Skeletal Muscle (2) Flashcards
0
Q
What are the different arrangements of skeletal muscle?
Give examples.
A
- Circular: orbicularis oris
- Convergent: Pectoralis major
- Parallel: Sartorius
- Unipennate: Exterior digitorum longus
- Multipennate: Deltoids
- Fusiform: Biceps brachii
- Bipennate: Rectus femoris
1
Q
What are the roles of skeletal muscle?
A
- Movement
- Stability of joints
- Posture
- Heat generation
2
Q
What is fasciculation?
A
- Muscle twitch
3
Q
Explain what is meant by 1st, 2nd and 3rd class levers.
A
- ALL: Force, load and fulcrum(pivot)
- 1st: Force and load on opposite ends acting in different directions
- 2nd: Force and load on the LHS upwards
- 3rd: Force and load on RHS upwards
4
Q
Give examples of 1st, 2nd and 3rd class levers
A
- 1st: Skull/spinal cord
- 2nd: Leg to foot
- 3rd: Biceps
5
Q
What are the different types of muscle groups and their roles?
A
- Agonist: prime movers
- Antagonist: opposes prime movers
- Synergists: assist prime movers (neutralises extra movement)
- Fixators: stabilises action of prime movers (non-moving joints)
6
Q
What are the different types of muscle contraction?
A
- Isotonic contraction: constant tension variable muscle length
- Isometric: constant length, variable tension (hand grip)
7
Q
What are the different types of isotonic contraction?
A
- Concentric: muscle shortens (lifting load with arm)
- Eccentric: muscle exerts a force whilst extended (downhill)
can cause delayed-onset muscle soreness
8
Q
What are type I, type IIa and type IIb muscle fibres?
A
- Type I: slow oxidative
- Type IIa: fast oxidative
- Type IIb: fast glycolytic
9
Q
Compare type I and type IIa muscle fibres.
A
- Aerobic
- High myoglobin levels
- Red colour
- Many mitochondria
- Rich capillary supply - (type IIa /pink)
- Fatigue resistant - (type IIa /moderate)
- Endurance activities & posture -(type IIa /walking/sprinting)
10
Q
How does type IIb differ to type IIa?
A
- Anaerobic glycolysis
- Low myoglobin levels
- White colour
- Few mitochondria
- Poorer capillary supply
- Rapidly fatigues
- Short, intense movement.
11
Q
What is proprioception?
A
- Feedback control of movement.
- Muscles tell CNS how much force is being exerted.
12
Q
What does a motor unit consist of?
A
- Motor neurone and muscle fibres it innervates.
13
Q
What is neuro-musculo communication?
A
- ‘cross-talk’
- signalling molecules communicate between nerves and muscles
- atrophy of muscle/nerve leads to atrophy of corresponding neurone/muscle.
14
Q
What is muscle tone?
A
- Baseline tone in muscles at rest due to: motor-neurone activity/muscle elasticity
