lumen
Describe the digestive system's interaction with the nervous system.
Vagus nerves activate parasympathetic system ~ produce HCl; in gastric phase, stomach swell further ~ increased secretion fo HCl and pepsinogen; when chem in duodenum, sends feedback to brain which decreases HCl
What are the 3 major parts of the small intestine?
Duodenum, jejunum, and ileum
What do the gallbladdedr adn pancrease empty into the small intestine?
bile, bicarbonate (neutralizes stomach HCl) and trypsin
Does the large intestine have villi and microvilli?
No, only the small intestine
What does bile do?
Contains salts that aid in fat breakdown and absorption; fats broken down into fat globules, which bile salts attach to; bile also contains bicarbonate, which neutralizes stomach HCl
Describe the processing of vile.
Bile is made by hepatocytes and flows into the bile canaliculi and then into teh bile ducts
Describe the flow of bile through the liver.
Blood flows from the hepatic portal arteries along the hepatocytes and into the central vein
What does the gallbladder do?
Stores bile made in the liver; absorbs salts and water to concentrate bile, contracts to release bile into duodenum
What does the pancrease do?
Secretes enzymes that break down fats, carbohydrates, and proteins; secretes lipase (cleaves long chain fatty acids), trypsin (protein breakdown), and bicarbonate ions (which neutralize HCl from the stomach)
What is the haustra?
Wall of colon forms a series of pouches; haustra permit expansion and elongation of the colon
What is the crop and gizzard?
Crop: expanded area of esophagus that stores food temporarily and moistens it

Gizzard: derived from the stomach, and grinds up food often using stones (called gastroliths) swallowed to provide an internal hard grinding surface
How does cow process food in its stomach?
Swallowed food accumulates in teh rumen and is regurgitated and chewed again, then is swallowed and passes through the remaining 3 chambers. Bacterial fermentation occurs in the reticulum.
What are animals called whose internal conditions change when the environment changes?
Osmoconformers as opposed to osmoregulators
What are the disadvantages of osmoregulation?
Energetically costly, depending on how different the animal's internal osmolarity is from teh environment, how permeable the animal's surfaces are to water and ion movement, and how costly it is to pump ions across membrane.
What four things are regulated by the kidneys?
- Blood volume and blood pressure
- Plasma ion concentrations
- Blood pH
- Valuable nutrients (such as glucose)
What animals have a concentrated plasma (high osmolarity)?
Sharks
Which kidney is higher?
Left
What is the position of the kidney maintained by?
Overlying peritoneum, contact with adjacent visceral organs, and supporting connective tissues
What does it mean that the kidneys areretroperitoneal?
They are located behind the peritoneum, outside oft he body cavity proper
Where do nephrons drain into?
Renal pelvis
What is the osmolarity of the adrenal cortex and medulla?
Cortex: 300 mOsm
Medulla: 1,200 mOsm
How does blood get from the capillary into the capsule?
Net pressure forces blood from capillary into capsule
How can a urine test check damage to capsules?
Little protein usually gest out of capillary into capsule, so urine test can check amount of protein that got through
What are the cells called that surround the capillary?
Podocytes
What are the forces favoring and opposing formation of the glomerular filtrate?
Favoritng: Glomerular capillary blood pressure (PGC = 60 mmHg)
Opposing: Fluid pressure in Bowman's space (PBS = 15 mmHg) and osmotic force due to protein in plasma (pieGC = 29 mmHg)
Net glomerular filtration pressure = 16
How does the vasa recta keep the concentration gradient?
Counter-current flow
What part of the nephron is impermeable to water?
Ascending limb
Why does the cortex have the same osmolarity as blood plasma?
Because both solutes and water are being lost
What are cells lining the cllecting duct sensitive to?
ADH (vasopressin), which increases channel's permeability to water
What are the two countercurrent systems in the kidney?
Descending & ascending tube in nephron; blood supply to system
What does the countercurrent multiplier system do?
Magnifies concentration of plasma filtrate coming in (compared with outgoing filtrate)
What leaves and enters the proximal tubule?
Leaves: HCO3-, NaCl, water, K+
Enters: H+, NH3
What leaves and enters the distal tubule?
Leaves: NaCl, water, HCO3-
Enters: K+, H+
What leaves the descending limb o the loop of Henle?
water
What leaves the ascending limb of hte loop of Henle?
NaCl
What is the purpose of the urea and water leaving the collecting duct?
Contributes to the concentration gradient
What percent of water, sodium, glucose, and urea is reabsorbed?
Water, sodium, and glucose: nearly 100%

Urea: 44%
WHat is the plasma volume and how many times is it filtered per day?
3L; filtered about 60 times per day
What does the ADH/vasopressing do to the kidney?
