Author Question: A healthy 33-year-old woman relocates to an area approximately 8000 ft above sea level. On her first ... (Read 99 times)

nelaaney · **on:** Jul 16, 2018

A healthy 33-year-old woman relocates to an area approximately 8000 ft above sea level. On her first day, she begins to hyperventilate, but in 24 hr she shows signs of recovery. What is the probable cause of her condition?

a. Hypoxemia-mediated hyperventilation
b. Hypercapnia
c. Hyperoxia-mediated hyperventilation
d. Increased H+

Question 2

A patient in the emergency room is displaying prolong inspiratory gasps interrupted by occasional expirations, what serious injury should be suspected on this patient?

1. Pneumotaxic center has been severed.
2. Vagus nerve has been severed.
3. Glossopharyngeal nerve has been severed.
a. 2 and 3 only
b. 1 and 2 only
c. 1 and 3 only
d. 1, 2, and 3

whitcassie · **Reply #1 on:** Jul 16, 2018

Answer to Question 1

ANS: A
High altitude causes a healthy person's ventilation to increase because low barometric pressure decreases the inspired PO2, and thus the arterial PO2, which in turn raises the sensitivity of pe-ripheral chemoreceptors to H+. The resulting increase in ventilation is less than expected, though, because hyperventilation lowers the PaCO2 and raises arterial pH.

Answer to Question 2

ANS: B
If a situation occurs where the higher pneumotaxic center and vagus nerves were severed, the DRG inspiratory neurons would fail to switch off, causing prolonged inspiratory gasps inter-rupted by occasional expirations (apneustic breathing). Vagal and pneumotaxic center impulses hold the apneustic center's stimulatory effect on DRG neurons in check.