muscular system unit 5 Flashcards
cardiac muscle
- loacted in heart only
- doesnt fatigue
- involuntary control
- bloody supply from coronary arteries
smooth muscle
- located in walls of digestive and circulatory system
- doesnt fatigue
- involuntary
- vasoconstriction
- vasodilation
skeletal muscle
- voluntary control
- connected to bones via tendons
- movement
- can fatigue during exercise
- create movements by making decisions
type 1 slow twitch fibres
STRUCTURE
- small fibre size
- large mitochondria and capillaries
FUNCTION
- slow contraction speed
- low force produces
- high resistance to fatigue
- e.g marathon runners
type 11a fibres
STRUCTURE
-large fibre size
- small number of mitochondria and capillaries
- low myoglobin
FUNCTION
- fastest contraction speed
- highest force produced
- lowest resistance to fatigue
type 11b fibres
STRUCTURE
- large fibre size
- moderate mitochondira and capillaries
- moderate myoglobin
FUNCTION
- fast contraction speed
- low resistance to fatigue
- high force produced
process of ramp like recruitment of muscle fibres
- all muscle fibres contribute the same amount of force during light effort
- when pace picks up ST fibres contribute first and around 60%
- FTa fibres then starts and contributes around 76%
- lastly FTb fibres start last and contribue around 92%
- continue to work at these percentages
fliding filament theory
1) nerve impulse is recieved and calcium ions are released from the sarcoplasmic reticulum
2) calcium ions attach to troponin which change the shape of tropomyosin
3) binding sites are exposed which allows cross bridges to be formed between actin and myosin
4) this pulls the z lines closer together
5) the sarcomere shortens in length
6) h zone disappears and atp breaks down into energy to break the cross bridges
7) this produces a power stroke which occurs in the myofibril
all or nothing law
- needs to be enough acetylcholine released to reach the threshold
- after this the motor unit will be stimulated
- not enough acetylcholine means the fibres wont contract
- enzyme atpase catalyses atp+h2o=adp+phosphate
isometric contractions
- muscles under tension
- hold the body in 1 position
- muscles stay the same length
isotonic contractions
- muscles shortens
- developing tension
- muscles become fatter and shorter
- upwards phase against gravity
isotonic eccentric
- muscles lengthen
- under tension
- downwards phase
deep muscles (7)
- transverse abdominals
- sternocleidomastiod
- rhomboid
- shoulder rotators
- erecor spinae
- wrist supinator
- wrist pronator
agonist
contracts to produce a movement
antagonist
relaxes to allow the movement to happen via the agonist
fixator
reduces undesired movement using the next joint up from the moving joint
synergist
muscle that aids the agonist by directing the movement
flexion
decreases the angle at a joint
extension
increases the angle at a joint
abduction
taking limbs away from the midline
adduction
bringing limbs in towards the midline
horizontal flexion
decreasing the angle at a joint going across the midline
horizontal extension
increasing the angle of a joint going away from the midline
lateral flexion
decreasing the angle of the spine sideways
