The Neuromuscular System Flashcards by Thomas Robinson

What does the autonomic nervous system regulate

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

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How does the autonomic nervous system work

Works involuntarily

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How is the movement of muscles controlled by

The brain via nerves

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What is the neuromuscular system

Where the muscles and nervous system work together to allow movement

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When do changes in the neuromuscular system take place

Before,during and after the exercise

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What system are the sympathetic and parasympathetic systems apart of

The autonomic nervous system

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What is the role of the parasympathetic and sympathetic systems

Transmit information from the brain to the parts of the body that need to adjust what they are doing to prepare for exercise

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What does the sympathetic system prepare

The body for exercise and is often referred to as the fight or flight response

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What does the parasympathetic system do

Opposite effect of the sympathetic system and relaxes the body and slows down many high energy functions

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What are the types of muscle fibres

Slow oxidative (type 1 or slow twitch fibres)
Fast oxidative glycolytic (type 2a)
Fast glycolytic (type 2b)

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What is the proportion of muscle fibres dependant on

Dependant on different people and what sport they play

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What muscles tend to have a greater proportion of slow twitch fibres

Postural muscles as they are involved in maintaining body position over a long period of time

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What are slow twitch fibres

-slower contraction speed than fast twitch fibres
-better adapted to lower intensity exercise
-Produce most of their energy anaerobically

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What are fast twitch fibres

-faster contraction speed than slow twitch fibres
-generate much greater force of contraction
-fatigue very quickly
-produce most energy anaerobically
-two types 2a 2b

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What are type 2a fibres

-fast oxidative glycolytic
-fibres more resistant to fatigue than 2b
-used for 1500m in athletics where a longer burst of energy is needed

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What are type 2b fibres

-Fast glycolytic
-fibres fatigue much quicker than type 2a
-used for highly explosive event e.g. 100m

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What is the contraction speed of each of the muscle fibres

Type 1: Slow (110m/s)
Type 2a: Fast (50m/s)
Type 2b: Fast (50m/s)

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What is the motor neurone size in each of the muscle fibres

Type 1: Small
Type 2a: Large
Type 2b: Large

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What is the motor neurone conduction capacity in each fibre

Type 1: Slow
Type 2a: Fast
Type 2b: Fast

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What is the force produced in each of the muscle fibres

Type 1: low
Type 2a: High
Type 2b: High

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What is the fatigability on each if the muscle fibres

Type 1:low
Type 2a:medium
Type 2b:High

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What is the mitochondrial density in each if the muscle fibres

Type 1: high
Type 2a: medium
Type 2b: low

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What is the myoglobin content on each if the muscle fibres

Type 1: High
Type 2a: medium
Type 2b: low

What is the capillary density in each muscle fibre

Type 1:high
Type 2a:medium
Type 2b:low

What is the aerobic capacity on each muscle fibre

Type 1:very high Type 2a:medium Type 2b:low

What is the anaerobic capacity of each muscle fibre

Type 1: low Type 2a: high Type 2b: very high

What is the glycolytic enzyme activity of each muscle fibre

Type 1: low Type 2a: high Type 2b: very high

What is the fibre type determined by

Genetics, however it is possible to increase the size of muscle fibres through training (hypertrophy)

What are muscle fibres grouped into

Motor units

What does a motor unit consist of

-Motor neurone - and it’s muscle fibre

Only one type of…..

Muscle fibre can be found in one particular motor unit

Muscle fibres work with…

The nervous system so that a contraction can occur. The motor neurone transmits the nerve impulse to the muscle fibre

Each motor neurone has….

Branches that end in the neuromuscular junction on the muscle fibre

What is a neuromuscular junction

Where the motor neurone and the muscle fibre meet

Each muscle is made up of what

Many motor units and they vary in size

What is the all or none law

Once the motor unit stimulates the muscle fibres either all of them contract or none of them contract

Is it possible for a motor unit to partially contract

What is the minimum amount of stimulation to start a contraction called

A threshold

What happens if the sequence of impulses is equal to or more than the threshold

All the muscle fibres in a motor unit will contract

What happens if the sequence of impulses is less than the threshold

Then no muscle action will occur

Define the all or none law

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 will contract

What is wave summation

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

What happens each time the nerve impulse reaches the muscle cell

Calcium is released

What is need to be present for a muscle to contract

Calcium

What happens if there are a repeated nerve impulses with no time to relax

Calcium will build up in the muscle cell. This provides a forceful, sustained, smooth contraction - tetanic contraction

Define tetanic contraction

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

When does spatial summation occur

Occurs when impulses are received at the same time at different places on the neurone which add up to fire the neurone

Define spatial summation

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

What does PNF stand for

Proprioceptors neuromuscular facilitation

What is PNF

An advanced stretching technique considered to be one of the most effective forms of flexibility training for increasing range of motion

What are the several mechanisms that make PNF possible

Muscle spindles Golgi tendon organs

What are muscle spindles

-very sensitive proprioceptors that lie between skeletal muscle fibres -they provide information to the central nervous system about how fast and how far a muscle is being stretched - the CNS sends an impulse which triggers the stretch reflex -this reflex action that causes the muscle to contract to prevent over stretching reduces risk of injury

Define muscle spindles

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

What are the Golgi tendon organs

-proprioceptors found in between the muscle fibre and tendon. -detect levels of tension in muscles -when muscle is contracted isometrically in PNF they sense the increase in muscle tension -send inhibitory signals to the brain which allows the antagonist muscle to relax and lengthen-autogenic inhibiton

Define Golgi tendon organs

Proprioceptors that are activated when there is tension in a muscle

Define isometric contraction

Where there is tension in a muscle but no visible movement

Define autonomic inhibition

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