The carrying of oxygen in the blood.

• This presentation provides information to help you with Objectives 211, 213, 215, and all the objectives related to hemoglobin.

• As you review this presentation independently, be sure to have your lecture notes and objectives handy.

1. Fig. 23-20. Why do

oxygen and carbon dioxide

move in the directions

indicated by the arrows?

(See Obj. 211.) This figure also

helps you to answer Obj.

213.

2. Objective 215 tells you about how much of the oxygen in the blood is

carried attached to the hemoglobin molecule.

• The next slide shows a picture of hemoglobin.

3. Fig. 2-20. The

hemoglobin molecule

4. It will help us understand the role of hemoglobin if we know how hemoglobin is studied in

the lab.

5. Fig. 23-21 Oxygen-

hemoglobin saturation

curve.

Look at this table.

6. Where did the numbers in the table come from?

7. Choose a Po2

value, go up to the red line,

then read across to

the value of the %

saturation.

8. Look at the numbers in the table and verify that they

have been read from the

curve.

9. How do we use this curve to understand hemoglobin’s ability to deliver oxygen from

the lungs to the tissues?

• We need to know the % saturation of hemoglobin in the lungs and in the tissues.

• We need to remember that an increase in % saturation means that hemoglobin has picked up O2. (Where did the O2 come from?)

• We need to remember that a decrease in % saturation means that hemoglobin has released O2. (Where did the O2 go?)

10. Here is Fig. 23-

20 again. What Po2

values are

shown ?

11. Po2 values

• Pulmonary Arteries = 40 mm Hg

• Blood goes through pulmonary capillaries

• Pulmonary Veins =100 mm Hg

• Systemic Arteries = 95 mm Hg

• Blood goes through systemic capillaries

• Systemic Veins = 40 mm Hg

12. Apply those

values to this graph from Fig.

23-21.

13a. How much of the hemoglobin lost its oxygen in going from systemic

arteries to systemic veins?

Location Po2 % saturation

Systemic arteries

95 mm Hg 97%

Systemic veins

40 mm Hg 75%

Difference Do the math!

13b. How much of the hemoglobin lost its oxygen in going from systemic

arteries to systemic veins?

Location Po2 % saturation

Systemic arteries

95 mm Hg 97%

Systemic veins

40 mm Hg 75%

Difference 22%

14. This means that 22% of the hemoglobin loses its oxygen as it passes from the systemic arteries

to the systemic veins.

• Where does this oxygen go?

15. Again, Fig. 23-20.

16. This means that oxygen is released to cells when the per cent saturation of hemoglobin

decreases.• What does it mean when there is an

increase in per cent saturation of hemoglobin?

• Where would you expect to see an increase in per cent saturation of hemoglobin?

17. For the answer to these questions, as well as material

to help you in Objectives 217-221, you need to go to

your lecture notes.

19. Fig. 23-22a shows the effect of changing the

pH. Go to your notes to

see the effect of changing pCO2 and

[BPG].

20. Fig. 23-22b shows the effect of

changing temperature.

21. How do these changes affect hemoglobin’s delivery of oxygen

between the lungs and the tissues?

• Go to your notes to find the answer to this important question.

22. What is myoglobin and what does its saturation look like?

• The answers to these questions can be found in your notes.

• Also, you will discover the usefulness of myoglobin as an oxygen-carrying molecule.

23. Fig. 23-23 shows the

difference between fetal

and adult hemoglobin.

24. How does this graph demonstrate hemoglobin’s ability to deliver oxygen from

the mother’s blood to the fetus’s blood?

• Go to your notes for the answer to this question.