1.  Four years ago, Ms. Smith is referred to you after a routine gyn exam showed that her thyroid was enlarged.  She indicates that her aunt and her mother both take some sort of thyroid medication.  Ms. Smith denies any alterations in weight, disposition or energy level.  Her blood is drawn and shows that her TSH is 4.1 mU/L (normal 0.4-4.2) and that her T4 is 0.9 ng/dl (normal 0.8-2.7).

a.  Why is her thyroid gland enlarged? (0.5 points)
 
 

Ms. Smith visits you again (4 years later), complaining of weight gain, tiredness, and sensitivity to cold.  Her thyroid gland is enlarged even more than it was previously.  Her TSH concentrations are elevated (18.6) and her T4 is low (0.6).

b.  Is Ms. Smith hyperthyroid or hypothyroid? (0.5 points)
 

c.  Does Ms. Smith have a primary endocrine disorder of the thyroid or a secondary disorder?  (1 point)
 

d.  Why is TSH elevated? (1 point)

e.  Autoimmune antibodies against the TSH receptor are detected in Ms. Smith’s blood.  Are these receptor agonists or antagonists? (0.5 points)

2.  Mr. Jones is admitted to the emergency room after being stabbed.  He is hemorrhaging, and has a rapid, thready pulse.  His blood pressure is lower than usual, but still within normal limits.  What are the homeostatic mechnisms allowing blood pressure to be maintained? (3.5 points)
 

3.  Individuals with unrelieved hypertension sometimes develop congestive heart failure (CHF).

a.  Why would you expect to observe left ventricular hypertrophy? (1 point)

After some period of time, the hypertrophied left ventricle begins to fail, i.e. it cannot pump sufficient blood to maintain an adequate cardiac output.

b.  Why would you consider administering digitalis to this individual considering that its mechanism of action is to increase cytoplasmic calcium concentrations?  (1 point)