BBIO 351: Principles of Anatomy & Physiology I
Winter 2016
Exam 2 (mostly repro/neuro)
Name: ___Dr. C____________
You will have 2 hours for this exam unless prior arrangements have been made with DRS. You
may use a pre-prepared double-sided 4-inch by 6-inch notecard or piece of paper. If you want
clarification of a question, please ask. Good luck!
[Max points available: 104, as marked below.]
1. Briefly describe the structure and function of microRNAs (miRNAs) in general. Then
describe, as specifically as possible, exactly how they affect production of luteinizing hormone
(LH). [6 points]
a. miRNAs in general:
 Short segments of RNA that bind to complementary sequences of mRNA and thus inhibit
translation of this mRNA
b. specific effect on LH:
 miR-200b and miR0-429 inhibit translation of the mRNA for ZEB1, which inhibits
transcription of the gene for the beta subunit of LH – so these miRNAs promote LH
production by inhibiting an inhibitor of it
2. Below is Figure 3 from Hasuwa et al. (2013). According to this figure, what effects (if any)
does ZEB1 have on (a) production of luteinizing hormone (LH) and (b) production of offspring?
Cite specific evidence from one or more parts of the figure. (Do NOT discuss the entire figure.)
[6 points]


a. ZEB1’s effect on LH:
ZEB1 represses transcription of the gene for LH’s beta subunit; this can be seen in Fig.
3E, where overexpressing ZEB1 reduces production of lhb mRNA
b. ZEB1’s effect on producing offspring:
ZEB1 limits fertility and offspring, as in in Fig. 3D, where overexpressing ZEB1 reduces
the number of babies delivered per episode of intercourse (as indicated by vaginal plugs)
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BBIO 351: Principles of Anatomy & Physiology I
Winter 2016
3. Contrast the reproductive roles of the endometrium and the myometrium. That is, how are
their structures and functions different? [5 points]
 The endometrium is the inner layer of the uterus. Its function is to nourish and protect
any fertilized oocytes that implant in it; this includes development of a placenta for
exchange of nutrients and wastes between the mother and child. It also secretes
prostaglandins during labor, which help the myometrium contract more forcefully.
 The myometrium is the muscular middle layer of the uterus. Its main job is to push the
child out of the uterus during labor and delivery; its contractions are coordinated and
forceful thanks to “priming” by estrogen (which installs gap junctions between cells and
increases myometrial oxytocin receptors) and a positive feedback loop involving
oxytocin.
4. For the figure below, clearly list (A) all components that are enzymes and (B) all components
that are protein kinases. The two lists may or may not overlap. [6 points]
a. Enzymes: glycogen phosphorylase, glycogen synthase, phosphorylase kinase, protein kinase A
[1 point off for each non-enzyme listed or enzyme omitted, up to a maximum of 4 points off]
b. Protein kinases: phosphorylase kinase, protein kinase A [1 point off for each non-kinase listed
or kinase omitted, up to a maximum of 2 points off; no points off for listing glycogen
phosphorylase, which is a kinase but not a protein kinase]
5. Describe one specific mechanism by which thyroid hormones alter ATP turnover and thus
cellular metabolism. [4 points]
 In some cells, thyroid hormones increase the insertion of Na/K pumps into the cell
membrane, increasing ATP consumption by these pumps, forcing ATP synthesis to
increase.
 In some cells, thyroid hormones increase the insertion of uncoupling proteins (UCPs) into
the mitochondrial membrane, allowing protons to pass into the mitochondrial matrix
without being coupled to ATP synthesis, forcing cells to break down more fuel (glucose,
fatty acids, etc.) to make a given amount of ATP.
6. Why is prednisone often given to patients after surgery, and what natural disorder is mimicked
by prednisone administration? [2.5 points per part = 5 points total]
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BBIO 351: Principles of Anatomy & Physiology I
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Winter 2016
Prednisone (a cortisol-like steroid) is given after surgery to suppress the immune system
and minimize inflammation. (Full credit for “suppress immunity,” “reduce
inflammation,” or anything similar.)
This mimics the natural disorder of Cushing’s syndrome, or hypercortisolism.
7. Below is a figure from your textbook. What part of this figure, if any, illustrates the principle
of positive feedback? Explain specifically why this figure does or does not fulfill the definition
of positive feedback. [5 points]
In positive feedback, a
deviation from the usual
state (or setpoint) causes
a further deviation away
from that usual state.
