10d.14 Exercise Example

Question 1

What does the oxyhemoglobin dissociation curve illustrate during exercise?

Answer 1

How hemoglobin’s affinity for oxygen changes between the lungs and active muscles.

Question 2

What three main factors change in muscles during exercise?

Answer 2

Increased temperature, increased CO₂, and decreased pH (more H⁺).

Question 3

How does increased temperature affect oxygen binding?

Answer 3

It decreases hemoglobin’s O₂ affinity, promoting oxygen release.

Question 4

What causes the temperature increase in muscles during exercise?

Answer 4

Heat generated by ATP breakdown and muscle contraction.

Question 5

What happens to the oxyhemoglobin curve when temperature rises?

Answer 5

It shifts to the right.

Question 6

How does a decrease in pH affect oxygen binding?

Answer 6

It reduces hemoglobin’s affinity for oxygen, enhancing O₂ release (Bohr effect).

Question 7

Why does pH drop in exercising muscle?

Answer 7

Lactic acid and hydrogen ions build up during anaerobic metabolism.

Question 8

What happens to the oxyhemoglobin curve when pH decreases?

Answer 8

It shifts to the right.

Question 9

How does increased CO₂ affect oxygen binding?

Answer 9

It decreases O₂ affinity, promoting oxygen unloading (Bohr effect).

Question 10

Why does CO₂ increase in exercising tissue?

Answer 10

Because metabolism produces CO₂ as a byproduct of energy use.

Question 11

What is the combined effect of high temperature, low pH, and high CO₂?

Answer 11

A rightward shift of the oxyhemoglobin curve → hemoglobin releases oxygen easily.

Question 12

What does a rightward shift of the oxyhemoglobin curve mean?

Answer 12

Decreased O₂ affinity and increased oxygen delivery to tissues.

Question 13

What happens in the lungs regarding temperature, CO₂, and pH?

Answer 13

Temperature is lower, CO₂ is lower, and pH is higher (more basic).

Question 14

What is the effect of lung conditions on hemoglobin’s O₂ affinity?

Answer 14

Increased O₂ affinity → hemoglobin binds oxygen tightly.

Question 15

What is the effect of active muscle conditions on hemoglobin’s O₂ affinity?

Answer 15

Decreased O₂ affinity → hemoglobin releases oxygen easily.

Question 16

What happens to CO₂ and H⁺ in the lungs?

Answer 16

CO₂ diffuses out, and H⁺ recombines with HCO₃⁻ to form CO₂ and H₂O for exhalation.

Question 17

What is the result of lower CO₂ and fewer H⁺ ions in the lungs?

Answer 17

Higher pH and a leftward curve shift, increasing O₂ binding.

Question 18

What does a leftward shift of the oxyhemoglobin curve mean?

Answer 18

Increased O₂ affinity — hemoglobin holds oxygen tightly.

Question 19

What is the Bohr effect?

Answer 19

The phenomenon where high CO₂ and low pH cause hemoglobin to release more O₂.

Question 20

In summary, what happens in the muscles during exercise?

Answer 20

The curve shifts right — hemoglobin releases O₂ due to ↑ CO₂, ↑ temperature, ↓ pH.

Question 21

In summary, what happens in the lungs during oxygen loading?

Answer 21

The curve shifts left — hemoglobin binds O₂ tightly due to ↓ CO₂, ↓ temperature, ↑ pH.

Question 22

What ensures oxygen is delivered exactly where it’s needed most?

Answer 22

Local tissue conditions that regulate hemoglobin’s O₂ affinity.