Neuromuscular System Flashcards
How many muscles are there in the body?
What percentage of weight do they make up?
600
40%
What does the SAN (sinoatrial node) control?
Contraction of the heart
What is the set rhythm of the heart and what is it called?
72bpm
Autorhythmicity
What are the three types of muscle tissue?
Cardiac muscle (heart) Smooth muscle (walls of the small intenstine) Skeletal muscle (hamstrings or triceps)
Is cardiac muscle voluntary or involuntary
Involuntary
Is smooth muscle voluntary or involuntary
Involuntary
Is skeletal muscle voluntary or involuntary
Voluntary
What is the appearance of the cardiac muscle
Striated
Striped or streaked
What is the appearance of the smooth muscle
Smooth, spindle shaped
What is the appearance of skeletal muscle
Striated
Striped or streaked
What is the function of cardiac muscle
Continuous beating to push oxygen around the body
What is the function of smooth muscle
To break down in digested good and drink
What is the function of skeletal muscle
Create bodily movement
Or to prevent unwanted movement
What are the four key characteristics of muscle tissue
Contactility: ability to shorten
Extensibility: ability to stretch and lengthen
Elasticity: ability to return to its original size and shape
Excitability: ability to respond to stimuli from the nervous system
What is perimysium
Connective tissue that wraps bundles of fibres
What is endomysium
Connective tissue that wraps single muscle fibres
What are myofilaments
Myosin and actin which are located inside sacromeres
What is epimysium
Connective tissue that wraps the whole muscle
What is the sliding filament theory
The myofilaments (actin & myosin) slide over each other, creating a shortening of the sarcomere which causes shortening or lengthening of the entire muscle
What are the structural features of slow twitch fibres TYPE 1
Small diameter Large myoglobin content Many mitochondria Many capillaries to deliver blood and oxygen Red in colour
What are the structural features of fast twitch fibres TYPE 2
Larger diameter Smaller myoglobin content Fewer mitochondria Fewer capillaries White in colour
What are the functional features of slow twitch fibres
Increased oxygen delivery Produce less force Long term contractions Resistant to fatigue Aerobic
What are the functions of fast twitch fibres
Decreased oxygen delivery Generate more force Short term contraction Less resistant to fatigue Anaerobic
What are the activities of slow twitch muscle fibres
Lower intensity aerobic exercises
Endurance based
Maintaining posture & stabilisation
What are the activities for fast twitch fibres
Rapid, intense movements
Strength training
Sprinting
Anaerobic training
What exercise will increase the size of fast twitch fibres
Intense exercise that brings about anaerobic metabolism
What exercise will develop the aerobic capacity of slow twitch fibres
Moderate intensity, aerobic endurance
What are intermediate fibres
Adapt depending on the type of training or exercise.
Cardio training - slow twitch
Resistance training - fast twitch
How do skeletal muscles create movement
Muscles receive a message from the brain to shorten
Muscles exert a force and pull on the bones
As one muscles contacts and shortens, the other relaxes and lengthens
What is the origin of the muscle
The fixed anchor point
The one nearest to the centre midline of the body
What is the insertion of the muscle
The one furthest away from the centre midline of the body
The end of the muscle attached to the bone
What is isotonic contraction
Muscles moving under tension by shortening or lengthening
What is concentric contraction
The muscle shortens under tension.
The curling upward phase of a bicep curl
What is eccentric contraction
The muscle lengthens under tension
The straightening downward phase of a bicep curl
What is isometric contraction
The muscle remaining the same length under tension
Holding a squat at the bottom of the movement
What is the agonist
The prime mover.
E.G : the biceps contacting during a bicep curl
What is an antagonist
The opposing muscle to the prime mover.
Triceps during a bicep curl
What is the synergist
Assists the prime mover.
The hamstrings assist the Glutes in a hip extension
What is a fixator
The muscle that contracts to stabilise the body
What is the nervous systems primary role?
Maintaining a constant balance of the internal environment (homeostasis)
What are three functions of the nervous system
Sensation
Integration
Response
Describe the role of sensation of the nervous system
Gathers information about the internal and external environment
What is the role of integration of the nervous system
Interperates and analyses the information gathered and decides on the appropriate action
Some voluntary and some involuntary
What is the role of response of the nervous system
Responds to the information analyses by initiating the appropriate action
What system does the nervous system work closely with?
The endocrine system
Responsible for releasing hormones to maintain homeostasis
What are the two primary divisions of the nervous system?
CNS
PNS
What is the CNS comprised of?
The brain and the spinal chord
Describe the CNS
Control base for the whole nervous system
All nerve impulses that stimulate muscles to contract and create movement originate from the CNS
What is the cerebrum of the brain?
The largest and most superior
Takes up most space of the skull
What is the cerebellum of the brain?
The smaller part
Inferior to the cerebrum and posterior to the brain stem.
Acts as a memory bank for all learnt skills.
Controlling the group action of muscles
Communicates and works with the cerebrum
What is the diencephalon of the brain?
Thalamus and hypothalamus
What is the brain stem of the brain?
Medulla oblongata, midbrain and pons/ the stalk like Component at the inferior aspect of the brain.
Lower portion is a continuation of the spinal chord
What does the spinal chord do?
Communication link between the brain and the PNS.
Analyses information and produces responses via reflex arc
What is the PNS system?
Consists of all the branches of nerves that lie outside the spinal chord.
Role is to transport messages through its nerve cells, to and from the CNS
What are neurons responsible for
Transmitting electrical messages
What are spinal nerves divided in to?
Sensory neurons
Motor neurons
What are sensory neurons
Carry messages to the CNS from the sensory organs
What are motor neurons
Transmit impulses from the CNS to muscles and glands with instructions
Anterior side of the spinal chord
What does a neuron consist of
Cell body: directs the activities of the neuron
Nucleus: stores the cells genetic info
( tells the cell what to do )
Axon: transmits messages away from the cell body
Myelin sheath: insulates the axon to speed up the transport of messages
What is the all or none law
When an impulse is sent down a neuron, all the muscle fibres are innervated.
The motor unit activates all of fibres or none at all.
Applies to individual motor units, not the entire muscle.
What is the ratio of motor units for muscles responsible for strength and largest force generation
1:2000
What is the ratio of motor units for muscles involved in finer movements?
1:50
What are the short term effects of exercise on the neuromuscular system
Increased muscle temperature
Increased ability to stretch further
Increased power output
Increased nerve to muscle link
Increased recruitment of muscle fibres
What are the long term benefits of exercise on the neuromuscular system?
Increased muscle endurance/hypertrophy/strength
Increased stores of glycogen and creating phosphate in muscle
Increased nasal metablolic rate
Improved posture
What are the muscle sense organs that form part of the autonomic nervous system?
Joint receptors: inform the brain about the position of the joint
Muscle spindles: inform the brain about the length of a surrounding muscle fibre - prevents over stretching
Golgi tendon organs: tell the brain how much tension a muscle is under
What are the two main factors that influence the rate of the neuromuscular development in early years?
Genetics: genetic potential for maximum growth determined by genes
Environment: opportunities to support neuromuscular development or restrictions that could hinder it, affect the potential for development in early years
What percentage of muscle increases in boys 5-11
42-54%
What Percentage of muscle increase in girls 5-13
40-45%
Describe the lifecycle of the neuromuscular system in teenagers
The growth of new neural pathways slows down but muscle tissue increases more in boys than girls
When does our neuromuscular growth stop
Age 25
