PART 1: TRUE OR FALSE (1 point each)web.stanford.edu/dept/humbio/Core/aside/handouts/4b20… · Web viewPART 2: MATCHING (1 point each) Answer the following matching questions

Page 1 Code Number ____________

PART 1: TRUE OR FALSE (1 point each)

Pick up your number 2 pencil and your scantron sheet and get rolling! Put your NAME, SUID#, and TEST CODE NUMBER on both sides of the scantron immediately. Please bubble in 'A' if the statement is TRUE and 'B' if the statement is FALSE. Remember to be careful when bubbling in your answer. ERASE COMPLETELY.

1. Positive feedback loops are needed for maintaining homeostasis.

2. The enteric nervous system operates completely independently of the central and peripheral nervous systems.

3. Myelin sheaths exist only on neurons of the peripheral nervous system because of the long distances that signals must travel in the peripheral nervous system.

4. The Na+/K+ pump propagates action potentials down axons.

5. Movement of only a few sodium and potassium ions across a neuron's cell membrane is sufficient to cause an action potential.

6. The blind spot in your visual field is caused by the axons of the ganglion cells forming the optic nerve.

7. Amines, amino acids, purines, and peptides are all chemical classes of neurotransmitters.

8. Red/green colorblindness is caused by the mutation of either red or green retinal.

9. Ganglion cells in the retina are the only kind of sensory neurons in the body that have on-center/off-surround receptive fields.

10. Olfactory sensor cells that bind to odorants synapse directly onto the brain.

11. If an individual ate a spoonful of sugar, only one specific region of the tongue would be stimulated in response to the sugar.

12. For salty taste, salt provides sodium ions that enter taste receptor cells to depolarize the cells directly.


PART 2: MATCHING (1 point each)

Answer the following matching questions on your scantron. Remember to choose the BEST answer for each question.

MATCHING #1. Brain Anatomy Using the vocabulary word bank below, match the correct anatomical terms to the following descriptions of function. Words may be used more than once or not at all. Be as specific as possible.

13. contains primary somatosensory cortex14. "relay station" for visual and auditory information15. involved in transferring information to long-term memory16. lesion causes a syndrome that includes loss of inhibition, personality change 17. brainstem nuclei involved in alertness and arousal18. main brain area involved with language comprehension19. an element of the limbic system involved in fear and anger

Brain Vocabulary:a. frontal lobeb. temporal lobec. parietal lobed. occipital lobee. reticular formationab. hippocampusac. amygdalaad. hypothalamusae. thalamusbc. Broca's areabd. Wernicke's area


MATCHING #2. Neuron Structure The following diagram illustrates a neuron located in the Peripheral Nervous System.

Identify the numbered structures using the terms listed below. Words may be used more than once or not at all. Be as specific as possible.

Neuron Structure Vocabulary:a. Astrocyteb. Axonc. Axon Hillockd. Cell Bodye. Dendritesab. Oligodendrocyteac. Schwann Cellad. Synaptic bouton


MATCHING #3. Neuronal Ion Channels The following diagram illustrates a neuron located in the Central Nervous System.

For each of the following channel types, indicate the associated region along the neuron.If none of the neuron regions above match a channel type, enter "d" for that channel type.Letters may be used more than once or not at all.

25. Ligand-gated Calcium channels26. Ligand-gated Chloride channels27. Ligand-gated Potassium channels28. Voltage-gated Potassium channels29. Voltage-gated Sodium channels


MATCHING #4. Neuronal Action Potential The following diagram shows the voltage change occurring at a point along the axon during an action potential.

Identify the point along the graph that best corresponds to the following situations. Letters may be used more than once or not at all.

30. The cell is most permeable to sodium.31. The cell is most permeable to potassium.32. Resting potential is maintained.33. Voltage approaches equilibrium potential for potassium.


MATCHING #5. Ear Structure The following diagram shows structures involved in audition. Match the following terms to the best associated region.

Identify the numbered structures using the terms listed below. Words may be used more than once or not at all. Be as specific as possible.

34. semicircular canal35. ossicles36. oval window37. pinna38. tympanic membrane39. resonates to low pitch sound


MATCHING #6. Receptive Fields

For an Off-Center/On-Surround Receptive Field, how do the following cells respond to light shone in the center region only? Use the options listed below. Letters may be used more than once or not at all.

Options:a. increased depolarization: action potentialb. increased hyperpolarization: action potential c. increased depolarization: graded potentiald. increased hyperpolarization: graded potentiale. no change in tonic voltage

ab. increased rate of action potential firing ac. decreased rate of action potential firing

40. Center photoreceptors41. Surround photoreceptors42. Center bipolar cells43. Surround bipolar cells44. Ganglion cell


PART 3: MULTIPLE CHOICE (2 points each)

Move to the second column of your scantron answer sheet and begin bubbling in your answers to these questions in row 51. Remember to choose the BEST answer for each question. Again, be careful when you bubble in your answer. ERASE COMPLETELY.

