resp 5

Question 1

what is the gas composition in the alveoli?

Answer 1

determines rate of O2 and CO2 diffusion between alveoli and capillaries

PO2 and PCO2 remain relatively constant during quiet respiration
O2 entering=O2 uptake
-fresh air diluted upon entering the lungs

Question 2

what is the graph of alveolar gases?

Answer 2

Question 3

Alterations in ventilation rate _______________

Answer 3

-alterations in ventilation rate independent of changes in the CVS will alter partial pressures of O2 and CO2, thus altering diffusion

Question 4

how is ventilation and alveolar blood flow (perfusion) matched?

Answer 4

bringing O2 from the atmosphere into the alveoli is only the first step of external respiration
-blood flow must be high enough to pick up available O2
-wasted ventilation/perfusion (when overworking of an organ)

Question 5

what is an example of local regional control?

Answer 5

gravity
-blood flow is higher at the base of the lung

Question 6

what happens to the lung because of gravity?

Answer 6

-more negative intrapleural pressure due to gravity at apex means alveoli are partially open and filled even at rest and therefore do not take in much air during ventilation

Question 7

what is the local control of ventilation and perfusion in the pulmonary arterioles?

Answer 7

-very little autonomic innervation

pul art primary influenced by decreasing O2 levels around them
-decreases in O2 cause constriction, opposite of systemic CVS (dilate) (presence of O2 sensitive K+ channels)

Question 8

what is the local control of ventilation and perfusion of bronchioles?

Answer 8

-bronchioles are sensitive to CO2 levels, increases (dilates) or decreases (constricts)

Question 9

what is the graph of local control?

Answer 9

Question 10

what happens when a blood clot prevents gas exchange?

Answer 10

Question 11

what is the summary slide of local control of ventilation/perfusion

Answer 11

Question 12

what is the graph of pulmonary gas exchange and transport?

Answer 12

Question 13

what is hypoxia and hypercapnia?

Answer 13

impaired diffusion from alveoli to blood or impaired blood transport results in hypoxia (too little oxygen)
-hypercapnia is often paired with (excess CO2)

Question 14

to avoid hypoxia and hypercapnia, the body has sensors to monitor the arterial blood and respond to three variables:

Answer 14

1. oxygen: ATP production
2. carbon dioxide: CNS depressant/ acid precursor
3. pH: denaturing of protein

Question 15

what are the types of hypoxia and the normal blood values in pulmonary medicine?

Answer 15

Question 16

what is the graph of how gases diffuse down partial pressure gradients?

Answer 16

Question 17

what is the web of alveolar gas exchange?

Answer 17

Question 18

what are two causes of low alveolar PO2 assuming perfusion remains constant:

Answer 18

1. inspired air has low O2 content
   -atmospheric pressure: PO2 at sea level is 160mm Hg, in Denver PO2 is 132mm Hg
2. alveolar ventilation
   -if atmospheric PO2 is normal and alveolar PO2 is still low then it must be a ventilation issue (hypoventilation)
   -Increased airway resistance, decreased lung compliance, or CNS issue (resp control center) decrease rate and/or depth of breathing

Question 19

Hypoxia can be caused by ________________________

Answer 19

inadequate amounts of O2 reaching alveoli

Question 20

what is another cause of hypoxia?

Answer 20

-if perfusion remains constant and hypoxia is not caused by hypoventilation or alterations in atmospheric PO2 then the problem usually lies within gas exchange between alveoli and blood