Neuromuscular system

Question 1

What does the Sympathetic system do?

Answer 1

It fires up the body for exercise. Flight or fight.

Question 2

What does the Parasympthetic system do?

Answer 2

It slows everything in the body down. ‘Rest and rerlax’

Question 3

Name the 3 types of muscle fibres

Answer 3

Type1 slow oxidative
Type IIa Fast oxidative glycolytic
Type IIx fast glycolytic

Question 4

Think of 3 sporting examples for each category where this muscle type provides the majority of the energy

Answer 4

Type IIa - 1500m, 200m swim, floor routine in gymnastics

Type IIx -Power lifting, 100m sprint, smash in tennis Type 1 - Marathon, cross country skiing, Tour de France

Question 5

A netball. player will use type IIx fibres to jump as high as possible to win a rebound. Give 3 characteristics of this fibre type

Answer 5

Fast contraction speed
Large motor neurone
High force Produced
Fatigues quickly

Question 6

Name and divide Characteristics of muscle fibres into Structural and functional characteristics.

Answer 6

Structural (make up of the fibre) -Motor Neurone size, Mitochnondrial density, Myoglobin content, capillary density
Functional(what the fibre does) - contraction speed, Motor neurone conduction capacity, Force produced, fatigability, aerobic capacity, Anaerobic capacity, Myosin ATPase/glycolytic enzyme activity.

Question 7

A Shot Putt thrower needs to produce as much force as possible. Describe how the shot putter can use motor units to achieve maximal contraction.

Answer 7

Lots of motor units recriuited
Large number of motor units for a stronger contraction
All or none law/explanation
Spatial summation - simultaneous impulses received at different places on the neurone need to add up to fire the neurone.
Use of fast twitch motor units produces more force
Wave summation - repeated nerve impulses with no time to relax.
Tetanus/tetanic(smooth sustained muscle contractions)
Leeds to a more powerful contraction

Question 8

Explain the role of the muscle spindles and golgi tendon organs in PNF stretching?

Answer 8

Golgi tendon organs are activated and detect a stretch
Muscles relax
inhibits stretch reflex and overides the muscle spindle
This is designed to prevent overstretching
It allows a greater range of movemnt to be used.
CRAC (contract/relax/antagonist/contract)

Question 9

What do you understand by the term motor unit?

Answer 9

Motor neurone and muscle fibre
All fast twitch or slow twitch
All or none Law

Question 10

Describe is the All or none Law

Answer 10

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 11

How are motor units involved inthe process of spatial summation?

Answer 11

Causes an increase in strength of contraction/more force in muscles
Use bigger/larger motor units
More motor units
Fast twitch units produce more force than slow twitch units.

Question 12

Describe the charcteristics of the main muscle fibre type used by marathon runners

Answer 12

Slow oxidative fibre
Slow motor neurone conduction capacity
High numbers of mitochondria
High myoglobin content
High capillary density
Low force production/less powerful

Question 13

Explain wave summation

Answer 13

Where there is a repeated nerve impulse with no time to relax soa smooth, sustained contracttion occurs, rather than a twitch

Question 14

Explain Spatial summation

Answer 14

When the strength of contraction changes by altering the number and size of the muscle’s motor unit

Question 15

What are ‘Muscle spindle’?

Answer 15

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

Question 16

Explain Autogenic inhibition.

Answer 16

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

Question 17

Describe Proprioceptive Neuromuscular facilitation (PNF) in practice.

Answer 17

Individual performs a passive stretch with the help of a partner until tension is felt- stretch detected by muscle spindles. If muscle being stretch too far stretch reflex should occur.
Individual then isometrically contract the muscle for 10secs pushing against partner- golgi tendon detect this contraction and are activated to send an inhibitory signal to override the excitory signal therfore delaying the stretch reflex.
as the leg is lifted again the goli tendon organs are responsible for the antagonistic muscle relaxing which means the leg stretches further.