3.1.1.4 Neuromuscular system

Question 1

autonomic nervous system

Answer 1

• regulates function of internal organs e.g. heart
• involuntary
• sympathetic nervous system = prepare for exercise (fight or flight)
• parasympathetic nervous system = relax body & slows down many high energy functions (rest and relax)

Question 2

neuromuscular system

Answer 2

-controls muscles during exercise
Brain -> Nerves -> Muscles
-nerves and muscles work together to = movement
-sympathetic and parasympathetic nervous system = help prepare neuromuscular system for exercise
-transmits info from brain to parts of body

Question 3

muscle fibre types

Answer 3

3 types of motor unit
2 = fast twitch fibres
1= slow twitch fibres

-muscles = mixture of all 3 types determined by genetics

Question 4

fast twitch glycolytic

Answer 4

FG or type 2x
fast (50) speed of contraction
highest force of contraction

large fibre & motor neurone size
high and very high PC and glycogen stores
anaerobic shot put

Question 5

fast twitch oxidative glycolytic

Answer 5

FOG or type 2a
fast (50) speed of contraction
high force of contraction

large fibre size
large motor neurone size
activity = 1500m

Question 6

slow twitch

Answer 6

ST or 1
-slow (110) speed of contraction

-small fibre size
high myoglobin content
small motor neurone size
aerobic activity (marathon)

Question 7

motor neurone size

Answer 7

the larger the diameter of motor neurone = faster speed of impulses

Question 8

postural muscles

Answer 8

• type 1 fibres - maintain body posture

- increase size muscle fibres- training = hypertrophy = greater strength of the muscle

Question 9

examples of events and muscle fibre types

Answer 9

100m: 30% type 1, 30% type 2a, 40% type 2 x
marathon: 70% type 1, 15% type 2a, 15% type 2x
footballer: 45% type 1, 40% type 2a, 15% type 2x

Question 10

motor unit

Answer 10

motor nerve and the muscle fibres it stimulates

• 1 neurone controls a number of muscle fibres
• single neurone = control fibres of same type not a mixture of fibre types

-always 1 nerve but number of fibres can vary

Question 11

motor neurone/nerve structure

Answer 11

-conducts nerve impulses to muscle fibres

• thicker nerve = faster impulse travels (type 2x = thickest)
• cell body and cytoplasm
• dendrites (collect signals)
• axons of nerve fibres (passes signals)
• myelin sheath
• node of Ranvier (gaps in the myelin sheath)
• axon terminal
• muscle fibres & synaptic end bulb
• neuro-musclar junction (where muscle joins with nerve)

Question 12

all or none law

Answer 12

-when a neurone is stimulated all fibres connected to that neurone are activated at once

Question 13

threshold definition

Answer 13

minimum amount of stimulation required to start a contraction

Question 14

ways to control force of contraction/variation in strength of muscle contraction (how can muscle vary force produced)

Answer 14

1. recruiting: slow twitch motor units for low intensity activity
2. wave summation: increasing frequency of nerve stimulus
3. spatial summation: varying number of motor units recruited

Question 15

fibre type and exercise

Answer 15

-recruitment (based on intensity of exercise)

low = ST motor units recruited
higher = FOG, FT, 2a
greatest intensity= FG, FT, 2x (powerful fast contractions)

Question 16

wave summation

Answer 16

REPEATED NERVE IMPULSE = SMOOTH SUSTAINED CONTRACTION (NO REST TIME)

• nerve impulse reach muscle cell = calcium
• calcium =present (sarcoplasm) =muscle contract
• same fibre group fired repeatedly will build the force exerted by wave summation

Question 17

tetanic contraction

Answer 17

• no time for relaxation between motor unit firing
• calcium builds up in muscle cells = causes complete lock up of muscle

1. twitch
2. summation
3. incomplete tetanus
4. complete tetanus

Question 18

spatital summation

Answer 18

STRENGTH OF CONTRACTION CHANGES BY ALTERING NO/SIZE OF MOTOR UNITS

• different fibre groups are fired in succession to control a movement
• total force across the space of a muscle is the sum of the effect of different fibre groups

3x motor units broken down = total force across muscle

Question 19

Action potential

Answer 19

when a neuron has an electrochemical impulse passing down its axon.