The green loop in the
figure qualifies as
positive feedback if we
think of a relaxed (noncontracting) uterus as
being the usual state. A
bit of contraction by the
uterus leads to secretion
of oxytocin, which
causes more intense
contractions, which
causes further secretion
of oxytocin, which
causes even more intense
contractions, etc.
8. A human-like alien species has neurons that basically work like ours, but that have a resting
potential of -100 mV, a peak voltage of 0 mV at the height of an action potential, and a threshold
voltage of -80 mV. This alien has myelinated axons whose nodes of Ranvier are spaced 10
millimeters apart. Its length constant for the passive spread of electrical signals down an average
axon is 1 mm. Will this alien’s axons be capable of saltatory conduction of action potentials?
Justify your answer. [5 points]
No, the alien’s axons will not be capable of salutatory conduction. In 1 mm, the change in
voltage will have decayed to 37% of its original amount (37% of 100 mV, or 37 mV). In 2 mm,
the change will have decayed to 37% of the 37% (37% of 37 mV, or 13.7 mV). In 3 mm, the
change will have decayed to 37% of the 37% of the 37% (5.1 mV), etc. Too little of the original
signal will reach the next node of Ranvier, 10 mm away, to reach threshold and generate an
action potential.
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BBIO 351: Principles of Anatomy & Physiology I
Winter 2016
9. In the diagram at right (from
chemwiki.ucdavis.edu), which side of the
cell membrane is the inside, or
intracellular side? Please label it!
[3 points]
The inside of the cell is on the right.
10. Cortisol and epinephrine are similar in all of the following ways EXCEPT [2.5 points]
a. Both are “stress hormones”
b. Both are produced by the adrenal cortex – YES
c. Both have the effect of raising blood glucose
d. Both are non-polypeptide hormones
e. All of the above are similarities.
11. The textbook explanation of lactation is that it depends on stimulation of ____ by ___ and
stimulation of _____ by ____. [2.5 points]
a. lactose synthesis, glucagon; lactose consumption, insulin
b. milk consumption, leptin; milk production, growth hormone (GH)
c. milk secretion, oxytocin; milk ejection, estrogen
d. milk secretion, prolactin; myoepithelial cell contraction, oxytocin – YES
e. milk secretion, prolactin; myoepithelial cell contraction, progesterone
12. The next page shows graphs of four components of the Goldman-Hodgkin-Katz (GHK)
equation versus time.
a. Briefly explain what each abbreviation stands for in the GHK equation. [1 point each
= 4 points total]
Vm: membrane potential or membrane voltage (0.5 point off if membrane was
mentioned but not potential or voltage, or vice versa)
PK: permeability of cell membrane to potassium ions
(0.5 point off if the specific ion was not mentioned)
[K+]i: concentration of potassium ions inside the cell
(0.5 point off if the subscript was not addressed or was explained incorrectly)
[K+]o: concentration of potassium ions outside the cell
(0.5 point off if the subscript was not addressed or explained incorrectly)
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BBIO 351: Principles of Anatomy & Physiology I
Winter 2016
b. On the next page, fill in the graphs to show whether/how each of these variables changes over
time, starting with the falling phase of an action potential. Note that separate lines should be
drawn for [K+]i and [K+]o. [2 points per line = 8 points total]
Vm should fall from a peak around +30 or +40 mV to a resting value of around -60 or -80 mV.
PK should start high (or you could show it ramping up quickly from low to high) and then fall at
the end of the action potential. [K+]i should be much higher than [K+]o, and both should remain
essentially constant. (Usually [K+]i is 100-150 mM and [K+]o is 5-15 mM, but you weren’t
expected to hit those exact concentrations.)
13. In the graph below, the dashed line (- - - -) shows how the overall electrochemical driving
force on a cation (positively charged) varies with a neuron’s membrane potential.
