Exam 2: chapter 28

Question 1

What is the function of type 2 pneumocytes?

Answer 1

secrete surfactant proteins to reduce surface tension

Question 2

neuromechanical control of ventilation includes

Answer 2

respiratory center, central and peripheral chemoreceptors

Question 3

where are central chemoreceptors located?

Answer 3

located in the medulla oblongata, PaCO2 controlled.

Question 4

Where are Peripheral chemoreceptors located?

Answer 4

located in the carotid or aortic arch. they are PaO2 and blood pH controlled

Question 5

what is the respiratory center affected by and what does it affect?

Answer 5

Affected by the central and peripheral chemoreceptors
Affects muscles of breathing → alveolar ventilation

Question 6

define recoil

Answer 6

Recoil: tendency of the lungs to return to resting state after inspiration
- Recoil decreases with age

Question 7

define compliance

Answer 7

Compliance: measure of lung and chest wall distensibility
-Compliance decreases with age

Question 8

What is the oxyhemoglobin curve?

Answer 8

A sigmoid curve that describes visually how oxygen binds to hemoglobin

Question 9

Oxyhemoglobin curve: What factors produce a shift to the right vs left? Why?

Answer 9

A right shift indicates decreased oxygen affinity of hemoglobin allowing more oxygen to be available to the tissues. A left shift indicates increased oxygen affinity of hemoglobin allowing less oxygen to be available to the tissues.

A decrease in the pH shifts the curve to the right, while an increase in pH shifts the curve to the left. This occurs because a higher hydrogen ion concentration causes an alteration in amino acid residues that stabilizes deoxyhemoglobin in a state (the T state) that has a lower affinity for oxygen.

A decrease in CO2 shifts the curve to the left, while an increase in CO2 shifts the curve to the right. CO2 causes an increase in H+ ion concentrations and a decrease in the pH, which will shift the curve to the right as explained above.

An increase in temp shifts the curve to the right and a decrease causes a shift to the left. Increasing the temperature denatures the bond between oxygen and hemoglobin, which increases the amount of oxygen and hemoglobin and decreases the concentration of oxyhemoglobin

Bohr effect – the shift in the oxyhemoglobin dissociation curve caused by changes in CO2 and hydrogen ion in the blood

Question 10

Which of the following would increase airway resistance? SELECT ALL THE APPLY

a. Bronchodilation
b. Bronchoconstriction
c. Edema of bronchial mucosa
d. Mucus
e. Airway tumors
f. Airway foreign bodies
g. High altitude - just less oxygen and doesn’t change airway resistance (air is thinner)

Answer 10

b. Bronchoconstriction
c. Edema of bronchial mucosa
d. Mucus
e. Airway tumors
f. Airway foreign bodies

Question 11

Which of the following would increase the work of breathing? SELECT ALL THAT APPLY

a. pulmonary edema
b. A decrease in chest wall compliance (spinal deformity, obesity) - decreased elasticity
c. Airway obstruction (bronchospasm, mucous plugging)
d. Asthma
e. Pain?

Answer 11

a. pulmonary edema
b. A decrease in chest wall compliance (spinal deformity, obesity) - decreased elasticity
c. Airway obstruction (bronchospasm, mucous plugging)
d. Asthma
Pain? - it depends - is it a lung issue? Finger cut? Sometimes it doesn’t increase the work of breathing