functional anatomy Flashcards
list the parts included in a skeletal muscle
ef pmem
epimysium
fascicle
perimysium
muscle fibre
endomysium
myofibril
define the epimysium
the connective tissue shealth around each muscle
define fascicle
a bundle of skeletle muscles surrounded by the perimysium
define the perimysium
the connective tissue which surrounds seach bundle on muscle fibers
define muscle fibres
surrounded by a plasma membrane called the sarcolemma which contains the sarcoplasm. a muscle fibre is composed of many fibrils, which give the cell its striated appearance.
define endomysium
connective tissue which surrounds each individual muscle fibre
define myofibril
small thread like strands that run through each muscle fibres.
what is the sliding filament theory
explains the shortening of the sacromere (in a concentric contraction) and then resulting in contraction in muscle
describe the first step of the sliding filament theory
when there’s a neurochemical stimulation calcium ions are released from the sarcoplasmic reticulum into sarcomere
prompting reaction in each muscle fibre between myosin and actin filaments
describe the second step in the sliding filament theory
myosin filaments creates cross bridges ( myosin heads) at regular intervals. these cross bridges attach and reattach at different times along the actin. pulling them to create tension.
describe the 3rd step of the sliding filament theory
the actin now moves into the centre of the sarcomere, shortening the myofibril and causing the actin and myosin filaments to be almost fully contracted position causing the H zone and I band to disappear.
describe the 4th step of the sliding filament theory
as each sarcomere shortens so does the total length of each muscle fibre
describe the 5th step of the sliding filament theory
when the contraction finishes the myosin and actin filaments return to a relaxed position
what are the different bands and zones of the sarcomere
h zone- distance between actin and filament
a band- length of myosin filament
I band- disnce from the edge of myosin to the z line
z line- edges of the sarcomere
draw a labeled diagram of a neuron
should include - dendrites, mylin shealth, axon, synaptic bulbs, cell body, nucleus, muscle fibres
outline what dendrites are
pass info from the sensory receptors to the cell body of the sensory neuron
outline what axons of motor neurons are
transmits electrical info/signals away from cell body to the muscle fibres
outline what the spinal cord does
transmits electrical messages from the brain to parts of the body
what is a motor unit
to create the desired movement
outline what nueron is
a cell within the nervous system that transmits impulse/signals to other nerve cell/muscles
describe the process on how the neuron creates movement
- brain recieves a signal from sensory nerve
- message travels via motor nueron- structure slide
- arrives at the nueromuscular junction and has to cross synapeses
- arrival action potential which opens calcium channel
5.influx of calcium triggers a biochemical cascade - this causes the release of acetglochline which is a neurotransmitter into the synapse
- signal on the end plate then transmit nerve signals to the muscle fibre
- signal release the calcium from the sarcoplasmic reticulum causing sliding filament theory.
- neruons extend across the length of the myofibril but only stimulate portions of the muscle belly
define the all or nothing principle
when a motor neuron receives stimulation potential to threshold, all the muscle fibres of the motor unit will contract with the same maximal force at the same time.
how can i produce more force?
- greater number of motor units
- type of fibre (type 2= fast twitch)
- size of motor neuron
what is a force-velocity relationship? and whats concentric and eccentric contraction
this describes the inverse relationship between force production and velocity of movement.
concentric contraction : as more forece is required the speed of movement cannot be fast and vice versa
eccentric contration: as mre force is required muscle velocity increases. as less force is required muscle velocity decreases.
draw a graph of the force-velocity relationship for muscle contraction and explain how a weight lifter uses force in power lifting events?
draws graph with negative trend with velocity at bottom and force on side
- they want to produce maximal force for his lift
- he needs to contract his muscle slowly
- this allows time for the sarcomere to form maximum number of crossbridges.
what is force length relationship
relates directly towards the amount of muscle force that can be produced at varying muscle length,
- when fully flexed/ extended ( out of range of contraction), not as much force can be produced compared to the mid range. (extended insufficient amount of overlap of actin and myosin and fully contracted preventing from contracting any further)
- the force lengthe relates directly towards the mid rnage ( resting length) of a muscle the greatest force production can be generated due to the optimal overlap of actin and myosin
wat which point in the force length relationship is the muscle producing the most amount of force?
the mid range
describe the different resting muscle length % and force in relation to the force length relationship (inverted U)
i) as the muscle contracts crossbridges linkage formation is impaired due to too much overlap of myofilaments
ii) a muscles normal resting length allows for optimal overlap of the myofilaments therefore maximising crossbridge attachments
iii) the muscle is stretching beyond its normal resting state. the reduced overlap of myofilaments causes a decrease in the number of available binding sites.
list the characteristics of type IIa muscle fibres
- fast twitch
- duration of 2m
- fast contraction speed -used for speed endurance
- moderate force contraction
fatigue resistance but not as much as slow twitch - possesses some aerobic characteristics ( such as moderate levels of myoglobin, mitochondria and blood capilaries.
- stimulated by relatively large motor nuerons and are stimulated in moderate frequency
list an example for type 2 a
400m,800m
list the characteristics type IIb
fast twitch
- duration of less than 10 seconds
- rapid contraction speed- used for speed, strngth and power
- high force of contraction
- high capacity for anaerobic ATP production
- fatigue very quickly- no oxygen
- generates greater force+ more powerful contraction as theyre lageer than red fibres
- possesses very few aerobic characteristics such as low levels for myoglobin, mitochondria and blood capilaries.
- very high anaerobic characteristics such as high levels of glycogen
- stimulated by very large motor nuerons and are stimulated at a very high frequency
list an example for type 2 b
100m/ 200m
describe the characteristics type 1
slow twitch
- duration over 2m
- slow contraction speed- used for endurance activities
- low force of contraction
- high capacity for ATP production- generates ATP using aerobic system
- fatigue resistance
- contract repeatedly for continuous activity
- possesses more aerobic charactersitics such as high levels of myoglobin, mitochondria and blood capilaries
- stimulated by relatively small motor nuerons and are stimulated at a low frequency
provide an example for slowtwitch muscle fibre
10k runner, endurance swimmer/cyclist
