1.3 Flashcards
What the autonomic nervous system regulates
The function of our internal organs (e.g. the heart) + some of our skeletal muscles
The way in which the autonomic nervous system works (1 word)
Involuntarily
What controls the movement of muscles during exercise
The brain via nerves
Define the neuromuscular system
Where the nervous system + muscles work together to allow movement
When do changes in the neuromuscular occur
Before, during + after exercise
Why does the neuromuscular system change
To prepare the body for exercise + allow for the changing demands of different intensities of exercise
What are the sympathetic + parasympathetic nervous systems part of
Our peripheral nervous systems
The role of the sympathetic + parasympathetic nervous systems
To transmit info from the brain to parts of the body which must adjust what they’re doing to prepare for exercise
The effect of the sympathetic nervous system
To prepare/ fire up the body for exercise (the fight or flight response)
The effect of the parasympathetic nervous system
Relaxes the body + slows down high energy functions (rest + relax)
The 3 types of muscle fibre
Slow oxidative (type 1) /slow twitch, Fast oxidative glycolytic (type 2a), Fast glycolytic (type 2b)
What 3 things determine the mix of the 3 different muscle fibres in our skeletal muscles
Genes, type of sport + function
How the proportion of muscle fibre types would vary for an endurance athlete
They would have a greater proportion of slow twitch (type 1) fibres in their leg muscles
How the proportion of muscle fibre types would vary for a sprinter
They would have a greater proportion of fast twitch (type 2) muscle fibres in their leg muscles
What types of muscle fibre will postural muscle fibres have a greater proportion of + why
Slow twitch fibres - due to them being involved in maintaining body position over a log period of time
11 characteristics used to distinguish types of muscle fibre
Contraction speed, motor neurone size, motor neurone conduction capacity, force produced, fatigability, mitochondrial density, myoglobin content, capillary density, aerobic density, anaerobic density + glycolytic enzyme activity
The contraction speed of Type 1 muscle fibres
Slow
The way in which slow twitch fibres produce most of their energy
Aerobically
What do the specific characteristics of type 1 muscle fibres allow them to do more effectively
Use oxygen more efficiently
The 4 structural characteristics of type 1 muscle fibres which allow them to work more effectively
High mitochondrial density, myoglobin content, capillary density and aerobic capacity
The 4 functional characteristics of type 2 muscle fibres (3 main ones)
Fast contraction speed (and motor neurone conduction capacity), High fatigability and force produced
The way in which type 2 muscle fibres produce most of their energy
Anaerobically
The main difference in functional characteristics between type 2a and 2b muscle fibres
Type 2a have higher fatigability
What are the functional characteristics of type 2a muscle fibres in relation to type 1 and 2b
They’re always in the middle
3 structural characteristics of type 2 muscle fibres which help them do their role more efficiently
High anaerobic capacity, Large motor neurone size, High glycolytic enzyme activity
What the characteristics of type 1 are always in relation to type 2 muscle fibres
They’re always opposite (high/low or large/small or fast/slow)
Functional characteristics of muscle fibres
Those to do with what the fibre does
Structural characteristics of muscle fibres
The make-up of the fibre
What is hypertrophy + what causes it
It’s where the muscle gets bigger + stronger due to training
The 2 components of the motor unit
A motor neurone + its muscle fibres
How muscle fibres are arranged into motor units
They’re grouped, The no. of types of muscle fibres which can be found in a single motor unit
The no. of types of muscle fibres which can be found in a single motor unit
1
What do muscle fibres work with in order for contraction to occur
The nervous system
The role of the motor neurone in muscle contraction
It transmits the electrical nerve impulse (the brain’s instructions) to the muscle fibre (from the nervous system/brain)
What do motor neurones branch into
Neuromuscular junctions
Neurones
Nerve cells
Where are neuromuscular junctions found
On muscle fibres
The 5 components involved in causing muscle contraction - in order