Makes distal tubules and collecting ducts permeable to water. Secreted by hypothalamus. Critical for allowing urine concentration; critical for monitoring urine concentration; more permeable ducts = more concentrated urine
What does aldosterone do to the kidney?
Secreted by the adrenal cortex and stimulates Na+ absorption by the distal tubules and collecting ducts; also stimulates K+ secretion
What does low blood Ca2+ do to the kidney?
Stimulates parathyroid hormone which increases tubular Ca2+ resorption in the proximal tubule
What does a large renal corpusle (Bowman's capsule) mean?
More water in raw filtrate
What do thick intermediate segments indicate in the nephrone?
Indicate that many cilia are present to drive filtrate through teh tubule, which means less water will be reabsorbed
What animals have extreme urine osmolarity?
Marine bony fish have concentrated urine; freshwater fish have copiuos dilute urine
What type of animals lack a glomerulus?
Saltwater fish
Why can't birds make a very concentrated urine?
Their loops are fairly short
How do birds get rid of excess salt?
Birds use nasal glands that release salt excretions into the nasal passages
How do sea turtles get rid of salt?
Sea turtles have modified tear ducts that secrete salt out around the eye
Where is the head source for ectotherms?
Outisde
What type of animals are ectotherms?
Fishes, amphibians, reptiles, and dinosaurs; (birds and mammals are endotherms)
What limits the head gradient with the environment in aquatic animals?
Gills/cutaneous respiration and blubber
What is the difference between head and temperature?
Heat is energy; temperature is the measure of heat
What is the value of one calorie?
Energy to heat 1 ml water 1 degree Celcius
What is the formula for the value of heat flow by conduction?
kA (Tb - Tenvironment) / L

k = thermal conductivity
A = surface area
Tb-Tenviron = temperature gradient
L = thickness
Is the temperature gradient positive or negative in hot environments?
Negative (Tb < Tair)
At what core temperature are the bodies of most mammals regulated?
37 degrees Celcius
What do monotremes (egg-laying mammals) regulate their body temperature at?
30-32 degrees Celcius
What do birds regulate their body temperature at?
39-40 degrees Celcius
Why do most mammas and birds regulate Tb around 37-39 degrees Celsius?
Globally, external temperatures are not usually greater than 37 degrees Celcius, so Tb < Tair and heat flows in; It's easier to generate heat to maintain a certain body temperature than to dissipate heat; you always have an avenue to lose heat; if regulate at too low of a temperature, too much heat comes in
Are metabolism, conduction, convention, radiation, and evaporation sources of heat loss or heat gain?
Metabolism: heat gain
Conduction: heat gain or heat loss
Convection: accelerates rate of heat gain or heat loss
Radiation: most often heat gain
Evaporation: nearly always heat loss
What is another way of thinking of convection?
Wind chill
Why is water a good vehicle to release heat?
It hast high heat capacity and conductance, with 580 cal/ml of water
What is the heat balance equation for constant Tb?
0 = + Hmetabolism +/- Hconduction & convection +/- Hradiation - Hevaporation
What is the formula for Hconduction & convection?
Hconduction & convection = kA (Tb-Tenvironment) / L
Why is clothing an effective insulation?
Traps air between layers; air has low conductivity and a relatively high insulation
List in order of increasing conductivity (and decreasing relative insulation).
Lowest: Air
Fat
Fur
Highest: Water
.Define homeostasis in terms of temperature
Regulation of a constant Tb
What responds to changes in blood flow temperature?
'Thermosensory' neurons in the hypothalamus
What happens if Thypothalamus < Tset
Hypothalamus stimulates heat production (shivering & activity) and reduces heat loss (peripheral vasoconstriction)
What happens if Thypothalamus > Tset?
Hypothalamus stimulates heat loss (sweating & vasodilation), and reduces heat gain (reduced metabolism)
Describe the evolution of goosebumps.
Goosebumps are from remnants of hair, which animasl raise to increase insulation
Describe the graph for metabolic rate vs. ambient temperature for endotherms.
Decreases from 10 to 20 degrees Celsius; constant in termoneutral zone from 20-42 degrees Celcius; increases above 42 degrees Celsius, quickly leading to death

20 degrees is the lower critical temperature; 42 degrees is the upper critical temperature
What is the slope of the graph for metabolic rate vs. ambient temperature.
Slope = conductance, because Hmetabolism = C (Tb-Ta) ~ C = Hmetabolism/(Tb-Ta)
What is the formula for Hmetabolism?
Hmetabolism = C (Tb-Ta)
How is the graph of metabolic rate vs. ambient temperature changed with larger size/increased insulation?
Decreased LCT, so downward slope is less ~ lower conductance
How does body size affect conductance?
Larger size = Decreased SA/V ~ decreased conductance
Why do children have to change their metabolic rate more rapidly?
They have a higher SA/V ratio and therefore a higher LCT
What are 2 key physiological adjustments of temperature regulation?
