Human Physiology Exam 1 2014

Front 1

1. It's cold and you have "goose bumps" on your forearm. Relate that to homeostasis for temperature regulation.

Back 1

if you were a mammal with more fur, that would fluff up your fur for better insulation and less heat loss

Front 2

2. Why might you feel particularly cold when you come out of the swimming pool soaking wet?

Back 2

it removes a lot of heat from your body as liquid water evaporates

Front 3

3. ACTH - - ANSWER EITHER (1) What gland does it stimulate? OR (2) What does that gland release in response?

Back 3

adrenal cortex, cortisol

Front 4

4. It was argued that considerably less quantity of hypothalamic hormones were needed to stimulate the anterior pituitary than hormone quantities from glands throughout the body like the thyroid. Why?

Back 4

the portal system delivers without dilution by the whole blood volume

Front 5

5. If there were not enough iodine in the diet, explain how (and in what direction) that would affect the level of thyroid stimulating hormone from the pituitary.

Back 5

low iodine would lead to low thyroxine (T3 and T4, i.e. thyroid hormone) and the lower negative feedback to the pituitary would increase TSH

Front 6

6. Explain how a membrane transport worked to convert red blood cells into red blood cell "ghosts" when Gorter and Grendel showed, in 1925, that there was enough lipid in a membrane to make two layers.

Back 6

osmosis brought water in until the cell burst and hemoglobin and carbonic anydrase were spilled out leaving only membranes

Front 7

7. Say something about why the movement of glucose across the membrane is called facilitated diffusion.

Back 7

diffusion because it is passive (not requiring energy), facilitated because the GLUT transporter is needed

Front 8

8. How is it that a protein such as rhodopsin can reside in a membrane whose interior is so hydrophobic?

Back 8

its alpha helices are mostly hydrophobic amino acids

Front 9

9. How did we visualize radioactively labeled phospholipids that had been separated on a TLC plate?

Back 9

by exposing photographic film (autoradiography)

Front 10

10. "Homeostasis of calcium ions in the blood stream is very important." Name one of the three hormones dedicated to this regulation.

Back 10

parathormone, calcitonin and vitamin D

Front 11

11. What is the body's natural ligand for the nicotinic receptor?

Back 11

acetylcholine

Front 12

12. What is the significance of a coated vesicle?

Back 12

it is used for receptor mediated endocytosis (pinocytosis), uses the protein clathrin to make them look coated

Front 13

13. Why might some synaptic excitation to a neuron's cell body and dendrites not trigger an action potential at the axon hillock?

Back 13

especially if there is inhibitory input, the net excitation might not be sufficient

Front 14

14. Obviously, potassium ions WOULD flow down their concentration gradient through a potassium channel. What is it about the Nernst equation that says they SHOULD not?

Back 14

the equillbrium assumption works out to say that electrical and chemical gradients are equal and opposite

Front 15

15. Two resistors in series on one side of a Wheatstone bridge might be called a "voltage divider." Why?

Back 15

voltage arises from a battery or from current flowing through a resistor, and when there are two it ought to be IR1 + IR2

Front 16

16. Curves that are referred to as "exponential" describe voltage as a function of time. What property of membranes and circuits create these delays in charging and discharging?

Back 16

capacitance

Front 17

17. When Ohm's law is plotted with current on the Y axis, what is the slope of the line?

Back 17

conductance, g, in Siemens

Front 18

18. What is the only thing that was shown with Cole and Curtis's work with the Wheatstone bridge?

Back 18

resistance goes down when the action potential goes by

Front 19

19. Draw or describe a sensory neuron in the dorsal root ganglion.

Back 19

has its cell body in the ganglion while the axon goes past into the spinal cord

Front 20

20. "An action potential depolarizes the membrane ahead of it to threshold." What is it about the space constant that relates to invertebrates having giant axons?

Back 20

space constant increases with the square root of the radius

Front 21

21. How do the cells that myelinate axons differ in the central vs. the peripheral nervous systems?

Back 21

cns oligodendroglia myelinate a few axons while pns Schwann cells myelinate only one

Front 22

22. How does experimental autoimmune encephalitis relate to myelin?

Back 22

eae is a model for multiple sclerosis

Front 23

23. What happens to the resistance of the postsynaptic membrane during an IPSP?

Back 23

goes down since potassium and chloride conductances increase

Front 24

24. "Calcium ions are important for synaptic vesicle release." ANSWER EITHER (1) How did calcium ions come to reside inside the presynaptic membrane? OR (2) What do these calcium ions bind to for vesicle release?

