Gas exchange and gas transport

Question 1



Question 2

Concentration and pressure are __________ related

Answer 2

Directly

Question 3

External ventilation stage two: pulmonary gas exchange (diffusional exchange of gases between _________ and _________. 

Answer 3

Alveolus and pulmonary capillaries

Question 4

Dalton’s law

Answer 4

Partial pressure: in a mixture of gases,

P(total) = P1 + P2 +P3 +…

Question 5

Henry’s law

Answer 5

Cg= Kg (Pg)

Cg= [g] in water
Pg= partial pressure of the gas in the air
Kg= henry’s constant (solubility of the gas in water) 

More simply, P= C if we know something about the solubility of the gas and water

Question 6

This law compares partial pressures in the air and solubility in water

Answer 6

Henry’s law

 *because Alveolus is lined with water

• CO2 is about 20 times more soluble in water than oxygen

Question 7

Three determinants of alveolar gas

Answer 7

1) metabolic rate
2) atmosphere P(gas)
3) ventilation rate

Question 8

(CO2 or oxygen) highest in cells and lowest in atmosphere

Answer 8

CO2

Opposite for oxygen

Question 9

What is the order of diffusion from the alveolar air space through the respiratory membrane to the capillary?

Answer 9

• Type 1 cell (epithelial cell in alveolar wall)
• areolar basement membrane
• capillary basement membrane
• endothelial cell in capillary wall
• opposite diffusional gas exchange occurs between systemic capillaries and tissues 

Question 10

External ventilation stage three….

Answer 10

Gas transport (transport of O2) 

Question 11

 ____% of O2 dissolved in plasma (this is the PO2)

____% carried on hemoglobin

Answer 11

1

99

Question 12

How many subunits does hemoglobin have?

Answer 12

For subunits. 02 can stick and carry four 02 molecules

Question 13

What causes the curve line instead of a straight line for the hemoglobin-oxygen disassociation curve.

Answer 13

Corporative binding 

Question 14

Key physiologic factors affecting Hb-O2 affinity

Answer 14

1. pH (Bohr effect)
2. Temperature
3. CO2 (carbamino effect)

Question 15

How does pH (Bhor effect) effect Hb-O2 affinity?

Answer 15

• H + bind to allosteric region of hemoglobin and decrease the affinity for O2
• Acid helps hemoglobin release O2 for use

Question 16

How does temperature affect Hb-O2 affinity?

Answer 16

An increase in temperature helps get more oxygen??

Question 17

How does CO2 (carbamino effect) influence Hb-O2 affinity? 

Answer 17

CO2 combined to a different allosteric site than H+

P(CO2) decreases and % of Hb increases

Question 18

Of total CO2 carried in the blood:
____% dissolved in plasma (PCO2)
____% carried on hemoglobin
____% dissolved in blood as bicarbonate ion (HCO3-) 

Answer 18

5
7
88

Question 19

At tissues, CO2 diffuses into blood and is converted into ________. At Long, bicarb is converted back to CO2 and diffuses into Alveolus 

Answer 19

Bicarbonate 

Question 20

When CO2 increases the results in the formation of each plus which….

Answer 20

Lowers pH (Bhor effect) 

Question 21

If H+ introduced form some other source, bicarb can act as a

Answer 21

Buffer

Question 22

There’s a close relationship between _____, _______, and pH

Answer 22

CO2, bicarb

Question 23

Henderson – Hasselbalch equation

Answer 23

pH= 6.1 + Log. [HCO3-]/ [CO2]

Question 24

What are The two things that affect acid/base disturbances?

Answer 24

1.  respiratory (always due to changes in PCO2) 

2. Metabolic (changes in bicarbonate) 

Question 25

Acidosis ——-> ________ PCO2 and _____ HCO3-

Alkalosis ——-> _________ PCO2 and _____ HCO-3

Answer 25

Increase, decreases

Deceases, increases

Question 26

Hyperventilation

Answer 26

ventilation above metabolic demand. Remove excess CO2, respiratory alkalosis
* anxiety 

Question 27

Hypoventilation

Answer 27

Ventilating below metabolic demand. Respiratory acidosis

* usually in morbidly obese

Question 28

Detect CO2, H +, 02. Very insensitive to 02 compared to others

Answer 28

Chemoreceptors

Question 29

Location of peripheral chemoreceptors

Answer 29

Carotid body

Question 30

Location of central chemoreceptors

Answer 30

Pons and medulla

Question 31

Adjustment of ventilation to match metabolic demand

Answer 31

hyperpnea