1. Acclimitization: physiological adjustment to long-term seasonal or geographical climate change
2. Fever: physiological resetting of hypothalamus 'thermostat' via release of prostaglandins within hypothalamus
What causes the release of the prostaglandins within the hypothalamus that lead to fever.
Endogenous pyrogens (IIL-1 and IL-6), which are released by macrophages and other cells associated with infection/inflammation
How does aspirin reduce fever?
Blocks action of prostaglandins that affect Tset
Fever is a regulated state of what?
Hypothermia
What are four aspects of heat acclimatization?
1. Improved cutaneous blood flow
2. Lowered threshold for sweating
3. Increased sweat output
4. Reduced salt concentration of sweat (defends against electrolyte loss)
Describe how the various elements of the Heat Balance Equation change.
Hmetabolism: change in activity
Hconduction & convection: change in insulation & movements in environment
Hradiation: Movement in environment
Hevaporation = physiology (sweating, blood flow, and breathing)
What aspects of the Heat Balance Equation are used by endotherms for heat gain and which are used by ectotherms?
Endoteherms: Hmetabolism
Ectotherms: Hconduction & convection; Hradiation
How do dolphins retain body heat?
Use of countercurrent exchange to reduce heat loss via flippers (heated blood is trapped on the inside, while cooled blood returns on the outside)
What is one way that humans reduce heat loss?
Allowing exposed fingers and feet to cool, but at the risk of frostbite
Describe how wading birds retain body heat.
Warm arteriole blood passes down leg, encountering cool veinous blood returning to the body, which traps heat inside the body; wade in cold water
Why does sweating work well on humans?
Highly effective evaporative heat loss; works well only with exposed skin, because convection facilitates evaporative heat loss); enhanced by upright bipedal posture
Why don't dogs sweat?
Have ability to lose substantial heat via nasal and oral evaporation as they have a larger surface area in nasal passages to cool air
How do ungulates, carnivores, and other animals living in hot environments or exercising keep Tbrain uniform?
Nasal evporative heat loss; counter-current heat exchange with cool venuous blood passing by and cooling warm arterial blood going to the brain (cooled before it gets to the brain); the cool venuous blood is also warmed up
Describe the 3 excretory skin gland types.
1. Eccrine sweat glands: independent of hair follicles; produce sweat (dilute, but NaCl loss)
2. Sebaceous glands: associated with hair follicles; secrete oils and fluids to keep skin and hair supple (contribute to body odors associated with sexual attraction/stimulation)
3. Apocrine gland: secrete oils and fluids contribute to body odor
Describe the evolutionary hair loss in humans (4 elements)?
- Sexual selection (mate attraction)
- Reduction of ectoparasites
- Increased heat loss (upright in warm environment)
- Hair loss co-evolved with the evolution of eccrine sweat glands in humans and presumably their hominid ancestors
Describe the two types of hair.
Vellus hair: "peach fuzz;" first hair produced in post-natal life; generally short, unpigmented, very fine; primarily covers the body in most individuals

Terminal hair: tends to be long,coarse, pigmented (retained on scalp, axilla, and groin areas)
How does hair density per unit ksin area change as body size increases.
Hair density per unit skin area decreases; larger primates have fewer hair follicles/area than smaller primates; humans fall on the same scaling regression line as other primates, having hair density nearly smilar to chimpanzees, gorillas, and orangutans
What is the difference between the way hair density is measured in humans vs. chimps?
Great apes and other mammals principally have terminal hair; humans principally have vellus hair
At what rate can water be lost due to sweating?
3L/hr
Describe the gender differences in sweating.
Women have higher threshold and sweat less than men for a comparable exercise, despite having more sweat glands/area than men; women & men have similar heat tolerance
What is the most important factor limiting evaporative heat loss via sweating?
Humidity; greater RH reduces evaporative heat loss
Why does huddling limit heat loss?
Reduces SA
What are the 3 major systems of integration?
Nervous system: point-to-point; sensory information, muscle control, and cognition

Endocrine system: broadcast from fixed source to dispersed targets; coordination of physiology, integration of physiology and behavior; regulation of gene expression

Immune system: Broadcast from mobile sources to mobile targets; detection of "non-self" indicators and coordination of mobile defenses; rapid clonal expansion
List the cells in the four quadrants of the immune diagram.
Soluble and innate/non-specific: complement, acute phase proteins, histamine, and cytokines

Soluble and acquired/adaptive/specific: antibodies

Cellular and innate/non-specific: macrophages, mast cells, polymorphonuclear cells

Cellular and acquired/adaptive/specific: B cells, T cells, and memory cells
What are the five types of leukocytes?
Monocytes, lymphocytes, polymorphonuclear granulocytes with an irregular nucleus (neutrophil, eonsinophil, and basophil)
Describe how blood cells are derived from pluripotent hematopoetic stem cells.