Question 20

Types of contraction

Answer 20

Twitch
Wave summation
Spatial summation
Tetanus

Question 21

Tetanus

Answer 21

• sustained muscle contraction

- motor neurone receives action potentials at a very rapid rate

Question 22

Synapse

Answer 22

When one neurone joins another neurone

Question 23

recruitment

Answer 23

based on intensity of exercise

low: ST motor unit recruited first
higher: FOG/FT/2a motor units recruited
greatest: FG/FT/2x motor units recruited

to produce powerful fast muscle contractions

Question 24

tetanic contraction

Answer 24

no time for relaxation between motor unit firing
calcium build up in muscle cell
cause complete lock up of muscle

Question 25

stretch reflex

Answer 25

reflex contraction of muscle in response to a sudden rapid stretch protecting muscle against possible tears/strains

Question 26

proprioceptors

Answer 26

help control muscle contractions - located in skeletal muscle, joint capsules & tendons and provide sensory info on: 1. body movement 2. orientation in space 3. muscle stretch

Question 27

reciprocal inhibition

Answer 27

process which occurs in an antagonistic pair of muscles inhibit stretch reflex -when agonist muscle contracts = sends out inhibitory nerve impulses to its opposing muscle (antagonist) causing it to relax as a result of reflex action e.g. bicep contracting switch off tricep

Question 28

muscle spindle

Answer 28

very sensitive proprioceptor found in skeletal muscle - prevent injury - afferent nerve stimulated when length of relaxed muscle stretched and exceeds certain limit - triggers off response via efferent nerve = initiates reflex muscle action = shortens a muscle/muscle group

Question 29

afferent nerve

Answer 29

sensory neurone

Question 30

efferent nerve

Answer 30

motor neurone

Question 31

tendon

Answer 31

muscle to bone

Question 32

ligament

Answer 32

bone to bone

Question 33

Golgi tendon organs

Answer 33

- located at junction between muscle and tendon - too much tension in muscle = muscle relax - excessive muscle contraction = Golgi tendon reflex or Autogenic inhibition - protect from tearing/pulling away from tendinous points of attachment to bones - activated after hold (isometric contraction) = further relaxation of muscle (muscle spindle reflex switched off)

Question 34

PNF stretching

Answer 34

Proprioceptive neuromuscular facilitation -flexibility -static /dynamic/ballistic not as effective as PNF -use alienation contraction and relaxation movement -passive or active CRAC technique -isometric contractions (hold/no movement)

Question 35

CRAC technique

Answer 35

contract relax antagonist contract

Question 36

Process of PNF

Answer 36

1. tension on tendon activate sensory neurone 2. sensory neurone stimulates interneurone 3. interneurone inhibits motor neurone 4. tension on tendon reduced - passive stretch - muscle spindles detect= limit = stretch reflex - isometric contraction (push away from partner) = tension in muscle = GTO reflex activated = autogenic inhibition detect tension = turns off stretch reflex - stop isometrically contracting stretch reflex temporarily switched off = increase range of movement

Question 37

interneurone

Answer 37

- connect spinal motor and sensory neurone | - transfer signals between sensory & motor neurons,

Question 38

motor end plate or neuromuscular junction

Answer 38

-connection between a motor neurone and its fibres

Question 39

4 functional characteristics list

Answer 39

1. speed of contraction 2. force of contraction 3. fatiguability 4. anaerobic/aerobic capacity

Question 40

6 structural characteristics list

Answer 40

1. fibre size 2. mitochondrial density 3. capillary density 4. myoglobin content 5. myosin/ATPase glycolytic enzyme activity 6. motor neurone size

Question 41

motor neurone definition

Answer 41

nerve cells that transmit brains instructions as electrical impulses to muscles