NAME _____________________

NAME ______________________

1. Give a physiological definition for each term. (20 points)

integrator

positive feedback

paracrine

exocrine

nitric oxide

membrane potential

G-protein

second messenger

saltatory conduction

chemoreceptor

2. Diagram/explain how and where effectors are involved in pool maintenance. (5 points)

3. Draw plots of cell activity for the following cells on a graph, labeling each with the appropriate letter. (10 points)

a. phasic and graded (* = strong stimulus; # = weak stimulus)

b. phasic and all-or-none (* = subthreshold stimulus; # = maximum stimulus)

c. tonic and graded (* = weak stimulus; # = strong stimulus)

d. tonic and all-or-none (* = threshold stimulus; # =maximum stimulus)

4. What makes some cells respond to a chemical messenger, while other cells do not respond? What determines the magnitude of this response? (5 points)

5. For each observation made during extracellular recording of a compound nerve, give a brief interpretation of the underlying physiology. (5 points)

OBSERVATION	INTERPRETATION
Destruction between recording electrodes makes the compound AP monophasic.
A compound AP is obtained when the nerve is stimulated at either end.
Graded response to increasing voltage above threshold.
Cold ringers shifts the compound AP to the right.
A second compound AP is not seen when two stimuli are 2 msec apart.

6. Name the labeled parts of the following recording from inside a post-synaptic neuron, and how ion channels are involved. (10 points)

	NAME	CHANNEL ACTIVITY
a
b
c
d

7. What role do equilibrium potentials play in the production of an action potential? (5 points)

8. Discuss the advantages/disadvantages of monosynaptic vs. polysynaptic spinal reflexes. (5 points)

9. Diagram the similarities/differences between the efferent nervous pathways. (10 points)

10. Define sensory adaptation in general terms. Then, select one sensory receptor and explain in detail how it adapts. (5 points)

11. REWRITE the following events in signal transduction of rods into the proper sequence, in the space provided. (5 points)

sodium channels close _______________________________________________

neurotransmitter release is decreased _______________________________________________

phosphodiesterase is activated _______________________________________________

rhodopsin is activated by photons _______________________________________________

cGMP is converted to GMP _______________________________________________

12. Select any hair cell, and explain how the appropriate stimulus leads to the generation of a receptor potential. (5 points)

13. Explain how damage from excess stretch (both passive and active) on joints is prevented by spinal reflexes. (5 points)

14. WHO AM I? Identify the sensory receptor by the clues. (5 points)

_______________________________ microvilli, olfactory mucosa

_______________________________ rapid deformation of cell membrane

_______________________________ frog keeps head level on tilted board

_______________________________ photopigment other than rhodopsin

_______________________________ rate of key chemical reaction