Pluripotent hematopoetic stem cell can become a lympoid stem call or a myeloid stem cell; lymphoid stem cells divided into B, T, and NK cells (20-40% of WBC count); myeloid stem cells can differentiate into erythrocytes, PMN (50-70% of WBC count), macrophages and dendritic cells, eonsinophils, mast cells, or megakaryocytes which become platlets
What are lymphocytes?
B cells, T cells, and NK cells
What is another name for PMN cells?
Neutrophils
WHat do neutrophils/PMN do?
Eat particles more likely to be foreign
What differentiate into macrophages and dendritic cells?
Monocytes
What do macrophages do?
Large phagocytes
What do dendritic cells do?
Have phagocytotic qualities, but primarily stimulate immune respon in spleen and lymph nodes
What do eosinophils do?
Release cationic acidic species (likely against megaparasites, such as intestinal worms)
What is another name for mast cells?
Basophil
What do mast cells/basophils do?
Release histamine, which influences vascular permeability
What are 5 aspects of innate immunity in the complement system?
1. Oposonization (invading bacteria are targeted)
2. Lysis of pathogens
3. Chemotaxisis
4. Inflammation
5. Cell activation
What does the disposal system of innate immunity do?
Clearance of immun ecomplexes and apoptotic cells
What are 4 aspects of adaptive immunity in the complement system?
1. Augmentation of antibody response
2. Promotion of T-cell response
3. Elimination of self-reactive B cells
4. Enhancement of immunologic memory
What is complement fixation?
The process of initiating hte complement cascade
Describe the complement cascade.
C3 breaks into C3b/C5 and C3a; C3b causes oposonization (enhancement of phogocytosis by coating pathogens with C3b); C5 breaks into C5b/C6 and C5a; C5B/C6, C7, C8, and C9 attack form a membrane attack complexes which essentially drill holes in pathogen membranes, causing cytolysis (loss of cellular contents through hole of transmembrane channel); C3a and C5a cause mast cells to produce, causing inflammation (increase of blood vessel permeability and chemotactic attraction of phagocytes)
What are cytokines?
Chemicals that activate cells; signal from one immune cell to another, maintaining complex C5-C9 coordination
Describe specifically what macrophages do.
Macrophage triggers t cells that recognize foreign antigen pieces that the macrophages display; macrophage produces Il-1, which stimulates RBC production, changes in endothelial cell walls to increase permeability, fibroblasts for clotting, hypothalamus to reset thermoregulation (fever), and T helper cells
What do the T helper cells do after beign stimulated by macrophages?
Produce IL-2, which stimulates clonal expansion of T-helper cell, cytotoxic cells, and B cell clones (memory cells)
What are IL-3 and 4 important for?
Stimulate B cells, mast cells, adn eosinphils
On which chromosome are the major histocompatibility proteins encoded?
Chromosome 6 (6p21.3); everyone has a unique MHC display
Which of the three classes of the MHC are the same for everyone?
Class III (in the middle of Class I and Class II)
Describe the initial innate/non-specific immune response to a wound.
- When there is a wound, capillary epithelial cells release prostaglandins and NO, which help cause vasodilation and help motivated collection of material at site of wound
- Platlets produce hypoxono O2(?) which cause formation of fibrogens
- Monocytes differenate inot macrophages
- PMNs activated
- Mast cells in tissue de-granulate, releasing histamine which causes openings between capillary epithelial cells
- Production of cytokines
- Pattern recogniition receptors recognize generic bacteria characteristics, such as certain monsaccharides
- C-reactive proteins (CRP) produced in liver in response to IL-1 within first few hours of infection; CRP identifies bacteria much like complement-refraction B, stimulates macrophages and reinforces inflammation activity and serves as marker of inflammation
- Complement fixation is stimulated by cytokines (such as IL-1 from macrophages)
Describe the general immune response involving the lymphocytes.
Antigen is presented to T helper cells; T cells (helper and cytotoxic) and B cells (big nucleus, little cytoplasm) proliferate when B cells are stimulated; turn into plasma cells with a lot of cytoplasm and a big ER to produce antibodies
Describe B cell adn T cell receptors.
B cells and T cells display receptors on theri surfaces which share structure and genetic coding with MHC proteins; antobidies also share this structure, as do the T cell markers CD3 (helper T cells) and CD9 (cytotoxic T cells)
How many variable regions do B and T cell receptors have for recognizing specific foreign antigens?
B has 2
T has 1
Where do B cells under go random recombination on their variable regions?
IN the bone marrow
Where does T cells develop?
T cell maturation is regionally organized within the thymus, "positive selection" and proliferation occur in the cortex and "negative selection" in the medulla
Describe specifically how T cells are made and processed.
