BIOL 253 Lab Final (Labs 5-7) UPDATED
ACTUAL Exam Questions and CORRECT
Answers
Which of these statements is true regarding intrathoracic pressure during quiet inspiration? -
CORRECT ANSWER - It drops below atmospheric
What are the rate and depth of breathing increased by? - CORRECT ANSWER - A raised
pCO2 in the blood
During inspiration, the diaphragm and other chest muscles ______, causing the thoracic cavity to
______. - CORRECT ANSWER - contract; expand
What do you expect to happen to your rate and depth of breathing if you were to re-breathe your
expired air? - CORRECT ANSWER - Increase
What changes would you predict in your measurements of depth and rate of breathing if your
airways decreased in radius? - CORRECT ANSWER - If airways decrease in radius, the
depth and rate of respiration would increase. This is because decreasing the radius increases the
resistance. The body would not be able to move as much air because of the increased resistance
slowing down the flow of air. Therefore, the body will compensate with deeper respirations at a
faster rate.
Describe what is happening to the relative concentration of oxygen in the pulmonary veins when
you hold your breath. - CORRECT ANSWER - When we inhale, we bring O2 into the
lungs, which then gets absorbed into the blood and then carried throughout the body. The O2 is
used or made into energy to carry out bodily functions. What remains is CO2, which is carried
back into your lungs by the circulating blood and then released when we exhale. When we hold
our breath, we get the accumulation of CO2 in our cells, so our relative concentration of O2 will
decrease.
How does the pulse rate change during the breathing cycle? Describe the mechanism that leads
to this change. - CORRECT ANSWER - During a breathing cycle, air moves in and out of
, the lungs by bulk flow. The respiratory muscles are responsible for the changes in the shape and
volume of the chest cavity that cause the air movements in breathing. Heart rate varies with
respiratory pattern i.e. faster with inspiration, slower with expiration.
o The negative pressure in the chest during inspiration sucks up blood from the lower
extremities, causing an increase in blood returning to the right atrium. The heart rate speeds up to
circulate this extra blood.
o Respiratory sinus arrhythmia helps to match pulmonary blood flow to lung inflation and
maintain an appropriate diffusion gradient of oxygen in the lungs.
If exercise has consisted of isometric contractions (like holding a plank for 2 minutes), would
breathing change from a baseline? Why, why not? Would recovery be similar to what we saw
with star jumps? - CORRECT ANSWER - Isometric contractions would change breathing
pattern from baseline - muscles still require oxygen
Recovery would be similar to the star jumps but the amount of oxygen required by the muscles
would be less compared to an aerobic based exercise
During normal respiration at rest, when the ambient temperature is below body temperature, with
each breath: - CORRECT ANSWER - the volume of the exhaled gas exceeds that of the
inhaled gas
Why is the forced vital capacity less than the vital capacity? - CORRECT ANSWER -
While forcing air out of the lungs, the pressure outside the airways increases rapidly and
substantially. If this external pressure exceeds the pressure within the airways, unsupported
airways can collapse. This results in air being trapped within alveoli, and it is unable to be
expired and measured.
Compare the rate of breathing with hyperinflated lungs with that in normal breathing. What
effect will this have on blood gases? - CORRECT ANSWER - When you increase the rate
of breathing, you increase the minute volume required to ventilate the anatomical dead space.
For example, if the rate increases from 20 to 40 breaths/min, dead space ventilation will have
doubled from 3 (20 breaths/min x 0.15 L) to 6 L/min (40 breaths/min x 0.15 L). If you do this
calculation for your data you will find that the increased minute volume will largely reflect this
increased dead space ventilation. Therefore, alveolar ventilation will be relatively unchanged and
blood gases unaffected.
ACTUAL Exam Questions and CORRECT
Answers
Which of these statements is true regarding intrathoracic pressure during quiet inspiration? -
CORRECT ANSWER - It drops below atmospheric
What are the rate and depth of breathing increased by? - CORRECT ANSWER - A raised
pCO2 in the blood
During inspiration, the diaphragm and other chest muscles ______, causing the thoracic cavity to
______. - CORRECT ANSWER - contract; expand
What do you expect to happen to your rate and depth of breathing if you were to re-breathe your
expired air? - CORRECT ANSWER - Increase
What changes would you predict in your measurements of depth and rate of breathing if your
airways decreased in radius? - CORRECT ANSWER - If airways decrease in radius, the
depth and rate of respiration would increase. This is because decreasing the radius increases the
resistance. The body would not be able to move as much air because of the increased resistance
slowing down the flow of air. Therefore, the body will compensate with deeper respirations at a
faster rate.
Describe what is happening to the relative concentration of oxygen in the pulmonary veins when
you hold your breath. - CORRECT ANSWER - When we inhale, we bring O2 into the
lungs, which then gets absorbed into the blood and then carried throughout the body. The O2 is
used or made into energy to carry out bodily functions. What remains is CO2, which is carried
back into your lungs by the circulating blood and then released when we exhale. When we hold
our breath, we get the accumulation of CO2 in our cells, so our relative concentration of O2 will
decrease.
How does the pulse rate change during the breathing cycle? Describe the mechanism that leads
to this change. - CORRECT ANSWER - During a breathing cycle, air moves in and out of
, the lungs by bulk flow. The respiratory muscles are responsible for the changes in the shape and
volume of the chest cavity that cause the air movements in breathing. Heart rate varies with
respiratory pattern i.e. faster with inspiration, slower with expiration.
o The negative pressure in the chest during inspiration sucks up blood from the lower
extremities, causing an increase in blood returning to the right atrium. The heart rate speeds up to
circulate this extra blood.
o Respiratory sinus arrhythmia helps to match pulmonary blood flow to lung inflation and
maintain an appropriate diffusion gradient of oxygen in the lungs.
If exercise has consisted of isometric contractions (like holding a plank for 2 minutes), would
breathing change from a baseline? Why, why not? Would recovery be similar to what we saw
with star jumps? - CORRECT ANSWER - Isometric contractions would change breathing
pattern from baseline - muscles still require oxygen
Recovery would be similar to the star jumps but the amount of oxygen required by the muscles
would be less compared to an aerobic based exercise
During normal respiration at rest, when the ambient temperature is below body temperature, with
each breath: - CORRECT ANSWER - the volume of the exhaled gas exceeds that of the
inhaled gas
Why is the forced vital capacity less than the vital capacity? - CORRECT ANSWER -
While forcing air out of the lungs, the pressure outside the airways increases rapidly and
substantially. If this external pressure exceeds the pressure within the airways, unsupported
airways can collapse. This results in air being trapped within alveoli, and it is unable to be
expired and measured.
Compare the rate of breathing with hyperinflated lungs with that in normal breathing. What
effect will this have on blood gases? - CORRECT ANSWER - When you increase the rate
of breathing, you increase the minute volume required to ventilate the anatomical dead space.
For example, if the rate increases from 20 to 40 breaths/min, dead space ventilation will have
doubled from 3 (20 breaths/min x 0.15 L) to 6 L/min (40 breaths/min x 0.15 L). If you do this
calculation for your data you will find that the increased minute volume will largely reflect this
increased dead space ventilation. Therefore, alveolar ventilation will be relatively unchanged and
blood gases unaffected.
