Muscular System

Question 1

Name 3 functional groups of proteins involved in sarcomere structure

Answer 1

• contractile
• regulatory
• structural

Question 2

How is the CONTRACTILE protein group involved with sarcomere contraction?

Answer 2

generate force during contraction

Question 3

How is the REGULATORY protein group involved with sarcomere contraction?

Answer 3

help switch the contraction process on and off

Question 4

How is the STRUCTURAL protein group involved with sarcomere contraction?

Answer 4

stabilise and binds together

Question 5

List two proteins in the CONTRACTILE group

Answer 5

• myosin

* actin

Question 6

List two proteins in the REGULATORY group

Answer 6

• tropomyosin

* troponin

Question 7

List two proteins in the STRUCTURAL group

Answer 7

• titin

* dystrophin

Question 8

Describe 3 events that occur in Step 1 (release of acetylcholine) in regulation of muscle contraction at neuromuscular junction.

Answer 8

1. nerve impulse stimulates entry of Ca+2 through voltage-gated ion channels
2. ACh is released into the synaptic cleft
3. ACh diffuses across synaptic cleft from the motor neuron to the motor end plate.

Question 9

Describe 2 events that occur in Step 2 (activation of ACh receptors) in regulation of muscle contraction at neuromuscular junction.

Answer 9

1. ACh molecules bind to a receptor on the motor end plate

2. Opens Na+ channels and Na+ enters the muscle cell

Question 10

Describe 4 events that occur in Step 3 (production of muscle action potential) in regulation of muscle contraction at neuromuscular junction.

Answer 10

1. flow of Na+ makes inside of fibre more positive
2. triggers a muscle action potential
3. MAP propogates along sarcolemma into the T-tubules
4. Sarcoplasmic Reticulum releases Ca+2 into sarcoplasm which attaches to the troponin

Question 11

Describe 1 event that occurs in Step 4 (termination of ACh activity) in regulation of muscle contraction at neuromuscular junction.

Answer 11

1. ACh is broken down by acetylcholinesterase (AChE)

Question 12

Name two types of muscle fibres

Answer 12

• slow oxidative

* fast oxidative

Question 13

Describe one characteristic of slow oxidative muscle fibres

Answer 13

lots of mitochondria, myoglobin and blood vessels

Question 14

Describe one characteristic of fast oxidative muscle fibres

Answer 14

• few mitochondria and blood vessels

* low myoglobin

Question 15

Descibe the method used for generating ATP for slow and fast oxidative muscle fibres

Answer 15

• slow oxidative - anaerobic respiration

* fast oxidative - anaerobic glycolysis

Question 16

Where are slow oxidative muscle fibres most abundant?

Answer 16

neck, back, leg muscles

Question 17

Where are fast oxidative muscle fibres most abundant?

Answer 17

shoulder, arm muscles

Question 18

List one primary function of slow oxidative muscle fibres

Answer 18

maintain posture and endurance activities

Question 19

List one primary function of fast oxidative muscle fibres

Answer 19

rapid, intense movements of short duration