Lecture 11

Question 1

What is required for the exchange of O2 and Co2?

Answer 1

Both gases must be transported between external and internal respiration sites

Question 2

How is the majority (98.5%) of O2 transported?

Answer 2

By the hemoglobin of erythrocytes

Question 3

Where is 1.5% of the O2 in blood transported?

Answer 3

Dissolved in the blood

Question 4

What is the portion of hemoglobin that contains iron?

Answer 4

Heme

Question 5

How many oxygen can each hemoglobin carry?

Answer 5

Four

Question 6

What does hemoglobin become when oxygen is binded?

Answer 6

Oxyhemoglobin

Question 7

What does the binding of the first O2 at the alveoli cause?

Answer 7

A conformational change in hemoglobin

Question 8

What does the conformational change in hemoglobin allow?

Answer 8

The binding of the next molecue

Question 9

What does the oxygen-hemoglobin dissociation curve describe?

Answer 9

The relationship of partial pressure to the binding of O2 to heme and the subsequent dissociation from heme

Question 10

What causes the affinity of an O2 molecule to increase?

Answer 10

More O2 binding

Question 11

What is the approximate partial pressure of O2 inside the arteries and capillaries?

Answer 11

100 mmHG

Question 12

What is the approximate partial pressure of O2 in highly active tissues?

Answer 12

20mmHg

Question 13

What is the approximate partial pressure of O2 in less active tissue?

Answer 13

55-60mmHg

Question 14

What is the approximate partial pressure of O2 inside veins?

Answer 14

40mmHg

Question 15

How does temperature impact hemoglobin dissociation?

Answer 15

It causes it to get faster

Question 16

What can increase body temp?

Answer 16

Highly active tissues

Question 17

How can certain hormones affect the O2-Hb saturation curve?

Answer 17

Production of 2,3-diphosphoglycerate

Question 18

What is DPG a byproduct of?

Answer 18

Glycolysis

Question 19

What does elevated DPG promote?

Answer 19

The disassociation of O2 from hemogolbin

Question 20

What is the Bohr effect?

Answer 20

The phenomenon that arises from the relationship between pH and O2s affinity for hemogolbin

Question 21

What does a lower pH cause? (O2-Hb curve)

Answer 21

Promotes O2 dissociation from hemoglobin

Question 22

What does a higher pH cause? (O2-Hb curve)

Answer 22

Inhibits O2 dissociation from hemoglobin

Question 23

What byproducts can cause blood to become more acidic?

Answer 23

From cell metabolism

Question 24

What are the 3 main mechanisms of CO2 transport?

Answer 24

1. Bicarbonate
2. Blood plasma
3. Bound to hemogolbin

Question 25

What is 70% of Co2 in blood transported as?

Answer 25

Bicarbonate

Question 26

How is bicarb produced in the blood?

Answer 26

In erythrocytes after Co2 diffuses into capillaries

Question 27

What causes Co2 and H2O to form carbonic acid?

Answer 27

Carbonic anhydrase

Question 28

What does the build up of HCO3 in blood cause?

Answer 28

Greater concentration of HCO3 in erythrocytes than in blood plasma

Question 29

What is the chloride shift and why does it occur?

Answer 29

HCO3 leaving and moving down the concentration gradient in exchange for chloride ions, exchanging one negative ion for another negative ion

Question 30

What happens to the chemical reaction that produced HCO3 changed at the pulmonary capillaries?

Answer 30

It is reveresed

Question 31

What % of CO2 is dissolved into the plasma?

Answer 31

7%

Question 32

What % of CO2 is bound to hemoglobin?

Answer 32

23%

Question 33

Where does CO2 bind on the hemoglobin? What does this form?

Answer 33

To the amino acids on the globin portion, carbaminohemoglobin

Question 34

What kind of partial pressure (Co2) does blood leaving the lungs (compared to the tissues)

Answer 34

Lower

Question 35

What kind of partial pressure (Co2) does blood in the pulmonary capillaries (compared to the alveoli)

Answer 35

Higher

Question 36

What is the Haldane effect?

Answer 36

Phenomenon that arises from relationship between the partial pressure of O2 and the affinity of hemoglobin for CO2

Question 37

When will hemoglobin favour the binding of CO2?

Answer 37

When O2 is not bound to heme

Question 38

What happens to the respiratory system pace during exercise?

Answer 38

It is altered to accommodate the O2 demands

Question 39

What is hyperpnea?

Answer 39

An increased depth and rate of ventilation to meet an increase in O2 demand

Question 40

What is hyperventialtion?

Answer 40

Increased ventilation depth and rate *independent* of the cellular O2 needs (leads to high pH)

Question 41

What happens to ventilation when exercise is initiated?

Answer 41

A steep rise in ventilation as a result of the afferent feedback from the body to the cardiorespiratory centres in the brain

Question 42

What happens to ventilation once exercise is happening?

Answer 42

A slower increase in ventilation as the body tunes the response

Question 43

What happens to ventilation after exercising for a few minutes?

Answer 43

The body is able to get into a steady state with ventilation stable to meet the bodys needs

Question 44

What happens to ventilation once exercise is completed

Answer 44

A fast decline to meet resting steady-state needs

Question 45

When we are below aerobic threshold (below VT1) what happens?

Answer 45

The increased ventilation meets our metabolic demands via hyperpnea

Question 46

What happens to our bodies after VT1?

Answer 46

Our bodies go into anaerobic metabolism and are producing more CO2 than the O2 we are consuming, hyperventilation to try and expel excess CO2

Question 47

What happens when we hit VT2?

Answer 47

Nearing point of exhaustion and there is a further increase in ventilation as we try and get every bit of O2 we can (anaerobic threshold)