Quiz 5

Question 1

What is cellular respiration?

Answer 1

Intracellular processes using oxygen to generate ATP + CO2 + H2O

Question 2

What is external respiration?

Answer 2

Movement of gases between atmosphere & cells

Question 3

What are the types of external respiration?

Answer 3

1. Ventilation
2. Gas exchange in the pulmonary circuit
3. Gas transport in the blood
4. Gas exchange in the systemic circuit

Question 4

What are the functions of external respiration?

Answer 4

-support cellular respiration
-regulation of pH via retention or elimination of CO2

Question 5

What is alveolar ventilation (Va)?

Answer 5

Volume of fresh air that reaches alveoli per minute

Question 6

What is hyperventilation?

Answer 6

Increase Va

Question 7

What is hypoventilation?

Answer 7

Decreased Va

Question 8

What are the 2 outcomes if ventilation is inadequate?

Answer 8

-Hypoxia = insufficient O2 availability to cells
-Hypercapnia = elevated CO2 levels

Question 9

What does gas exchange (diffusion) require at lungs & tissues?

Answer 9

A gradient in partial pressure.

Question 10

What is partial pressure (Pgas)?

Answer 10

Pressure of a single gas

Question 11

What is Dalton’s Law?

Answer 11

Total pressure exerted by mixture of gases = sum of pressures exerted by individual gases

Question 12

At sea level what is the Patm?

Answer 12

760 mmHg

Question 13

What happens to Pgas and Patm at different altitudes?

Answer 13

Pgas & Patm change, but % gas in atmosphere is constant

Question 14

What is the normal Po2 in our alveoli?

Answer 14

100 mmHg

Question 15

What is the normal Pco2 in our alveoli?

Answer 15

40 mmHg

Question 16

What happens to alveolar Po2 & Pco2 if we hypoventilate?

Answer 16

PO2 Decr. & PCO2 Incr.

Question 17

What happens to alveolar Po2 & Pco2 if we hyperventilate?

Answer 17

PO2 Incr. & PCO2 Decr.

Question 18

In peripheral tissues what is the PO2?

Answer 18

40 mmHg

Question 19

In peripheral tissues what is the PCO2?

Answer 19

46 mmHg

Question 20

What are the factors that increase alveolar gas exchange?

Answer 20

• Incr. partial pressure gradient
• Incr. surface area
• decr. diffusion distance

Question 21

What are conditions that decrease alveolar gas exchange?

Answer 21

-Decr. surface area
- Decr. partial pressure gradient
- Incr. diffusion distance

Question 22

What is Henry’s Law?

Answer 22

Movement of gas from air to liquid is proportional to:
1. Solubility
2. Pressure Gradient

Question 23

What is the Law of mass action?

Answer 23

-Incr. Plasma PO2 causes incr. in binding
-Decr. in plasma PO2 causes decr. in binding and more release O2

Question 24

What does the amount of O2 bound to Hb depend on?

Answer 24

-% saturation of Hb due to Po2
-Number of O2 binding sites (# of RBCs & Hb content per RBC)

Question 25

What is the oxyhemoglobin saturation curve?

Answer 25

Shows % of available binding sites occupied determined by plasma Po2

Question 26

Why is the shape of the oxyhemoglobin saturation curve important?

Answer 26

Sigmodial “S” shape important for delivering O2 to active tissues

Question 27

What does a right shift curve in the oxyhemoglobin saturation curve mean?

Answer 27

Right-shifted curve occurs in active or chronically hypoxic tissues and increases O2 delivery to cells

Question 28

What is a right shift curve in the oxyhemoglobin saturation curve caused by?

Answer 28

-Incr. PCo2
-Decr. pH (due to more lactic acid)
-Incr. temperature
-Incr. 2,3-BPG

Question 29

What is 2,3-BPG?

Answer 29

A molecule that is a byproduct of cellular metabolism in chronically hypoxic cells

Question 30

What are the 3 ways CO2 is transported in the blood?

Answer 30

1. Dissolved in plasma: 7%
2. Bound to hemoglobin: 23%
3. Converted to bicarbonate: 70%

Question 31

What is the law of mass action for bicarbonate?

Answer 31

-Hypercapnia –> right shift –> incr. H+ = acidosis
-Hypocapnia –> left shift –> decr. H+ = alkalosis