Phys III - Exam 3 Flashcards
(33 cards)
At the end of expiration, what is the relationship between alveolar P, atmospheric P, and pleural P?
alveolar P = atmospheric P > pleural P
When would transpulmonary pressure be at its highest value?
when the lung is fully inflated
What expiratory muscle is an important spine stabilizer?
transverse abdominus
What is a major function of surfactant?
reduces surface tension
What happens to airway resistance during expiration?
increases
If physiologic dead space = 200 ml and anatomic dead space = 100, what is the nonfunctional alveolar volume?
100 ml
A person who is breathing at a rate of 12 breaths per minute with an average fluid volume of 450 ml per breath has an arterial PCO2 of 35 mmHg. What breathing pattern do they have?
hyperventilation
What three volumes/capacities cannot be determined with basic spirometry?
RV, FRC, and TLC
What effect will histamine binding to H2 receptors have on airway smooth muscle?
dilation
What local effect with Prostaglandin F series have on airway smooth muscle?
constriction
If alveolar oxygen is abnormally low, what effect would that have on vascular smooth muscle locally?
vasoconstriction
Without surfactant, as alveolar radius decreases, what happens to the collapse tendency of the lung?
increases
TRUE OR FALSE: Since carbon dioxide is slightly larger than oxygen, its diffusability in aqueous fluid is slightly less than that of oxygen.
false
At rest, flow near the apex of the lung when a person is in an upright position is best described as which of the following?
No flow
Intermittent flow
Continuous flow
intermittent flow
Compared to atmospheric air, alveolar air has a lower concentration of which of the following? Pick all correct responses.
nitrogen
oxygen
carbon dioxide
water vapor
nitrogen and oxygen
What effect does stimulation of the SNS have on sensitivity of central chemoreceptors to hypoxia?
increases
decreases
no effect
no effect (peripheral chemoreceptors)
Endogenous production of which of the following promotes vasodilation?
oxygen norepinephrine angiotensin II ADH carbon monoxide
carbon monoxide
Normally, what percentage of CO2 in the blood is simply dissolved?
7%
If the ventilation/perfusion ratio is .2, what is there an increase of?
physiologic shunt blood
The basic ventilatory response is set by neurons in which of the following areas?
ventral respiratory group dorsal respiratory group pneumotaxic center apneustic center spinal cord
dorsal respiratory group
Stimulation of pneumotaxic center would cause what change in breathing?
rapid and shallow
slow and deep
apnea
hyperpnea
rapid and shallow (because it inhibits the duration of inspiration)
Stimulation of stretch receptors in the lungs at tidal volumes greater than 1500 ml will have what effect on the dorsal respiratory group?
stimulate
inhibit
no effect
inhibit
Compared to a resting cardiac output, if the velocity of pulmonary capillary blood flow increases 3 fold, how would arterial PO2 be affected?
unchanged
“Under resting conditions blood is fully oxygenated by the time it has passed the first 1/3 of pulmonary capillary. Even if velocity increases 3x, full oxygenation occurs.” Slide 52
A deep sea diver is at 180 feet and is running low on his breathing gas. What would happen if he ascends too rapidly and doesn’t have ample time to decompress?
Nitrogen bubble out of blood/tissues and causes problems
“Nitrogen bubbles out of fluids after sudden decompression.” Slide 107
