Exercise physiology 1

Question 1

Oxygen need increases X fold with exercise

Answer 1

10

Question 2

What is limiting for glucose oxidation and aerobic performance?

Answer 2

 Oxygen supply : adequate respiration is crucial

Question 3

What is the process of oxygen being taken up from lungs to blood?

Answer 3

diffusion

Question 4

O2 is transported in the blood bound to haemoglobin, because free oxygen..

Answer 4

Is hardly soluble in blood (plasma)

Question 5

Synthesis of erythrocytes (RBC) occurs continuously in bone marrow, controlled by

Answer 5

EPO

Question 6

EPO is produced in X, its secretion stimulated by X

Answer 6

liver, low arterial O2 pressure

Question 7

What happens when you administer EPO (doping)?

Answer 7

increases max oxygen consumption and performance

Question 8

Binding of haemoglobin to oxygen is dependent on..

Answer 8

Local O2/CO2 concentration
temperature
pH

Question 9

What happens at low oxygen tension with haemoglobin?

Answer 9

Low oxygen tension: haemoglobin loses binding to oxygen -> released -> consumed

Question 10

Affinity of haemoglobin with O2 depends on..

Answer 10

1. Temperature: temp up, affinity down
2. pH: H+ binds reversibly to HB -> competition with O2 (=bohr effect)
   pH down, affinity down
3. PO2
   CO2 binds reversibly to Hb -> competition with O2
   PCO2 up, affinity down
4. 2,3-diphosphoglycerate (2,3-DPG)
   Produced in RBC in response to low oxyhaemoglobin (oxHb)
   OxHB down -> 2,3DPG down up, affinity down

Question 11

What happens when affinity goes down of Hb and oxygen?

Answer 11

• When affinity goes down, oxygen is released to muscles if needed!

Question 12

Why does the difference between blood oxygen content in arteries and veins becomes larger during exercise?

Answer 12

This difference = the amount of blood consumed by the muscles (oxygen in the blood – oxygen coming back from the tissues)

Question 13

Why does the arterial O2 content stay roughly the same during exercise, whilst the venal O2 content diminishes?

Answer 13

Arterial O2 content stays roughly the same, bc the O2 concentration is 100% from the lungs.

Question 14

During exercise, there is an increase/decrease in…

• A in PO2
• B in PCO2
• C in pH (more H+)
• D in 2,3-DPG (maximal exercise)
• E in Temp

Answer 14

A Decrease
B Increase
C Decrease
D Increase
E Increase

Question 15

These intramuscular factors, result in…

• Causes A in affinity between Hb en O2
• Intramuscular release of oxygen B
• Venous O2 content C
• Arteriovenous O2 difference D

Answer 15

A decrease
B increases
C decreases
D increases

Question 16

Muscle regulates its own consumption without increased blood flow: true/false

Answer 16

true

Question 17

During exercise, there is an increased tidal volume (volume air/breath). What remains unchanged?

Answer 17

• Lung capacity + residual volume remains unchanged!

Question 18

Is the vital capacity (part of lungs used for breathing) changed in endurance vs untrained subjects?

Answer 18

No

Question 19

What does stimulate development of larger vital capacity?

Answer 19

Swimming/diving, because of the water pressure -> strengthen inspiratory muscles

Question 20

Gas exchange only occurs in X, not in bronchi or bonchioles

Answer 20

alveoli

Question 21

 Resting: breathing under involuntary control of the chemoreceptors which detect..

Answer 21

PO2, PCO2/pH in the carotid artery

(=major blood vessels that provide your brain’s blood supply)

Question 22

What chemical signal is most important during normal respiration?

Answer 22

PCO2

Question 23

During exercise, chemoreceptors in the carotid artery do not seem to play a major role
(Arterial PO2 and PCO2 are relatively stable). What does play a major role?

Answer 23

 Central command (motor cortex),
 Peripheral input from joints, tendons and muscles (mechanoreceptors + chemoreceptors)

Question 24

What is the Ventilatory threshold?

Answer 24

point where ventilation increases disproportional to VO2

Question 25

What is the Lactate threshold?

Answer 25

point where lactate levels in the blood start to increase (>1mM)

Question 26

What is the Onset of Blood Lactate Accumulation (OBLA)?

Answer 26

Point where blood lactate > 4.0 mM (anaerobic threshold)

Question 27

Besides conversion of CO2, also intrafibrillar buffering of acid (lactate) occurs.
- Buffer capacity related to percentage X
- Histidine-containing peptides, such as X, seem to be involved

Answer 27

T2 fibers (more T2, more buffering)
- In sprinters and rowers, but not long-distance runners, buffer capacity is increased
Histidine-containing peptides, such as carnosine, seem to be involved
Higher carnosine = better performance

Question 28

• Pulm. vent does not seem to be a limiting factor for oxygen delivery at max O2 consumption
  True/false

Answer 28

True

Question 29

Arterial PO2 is affected by exercise
True/false

Answer 29

False

Question 30

What is an exeption in which extra oxygen supply with pulmonary ventilation does lead to improved performance?

Answer 30

High-intensity exercise may, in some cases, result in arterial desaturation (EIAH) = blood leaving the lungs is not completely saturated with oxygen. Can be prevented with extra oxygen supply -> improves performance.
Happens more in athletes than non-athletes.

Question 31

Why is pulmonary ventilation not limiting to performance?

Answer 31

Usually, the blood has more than enough time when it passes the alveoli to be diffused with the same amount of oxygen as in the alveoli (equilibrium). However, during exercise, Blood flow increases, it is so fast that the time the blood passes the alveoli is too short. Gets too little oxygen.

If it is not the respiration that is limiting, perhaps role for the CVD?