T cells are released from bone marrow into cortex of thymus; at the beginning, they express neither CD4 or CD8 surface proteins; when they come into the cortex of the thymus, they ware known as DN1-3 (double-negative precursor cells) and undergo “positive selection” for recognition of MHC I & II antigen, expression of both CD4 and CD8, and expression of TCR; those that were selected clonally expand and now have the ability to produce both CD4 and CD8, they are called DP (double-positive cells); the DP then lose expression of either CD4 of CR8 to become SP (single-positive cells); SP undergo “negative selection” against self-antigens in the medulla before release into circulation (anything that reacts to native proteins is killed off)
What do dendritic cells do?
Specialized macrophages in the cortex of the lymph nodes that absorb and present antigens to multiple B and T cells, including memory cells (when memory cells see antigens, there is a quickened response to previously addressed antigen)
What are four antigen-presenting cells?
B cells, dendritic cells, macrophages, and any virus-infected nucleated cell
What does MHC-I present?
Intra-cellular antigens
What does MHC-II present?
Extra-cellular antigens
What does the type of MHC protein determine?
Determine the type of T cell that is stimulated
How are intra-cellular antigens presented?
Virus protein, for example, is ground by proteasomes; peptide fragments are displayed by MHC class I; recognized by CD8 T cells
How are extra-cellular antigens presented?
Antigens are endocytosed into a vesicle; in the vesicle, they are attached to MHC II proteins, which are recognized by CD4 T cells when presented on the cell surface
Why do CD8 t cells have to look for cells that are already infected?
Viruses do not display antigens on the outside of the cell; they are activated inside of the host cell
What do CD8 T cells do?
Destroy the infected cell by secreting “perforins” (proteins that induce hole sint eh cell membrane and therefore cause apoptosis
What type of cells present antigens bound to MHC-II proteins?
Macorphages and B cells
What does activation of T and B cells result in?
In the lymph node or spleen, activation of T and B cells results in clonal expansion of both cell types, transformation of B cells into secretory plasma cells, which produce antibodies, and the creation of memory B cells which stay behind in lymph nodes
How are the MHCII and MHCI responses connected?
Through cytokines, such as IL2, response to MHCII also activate response to MHCI and vice versa
What does the activation of helper T cells stimulate?
Clonal expansion of cytotoxic T cells, increasing the specific immune response to viral infections
What is the lymph system basically designed to do?
Increase the change of antigen and lymphocyte interact
How does lymph flow?
Lymph (macrophages, in particular) flows through lymph nodes from afferent ducts entering at the cortical surface, past nodules containing germinal centers, through the medulla to the efferent duct; eventually flow back to the hear through the superior vena cava
What are germinal centers?
Areas of B cel clonal expansion
Where do T cells expand in the lymph node?
In the medulla
Where do the lymphocytes go that were clonally expanded in the lymph node?
Flow out of efferent ducts and eventually back to the heart through the superior vena cava to be sent with the blood throughout the body in search of the “enemy”
What type of antibody is most plentiful?
IgG
What aspect of the unit structure is shared by all antibodies?
Share a similar unit structure with two “heavy” chains and two “light” chains; the tips of the two branches containt he antigen binding sight
What varies in the structures of the different types of antibodies?
Vary in having particular additions to the Fc (trunk) portion
What happens when an antigen binds to the binding site in the variable region?
Induces conformational changes in the constant regions that result in binding activity changes with functional consequences
Describe IgG.
Molecules are nearly identical to B cell receptors; when antigen binds to the antibody, the Fc portion of the IgG molecule facilitates binding by macrophages and PMNs (to Fc portion) and triggers complement fixation (and subsequently the release of cytokines (C3b binds phagocyte) and generation of membrane attack complex (MAC)). IgG is ordinarily more specific in its antigen binding than IgM, but appears somewhat more slowly; Fc region also facilitates transpot acrosst eh placenta from mother to fetus so if mother is infected, passes antibodies to fetus
Describe IgM.
IgM is a pentameric molecule with five times the number of binding sites as an IgG antibody, making it particularly effective in forming complexes (ten binding sites); tends to be less specific than IgG in its binding and is produced more rapidly in the initial response to an infection
How do antibody complexes localize the infection?
Agglutinate antigen-bearing clel,s, helping to localize infection and mobilize non-sepcific responses (particularly IgM and IgA)
Describe IgA
“Two unit” antibody that is combined with a secretory protein, allowing it to be secreted by mucosal linings of the oral cavity and gut, nasal, and respiratory passages, and into breast milk (so even when can no longer share IgG, can still share IgA; like IgM, IgA is effective in forming antibody complexes and localizing infections before they enter tissues or blood stream; activates macrophages and triggers complement fixation
Describe IgE.
Fc portion of IgE antibodies binds to receptors ont eh surface of mast cells, stimulating degranulation and release of histamine and other cytokines
How does histamine influence the respiratory tract?
