Muscle Physiology

Question 1

Hypercalcemia

Answer 1

• DECREASE muscle excitability
• aka hyperparathyroidism
• raises threshold for Na+ gates to decrease muscle excitability
• Na+ channels become harder to activate

Question 2

Hypocalcemia

Answer 2

• INCREASED excitability
• aka hypoparathryoidism
• Na+ gated channels stay open too long

Question 3

Isotonic

Answer 3

• Contraction of muscle that causes no shortening of the muscle or load movement
• Afterload>preload
• Muscles are NOT doing work
• Every muscle contraction begins this way!!

Question 4

Isometric

Answer 4

• Muscle contraction causes muscle shorting and displacement of load
• When preload>afterload
• Muscles are doing work

Question 5

Eccentric

Answer 5

• Muscle lengthening contraction
• Load>muscle force
• i.e. Controlled sit

Question 6

Concentric

Answer 6

• Muscle shortening contraction

- Load>muscle force