Put your name here ->
BIOL 415 Nerve cell mechanisms in behavior
Test 2 Tuesday April 3, 2018 ­p; Prof. Stark
All questions are short answer. 65 points total
For Questions 1-5, go here
1. Give a name, number or function of the cranial nerve indicated.
occulomotor, 3, eye movement, pupil, accomodation
2. Give the function (for both) or a name (for either) area of white matter
outgoing voluntary motor tract, cerebral peduncle, trapezoid body
3. What is this white area called?
4. Answer either (1) What is this structure called? Or (2) Say one of the
things you would see if you removed that structure.
septum pellucidum, head of the caudate and lateral ventrical
5. What is this area called?
hypothalamus, third ventricle
For Questions 6 - 10, go here
6. What is this white matter called?
7. What is this large structure in the middle of the brain called?
8. What is this white matter called?
9. What is the white matter on the outside of this structure called? (Alternatively,
you could say one of the tracts on the midsagittal slice you see that are
formed from these axons.)
fimbria, fornix, hippocampal commisure
10. What white matter is being ripped here?
For Questions 11 - 15, go here
11. What kind of information is being carried by this tract?
12. What is this cross-over structure called?
13. What is this large area of the brain called?
14. You definitely saw this huge nerve in your dissection (pointed to twice).
Give a name or number. Hint: there are 3 branches coming in from touch sensation
in the face.
15. What is the name associated with the gray matter you needed to scrape
away (from the mid-sagittal plane) to reveal this tract?
massa intermedia, thalamus
16. Using a stereotaxic atlas of the rat brain and a stereotaxic apparatus,
what do you measure from on the rat's head to find a defined brain location
like the ventromedial nucleus of the hypothalamus?
bone sutures bregma and lambda
17. Why do they call part of the basal ganglia the "striatum?"
looks striated from branches of white matter off the internal capsule
18. The most obvious of the "membranes" (meninges) of an "un-peeled"
brain is a very thick and tough one called the (what)?
19. When you remove the cerebellum, you are looking at the floor of which
20. Other than cerebral cortex, name a major component of the telencephalon.
basal ganglia, hippocampus, olfactory bulb, basal forebrain
21. How did Pruisinger propose that a protein (without DNA or RNA) can be
infectious and alter the proteins in the victim, making those proteins infectious.
protein in scrapie configuration converts protein in control configuration
into the scrapie form
22. In the corticospinal tract, these motor cells in the precentral gyrus
make their first synapse (where?).
to the spinal motor neuron in the ventral horn
23. The afferent from a nociceptor has its cell body in the dorsal root
ganglion. Where is the first synapse? (Answer both: location plus which
side, using the appropriate term to answer which side.)
dorsal horn gray matter ipsilateral
24. Tell me a place where the 2-point discrimination threshold for fine
touch is less than 5 mm.
fingertips, lips, tongue
25. The head of a neurosurgery patient is opened to expose the brain using
only local anesthetic. Answer either: (1) How do they get away with that?
Or (2) Why would they do it that way?
no pain receptors in the brain, to make certain they are not messing with
a really critical function
26. Where does a sensory receptor for discriminative touch make its first
gracile or cuneate nucleus in lower medulla
27. "A hemisection of the spinal cord leads to a contralateral loss
of spinothalamic input from below the injury." This is in contrast
with what other loss of what other system?
ipsilateral of lemniscal
28. You were introduced to the term "neospinothalamic" whose input
is from A-delta fibers. In comparison, answer either (1) What slower fibers
have input for the more evolutionary ancient system? Or (2) What is this
more ancient system called?
C fibers, paleospinothalamic
29. Histological autoradiography demonstrated that a radioactive amino acid
was incorporated into those disks of the outer segment nearest to the inner
segment. What eventually happened to this band of radioactivity?
over a few weeks, it moved up the outer segment until those disks were shed
and phagocytosed by the RPE
30. In terms of cGMP levels, explain why the rod hyperpolarizes in response
with the cation channel continuously gated by cGMP in the dark, the cell
is depolarized, and when PDE is activated in phototransduction, the channel
closes because cGMP has been turned into 5' GMP
31. Why would you go blind with poorly controlled diabetes?
32. Everybody should get tested for glaucoma regularly. Answer either (1)
What is being measured? Or (2) Why, if left untreated, would glaucoma lead
pressure of the eyeball, ganglion cells die
33. The mechanism by which one gene (for long wavelength cones in New World
monkeys) became the yellow-green cone rhodopsin pair (in Old World monkeys)
is the general mechanism for the origin of the G protein coupled receptor
superfamily. How did one gene become two?
unequal crossing over in meiosis
34. Why is there a "ring scotoma" (doughnut-shaped blind area)
in people afflicted with retinitis pigmentosa?
rods go first, that is where they are prevalent
35. How come surgical manipulations of the cornea such as LASIK and RK can
be so effective in correcting myopia?
because the curved cornea-air interface, with its huge difference in index
of refraction, is a powerful lens and these surgeries change the shape of
36. Abnormal elongation of the eyeball is associated with what refractive
37. Dark spots moving against a light background cause some ganglion cells
in the frog retina to fire. Explain why this was considered an important
it shows feature detection of a biologically relevant stimulus, bug detectors
38. Specifically, what crossed the LGN (lateral geniculate nucleus) synaptic
cleft to allow Hubel to see the ocular dominance columns using autoradiography?