Back 24

through a voltage-gated calcium channel, synaptotagmin (also calmodulin would be acceptable)

Front 25

25. An action potential arrives at the axon's terminal. What does not happen in the case of poisoning with Clostridium botulinum?

Back 25

vesicles are not released

Front 26

26. One type of receptor for acetylcholine is ionotropic, a ligand-gated channel, the nicotinic receptor. What is the other type?

Back 26

metabotropic, G protein-coupled receptor, muscarinic

Front 27

27. How are melanin and dopamine related?

Back 27

both have l-DOPA as a precursor, substantia nigra is dark because of melanin and produces dopamine

Front 28

28. What is the function of that place inside the brain called, alternatively, putamen plus caudate, striatum, basal ganglia, or extrapyramidal system?

Back 28

smoothen out (coordinate) voluntary motor movements

Front 29

29. Give ONE step in the cascade between the binding of the hormone epinephrine to a receptor and the production of glucose from glycogen.

Back 29

activate G protein, activation of adenylate cyclase, production of cAMP, activation of protein kinase A, activation of phosphorylase kinase, activation of phosphorylase

Front 30

30. ANSWER EITHER (1) For what ailment would you use an inhaler with the beta-2 adrenergic agonist, terbutaline? OR (2) What does it do to bronchioles?

Back 30

asthma, dilates them

Front 31

31. A portion of the parasympathetic output comes from the sacral portion of the spinal cord. What part of the central nervous system is the source for the rest of the parasympathetic output?

Back 31

brain

Front 32

32. Why would atropine have the effect it has on gastrointestinal motility?

Back 32

blocking muscarinic cholinergic transmission, decreasing the rest and digest parasympathetic output, would slow peristalsis

Front 33

33. The sympathetic nervous system increases cardiac output by increasing contraction strength (stroke volume) and (what?).

Back 33

duh heart rate

Front 34

34. Under what circumstances would a physician prescribe an inhibitor for the phosphodiesterase that acts on cyclic GMP?

Back 34

for erectile dysfunction

Front 35

35. What is the unit called, along the myofibril, from one z-disk to the next z-disk?

Back 35

sarcomere

Front 36

36. Which muscle protein is affected by Duchenne muscular dystrophy?

Back 36

dystrophin

Front 37

37. When ATP comes into the previously empty binding pocket on the myosin head group, what happens?

Back 37

the binding of actin and myosin is terminated

Front 38

38. Why, in his Nobel prize winning work, did Sir Bernard Katz decrease the extracellular calcium in the neighborhood of the end plate?

Back 38

to decrease vesicle release

Front 39

39. CHOOSE ONE Under what circumstances would you be given (1) an acetylcholinesterase inhibitor OR (2) a paralytic?

Back 39

myasthenia gravis, to relax muscle for surgery

Front 40

40. What TWO locations are there calcium channels in a striated muscle cell?

Back 40

t-tubules and sarcoplasmic reticulum

Front 41

41. What is glycogenolysis?

Back 41

production of glucose from its polymer (glycogen) in muscle and liver

Front 42

42. What modification must be made so that smooth muscle myosin can form cross bridges with actin?

Back 42

myosin light chain must be phosphorylated

Front 43

43. When two amino acids are joined in a peptide bond, it is called dehydration synthesis. What is it called when the two amino acids are broken apart?

Back 43

hydrolysis

Front 44

44. When a fatty acid has a few double bonds, why is it called "polyunsaturated?"

Back 44

it is not saturated with as many hydrogens as it would be with single bonds

Front 45

45. Using hemoglobin as an example, what is the quaternary structure of this protein?

Back 45

two alpha and two beta subunits linked together

Front 46

46. What do humans do to get rid of the nitrogen generated if amino acids are used for calories?

Back 46

turn it to urea

Front 47

47. "Glycolysis, 9 steps yielding two molecules of pyruvic acid from one molecule of glucose, looks the same in aerobic vs anaerobic metabolism." Then what is the difference in anaerobic conditions?

Back 47

pyruvic acid is converted to lactic acid

Front 48

48. "Most of the ATP is not generated in glycolysis plus the Krebs cycle." Then where, in the metabolic pathway, is it generated?

Back 48

oxidative phosphorylation and electron transport

Front 49

49. Under the influence of insulin, how can there be a rapid increase in the amount of glucose that can be transported into muscle and liver cells?

Back 49

the GLUT4 transporters are at the ready in vesicles and moved to the plasmalemma

Front 50

50. "The insulin receptor is called a 'receptor tyrosine kinase.'" Why is the word "tyrosine" in this expression?

Back 50

the enzyme phosphorynates the tyrosine residue (amino acid)