Session 2 - Muscle Structure, Morphology and Mechanics Flashcards
List the arrangement of muscles from bone to myofilaments
-Bone, tendon, muscle, fascicle, fibre. myofibril, myofilaments
What are the possible arrangements of skeletal muscle?
- Circular
- Convergent
- Multipennate
- bipennate
- Unipennate
- Parallel
- Fusiform
What are the main functions of skeletal muscle?
- Movement
- Posture
- Joint stability
- Heat generation
What is fasciculation?
-Muscle twitch
What is the agonist muscle during a movement?
-The prime mover which exerts a force or effect (main muscle responsible for movement)
What is the antagonist during a movement?
-The muscle which opposes the prime mover, allowing control of a movement
What does a synergist muscle do in a movement?
-Assists prime mover by neutralising extra motion, eg sideways motion
What is the function of a fixator during a movement?
-A muscle which stabilises the action of the prime mover eg fixes a non-moving joint when prime mover acts over two joints
What is a 1st class lever?
-The load is on the opposite side to the muscle, central to the fulcrum eg skull
What is a second class level?
-The load is on the same side to the muscle but close to the fulcrum
What is a third class lever?
-The load is on the same side of the muscle far away from the fulcrum
What is compartment syndrome?
- Compartments of limbs surrounded by non-expandable fascia
- Anything which causes a large increase in pressure in the compartment can lead to compression of the blood supply and nerves, possible leading to necrosis of compartment
What is isotonic contraction?
-Contraction of the muscle resulting in constant muscle tension and varying muscle length
What is the difference between concentric and eccentric isotonic muscle contraction?
- Concentric muscle shortens in length
- Eccentric muscle extends in length
What is delayed-onset muscle soreness, what is a common cause?
- Muscle soreness wich becomes symtomatic a few days after the causing factor
- Walking down hill
What is isometric contraction?
-Contraction of muscle where muscle stays the same length but there is varying tension eg hand grip
Why can isometric contraction be important in the elderly or those with hypertension?
-There is a small muscle mass involved in isometric contraction, however it has a large effect on blood pressure
Describe type I muscle fibres
-Aerobic, red with rich capillaries, many mitochondria and fatigue resistant, slow oxidative with endurance
Describe type IIa muscle fibres
-Aerobic, red/pink with rich capillary supply, many mitochondria and moderately fatigue resistant, fast oxidative,
Describe type IIb muscle fibres
-Anaerobic, white with poor capillary supply, few mitochondria and fatigue rapidly, short intense movements
What is proprioception?
-Awareness of self
How does proprioception work?
- Feedback control by proprioceptors
- Proprioreceptor muscle spindles send messages about tension and stretch being exerted on the muscle to the brain
What is a motor unit?
-A motor neurone and the muscle fibres it innervates (ie each axon innervates several muscle fibres
How is the number of muscle fibres per axon determined?
-Depends on how fine of control needed for the movement