Causes constriction of bronchioles and mucus secretion; attempt to keep foreign particles from getting in
What does HIV attack?
Attacks helper T cells; binds to CD4 protiens to facilitate entry into the cell; also depletes memory B cells
What year was a particularly bad flu season?
2003-2004
What demographic group was hit particularly hard by the 2003-04 flu season in terms of mortality?
Infants
What are the 3 components of the epidemiological triangle?
Agent, host, and environment
What are four agent factors?
1. Virulence: how much damage does it do
2. Transmission (route and probability): how contagious is it?
3. Life cycle
4. Evasion
What are the four basic strategies of evasion by antigens?
1. Outrun: proliferate faster than lymphocytes
2. Lay low: hide
3. Outwit: tricks to evade
4. Disable: battle
Give an example of a pathogen that outruns the immune system.
Cholera; rapid ~ spreadse squickly and kills quickly ~ not transmitted by people, but water
Give an example of a pathogen that lays low in the immune system.
Herpes canb e contracted as chicken pox as a child; hides in dorsal nerves, which aren't highly patrolled by immune cells; years later, when immune system is suppressed, it erupts as shingles
Give an example of a pathogen that outwits the immune system.
Protozoans and amalaria; sleep sickness protozoans (trypanosoma brucei), for example, can rearrange their antigens as they reproduce
Give an exmaple of a pathogen that disables the immune system.
HIV attacks the imune system proper
What are 5 host factors?
Constraints on allocatin of energy and other resources to allocation immune system:
1. Passive and acquired immunity
2. Nutritional status
3. Age
4. Reproductive status
5. Co-morbidity
Describe the graph of immune system defenses on plotted as % Schick negative vs. age.
Decreases until 9 months, stays low until 12 and then continues to rise as the body re-builds antibodies with its own exposure

Graph measures antibodies to dyptheria
What demographic does AIDs mostly affect in Botswana?
The younger and reproductively active; greater percentage of males have AIDs
What are 4 environmental factors?
Probability of transmission:
1. Encounter rates with agent
2. Encounter rates with susceptibles
3. Vectors
4. Seasonality
What type of pathogens were common to hunters and gatherers?
Pathogens with long latencies, dormant life cycle stages, non-human reservoirs, and transmission vectors

Directly transmittable diseases were probably rare
What types of pathogens appear to have originated in domestic animals?
Transmittable diseases
What are diseases called that are transferred from animals to humans?
Zoonotic diseases
Give examples of stage 1-5 zoonotic diseases.
Stage 1 (agent only in animals): rabies
Stage 2 (primary infection only from animals): ebola
Stage 3 (limited outbreak from animals or humans): dengue
Stage 4 (long outbreak from animals or humans) and stage 5 (only from humans): HIV-1 M
Adoptin of agriculture as a subsistence led to what four changes?
- Larger populations
- Fixed residence
-Seasonality in workload and food abundance
- Alteration of local ecology
What led to the spread of epidemic diseases?
- Emergency of long-range sea and land-based trade routes
- Conquest and invasion
- Migration
- Industrialization (crowding, nutritional stats, population mixing)
What demographic was particularly affected by the 1918 influenza strain and why?
Young men, including those who did not go to war; co-morbidity with tuberculoses & men had a higher rate of TB
What are influenza viruses classified by?
Classified by two of their surface proteins, hemagglutinin and neuramidas; these proteins, which provide antigens for the immune system, continuously evolve so that each year’s strain is slightly different from the last (the shift in 1918 was classified as H1N1)
Describe the changes between a 5 and 6-week-old fetus that are related to sexual development.
Primordial germ cells sprout from the dorsal mesentery; epithelium thickens and sex cords grow out of genital ridge; Mullerian duct formed by invagination along the nephritic ridge; Wolffian duct, mesonephric tubule, and bowman’s capsule related to dorsal aorta
Draw diagrams of 5 week and 6 week fetus.
In urogenital lecture
Describe the formation of the testes in the fetus around 8-12 weeks.
Degeneration of Mullerin duct; primordial stem cell migrate into genital ridge; Wolfian duct connects to sex cords, which eventually become seminiferous tubules
Describe the formation of the ovaries in the fetus around 8-12 weeks
Degeneration of Wolfian Duct and mesonephrous tubules; Mullerian duct does not degernate, becoming oviduct/uterine tube; cells from sex cord surround primordial germ cells (which become eggs) and form primordial follicles; granulose cells surround developing egg
What are other names for the Wolfian Duct?
Ductus Deferens/Vas Deferens
What is the Wolfian duct an ancient derivative of?
Kidney tubule
Why do women ovulate into the coelem?
Oviduct is opened at the top, so ovulate into coelem and then absorbed into Mullerian Duct
where are the rete cords?
At the base of the Wolffian Duct
What is the mesonephric duct?