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BBIO 351: Principles of Anatomy & Physiology I
Winter 2016
a. According to this graph, what is the equilibrium potential for this cation? [3 points]
about +25 mV (any estimate in the range of +20 to +30 mV is fine)
b. Is this cation more concentrated inside the cell or outside the cell? [3 points]
this cation is more concentrated outside the cell
14. In a female patient, if gonadrotropin releasing hormone (GnRH) levels are way above normal
but luteinizing hormone (LH), follicle stimulating hormone (FSH), and estrogen levels are way
below normal, the primary defect probably resides in the [2.5 points]
a. anterior pituitary – YES
b. hypothalamus
c. ovaries
d. posterior pituitary
e. testes
15. The corpus luteum is formed from [2.5 points]
a. a follicle that has released an oocyte – YES
b. cells of the anterior pituitary
c. cells of the posterior pituitary
d. cells of the endometrium of the uterus
e. oocytes that were not released from the ovaries
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BBIO 351: Principles of Anatomy & Physiology I
Winter 2016
16. Ovarian follicles and thyroid follicles both consist of [2.5 points]
a. corpora lutea
b. fluid-filled spaces surrounded by a ring of cells – YES
c. sites of gamete development
d. thyroglobulin to aid in hormone synthesis
e. all of the above
17. What is one way, seen in Hasuwa et al. (2013), that anterior pituitary cells can be
distinguished from posterior pituitary cells? [2.5 points]
a. Only anterior pituitary cells are below the hypothalamus.
b. Only anterior pituitary cells have the lhb gene.
c. Only anterior pituitary cells stain positive for production of LH. – YES
d. Only anterior pituitary cells stain positive for production of progesterone.
e. The two cannot be distinguished; this is a trick question.
18. During “fight-or-flight” exercise, the body constricts some arterioles, rather than dilating all
arterioles at the same time, to prevent a fall in [2.5 points]
a. blood glucose levels
b. blood pressure – YES
c. catecholamine levels
d. cortisol levels
e. temperature
19. Sea slugs (Aplysia) illustrate the Krogh principle because [2.5 points]
a. they are evolutionary predecessors of “regular” (land) slugs.
b. they are extremely rare in nature.
c. they are the smartest mollusks known.
d. they have exceptionally high extracellular sodium concentrations.
e. they have simple, easy-to-study circuits of large neurons. – YES
20. Luteinizing hormone is a(n) [2.5 points]
a. amino acid derivative
b. lipid derivative (steroid)
c. nucleic acid
d. protein made up of alpha and beta polypeptides – YES
e. single peptide chain
21. A node of Ranvier is… [2.5 points]
a. a gap between myelin sheaths
b. a site of action potentials
c. a site of voltage-gated channels
d. all of the above – YES
22. Where is melatonin produced? [2.5 points]
a. anterior pituitary b. hypothalamus c. melanocytes d. pineal gland-YES e. posterior pituitary
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BBIO 351: Principles of Anatomy & Physiology I
Winter 2016
23. In the graph below, which of the following could be the Y axis? [2.5 points]
a. blood [glucose], if a meal is eaten at time = 2 hours
b. blood [insulin], if a meal is eaten at time = 2 hours
c. blood [LH], if ovulation occurs at time = 2 hours
d. blood [melatonin], if darkness begins at time = 2 hours – YES
e. rate of glycogen breakdown in the liver, if a meal is eaten at time = 2 hours
24. If you wanted to calculate a neuron’s membrane potential based on the concentrations of
multiple ions inside and outside of the cell, you would use [2.5 points]
a. the Fick equation
b. the Goldman-Hodgkin-Katz (GHK) equation – YES
c. the equation for length constant (lambda, or λ)
d. the Nernst equation
e. the Ranvier equation
25. Judging from the specific ion channels that they block, lidocaine and tetrodotoxin (TTX)
disrupt the function of which part(s) of a neuron? [2.5 points]
a. axons – YES
b. cell body (soma)
c. dendrites
d. both cell body (soma) and dendrites
e. none of the above
26. If a neuron’s “resting” membrane potential is -65 mV, the membrane potential at which it
reaches its threshold could be [2.5 points]
a. -80 mV b. -65 mV c. -50 mV-YES d. 0 mV e. +15 mV f. +50 mV g. +65 mV
27. Estrogen contributes to ovulation because [2.5 points]
a. high estrogen levels positively feed back on GnRH and LH production, enabling the LH surge
– YES
b. estrogen’s negative feedback prevents LH levels from overshooting
c. estrogen’s production by the corpus luteum causes the follicle to burst
d. estrogen stimulates progesterone production, which in turn promotes ovulation
e. none of the above; estrogen does not promote ovulation in any way
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