COMPARATIVE ENDOCRINOLOGY

                                                                  Z426

Exam #1: 100 Points

 

Write your name and ID# on the back of the last page of the exam.  You have 55 minutes to complete this exam.  You should have 5 pages; there are 6 questions plus one extra credit question.  Please answer the questions as completely and specifically as you can.  Use the point values assigned to each question as a guide for the level of detail required for what I will consider a complete answer.  Feel free to continue your answers on the back of the pages if necessary.  Good luck!

 

1.       Provide the name of the functional class of chemical regulators in the space on the left that best (i.e., be as specific and accurate as you can) corresponds to or fits the description provided on the right. (2 pts. each).

 

a.                                               secreted by the axons of conventional neurons.

 

b.                                               cAMP and cGMP are members of this functional class of chemical regulators.

 

c.                                               secreted by an animal into the environment, they elicit rapid responses in receiving conspecifics.

 

d.                                               kinins and auxins and gibberellins (OH MY!).

 

e.                                               skunks emit an odor as a defense mechanism that falls into this class of chemical regulators.

 

f.                                                transmitted via the interstitial fluid to target cells.

 

g.                                               transmitted via the blood to target cells.

 

2.      Provide the name of the chemical class of chemical regulators in the space on the left that best (i.e., be as specific and accurate as you can) corresponds to or fits the description provided on the right. (2 pts. each).

 

a.                                               synthesized in the ribosomes of rough endoplasmic reticula, under the direction of DNA transcription, mRNA translation, and post-translational events.

 

b.                                               adrenaline and nor-adrenaline.

 

c.                                               androgens, estrogens, and corticosteroids.

 

d.                                         ญญญญญญญญญญ      inhibited by aspirin, these chemical regulators elicit diverse actions, such as smooth muscle contraction, fever, and inflammation.

 

e.                                               Prostaglandins, thromboxanes, and leukotrienes.

 

 

3.       Discuss how responses by target cells to peptide and protein hormones are eventually terminated (turned off) (10 pts.).

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

4.       Name the two distinctly different types of neurosecretory cells found in vertebrates, describe how they differ, give a specific example of a neurohormone secreted by each type, and describe how they differ in regard to how their secretions are conveyed to their targets (16 pts).

 

5.       Choose one of the following two questions to answer (25 pts.):

 

List the regions and subregions of the pituitary: 1) based on histoanatomy, and 2) based on embryological/functional divisions.  Then, discuss using diagrams of the embryogeny of the pituitary, how some tissues derived from stomodeal ectoderm and some derived from neural ectoderm ultimately appear in the posterior lobe in many vertebrates.  

 

OR     

 

Discuss: 1) the mechanism of action for peptide/protein chemical regulators in target cells, 2) why these regulators interact with target cells where they do, and 3) how fast target cells can respond in comparison to cells responding to steroid chemical regulators.

6.              Choose one of the following two questions to answer (25 pts.):

 

Discuss the synthesis, storage, and secretion of thyroid hormones.

 

OR

 

Discuss the transport, mechanism(s) of action in target cells, and metabolism and secretion of steroid regulators.

 

EXTRA CREDIT (4 pts.): If the concentration of radioactively labeled hormone in a RIA is 0.002 mg/L and there is a 66% reduction relative to the control in the radioactivity of the precipitate, what is the concentration of the unknown, non-labeled hormone?  Show your calculations.