Exam 1                      Biology 326 Fall 2009                                  NAME:_____________________________

Answer the following questions ONLY in the space provided or designated. Points per question are given in parentheses.

1. (5) Describe a realistic mechanism by which a post-synaptic cell can become hyperpolarized.

2.(14) Define and explain the significance of the following terms:

           a. Tropic Hormone

           b. membrane resistance

           c. internal environment

           d. giant axons

           e. synergism

           f. autonomic nervous system

           g. Na⁺/K⁺ ATPase

3. (5) Explain how steroid hormones act to modify cellular activity

4.(10) ON THE BACK OF THIS PAGE Compare the regulation of Aldosterone and Cortisol by the adrenal gland.

5. (6) Describe how the effect of a typical G protein mediated hormone are turned off.

6. (5) How might a target cell modify its threshold for a hormone?

7.(5) What is the refractory period in a nerve cell and explain its significance in action potential propagation

8. (5) Compare and contrast spatial and temporal summation

9. (7) Compare and contrast the control of insect molting hormones with that of thyroid stimulating hormone.

10. (6)ON THE BACK OF THIS PAGE. In diagram/picture form illustrate the balance concept

11. (5) How does the nervous system differentiate modality and quality of a sensory signal.

12. (7) What are the morphological and functional differences between a typical chemical synapse and an electrical synapse?

13. (5) How do physiological systems design control systems to allow very exact regulation without suffering a catastrophe due to instability?

14. (15) ON THE BACK OF THIS PAGE. Draw and action potential. Label the different phases of this action potential and then indicate what membrane events are occurring during each phase.