O2 and CO2 unloading

Question 1

Does Hb unload the same amount of O2 to all tissues?

Answer 1

No. Hb doesn’t unload the same amount of O2 to all tissues- some need more O2, eg if exercising, some less, eg at rest.

Question 2

What 4 factors adjust the rate of O2 unloading into tissues?

Answer 2

Ambient PO2 (in tissue)
Temperature
Bohr Effect
BPG

Question 3

How does the ambient PO2 of tissue impact the unloading rate of O2?

Answer 3

Since an active tissue consumes O2 rapidly, the PO2 remains low. At low PO2 HbO2 releases more O2

Question 4

How does thetemperatuire of tissue impact the O2 unloading rate?

Answer 4

Active tissue are warmer than less active tissues

Warmer tissues promote O2 unloading (extract more O2 from blood passing by)

Question 5

What is the Bohr effect?

Answer 5

↑ PCO2 and/or ↑H+ concentration (↓pH) weaken the HbO2 bond- so more O2 unloading

Question 6

How does the Bohr effect work?

Answer 6

Active tissues make more CO2. We shift the equation to the right, so it raises the H+ concentration and ↓blood pH
H+ weakens the bond between Hb and O2 and therefore promotes O2 unloading.

Question 7

The effect of pH on Hb saturation is the _____effect

Answer 7

Bohr

Question 8

RBCs must get their energy needs through anaerobic pathways, and one of the intermediate steps in this pathway is _____.

Answer 8

BPG

Question 9

What happens with an increase of BPG in the RBC?

Answer 9

The higher the concentration of BPG in the RBC the greater the release of O2 from Hb

Question 10

What 4 things increase the BPG concentration?

Answer 10

Thyroid hormones
Growth hormone
Epinephrine
Testosterone

Question 11

What is the Haldane effect?

Answer 11

Low HbO2 enables the blood to transport more CO2

O2 is going out to tissues and is replaced with CO2

Question 12

What 2 mechamisms cause CO2 unloading?

Answer 12

1- HbO2 does not bind CO2 as well as HHb does
2- HHb binds more H+ ions than HbO2 does, and by removing H+ ions from solution, HHb shifts the equation to the right (removing CO2)
CO2 → H2O → H2CO3 → HCO3- + H+

Question 13

A high _______ rate keeps oxyhemoglobin levels relatively low, and thus allowing more CO2 to be transported by the above two mechanisms

Answer 13

metabolic

Question 14

As more CO2 enters the systemic bloodstream it causes the O2 to disassociate from Hb, this is the ____ effect . Which in turn, allows more CO2 to combine with the Hb, which is the ______ effect.

Answer 14

Bohr

Haldane

Question 15

Gas exchange not only requires good ______ of the alveolus, but also good ______ of its lung capillaries.

Answer 15

ventilation

perfusion

Question 16

What is perfusion coupling?

Answer 16

The ability to match ventilation and perfusion to each other is critical
Airflow matches bloodflow

Question 17

Arterioles respond to ____; Bronchioles respond to _____. (gasses)

Answer 17

PO2

PCO2

Question 18

If part of a lung is blocked by mucus, tumor, what happens to the blood flow?

Answer 18

It will be redirected.

Because if it’s poorly ventilated there is little point of sending blood there

Question 19

Poor alveolar ventilation results in low ___and high ____ levels in the alveoli. (gasses)

Answer 19

O2

CO2

Question 20

If ↑ PO2 then blood vessels will _______ to bring more blood to O2

Answer 20

vasodilate

Question 21

Rising PCO2 causes local ________, to eliminate excess CO2

Answer 21

bronchodilation

Question 22

If airflow through bronchioles is lower than normal, then there is rising _____ level.

Answer 22

PCO2

Question 23

COPD tends to reduce pulmonary ________ and _____ capacity

Answer 23

compliance

vital

Question 24

Any disease in which there is long-term obstruction of airflow and substantial reduction in pulmonary ventilation is called ….

Answer 24

COPD

Question 25

What are the two major COPDs?

Answer 25

Emphysema

Chronic bronchitis

Question 26

What are the normal causes of COPD?

Answer 26

They are almost always caused by cigarette smoking, but occasionally from air pollution or occupational exposure to airborne irritants

Question 27

What happens with emphysema?

Answer 27

Destruction of alveolar walls (type I cells)

Question 28

What happens with chronic bronchitis?

Answer 28

The cilia are immobilized and reduced in number
At the same time, goblet cells enlarge and produce excess mucus in bronchial mucosa
This thick mucus provides a growth medium for bacterial