Muscle physiology

Question 1

3 types of muscle:

Answer 1

• smooth
• skeletal
• cardiac

Question 2

What is skeletal muscle?

Answer 2

voluntary, striated muscle making up 40% of body mass

Question 3

sarcomere

Answer 3

• smallest functional unit of skeletal and cardiac muscle

- shorten and expand with contractions

Question 4

thick filament

Answer 4

has globulin head allowing it to interact with thin filament for muscle contraction

Question 5

thin filaments function

Answer 5

slide over thick filaments toward centre of sarcomere to produce contraction

Question 6

What are the 4 proteins of thin filaments?

Answer 6

• f actin
• tropomyosin
• troponin
• nebulin

Question 7

what is involved in the planning of movement?

Answer 7

prefrontal cortex and premotor area of brain

Question 8

What is a neuromuscular junction?

Answer 8

synapse between motor neurone and skeletal muscle fibre

Question 9

Excitation contraction coupling:

Answer 9

contraction by causing calcium release by AP

Question 10

Relaxation phase:

Answer 10

calcium pumps back into sarcoplasmic reticulum via active transport allowing myosin heads to disengage from actin

Question 11

Contration:

Answer 11

Ca+ is released from SR, binds to troponin, and moves tropomyosin allowing access to myosin binding sites

Question 12

What are the 3 phases of muscle twitch?

Answer 12

1. Latent- delay after action potential
2. Contraction- Calcium release allows cross bridge
3. Relaxation- tension is reduced

Question 13

cause of muscle fatigue

Answer 13

loss of ATP

Question 14

what is a motor unit

Answer 14

a motorneuron and all the muscle fibres it innervates

Question 15

define isometric strength test

Answer 15

tension without contraction

Question 16

what does an EMG represent

Answer 16

measures muscle response or electrical activity in response to a nerve’s stimulation of the muscle.