CH. 17 Respiratory System: Gas Exchange and Regulation of Breathing

Question 1

Of the four hemoglobin proteins, how many hold oxygen rather than give it?

Answer 1

3 hold oxygen; 1 gives

Question 2

What does the ideal gas law state?

Answer 2

pressure of a gas depends on the temperature, number of gas molecules, and volume

Question 3

What is the definition for a partial pressure?

Answer 3

the partial pressure of a gas is the pressure that each gas in a mixture would exert if it were by itself in the container

Question 4

What does Dalton’s law of partial pressures indicate?

Answer 4

pressure depends on the total number of gas particles, not on the types of particles

Question 5

In what two forms do gas molecules exist?

Answer 5

1. gas form

2. dissolved in liquid

Question 6

What does partial pressure of a gas affect in regard to a solution?

Answer 6

the concentration (amount of gas) dissolved in solution

Question 7

Is carbon dioxide or oxygen more soluble in water?

Answer 7

carbon dioxide

Question 8

What do the diffusion of gases depend on?

Answer 8

gases diffuse down pressure gradients

Question 9

What is the partial pressure of oxygen and carbon dioxide in:

1. pulmonary veins
2. systemic arteries
3. cells
4. systemic veins
5. pulmonary arteries

Answer 9

Oxygen/Carbon Dioxide

1. 100 mm Hg / 40 mm Hg
2. 100 mm Hg / 40 mm Hg
3. less than or equal to 40 mmHg / greater than or equal to 46 mmHg
4. 40 mmHg / 46 mmHg
5. 40 mmHg / 46 mmHg

Question 10

What allows for a rapid diffusion between alveoli and blood?

Answer 10

1. small diffusion barrier

2. large surface area

Question 11

What is the concentration of oxygen and carbon dioxide that is exchanged in vascular bed dependent on?

Answer 11

metabolic activity of the tissue

- greater rate of metabolism = greater exchange

Question 12

What 3 factors affect alveolar partial pressures? Which is most critical?

Answer 12

1. Partial pressures of oxygen and carbon dioxide inspired
2. minute alveolar ventilation
3. rates at which respiring tissues use oxygen and produce carbon dioxide (most critical)

Question 13

What is hyperpnea?

Answer 13

increased ventilation due to increased demand

Question 14

What is hypoventilation?

Answer 14

ventilation does not meet demands

• arterial PO2 decreases
• arterial PCO2 increases

Question 15

What is hyperventilation?

Answer 15

ventilation exceeds demands

• arterial PO2 increases
• arterial PCO2 decreases

Question 16

How is most of the oxygen in blood transported?

Answer 16

transported by hemoglobin

Question 17

How many oxygens can hemoglobin bind?

Answer 17

up to four oxygen molecules

Question 18

What does saturation of hemoglobin refer to?

Answer 18

measure of how much oxygen is bound to hemoglobin

Question 19

What does a left shift on the hemoglobin-oxygen dissociation curve indicate?

Answer 19

more loading of oxygen and less unloading

Question 20

What does a right shift on the hemoglobin-oxygen dissociation curve represent?

Answer 20

less loading of oxygen and more unloading

Question 21

What effects does a higher temp. have on the hemoglobin-oxygen dissociation curve?

Answer 21

1. active tissues
2. shift right
3. more oxygen unloading in tissues
4. more oxygen delivery to tissues

Question 22

What effects does pH have on the hemoglobin-oxygen dissociation curve?

Answer 22

1. Bohr effect: lower pH and increases oxygen unloading
2. active tissues:
   - produce more acid; pH decreases in tissues
   - decreased pH causes shift right in saturation curve
   - more oxygen is unloaded to tissues

Question 23

What is produced when carbon dioxide reacts with hemoglobin?

Answer 23

carbaminohemoglobin

Question 24

What occurs when carbon dioxide reacts with hemoglobin?

Answer 24

increased metabolic activity and increased oxygen unloading in active tissue

Question 25

What role does carbonic anhydrase play in carbon dioxide transport?

Answer 25

• carbon dioxide exchange and transport in systemic capillaries and veins
• carbon dioxide exchange and transport in pulmonary capillaries and veins

Question 26

What nerves are involved in inspiration and what muscles do they act on?

Answer 26

phrenic nerve -> diaphragm

external intercostal nerve -> external intercostal muscles

Question 27

What nerves are involved in expiration and what muscle does it act on?

Answer 27

internal intercostal nerve -> internal intercostal muscle

Question 28

What are the two respiratory control centers located on each side of the medulla?

Answer 28

ventral respiratory group (VRG): nucleus ambiguus

dorsal respiratory group (DRG): nucleus tractus solitarius

Question 29

What is the purpose of the central pattern generator?

Answer 29

establishes respiratory cycle

Question 30

What components send peripheral information to the respiratory centers?

Answer 30

1. chemoreceptors
2. pulmonary stretch receptors
3. irritant receptors
4. muscle and joint proprioceptors

Question 31

What do chemoreceptors do? and What are the two types?

Answer 31

detect blood levels of oxygen and carbon dioxide

1. peripheral chemoreceptors in carotid bodies
2. central chemoreceptors in medulla oblongata

Question 32

What occurs when ventilation to certain alveoli decreases?

Answer 32

1. increased PCO2 and decreased PO2 in blood and air
2. increased PCO2 in bronchioles -> bronchodilation
3. decreased PO2 in P. arterioles -> vasoconstriction

Question 33

What occurs when ventilation to certain alveoli decreases?

Answer 33

1. increased PCO2 and decreased PO2 in blood and air
2. increased PCO2 in bronchioles -> bronchodilation
3. decreased PO2 in P. arterioles -> vasoconstriction

Question 34

What occurs if perfusion to certain alveoli decreases?

Answer 34

1. increased PO2 and decreased PCO2 in blood and air
2. increased PO2 in P. arterioles -> vasodilation
3. decreased PCO2 in bronchioles -> bronchoconstriction

Question 35

What regulates blood pH?

Answer 35

respiratory and renal systems