pe- functional anatomy

Question 1

origin/insertion

Answer 1

origin- attachment point at the proximal end
insertion- attachment point at the distal end

Question 2

Cocentric contraction

Answer 2

muscle shortens, e.g. upward phase of bicep curl

Question 3

Eccentric contraction

Answer 3

muscle lengthens, e.g. lowering phase of bicep curl

Question 4

isometric contraction

Answer 4

muscle contracts, no movement occurs, e.g. plank

Question 5

epimysium

Answer 5

connective tissue surrounding the entire skeletal muscle belly

Question 6

perimysium

Answer 6

layer of connective tissue surrounding individual fascicles

Question 7

endomysium

Answer 7

layer of membrane surrounding individual muscle fibres

Question 8

fascicle

Answer 8

A bundle of skeletal muscle fibres

Question 9

Muscle Fibres

Answer 9

made up of myofibrils, contain actin and myosin

Question 10

myofibrils

Answer 10

long filaments that form muscle fibres

Question 11

Sarcomere

Answer 11

comprises the unit between the two Z lines

Question 12

Z Lines

Answer 12

Close together in Cocentric contractions

Question 13

Actin

Answer 13

Thin protein attached to Z lines

Question 14

Myosin

Answer 14

Thick protein contains cross bridges

Question 15

Cross bridges

Answer 15

Pull actin filaments towards sarcomere midline

Question 16

H Zone

Answer 16

Space between actin filaments

Question 17

I Band

Answer 17

Light band contains thin actin filament

Question 18

A Band

Answer 18

Thick and thin filaments, centre of sarcomere spans H-Zone

Question 19

Sliding filament theory

Answer 19

1. Calcium is released by sarcoplasmic reticulum into the sarcomere
2. Actin filaments reveal binding site for the myosin head to connect
3. Myosin heads bind to actin filaments, creating cross bridge
4. ATP breakdown releases energy to stimulate myosin cross bridges to pull actin filaments towards sarcomere midline
5. Shortening of sarcomere occurs as actin/myosin filaments “slide over” each other, causing Z lines to come closer together and H zone to shorten
6. Shortened each sarcomere shortens myofibril resulting in shortening of muscle fibres, movement occurs
7. Cross bridges attach and re attach at different times to create movement and retain tension
8. Process repeats if neural impulse is present or the muscle relaxes if neural impulse ends

Question 20

Motor Neuron

Answer 20

A cell within the nervous system that transmits impulses/signals to other nerve cells

Question 21

Dendrites

Answer 21

Detects impulse from sensory receptor, deliver it to cell body

Question 22

Cell body

Answer 22

Contains nucleus, directs neuron’s activities, sends message to axon

Question 23

Axon

Answer 23

Transmits message away from cell body to the muscle

Question 24

Motor Unit

Answer 24

The motor neuron and the fibres

Question 25

Nervous control of muscular system (process of creating movement): Sensory Neurons-

Answer 25

Detect stimulus sound and send impulses to the brain

Question 26

Brain-

Answer 26

Interprets information and sends impulse potential for movement to occur

Question 27

Spinal Cord-

Answer 27

Transmits signal from brain to the muscles via motor neuron

Question 28

Motor Neuron-

Answer 28

Transmits signal away from cell body to muscle fibres

Question 29

Motor Unit-

Answer 29

Once signal threshold is reached, all attached fibres will contract to their 100% intensity

Question 30

Motor Unit size small:

Answer 30

Fine motor skills, precise movement Small number muscle fibres Small motor unit+ action potential e.g. the eye

Question 31

Motor Unit size large:

Answer 31

Gross motor skills, large movement Many muscle fibres required Large motor unit+ action potential e.g. quad when kicking ball

Question 32

All or none principle:

Answer 32

When a motor unit recieves action potential that exceeds the threshold, all muscle fibres associated will contract to their maximum potential

Question 33

Type I Muscle fibres ( slow twitch)

Answer 33

Aerobic- Colour Red Slow contraction speed, low force production Small diameter+ motor neuron size High fatigue resistance High capillary, mitochondrial, Oxiodative density Low glycolytic capacity Fuel source: Triglycerides, glycogen e.g. Marathon runner, endurance cyclist

Question 34

Type IIa muscle fibres ( fast twitch)

Answer 34

Long term anerobic- Colour white Fast contraction speed, high force production Intermediate fibre diameter, Large motor neuron size Intermediate fatigue resistance Intermediate capillary, mitochondrial, Oxiodative density High glycolytic capacity Fuel source: creatine phosphate, glycogen E.g. 800m runner (speed endurance based acitvities)

Question 35

Type IIb muscle fibres ( fast twitch)

Answer 35

Short term anerobic- Colour white Very fast contraction speed, very high force production Large fibre diameter, Very large motor neuron size Low fatigue resistance Low capillary, mitochondria, Oxiodative density High glycolytic capacity Fuel source: creatine phosphate, glyocogen e.g. 100m sprint, javelin ( explosive movements)

Question 36

Role of genetics

Answer 36

Specific % of Red/white Fibres is genetically determined, remain the same whole life High Percentage of type I fibres (80+%) is successful at endurance events High percentage of type II fibres (80+%) successful at explosive events

Question 37

Force- Velocity

Answer 37

- Describes relationship between force production and the velocity of movement. - Max force at low velocity - As velocity increases, force generated decreases - Only small force generated when muscle contracts at maximum velocity

Question 38

Force- length

Answer 38

- Relates to the amount of force that can be produced at varying muscle lengths. - When muscle is shortened only small force can be generated due to greatest overlap of actin and myosin filaments, reducing potential to contract - When muscle at mid length (resting length), greatest force generated due to optimal overlap of actin and myosin filaments - When muscle fully lengthened, only small force can be generated due to insufficient overlap of actin and myosin filaments, reducing potential to contract