1.3 The Neuromuscular System

Question 1

What does the autonomic nervous system regulate ?

Answer 1

The function of our internal organs such as the heart and also controls some of our skeletal muscles with in the body

Question 2

How does the autonomic nervous system work ?

Answer 2

Involuntary, things take place which we do not notice

Question 3

What is the movement of muscles during exercise controlled by ?

Answer 3

Brain via nerves

Question 4

Neuromuscular system

Answer 4

where the nervous system and the muscles work together to allow movement

Question 5

Three main types of muscle fibre

Answer 5

Slow oxidative (type I)
Fast oxidative glycolytic (type IIa
Fast glycolytic (type IIb)

Question 6

Aerobic

Answer 6

literally means ‘with oxygen’ so it refers to exercise that is low to medium intensity where the oxygen demand of the muscles can be met

Question 7

Anaerobic

Answer 7

Means ‘without oxygen’ and refers to exercise at high intensity such as sprinting, where the demand for oxygen by the muscles is so high that it cannot be met.

Question 8

Slow twitch fibres (type 1)

Answer 8

These fibres have a slower contraction speed than fast twitch fibres and are better adapted to lower intensity exercise such as long-distance running. They produce most of their energy aerobically (using oxygen)

Question 9

Fast twitch fibres (Type II)

Answer 9

These fibres have a much faster contraction speed and can generate a greater force of contraction. However, they also fatigue very quickly and are used for short, intense bursts of effort. They produce most of their energy anaerobically (without oxygen).

Question 10

Two types of fast twitch fibre and their characteristics

Answer 10

• Type Ila fast oxidative glycolytic - these fibres are more resistant to fatigue and are used for events such as the 1500m in athletics where a longer burst of energy is needed.
  • Type Ilb fast glycolytic - these fibres fatigue much quicker than type lla and are used for highly explosive events such as the 100m in athletics where a quick, short burst of energy is needed.

Question 11

Characteristics of Slow twitch muscle fibres (Type I)

Answer 11

Small motor neurone size
High mitochondrial density
High capillary density
Slow contraction speed (110)

Question 12

Characteristics of Fast twitch type IIa muscle fibres

Answer 12

Large motor neurone size
Medium mitochondrial density
Medium capillary density
Fast contraction speed (50)

Question 13

Characteristics of Fast twitch type IIb muscle fibres

Answer 13

Large motor neurone size
Low mitochondrial density
Low capillary density
Fast contraction speed (50)

Question 14

Hypertrophy

Answer 14

Where the muscle has become bigger and stronger. (Through training)

Question 15

Motor unit

Answer 15

A motor neurone and its muscle fibres.

Question 16

Motor neurones

Answer 16

Nerve cells which transmit the brains instructions as electrical impulses to the muscles

Question 17

Neuromuscular junction

Answer 17

Where the motor neurone and muscle fibre meet

Question 18

What is each muscle made up of

Answer 18

Many motor units and they vary in size . A small muscle will have motor units that only have a few fibres per motor neurone . However a large muscle will have motor units with a motor neurone feeding hundreds of fibres

Question 19

All or none law

Answer 19

Where a sequence of impulses has to be of sufficient intensity to stimulate all of the muscle fibres in a motor unit in order for them to contract. If not, none of them contract.

Question 20

For low intensity activity what motor units will the brain recruit

Answer 20

Slow twitch motor units

(Jogging , long-distance swimming)

Question 21

For high intensity activity what motor units will the brain recruit

Answer 21

Fast twitch motor units

(Sprinting , power lifting )

Question 22

How to increase the strength of contraction

Answer 22

Wave summation
Tetanic summation
Spatial summation

Question 23

Wave summation

Answer 23

Where there is a
repeated nerve impulse with no time to
relax so a smooth, sustained contraction
occurs, rather than twitches.

Question 24

Tetanic contraction

Answer 24

A sustained muscle contraction caused by a series of fast repeating stimuli

Question 25

Spatial summation

Answer 25

When the strength of a contraction changes by altering the number and size of the muscles motor units

Question 26

What needs to be present for a muscle to contract

Answer 26

Calcium

Question 27

What is PNF (Proprioceptorive neuromuscular facilitation) ?

Answer 27

an advanced stretching technique for increasing range of motion . There are a few different PNF techniques but the most practical is the CRAC technique (contract-relax-antagonist-contract)

Question 28

What is involved in PNF

Answer 28

Two Proprioceptors:
muscle spindles
Golgi tendon organs

Question 29

Muscle spindles

Answer 29

These detect how far and how fast a muscle is being stretched and produce the stretch reflex

Question 30

Golgi tendon organs

Answer 30

These are activated when there is tension in a muscle

Question 31

Isometric contraction

Answer 31

Where there is tension in a muscle but no visible movement

Question 32

Autogenic inhibition

Answer 32

Where there is a sudden relaxation of the muscle in response to high tension. The receptors involved in this process are Golgi tendon organs