Woffian duct = archinephric duct
What is the three-part kidney concept?
Formation of hte vertebrate kidney involves development at three regions along the archinephric duct: the pronephros (disappears in human men and women); mesonephros (disapperas in a woman; in man, forms mesonephric tubules which connect testes to outside through Wolffian Duct), and metanephros (forms kidney in human man and woman)
What was the kidney like in early vertebrates?
All along the body in the retroperitoneal position
Where was the kidney in early fishes?
Pronephros (head kidney) and mesonephros
Describe the kidneys in salamanders.
Mesonephros; uses kidney ducts in sperm transport in mammals
Describe the mammalian kidneys in mammals.
Mammalian kidney is a metanephros
What are the stages of development of a mammal kidney?
Pronephros in early embro; mesonephros in intermediate embryo; and metanephros in late embryo and adult; "ascent" of the kidney; most of the mesonephros degenerates
List the major features in the evolution of the urogential system and state when they arose.
- Archinephric Duct (all have it)
- Functional pronephros in adult (specific to hagfish)
- Urinary bladder as outgrowth from cloaca (coelacanths, lungfish, caecilians, turtles, and "above")
- Seminiferous tubules in testes (caecilians and above)
- Metanephros (turtle and above)
- Female loses archinephric duct (turtles and above)
- Uterine tubes: platypus/ecindas and above
- Nipples & yolk sack placenta: opossums/kangaroos and above
What does the SRY gene do?
Produces testis determining factor (TDF)
What does testis determining factor (TDF) do?
Causes migrating stem cells to associate with the inner, medullary portion of the sex cords. These then join to the Wolffian duct system; sperm cells will eventually be shed into this duct system
What doe shte Wolffian duct system differentiate into?
Seminiferous tubulues, rete testis, epididymis, and vas deferens
What happens in the absence of testis determining factor (TDF)?
Germ cells associate with the outer cortical portion of the sex cords, which produce clusters of grandulosa cells to surround each oögonium; these primordial follicles remain in the cortex of the gonad and will potentially be shed to the exterior of the organ during ovulation
What are the two types of cells associated with the testes?
- Sertoli cells (inside of the seminiferous tubules related to sex cords)
- Leydig cells (develop from non-sex cord cells in matrix)
What do the hormones produced by the sertoli cells do?
Anti-mullerian hormone causes mullerian duct regression
What do the hormones produced by the leydig cells do?
Testosterone; influence on wolffian ducts causes formation of epididymis, vas deferens, and seminal vesicles; when testosterone is changed to dihydrotextosterone (DHT) cit casuses formation of penis and scrotum
What happens in the absence of SRY?
Fetus becomes a female
What happens in the absence of anti-Mullerian hormone?
Mullerian duct does not degenerate and retain presumptive oviducts
What happens in the absence of testosterone?
The fetus is phenotypically female; genotypically male
What happens when testosterone is not broken down into DHT?
Seems externally female
What happens when there is a deficiency of 5alpha-reductase?
Testosterone cannot be converted to DHT; results in female-like external genitalia at birth; at puberty, higher levels of testosterone lead to enough DHT to masculinize the external genitalia and promote other male secondary sexual characteristics
What are the names of the mitotically-active 'gametocytes?'
Spermatogonia and oogonia
What happens to spermatogonia and oogonia?
Males retain spermatogonia thorughout adult life; female oogonia enter prophase of their first meitoic division during mid-gestation and all mitosis ceases
What type of division are spermatocytes and oocytes committed to?
Meiosis
What are spermatocytes and oocytes called once they have completed meiosis?
Spermatids and ootids
What are spermatids and ootids called when they are ready for fertilization?
Spermatozoa and ova
What is the timeline for the conversion of germ cells to oogonia to primary oocytes?
germ cells until 3 months pregnancy; oogonoia dwindling until shortly after birth; primary oocytes dwindling until menopause
Is the loss of oocytes due to atresia the same as ovulation?
No; birth ocontrol, which decreases ovulation does not change atresia, as atresia is constant
What are three features that are the same for ovaries and testes?
1. Cooperation between inner and outer cell populations
2. Outer cells respond to LH, produce testosterone
3. Inner cells respond to FSH, nurture gametes, convert testosterone to estradiol, and secrete inhibin
Draw seminiferous tubules and ovaries.
In 'Reproductive Physiology' Lecture
What do leydig cells do?
Respond to LH by producing testosterone
What are sertoli cells derived from?
Sex cords
What do sertoli cells do?
Respond to FSH to nurture sperm cells and maintain cytoplasmic connections with developing sperm cells to foster nutrient transport; convert some testosterone to estradiol
What do granulosa cells do?
Respond to FSH to mitotically divide; nurture oocytes & maintain cytoplasmic connections with oocytes; convert testosterone to estradiol, which supports development of follicle
What do theca cells do?
