NEUROMUSCULAR SYSTEM Flashcards
MOTOR NEURONE
Type of nerve cell that transmits signals from the central nervous system to muscles or glands, causing them to respond or take action. Essential for voluntary movements
MOTOR UNITS
Made up of a single motor neurone and all the muscle fibres it controls. When motor neurone sends a signal, all the muscle fibres in the unit contract together. Motor units vary in size, smaller ones more precise movement, larger ones for powerful movements
THE NEUROMUSCULAR JUNCTION
The place where motor neurone and muscle fiber connect. Communicate with nerve and muscle to contract
CNS
Brain and spinal cord
PERIPHERAL NERVOUS SYSTEM
Nerves connecting the CNS to the muscles
BREAKDOWN OF CNS
Brain decides to make a movement, it sends a message through the spinal cord to reach the right muscles
BREAKDOWN OF MOTOR NEURONS
These nerves carry the message from the spinal cord to the little group of muscle fibres.
BREAKDOWN OF NEUROMUSCULAR JUNCTION
This is where the nerve meets the muscle. when nerve reaches neuromuscular junction, it releases a chemical that tells muscle fibres to contract
BREAKDOWN OF MUSCLE CONTRACTION
When the muscle fibre receive the signal, they contract, causes movement
when you decide to move a muscle, your brain sends a signal through nerves to that muscle
NEUROTRANSMITTER
Chemical messenger
- Acetylcholine is a neurotransmitter
-muscle contraction
-other function- helps with memory, attention, and alertness in the brain, essential for learning an focus
MOTOR UNIT SIZE
refers to the number of muscle fibres controlled by a single motor neuron
SMALL MOTOR UNIT SIZE
Fewer muscle fibres per motor neuron: a small motor unit typically has a motor neuro controlling a smaller number of muscle fibres (e.g. 10-100 fibres)
LARGE MOTOR UNIT SIZE
More muscle fibres per motor neuron: a large motor unit controls a larger number of muscle fibres (e.g. 500-1000 fibres or more)
ALL-OR-NONE LAW
Refers to how a muscle will contract or not at all. Impulse must reach beyond action potential threshold.
STRONG CONTRACTION
Impulses sent down lots of/ all motor units
WEAK CONTRACTION
Impulses sent down fewer motor units so fewer muscle fibres contract
SMALL MOTOR UNIT RECRUITMENT
Fine movement
LARGE MOTOR RECRUITMENT
Gross movement
SHORT-TERM RESPONSES OF THE NEUROMUSCULAR SYSTEM
(1) Increase in nerve transmissions : immediate increase in neural impulses to the muscles from the CNS
(2) Immediate muscle activation : increase in nerve impulses - rapid recruitment of motor units, enhancing muscle contraction strength and speed.
(3) Motor unit recruitment : smaller motor units are recruited first for low-intensity activities, while larger motor units are recruited as exercise intensity increases
(4) Muscle fibre type recruitment : slow-twitch fibres are recruited for low intensity endurance activities, while fast-twitch fibres are recruited for high-intensity, explosive movements
(5) Reflex responses : reflex arcs respond rapidly to changes in muscle length (muscle spindle) and tension (golgi tendon organ), helping to maintain posture and joint stability.
(6) Blood flow regulation : blood flow to the active muscles increases rapidly to deliver oxygen and nutrients while removing metabolic by-products like lactic acid (increase vascular shunting)
LONG-TERM RESPONSES OF THE NEUROMUSCULAR SYSTEM
(1) Increased motor unit recruitment : allows for more efficient and coordinated muscle contractions during exercise & more force to be produced
(2) Enhance muscle activation : both strength and endurance training lead to increased muscle activation levels, allowing for greater force production and endurance capacity
(3) Muscle fibre type adaptations : Strength training can lead to hypertrophy and increased strength primarily in fast-twitch muscle fibres. Endurance training, on the other hand, enhances the oxidative capacity of slow-twitch muscle fibres
(4) Increased motor unit synchronisation & improved motor neuron firing rates : improved nerve-to-muscle connections contribute to increase force production and so, strength and power output.
(5) Summation of motor units : the ability to summate (fire a lot of impulses in target muscle all at once)
(6) Muscle hypertrophy : strength training leads to an increase in muscle size, known as muscle hypertrophy. Primarily due to an increase in the size and number of myofibrils within muscle fibres
MUSCLE FIBRE TYPES
Type 1 (SO) - slow oxidative
- slow twitch
- low fatigue rate
- long distance
- aerobic
- oxidative
Type 2A (FOG) - fast oxidative glycolytic
- fast twitch
- oxidative - glycolytic
- 400/800m
-anaerobic
- less force, more fatigue resistance
Type 2B (FG) fast glycolytic
- fast twitch
- glycolytic
- short sprints
- high fatigue rate
- anaerobic
- greatest force
FUNCTION OF TYPE 1 MUSCLE FIBRE
CONTRACTION SPEED- slow
POWER OUTPUT- low
FATIGUE RESISTANCE- high
ENERGY SOURCE- primarily aerobic
PRIMARY ACTIVITIES- endurance activities
FORCE PRODUCTION- low
METABOLIC RATE- slow
STRUCTURE OF TYPE 1 MUSCLE FIBRE
MITOCHONDRIAL DENSITY- high
CAPILLARY DENSITY- high
MYOGLOBIN CONTENT- high
FIBRE DIAMETER- small
GLYCOGEN STORES- low
FUNCTION OF TYPE 2A MUSCLE FIBRES
CONTRACTION SPEED- fast
POWER OUTPUT- moderate- high
FATIGUE RESISTANCE- moderate
ENERGY SOURCE- aerobic and anaerobic
PRIMARY ACTIVITIES- moderate intensity
FORCE PRODUCTION- moderate
METABOLIC RATE- intermediate
