BSC2086 Lecture Exam 3 Questions and Answers with Verified
Solutions | Latest Update
QUESTION
Ch 22. Inspiration: sequence of events
Answer:
1. Inspiratory muscles contract (diaphragm descends; rib cage rises).
2. Thoracic cavity volume increases.
3. Lungs are stretched; intrapulmonary volume increases.
4. Intrapulmonary pressure drops (to -1 mm Hg).
5. Air (gases) flows into lungs down its pressure gradient until intrapulmonary pressure is 0
(equal to atmospheric pressure).
QUESTION
Ch 22. Expiration: What drives quiet expiration?
Answer:
Quiet expiration is a passive process in healthy people that depends more on lung elasticity than
muscle contraction.
QUESTION
Ch 22. Expiration: sequence of events
Answer:
1. Inspiratory muscles relax (diaphragm rises; rib cage descends due to recoil of costal cartilages).
2. Thoracic cavity volume decreases.
3. Elastic lungs recoil passively; intrapulmonary volume decreases.
4. Intrapulmonary pressure rises (to 11 mm Hg).
5. Air (gases) flows out of lungs down its pressure gradient until intrapulmonary pressure is 0.
QUESTION
Ch 22. What is a substance made in the body that impacts alveolar surface tension? How does it
substance work?
Answer:
SURFACTANT To counteract water and prevent alveolar collapse the body creates surfactant, a
detergent-like lipid and protein complex that helps reduce surface tension of alveolar fluid œ
reduces energy needed to overcome surface tension for lung expansion
, QUESTION
Ch 22. Chemical factors influencing breathing rate and depth. One is more important than the
others.
Answer:
Changing levels of PCO2, PO2, and pH all influence breathing rate and depth. The most
important is the influence of PCO2.
-If blood PCO2 levels rise, CO2 accumulates in brain and joins with water to become carbonic
acid.
-If blood PCO2 levels decrease, respiration becomes slow and shallow, possibly resulting in
breathing cessation called Apnea.
QUESTION
Ch 22. Pressures associated with the lungs. What are the ones listed here and what is their
purpose. (Intrapleural pressure/Intrapulmonary pressure)
Answer:
Intrapleural pressure: pressure in the pleural cavity that fluctuates with breathing. It becomes
more negative as chest wall expands during inspiration. Intrapulmonary pressure: pressure in
alveoli aka intra-alveolar pressure that fluctuates with breathing. It decreases during inspiration
(+lung volume) and increases during expiration.
QUESTION
Ch 22. Oxygen Transport: Be familiar with and understand the oxygen-hemoglobin dissociation
curve
Answer:
PO2 heavily influences binding and release of O2 with hemoglobin. The oxygen-hemoglobin
dissociation curve is an S-shaped curve that represents the percent of Hb saturation plotted
against PO2 concentrations.
QUESTION
Ch 22. Oxygen Transport: How do changes in pH and BPG concentration impact hemoglobin's
affinity for oxygen (i.e. hemoglobin's oxygen carrying capacity).
Answer:
Increasing the pH of blood therefore increases hemoglobins affinity for oxygen. Increase in BPG
can modify the structure of hemoglobin, decreasing its affinity for O2.
Solutions | Latest Update
QUESTION
Ch 22. Inspiration: sequence of events
Answer:
1. Inspiratory muscles contract (diaphragm descends; rib cage rises).
2. Thoracic cavity volume increases.
3. Lungs are stretched; intrapulmonary volume increases.
4. Intrapulmonary pressure drops (to -1 mm Hg).
5. Air (gases) flows into lungs down its pressure gradient until intrapulmonary pressure is 0
(equal to atmospheric pressure).
QUESTION
Ch 22. Expiration: What drives quiet expiration?
Answer:
Quiet expiration is a passive process in healthy people that depends more on lung elasticity than
muscle contraction.
QUESTION
Ch 22. Expiration: sequence of events
Answer:
1. Inspiratory muscles relax (diaphragm rises; rib cage descends due to recoil of costal cartilages).
2. Thoracic cavity volume decreases.
3. Elastic lungs recoil passively; intrapulmonary volume decreases.
4. Intrapulmonary pressure rises (to 11 mm Hg).
5. Air (gases) flows out of lungs down its pressure gradient until intrapulmonary pressure is 0.
QUESTION
Ch 22. What is a substance made in the body that impacts alveolar surface tension? How does it
substance work?
Answer:
SURFACTANT To counteract water and prevent alveolar collapse the body creates surfactant, a
detergent-like lipid and protein complex that helps reduce surface tension of alveolar fluid œ
reduces energy needed to overcome surface tension for lung expansion
, QUESTION
Ch 22. Chemical factors influencing breathing rate and depth. One is more important than the
others.
Answer:
Changing levels of PCO2, PO2, and pH all influence breathing rate and depth. The most
important is the influence of PCO2.
-If blood PCO2 levels rise, CO2 accumulates in brain and joins with water to become carbonic
acid.
-If blood PCO2 levels decrease, respiration becomes slow and shallow, possibly resulting in
breathing cessation called Apnea.
QUESTION
Ch 22. Pressures associated with the lungs. What are the ones listed here and what is their
purpose. (Intrapleural pressure/Intrapulmonary pressure)
Answer:
Intrapleural pressure: pressure in the pleural cavity that fluctuates with breathing. It becomes
more negative as chest wall expands during inspiration. Intrapulmonary pressure: pressure in
alveoli aka intra-alveolar pressure that fluctuates with breathing. It decreases during inspiration
(+lung volume) and increases during expiration.
QUESTION
Ch 22. Oxygen Transport: Be familiar with and understand the oxygen-hemoglobin dissociation
curve
Answer:
PO2 heavily influences binding and release of O2 with hemoglobin. The oxygen-hemoglobin
dissociation curve is an S-shaped curve that represents the percent of Hb saturation plotted
against PO2 concentrations.
QUESTION
Ch 22. Oxygen Transport: How do changes in pH and BPG concentration impact hemoglobin's
affinity for oxygen (i.e. hemoglobin's oxygen carrying capacity).
Answer:
Increasing the pH of blood therefore increases hemoglobins affinity for oxygen. Increase in BPG
can modify the structure of hemoglobin, decreasing its affinity for O2.
