L28 Acid-base Balance During Exercise

Question 1

Define Acid

Answer 1

Molecule that liberates H+ ions

Question 2

Define base

Answer 2

Molecule that can combine with H+

Question 3

Define pH

Answer 3

Expression of H+. Normal = 7.4

Question 4

Define Acidosis

Answer 4

Increase of acid. Decrease of bases. pH < 7.4

Question 5

Define alkalosis

Answer 5

Decrease in acid. Increase in bases. pH > 7.4

Question 6

What re the major groups of acids formed in the body?

Answer 6

1. Volatile acids end products of metabolism - Co2
2. Fixed acids - sulphuric and phosphoric acid
3. Organic acids - lactic and oxaloacetic acid

Question 7

Why is maintenance of acid balance important to physical performance?

Answer 7

contributes to fatigue
Must increase blood buffering capacity to tackle this
H+ can inhibit enzymes and hinders muscle contractile process by competing w/calcium (H+). Reduced Hb-O2 affinity

Question 8

What are the intra cellular and extra cellular buffers?

Answer 8

Intra - proteins, bicarbonate, phosphate groups

extra - blood buffers. Bicarb, proteins, Hb

Question 9

Discuss respiratory compensation for metabolic acidosis. What would happen to blood pH in athlete hyperventilated @ rest and why this would occur

Answer 9

• pulmonary ventilation removes H+ from blood as HCO-3 reaction.
  Hyper ventilation results in CO2 exhaustion due to reducing the partial pressure of CO2 and H+ concentration thus increasing pH and causing alkalosis

Question 10

What is the effect of using sodium bicarbonate as a buffer during high intensity exercise

Answer 10

It can increase time to exhaustion so you can work harder for longer

Question 11

How do the kidneys deal with acid-base balance

Answer 11

When blood pH decreases the filtered bicarbonate ions are reabsorbed.
New bicarbonate ions can be made in the tubular epithelial cells as long as H+ ions are available - Done during acidosis