functional anatomy pt 2

Question 1

list the parts included in a skeletal muscle

Answer 1

ef pmem
epimysium
fascicle
perimysium
muscle fibre
endomysium
myofibril

Question 2

define the epimysium

Answer 2

the connective tissue shealth around each muscle

Question 3

define fascicle

Answer 3

a bundle of skeletle muscles surrounded by the perimysium

Question 4

define the perimysium

Answer 4

the connective tissue which surrounds seach bundle on muscle fibers

Question 5

define muscle fibres

Answer 5

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.

Question 6

define endomysium

Answer 6

connective tissue which surrounds each individual muscle fibre

Question 7

define myofibril

Answer 7

small thread like strands that run through each muscle fibres.

Question 8

what is the sliding filament theory

Answer 8

explains the shortening of the sacromere (in a concentric contraction) and then resulting in contraction in muscle

Question 9

describe the first step of the sliding filament theory

Answer 9

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

Question 10

describe the second step in the sliding filament theory

Answer 10

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.

Question 11

describe the 3rd step of the sliding filament theory

Answer 11

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.

Question 12

describe the 4th step of the sliding filament theory

Answer 12

as each sarcomere shortens so does the total length of each muscle fibre

Question 13

describe the 5th step of the sliding filament theory

Answer 13

when the contraction finishes the myosin and actin filaments return to a relaxed position

Question 14

what are the different bands and zones of the sarcomere

Answer 14

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

Question 15

draw a labeled diagram of a neuron

Answer 15

should include - dendrites, mylin shealth, axon, synaptic bulbs, cell body, nucleus, muscle fibres

Question 16

outline what dendrites are

Answer 16

pass info from the sensory receptors to the cell body of the sensory neuron

Question 17

outline what axons of motor neurons are

Answer 17

transmits electrical info/signals away from cell body to the muscle fibres

Question 18

outline what the spinal cord does

Answer 18

transmits electrical messages from the brain to parts of the body

Question 19

what is a motor unit

Answer 19

to create the desired movement

Question 20

outline what nueron is

Answer 20

a cell within the nervous system that transmits impulse/signals to other nerve cell/muscles

Question 21

describe the process on how the neuron creates movement

Answer 21

1. brain recieves a signal from sensory nerve
2. message travels via motor nueron- structure slide
3. arrives at the nueromuscular junction and has to cross synapeses
4. arrival action potential which opens calcium channel
   5.influx of calcium triggers a biochemical cascade
5. this causes the release of acetglochline which is a neurotransmitter into the synapse
6. signal on the end plate then transmit nerve signals to the muscle fibre
7. signal release the calcium from the sarcoplasmic reticulum causing sliding filament theory.
8. neruons extend across the length of the myofibril but only stimulate portions of the muscle belly

Question 22

define the all or nothing principle

Answer 22

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.

Question 23

how can i produce more force?

Answer 23

• greater number of motor units
• type of fibre (type 2= fast twitch)
• size of motor neuron

Question 24

what is a force-velocity relationship? and whats concentric and eccentric contraction

Answer 24

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.

Question 25

draw a graph of the force-velocity relationship for muscle contraction and explain how a weight lifter uses force in power lifting events?

Answer 25

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.

Question 26

what is force length relationship

Answer 26

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

Question 27

wat which point in the force length relationship is the muscle producing the most amount of force?

Answer 27

the mid range

Question 28

describe the different resting muscle length % and force in relation to the force length relationship (inverted U)

Answer 28

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.

Question 29

list the characteristics of type IIa muscle fibres

Answer 29

- fast twitch - duration of10sec - 2min - fast contraction speed -used for speed endurance - moderate force contraction moderate rate of fatigue - high glycolic capacity - moderate oxidative density - 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

Question 30

list an example for type 2 a

Answer 30

400m,800m

Question 31

list the characteristics type IIb

Answer 31

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

Question 32

list an example for type 2 b

Answer 32

100m/ 200m

Question 33

describe the characteristics type 1

Answer 33

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 - slow fatigue rate - high oxadative density - 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

Question 34

provide an example for slowtwitch muscle fibre

Answer 34

10k runner, endurance swimmer/cyclist

Question 35

In the space provided, draw a graph of the force-length for muscle contraction and explain its application to the starting position as indicated in the above dart-throwing progression.

Answer 35

Damon starts his throw with his arm bent at the elbow which allows optimal/resting/mid-range muscle length to occur in the triceps. 1 Above is due to the ability to engage/use maximum cross bridges. 1 Force is low when muscle is lengthened due to little overlap of actin and myosin. 1 Force is low when muscle is contracted (shortened) due to large overlap of actin and myosin.

Question 36

Outline three ways in which Newton’s Second Law of Motion would assist Reece to kick the ball for distance. (3 marks)

Answer 36

 increase the speed of the kicking leg  increase the run-up speed  increase contact time of the foot on the ball  increase force by using correct segmental interaction  apply a follow-through when kicking the ball to prevent deceleration.

Question 37

Name and outline the function of the five key components required for netball shooters neuromuscular system that makes the movement to intercept happen. (10 marks)

Answer 37

Sensory neuron: (1 mark)  detects ball movement from the sensory receptors and sends information to the brain. (1 mark) 1–2 Brain: (1 mark)  receives information from the sensory neuron: interprets the information and makes decisions based on inputs, sends response to the spinal cord/motor neuron. (1 mark) 1–2 Spinal cord: (1 mark)  receives information from the brain and transmits electrical signals to the motor neuron. (1 mark) 1–2 Motor neuron: (1 mark)  receives electrical signals from spinal cord/brain and transmits electrical signals to the muscle fibres to innervate. (1 mark) 1–2 Motor unit: (1 mark)  contracts muscle fibres to initiate movement to intercept ball. (1 mark)