Important Note:

It is permitted to work on these problems as a group but you must write out your answers in your own words on your own.
Otherwise it will not help you to understand the physiology.

1.  I have decided that you all deserve a wonderful holiday at the end of our semester studying physiology so I have invited you to a
party at my parents’ home.  Their home is located on a mountain outside of Masonville Colorado (altitude 3000 feet).  At this
altitude, atmospheric pressure is approximately 640 mm Hg rather than 760 mm Hg.  What do you predict will happen to these
endpoints (increase, decrease, no change)?  Explain your answers (0.5 points each)
 a.  PO2 of air

 b.  PO2 of arterial blood

 c.  percent hemoglobin saturation (arterial blood)

 d.  Depth of breathing (tidal volume)

 e.  Arterial PCO2

 f.  Arterial pH

2.  What do you predict will happen to the following endpoints in an individual (at sea level) who suffers from sleep apnea?  Explain
your answers (0.5 points each)

 a.  PO2 of arterial blood

 b.  PCO2 of arterial blood

 c.  airway resistance while lying down

 d.  What is CPAP and why is it used?

3.  How would plasma osmolarity change in the following situations (increase, decrease, no change)?  When would ADH be
secreted? (0.5 points each)

 a.  Drinking a large volume of plain H2O

 b.  I.V. isotonic saline

 c.  Drinking salt water (hypertonic saline)

 d.  Eating salted pretzels without drinking water

 e.  Sweating heavily and drinking water to replace volume

 f.  Sweating heavily and drinking Gatorade to replace volume

 g.  Dehydration due to low fluid intake

 h.  Hemorrhage

4.  In an individual with congenital adrenal hyperplasia, the adrenal medulla cannot synthesize aldosterone due to a defective enzyme
in the steroidognic pathway.  What would you expect to see regarding sodium and potassium concentration in urine and plasma in this
individual? ( 1point)