51. Which of the following is NOT a way to obtain knowledge about the FUNCTION of the brain?

a. PET scansb. Functional magnetic resonance imaging (fMRI)c. Patients with brain damage and lesionsd. Studying homologies of brains of different speciese. All of the above are ways we know about brain function.

52. Voluntary motor control systems exemplify which of the following themes of brain organization?

a. Allocation of brain space corresponds to importance.b. More complex functions are localized to more anterior regions of the neuraxis.c. Pathways cross the midline.d. A and B only are themes of brain organization exemplified by the voluntary motor control systems.e. All of the above are themes of brain organization exemplified by the voluntary motor control systems.

53. Which of the following drug mechanisms of action could increase the neuromodulator activity of a neurotransmitter on neighboring cells?

a. Disruption of neutrotransmitter synthesis in the presynaptic cell.b. Blockage of fusion of vesicles with the presynaptic cell membrane.c. Increase of neurotransmitter reuptake in the presynaptic cell.d. Degradation of postsynaptic ligand-gated receptors in neighboring cells.e. Sequestration of reuptake proteins in the presynaptic cell.

54. Which of the following correctly differentiates between the action of nitric oxide (NO) and acetylcholine (ACh)?

a. NO can act as a paracrine signaling molecule; acetylcholine cannot.b. Ach binds to ligand-gated channels; NO does not.c. NO binds to voltage-gated channels; Ach does not.d. All of the above correctly differentiate between Ach and NO.e. None of the above correctly differentiate between Ach and NO.


55. Which of the following statements about integration in the visual system is TRUE?

a. Axons from ganglion cells end and form synapses in the occipital lobe.b. Retinotopic organization of visual information is preserved in the lateral geniculate nucleus

(LGN).c. If the optic chiasm is severed, visual information will reach the thalamus, but not the visual

cortex.d. Parvocellular layers of the LGN relay information about motion and flicker perception to the

cortex.e. Information from the left eye is only represented in the right occipital lobe.

56. Which of the following statements about how the auditory system transduces sound is FALSE?

a. Ossicles are used to amplify the signal.b. Sound is broken down into its Fourier components by the pinnae.c. If the Eustachian tube is clogged, pressure in the middle ear cannot be adequately equilibrated.d. In the cochlea, frequency of the sound is coded by position along the basilar membrane.e. Movements of stereocilia on hair cells are used to trigger changes in action potential firing

patterns in auditory sensory axons.

57. Umami is a taste associated with:

a. sugarsb. sodium ionsc. hydrogen ionsd. glutamatee. celery

58. Which of the following sensory systems use mechanosensors?

a. olfactoryb. gustatoryc. vestibulard. auditorye. more than one of the above


59. Which of the following is TRUE regarding sodium channels on a neuron?a. During an action potential, both inactivation or activation gates are never open simultaneously. b. At resting potential, prior to firing an action potential, the inactivation gate is closed and the

activation gate is open.c. At resting potential, prior to firing an action potential, the inactivation gate is open and the

activation gate is closed.d. The activation gate is shaped as "ball and chain" appendage on the intracellular face of the

channel. e. A and B are true regarding sodium channels on a neuron.

60. Which of the following statements are FALSE?

a. Two adjacent objects in space would signal adjacent LGN neurons.b. Two adjacent objects in space would signal adjacent visual cortex neurons.c. Although an object is projected upside-down on the retina, the right-left horizontal axis is

maintained.d. All six layers of the LGN have retinotopic linear receptive fields.e. Individuals blinded in one eye will not have the ability to perceive depth.

61. Which of the following statements about alpha motor neurons is TRUE?

a. There are two classes of alpha motor neurons, excitatory and inhibitory.b. Alpha motor neurons are used to adjust muscle spindle length in response to stretch.c. Alpha motor neurons primarily innervate and inhibit intrafusal muscle fibers.d. Alpha motor neurons are always excitatory and trigger muscle contraction. e. Alpha motor neurons are primarily used in the autonomic nervous system.


PART 4: SHORT ANSWER (34 points)

Please put away your scantron and take out a black or blue PEN. NO REGRADES will be given for answers written in pencil. Be sure to put your final answers on the lines and inside the boxes for each question. Answers that exceed the allotted space will not be graded.

