Ch 18

Question 1

What is the primary variable that the body senses to regulate respiration?

Answer 1

CO2 levels

Question 2

What is the normal partial pressure of O2 in the arteries and veins?

Answer 2

100 mm Hg in the arteries
≤ 40 mm Hg in the veins

Question 3

What is the normal partial pressure of CO2 in the arteries and veins?

Answer 3

40 mm Hg in the arteries

≥ 46 mm Hg in the veins

Question 4

What does it mean that diffusion goes to completion in external and internal respiration?

Answer 4

The O2 and CO2 levels of the blood match the levels in the alveolar space (external) and tissues (internal)

Question 5

What kind of lung disease is a product of low compliance?

Answer 5

Restrictive lung disease

Question 6

What condition results from the destruction of alveoli? What else results from this?

Answer 6

Emphysema

This also causes less surfactant production

Question 8

How much of the O2 in our blood isn’t bound to hemoglobin?

Answer 8

2%

Question 9

What is the Bohr effect?

Answer 9

Lower pH values lower the hemoglobin’s affinity for oxygen, making it easier to deliver to tissues

Question 10

What things shift the oxygen-hemoglobin binding curves to the right?

Answer 10

pH (lower pH -> right)
Temperature (higher temperature -> right)
Partial pressure of CO2 (higher pressure -> right)
Amount of 2,3-DPG (more 2,3-DPG -> right)

Question 11

What percentage of CO2 in the blood is
1. dissolved
2. Converted to bicarbonate ion
3. Bound to hemoglobin

Answer 11

1. 7%
2. 70%
3. 23%

Question 12

What 3 molecules bind to hemoglobin?

Answer 12

O2
CO2
H+

Question 13

What passive transport mechanism allows for the flow of HCO3- across the RBC in exchange for Cl-?

Answer 13

The chloride shift

Question 14

Where are the peripheral chemoreceptors that sense changes related to respiration? What do they sense?

Answer 14

Carotid and aortic arteries

Sense changes in PO2, pH, PCO2

Question 15

How do the glomus cells elicit a response?

Answer 15

Low blood PO2 causes the K+ channels to close, depolarizing the cell and opening the voltage-gated Ca2+ channel. The resulting exocytosis releases neurotransmitters onto a sensory neuron

Question 16

Where are the central chemoreceptors that are related to respiration? What do they sense?

Answer 16

Medulla oblongata

They measure CO2 in the CSF. They are also sensitive to H+, but only after the CO2 diffused into the CSF is converted by carbonic anhydrase

Question 17

What is the enzyme that shifts CO2 to HCO3-?

Answer 17

Medulla oblongata

They measure CO2 in the CSF. They are also sensitive to H+, but only after the CO2 diffused into the CSF is converted by carbonic anhydrase