The Endocrine System and Exercise

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Questions and Answers

What is the main cause of muscle fatigue?

Accumulation of lactic acid

Depletion of PCr and glycogen stores (correct)

Failure of actin and myosin to bind

H+ ions binding to receptors

What is the normal range for muscle pH?

6.5-7.0

6.9-9.5

7.1-7.4 (correct)

7.5-8.0

Which substance can be used as a fuel source in muscles?

Ammonia

H+ ions

Lactic acid

Lactate (correct)

What is the effect of H+ ions on muscle pain?

Stimulation of nerve fibers Signup and view all the answers

What is the primary cause of delayed-onset muscle soreness (DOMS)?

Eccentric exercise Signup and view all the answers

How does sodium bicarbonate help in fighting fatigue?

It buffers H+ ions Signup and view all the answers

What is the effect of caffeine on muscle soreness?

It increases fatty acid utilization Signup and view all the answers

What is the IOC's upper limit for caffeine intake in urine?

9-13 ug/mL Signup and view all the answers

What is the primary cause of impaired muscle function during fatigue?

Spread of metabolites causing immune response Signup and view all the answers

What is the main effect of carbohydrate supercompensation?

Enhancing glycogen stores Signup and view all the answers

What is the main effect of lactic acid buildup in muscles?

Causing muscle tenderness Signup and view all the answers

What is the main impact of H+ ions on enzyme function?

Inhibiting enzyme activity Signup and view all the answers

What is the role of epinephrine and norepinephrine during exercise?

Increase cardiac output and redistribute blood to exercising muscles Signup and view all the answers

What is the effect of cortisol on the body during overtraining?

Increase in cortisol levels Signup and view all the answers

What is the impact of hyperthyroidism on metabolic rate?

Faster metabolic rate Signup and view all the answers

What effect does resistance training have on the hormone response?

Decreases hormone response (IGF, GH) Signup and view all the answers

Which hormone is responsible for increasing muscle size through protein synthesis?

Insulin-like growth factor (IGF) Signup and view all the answers

What is the impact of sweating on blood plasma volume?

Decreases blood plasma volume Signup and view all the answers

Which hormone is responsible for maintaining blood plasma levels?

ADH & aldosterone Signup and view all the answers

What is the role of myokines in muscle remodeling?

Increases muscle remodeling Signup and view all the answers

What is the effect of leptin during heavy intensity exercise?

Leptin secretion decreases Signup and view all the answers

What is the effect of growth hormone on fat metabolism?

Important for fat metabolism Signup and view all the answers

What happens to cortisol levels when working at less than 50% intensity?

Decrease in cortisol levels Signup and view all the answers

What is the impact of hyperthyroidism on body size?

Faster metabolic rate and very skinny body size Signup and view all the answers

Study Notes

Muscle Fatigue and Fuel Sources

Muscle fatigue is caused by the accumulation of H+ ions, which can lead to muscle pain
Normal muscle pH range is slightly alkaline, between 7.35 and 7.45
Muscles can use carbohydrates, fats, and proteins as fuel sources
H+ ions cause muscle pain by activating pain receptors

Delayed-Onset Muscle Soreness (DOMS)

DOMS is primarily caused by micro-trauma to muscle fibers and surrounding connective tissue

Sodium Bicarbonate and Caffeine

Sodium bicarbonate helps fight fatigue by buffering excess H+ ions
Caffeine reduces muscle soreness by blocking adenosine receptors, which reduces pain perception
The International Olympic Committee (IOC) sets an upper limit of 12 μg/mL for caffeine intake in urine

Impaired Muscle Function and Fatigue

Impaired muscle function during fatigue is primarily caused by the accumulation of H+ ions and lactic acid
Lactic acid buildup in muscles impairs muscle function by reducing pH levels

Hormonal Responses to Exercise

Epinephrine and norepinephrine are released during exercise to increase energy availability
Cortisol levels increase during overtraining, leading to muscle breakdown and impaired recovery
Hyperthyroidism increases metabolic rate, while hypothyroidism decreases it
Resistance training increases the release of anabolic hormones, such as testosterone
Testosterone is responsible for increasing muscle size through protein synthesis

Fluid Balance and Hormones

Sweating reduces blood plasma volume, which can lead to dehydration
Aldosterone is responsible for maintaining blood plasma levels
Myokines are involved in muscle remodeling and repair
Leptin levels decrease during high-intensity exercise
Growth hormone increases fat metabolism
Cortisol levels decrease when working at less than 50% intensity
Hyperthyroidism is associated with weight loss and decreased body size

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Description

Test your knowledge of the endocrine system's role in exercise with this quiz. Explore how hormones like epinephrine, norepinephrine, ADH, and aldosterone impact fuel mobilization, blood flow control, and other physiological responses during physical activity.