Muscle spindle, Sensory nerve, Spinal cord, Motor nerve, Muscle (fibres)
The role of the muscle spindle in causing contraction
It senses the muscle-stretching + sends an impulse to the spinal cord
How many units are found in a muscle + what are their sizes in relation to the others in the same muscle
There’s many motor units in each muscle which vary in size
How the number of muscle fibres per motor unit varies for the size of muscle
Larger muscles have more fibres (100s) and smaller muscles only have a few fibres per motor unit
What small muscles are used for
Fine motor control
What large muscles are used for
Gross motor control
The all or none law
Where the sequence of impulses delivered by the motor neurone has to be of sufficient intensity to stimulate all of the muscle fibres in a motor unit in order for them to contract - if it’s not of sufficient intensity - none of them contract (motor units can’t partially contract)
The threshold of a motor unit
The minimum amount of intensity required to cause contraction of an individual motor unit (varies per unit)
The 2 types of motor unit
Fast twitch + slow twitch
The type of motor unit which the brain will recruit for low intensity/endurance exercise
Slow twitch
The type of motor unit the brain will recruit for activities requiring a greater force of contraction
Fast twitch
The 2 ways to increase strength of muscle contraction
Wave + spatial summation
The effect of increased freq. of stimuli on muscles
Increased muscle tension/force of contraction
What is wave summation
Where there’s a high frequency of stimulation of a muscle due to repeated activation (lots of nerve impulses) of a motor neurone with no time to relax - causes build-up of calcium in muscle cells
The type of contraction which wave summation results in + 3 of its features
Tetanic contraction, Smooth, sustained + forceful
What is released each time a nerve impulse reaches a muscle cell
Calcium
What must be present in order for muscles to contract
Calcium
Spatial summation
The recruitment of additional/bigger/stronger motor units in a muscle which allow impulses to be received at the same time at different places on the neurone - add up to fire the neurone
Proprioceptive neuromuscular facilitation (PNF)
A stretching technique to increase range of motion
What is CRAC technique a type of
PNF technique
What CRAC stands for
Contract (stimulates golgi tendon organs), Relax Antagonist (stimulates muscle spindles on a delay), Contact
How many times is CRAC repeated
Until no more gains are possible
How muscle action is controlled in order for movement in PNF to be effective
Using internal regulatory systems/proprioceptors (muscle spindles + golgi tendon organs)
What are proprioceptors a type of
Sensory organ
The role of proprioceptors
To inform the body of the extent of movement that’s taken place
The 2 types of proprioceptors used in PNF
Golgi tendon organs + muscle spindles
What are muscle spindles
V. sensitive proprioceptors
Where muscle spindles are found
Between skeletal muscle fibres
What muscle spindles are also known as
Stretch receptors
The type of signals which muscle spindles provide to the central nervous system
Excitory signals
The role of muscle spindles
To detect the extent + speed at which a muscle is being stretched
What do muscle spindles produce
The stretch reflex
What CNS stands for
The central nervous system
What causes the stretch reflex
The CNS receives the impulse from the muscle spindles + sends an impulse back to the muscle telling it to contract
The purpose of the stretch reflex
To prevent over stretching + injury
The 3 components/fibres found in muscles (from inside t outside)
Intrafusal, sensory + extrafusal
How the shape of the muscle spindle changes when it’s contracted
The extrafusal fibres + the intrafusal ‘rope’ of fibres gets thicker
Where are golgi tendon organs found
Between the muscle fibre + tendon
What do golgi tendon organs detect
Tension levels in muscles
What the golgi tendon organs sense during PNF
Tension from the isometric muscle contraction
How golgi tendon organs respond to muscle tension
Autogenic inhibition (they send inhibitory signals to the brain to allow the antagonist to (suddenly) relax + lengthen)
How golgi tendons delay the stretch reflex to allow the antagonist to stretch further
Their inhibitory signals override the excitory signals from the muscle spindles