3H labeled protein
39. A thin bar of light made the simple cell fire quickly. Why did a wider
bar not do likewise?
because the wider bar also hit the inhibitory areas in the receptive field
of that cell
40. While an electrode is advanced obliquely through the cat's visual cortex,
first the left eye predominates, then the right eye. What else has been
changing during that advancement?
41. What is the most obvious thing that happens between the pretectum and
the Edinger-Westfall nucleus?
42. If Hubel and Wiesel had looked for a grandmother cell instead of the
cells they identified (e.g. simple cell), why wouldn't they have gotten
a Nobel Prize?
their systematic approach was very productive, good thing they didn't start
looking for a needle in a haystack
43. What is the relevance of the value 0.0002 dynes/cm2 in hearing?
that is the denominator, the pressure standard in defining dB
44. The human audibility curve plots Y as a function of X. Answer either
what is on the Y OR X axes.
ordinate is threshold (or sensitivity) plotted in intensity, plotted logarythmically,
abscissa is frequency in Hz where log plotting is for convenience
45. What causes the channels that mediate hearing to open?
mechanosensitive, would be membrane deformation, assisted by tip links
46. A figure was shown to you with hair cells and the axons they are connected
to. On the basis of how that figure was labeled, it was stated that outer
hair cells do not function as receptors. What was it about the axons connected
to outer hair cells that raised this issue?
those axons were called efferent
47. Mutants of the whirler gene cause improper detection of head orientation.
Why is it no surprise that the animals are also deaf?
affects stereocilia, and hair cells are used in hearing and balance
48. For what aspect of hearing is the speed of sound relevant?
49. While jogging, you trip and start to fall. Name a sensory organ or a
spinal pathway involved in the elicited responses of your spinal motor neurons.
vestibular apparatus, vestibulospinal tract
50. "Three SNPs associated with PTC insensitivity: A49P, V262A, I296V."
Translate either (1) SNP, (2) PTC or (3) A49P, V262A, I296V.
single nucleotide polymorphism (genetic change), a bitter chemical tastant
for which there are tasters and non-tasters (based on a gene) in humans,
the number is the amino acid position - the first letter is the normal amino
acid, the second letter is what it is changed to
51. In olfactory transduction, cAMP is made by adenylate cyclase. What does
this cAMP do?
52. Bitter stimulation, or stimulation with amino acids, activates PLC (phospholipase
C) to create IP3. In this example, the IP3 activates a different Ca2+ channel
than the IP3 receptor of the endoplasmic reticulum. Give the name or location
of this channel.
TRPM5 in plasmalemma
53. Relative to all the other G protein coupled receptors we have discussed
in this course, what is unusual about the ones for sweet and umami?
they are dimers
54. Relative to visual and auditory receptor cells, what is the notable
difference in the life expectancy of olfactory (and gustatory) receptor
taste and smell receptor cells die and get replaced
55. In addition to the 5 primaries for taste stimulation, with input via
cranial nerves VII, IX an X, it is argued that stimulants like capsaicin
contribute to our overall appreciation of gustation. Answer either (1) Which
cranial nerve is used? Or (2) What is the term for the receptor type?
5 trigeminal, polymodal nociceptive
56. Taste projected near to where the tongue's somatosensory representation
was on cortex. Relate this to the situation for olfaction.
smell, by contrast, projects to a deep, dark, mysterious assortment of places,
the limbic system
57. Why do male moths have more elaborate antennae than females?
to detect sex attractant pheromones from female
58. "A hallmark of mature glomeruli is that they are innervated exclusively
by axons from olfactory neurons expressing the same olfactory receptor."
What kind of molecule is this receptor?
G protein coupled receptor
59. Consecutive muscle twitches that come close enough together in time
fuse to a steady and stronger contraction. What is this called?
60. The numbers 13 vs 1730 were given for extraocular vs gastrocnemius muscles
respectively (and explained in terms of muscles for fine vs gross movement
respectively). 13 and 1730 what?
number of muscle cells (fibers) per motor unit (one spinal motor neuron)
61. What cells degenerate in ALS (amyotrophic lateral sclerosis, Lou Gehrig's
spinal motor neurons
62. How is it that, in the knee-jerk reflex, the flexor is inhibited from
through an inhibitory interneuron
63. "The motor loss from a half spinal cord lesion is more like the
lemniscal sensory loss than it is like the spinothalamic sensory loss."
decussation in medulla, so ipsilateral
64. Where are the cells that form the lateral and medial tracts of the pyramidal
65. Name a brain location other than the motor cortex that sends a motor
tract down the spinal cord.
reticular formation, vestibular nucleus, red nucleus, superior colliculus
return to syllabus
return to Stark home page
last revised 3/23/18