Respiratory physiology

Question 1

Dalton’s law

Answer 1

partial gas pressure is proportional to its abundance/percentage

Question 2

Henry’s law

Answer 2

At a given temperature, the amount of gas dissolved is proportional to its partial pressure

Question 3

Fick’s Law

Answer 3

Gas diffusion depends on molecular weight, solubility, surface area, membrane thickness

Question 4

Arriving blood at the alverolar membrane has _____ PO2 and ____ PCO2

Answer 4

Low PO2
High PCO2

Question 5

Arriving Air at the alveolar membrane has ____ PO2 and ___ PCO2

Answer 5

High PO2
Low PCO2

Question 6

What is the formula for perfusion and ventilation, and what is the typical value

Answer 6

V/Q = 0.8

Question 7

Why does alveoli air have more CO2 than the atmosphere

Answer 7

Alveoli have dead space that retains CO2. Also there is no gas exchange between breaths, which retain CO2.

Question 8

PO2 value in alveolar gas

Answer 8

100 mmHG

Question 9

PCO2 in alveolar gas

Answer 9

40 mmHg

Question 10

PCO2 in blood arriving to alveoli

Answer 10

45 mmHG

Question 11

PCO2 in atomostphere

Answer 11

3 mmHg

Question 12

PO2 in atmosphere

Answer 12

160 mmHg

Question 13

WHy does CO2 still diffuse with such a small pressure gradient

Answer 13

CO2 still diffuses because it is very soluble in plasma.

Question 14

Trace through the PULMONARY circuit

Answer 14

heart -> pulmonary artery -> pulmonary capillaries -> pulmonary vein -> heart

Question 15

Trace through the BRONCHIAL circuit

Answer 15

thoracic aorta -> bronchial artery -> capillaries in respiratory tissues -> bronchial vein -> pulmonary vein -> thoracic aorta

Question 16

What change does a rightward shift of the O2 dissociation curve represent?

Answer 16

decreased affinity of Hb for O2

Question 17

What change does a leftward shift of the O2 dissociation curve represent?

Answer 17

Increased affinity of Hb for O2

Question 18

What factors shift the curve to the right?

Answer 18

lower pH
higher temp
higher 2,3 BPG
higher PCO2
higher P50

Question 19

What factors shift the curve to the left?

Answer 19

higher pH
lower temp
lower 2,3 BPG
lower PCO2
lower P50

Question 20

what is P50

Answer 20

the PO2 when Hb is 50% saturated

Question 21

An increase in P50 ____ affinity for O2

Answer 21

decreases

Question 22

a decrease in P50 _____ affinity for O2

Answer 22

increases

Question 23

What is the Bohr effect and what does it facilitate>

Answer 23

Idea that increase in PCO2 decreases Hb affinity for O2. This facilitates O2 delivery at tissues.

Question 24

What is the 2 differences btwn fetal Hb and adult Hb

Answer 24

fetal Hb binds O2 better than adult Hb
- fetal Hb contains 2 gamma units instead of 2 beta units

Question 25

which way would a fetal O2 curve be shifted compared to adult

Answer 25

shifted to the left (increased affinity)

Question 26

what cells in the body detect hypoxia?

Answer 26

renal interstitial fibroblast

Question 27

How is hypoxia counteracted in the body?

Answer 27

renail interstitial fibroblasts increase erythropoietin release (EPO) to target bone marrow and increase RBC production.

Question 28

How is CO2 carried in the blood, roughly what percentage?

Answer 28

70% in the form of H2CO3 23% bound to Hb 7% dissolved in plasma

Question 29

What is the haldane effect and what does it facilitate?

Answer 29

idea that increased O2 (oxygenation) of Hb will decrease its affinity for CO2. Facilitates dumping of CO2 at lungs for exhalation.

Question 30

Hyperventilation leads to ____ CO2 levels

Answer 30

Hyperventilation leads to decreased CO2 levels

Question 31

does hyperventilation cause acidosis or alkalosis?

Answer 31

Hyperventilation causes alkalosis

Question 32

What is the bicarbonate equation?

Answer 32

CO2 + H2O <-> H2CO3 <-> H+ + HCO3-

Question 33

Does holding breath/decreasing respiration lead to acidosis or alkalosis?

Answer 33

acidosis

Question 34

What are the two way by which carbon monoxide poisoning can occur?

Answer 34

association or dissociation

Question 35

what is associative carbon monoxide poisoning

Answer 35

Carbon monoxide has a higher affinity for heme group than O2, therefore blocks by competitive binding

Question 36

what is dissociative carbon monoxide poisoning?

Answer 36

CO binding to heme decreases P50 (PO2 when 50% heme is sat). A decrease in P50 leads to an increase in O2 affinity, leading to less O2 being delivered to tissues.

Question 37

What is angiotensin converting enzymes (ACE) role in respiration?

Answer 37

controls blood pressure to influence blood flow in response to changes in PO2 or PCO2.