Exercise

Question 1

What are three sources of ATP

Answer 1

• cell supply: small amount
• Phosphocreatine: short, intense exercise; sprinting and power lifting
• Carbohydrates and dats

Question 2

Compare aerobic metabolism to anaerobic metabolism

Answer 2

Aerobic metabolism is most efficient: through glycolysis-citric acid pathways, but requires oxygen, used for long term endurance exercise
- anaerobic metabolism is faster, pyruvate to lactate, fatty acids not used, but less afficient than aerobic

Question 3

What are the three types of hormones regulating metabolism during exercise

Answer 3

• Conversion of triglycerides to glycerol and fatty acids: cortisol, catecholamines, growth hormone
• Conversion of liver glycogen raises plasma glucose levels: glucagon, catecholamines, cortisol
• Insulin secretion suppressed during exercise: cells other than muscle fibers reduce glucose uptake, actively-contracting muscle cells do not require insulin for glucose uptake

Question 4

What are three factors that limit exercise?

Answer 4

• Oxygen consumption is related to exercise intensity: is a measure of cellular respiration
• Excess postexercise oxygen consumption used to restore ATP, myoglobin levels of oxygen
• ability to deliver oxygen and nutrients to the muscle at a rate that supports aerobic metabolism

Question 5

How does the ability of muscle fibers to obtain and use oxygen limit exercise?

Answer 5

• Mitochondria are limited in number
• insufficient oxygen supply
• not limiting for maximum exercise capacity
• influences submaximal exercise capacity

Question 6

What are the three ventilatory responses to exercise

Answer 6

• increased rate and depth of breathing
• Exercise hyperventilation feedforward signals from the motor cortes and sensory feedback from peripheral receptors
• Carotid and aortic chemoreceptors
• Proprioreceptors in joints
• Mechanoreceptors in muscles
• Arterial Po2, Pco22 and pH do not change significantly during mild to moderate exercise

Question 7

What are the three cardiovascular responses to exercise?

Answer 7

• Cardiac output rises dramatically due to faster heart rate and greater stroke volume
• Distribution of blood flow shifts toward muscle
• blood pressure rises slightly during exercise because of skeletal muscle dilation

Question 8

What is the breakdown if the cardiac output equation?

Answer 8

CO = (SA node rate (dec. parasympathetic activity) + autonomic nervous system input (^ sympathetic activity) x (venous return + force of contraction (^ sympathetic activity)

Question 9

How does the baroreceptor reflex adjust to exercise?

Answer 9

THEORIES:

• signals from motor cortex reset baroreceptor threshold
• afferent neurons are blocked by presynaptic inhibition
• muscle chemoreceptors (postulated) are sensitive to metabolites

Question 10

How does the body regulate temperature homeostasis during exercise

Answer 10

• Sweating: evaporative cooling
• Increased cutaneous blood flow - convection
• Body adapts to repeated exercise in hot environments

Question 11

What is the feedforward sequence response to exercise

Answer 11

proprioreceptors in muscle and joints -> motor cortex -> descending signals to

1. Exercising muscles
2. Cardiovascular control centre
3. Respiratory control centre
4. Limbic system
   - sympathetic discharge casuing vasoconstriction, increasing blood pressure

Question 12

What is the Rating of Perceived Exertion RPE

Answer 12

• conscious manifestation of the integration of signals from muscle, joints, central CV and respiratory functions, CNS and psychological

Question 13

What are the three RPE equations?

Answer 13

• ^ RPE infinite to core body temperature
• ^ RPE 1/infinite arousal/fuel reserves
• “maximally tolerable” = physiological limits

Question 14

What is the endspurt phenomenon?

Answer 14

Decreased uncertainty of your ability to complete something towards the end