Respond to LH, causing them to produce testosterone; some enters blood stream, but most goes to granulosa cells
Where does the testosterone go that is produced by the theca cells?
Some enters bloodstream, but most goes to granulosa cells
What are theca cells derived from?
Matrix rather than sex cords
What produces inhibin and what does it do?
Sertoli and granulosa cells produce inhibin, which inhibits FSH
What is the corpus luteum?
When ovulate, granulos and theca cells remaining in follicle comingle and form corpus luteum, which produces progesterone
What is GnRH?
Synthesized and released from the hypothalamus; causes anterior pituitary to produce FSH and LH
How does GnRH have to be released
In pulses
What is Kallmann's syndrome
the GnRH neurons do not migrate properly from the olfactory placode to the hypothalamus during development; therefore, failure of development of GnRH and proper GnRH-secreting neurons of the hypothalamus
What is a treatment to Kallman's syndrome?
Pulsatile GnRH can be delivered with a pump in large boluses every 60 minutes to stimulate pituitary gonadotropin production
Describe how hormones from the pituitary influence the male sexual process.
- LH stimulates Leydig cells to produce testosterone
- FSH stimulates Sertoli cells to support spermatocyte maturation (and the conversion of some testosterone to estradiol)
- When Sertoli cells ar eactive, they also produce inhibin, which supporesses FSH. Once initiated, sperm production can continue with the support of testosterone alone (without FSH)
Describe how hormones from the pituitary influence the female sexual process.
- LH causes theca cells to produce estradiol, which is converted to estrogen by the granulosa cells
- FSH cause granulosa cells to facilitate oogenesis; also produces inhibin to shut off FSH that other smaller follicles still require so only one follicle progresses to ovulation each month
- Ovulation interrupts oocyte maturation, which is started up again by a rise in FSH after menstruation
Describe selection of the dominant follicle.
FSH causes granulosa cell proliferation, which causes estradiol and inhibin production; estradiol production causes follicle growth and oocyte maturation; inhibin production causes selective FSH suppression

The first follicle to reach critical size produces enough estradiol (E2) to support its own growth, enough inhibin to suppress FSH
What happens when the dominant follicle reaches a critical size?
The estradiol feedback triggers a "urger" of LH from the pituitary that in turn causes ovulation
What are the 3 parts of the blastocyst and what happens to them?
Inner Cell Mass: becomes fetus
Blastocoele: becomes amniotic sac
Trophoblast: accomplishes implantation and develops into fetal portions of the placenta
What does the progesterone released from the corpus luteum after ovulation do?
Causes the endometrium to prepare for implantation. If that doesn't occur, the corpus luteum regresses, steroid levels drop, and FSH rise to start a new cycle of oocyte maturation
How do you get a woman who wishes to undergo in vitro fertilization to produce more than one ovum?
Give her FSH to keep follicles maturing
Describe tehe kJ/day of added tissue, maintenance of added tissue, and added fat during the weeks of gestation.
Added tissue and maintenance of added tissue increases all 40 weeks; added maternal fat increases and then is quickly used up during weeks 30-40 (a negative amount of kJ/day is stored)
Is ovarian function reflected by menstrual patterns?
Not necessarily; even when women are menstruating regularly, there are may be significant differences in their hormonal profiles associated with differences in fecundity (women can menstruate without ovulating)
Where do steroid hormones bind?
Steroid hormones are lipid and water soluble, so they pass through the capillary and other membranes to enter target cells and all body fluids, including saliva
What is the relationship between estradiol and the likelihood of conception?
If there is more estradiol, more likely to conceive
Is weight loss and gain associated with hormonal changes?
Yes
What is the effect of joggers' lower estradiol profiles?
Affects ovarian function rather than menstrual regularity
What is the relationship between amount of activity and amount of estradiol?
More activity, lower estradiol
How does birth solve the metabolic crisis of late gestation?
Easier to pass calories through milk than through placenta
How does nursing stimulate milk production?
Via prolactin
What effect does nursing have on ovarian function?
Nursing suppresses ovarian function ~ when nurse for a long time, stay amenorrheic for a long time
Why do women in !Kung San take two years to resume ovulation?
Breast feed for a long time; takes even longer than long breastfeeders in Us, becuase poorer nutrition
What are four aspects of men that are influenced by testosterone?
1. Sperm production
2. Muscle mass
3. Sex drive
4. Male-male competition
When exposed to a sexual stimulus, do testosterone levels rise?
Yes
List the demographic groups in order of increasing testosterone levels.
Married with children, married without children, and then unmarried
Describe the difference in testosterone levels between Hadza and Datoga Fathers
Hadza fathers hold children frequently, interact with children frequently, and sleep in close proximity to children, whereas Datoga fathers are the opposite; accordingly, Hadza fathers have much greater decreases in testosterone levels when they have kids