PROBLEM #1 (7 points) Given below are the typical ion concentrations inside and outside a neuron:

Ion Species Concentration Inside Concentration OutsideK+ 490 30Na+ 50 480Cl- 50 560

A certain drug you administer alters a cell's membrane permeabilities to certain ionic species. The permeabilities change to:

PK+ : PNa+ : PCl- = 1 : 10 : 0.95

A. (3 points) Determine the equilibrium potential of the membrane for sodium, to two decimal places.

B. (3 points) Calculate the resting potential of the cell once it has been exposed to the drug, to two decimal places.

C. (1 point) Is this a higher or lower voltage than the resting potential of a neuron with normal permeabilities to ionic species? (Circle one)

HIGHER LOWER


PROBLEM #2 (15 points):

A. (9 points) A rod cell is exposed to red light.

i. (1 point) Put the following bolded terms in the order they change in response to light in this

rod cell. Order the numbers from what happens first to what happens last in the box below.

ii. (6 points) Circle the associated changes that occur in response to the red light.

1. cGMP: high levels low levels

2. chromophore: cis trans

3. glutamate: increased decreased

4. opsin: active inactive

5. Voltage of rod cell: depolarized hyperpolarized

6. Na+ channels: open closed

iii. (2 point) What is the role of phosphodiesterase in this transduction sequence?

(happens first) (happens last)


B. (2 points) The above rod responds to light in the surround of an OFF-CENTER, ON SURROUND ganglion receptive field.

i. (1 point) When this rod responds to red light, which channel will open in the associated

BIPOLAR CELL? (Circle one) Na+ K+

ii. (1 point) When this rod responds to a blue light, which channel will open in the associated

GANGLION CELL? (Circle one) Na+ Cl-

C. (4 points) A prism produces a horizontal green band of light (shown below) upon the temporal retina of the left eye, causing a neuron in the LGN to fire at a dramatically increased rate.

i. (2 points) Combining this knowledge with the description of the receptive field in Part B, identify where on the retina light activates the receptive field. Draw where the receptive field falls on this retina.

x x x x x x

x x x x x x x

x x x x x x x

x x x x retina

x x x x x x x

ii. (1 point) Which LGN will the green band be processed in? Left Right Both

iii. (1 point) Which visual cortex will the green band be processed in? Left Right Both


PROBLEM #3 (7 points)

You have discovered an animal that has a new, unknown sensory system. Congratulations! This new sensory system is chemosensory and you suspect that it is very similar to the olfactory system.

Based upon: 1) what you know about the general functional steps that all sensory systems must go through AND 2) your hypothesis that the new sensory system is very similar to the olfactory system, complete the following chart. Fill in the blanks such that each functional step in the flowchart on the left corresponds to an appropriate candidate mechanism in the flowchart on the right.

Functional Steps of a Sensory System Candidate Mechanism

Part B.

Effector Protein

Membrane channels open(Indicate: which ion? inward

or outward ion flow?)

Electrical response of sensory cell

Transmission to the brain

Signal Molecules

Signal Detection


PROBLEM #4 (5 points)

For the following question, assume that the animal model system is exactly like the human.

You are studying nervous system regulation of the mammalian heart by looking at the rat heart in vitro.

A. (4 points) You inject a dye into an axon synapsing onto the heart, and you discover that this axon comes from a cell body in a ganglion that is located very close to the heart. You stain for several neurotransmitters and discover this neuron secretes acetylcholine (ACh) onto the heart.

1. Knowing this, you can conclude that this neuron is probably part of the: (Circle one)

SENSORY / VOLUNTARY / SYMPATHETIC / PARASYMPATHETIC

nervous system.

2. This axon is an: (Circle one) AFFERENT / EFFERENT fiber.

3. You would expect to find: (Circle one) NICOTINIC / MUSCARINIC / ALPHA

receptors on the post-synaptic side of the synapses of this axon.

4. When this axon is actively firing action potentials, it will contribute to: (Circle one)

ACCELERATING HEARTBEAT / SLOWING HEARTBEAT.

B. (1 point) You stain the heart for adrenergic receptors and find many epinepherine receptors. What region of what organ is the primary source of the epinepherine that attaches to these receptors?


POSSIBLY USEFUL EQUATIONS

PLEASE DO NOT REMOVE THIS PAGE FROM YOUR EXAM!!

Ex (or Vx) = RT ln [X]outside cell = 58 mV log [X]outside cell

zF [X]inside cell [X]inside cell

Vm = 58 mV log PK[K+]out + PNa[Na+]out + Pcl[Cl-]in

PK[K+]in + Pna[Na+]in + Pcl[Cl-]out

SECTION POINTS POSSIBLE POINTSEARNED

TRUE/FALSE and MATCHING

44

MULTIPLE CHOICE 22

PROBLEM 1 7

PROBLEM 2 15

PROBLEM 3 7

PROBLEM 4 5

TOTAL 100

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PART 1: TRUE OR FALSE (1 point each)web.stanford.edu/dept/humbio/Core/aside/handouts/4b20… · Web viewPART 2: MATCHING (1 point each) Answer the following matching questions