Week 3- control of movement- structure and function Flashcards
What does the nervous system coordinate with?
endocrine system
What makes up the central nervous system?
brain and spinal cord
What makes up the peripheral nervous system?
nerves outside of the CNS
What are sensory diversion?
afferent fibres transmit impulses from receptors to CNS
What are Motor diversions?
efferent fibres transmit impulses from the CNS to effector organs
What is the resting potential of the cell?
negative (polarised)
–40 to -75
What is the magnitude of the resting membrane potential determined by?
-permeability of plasma membrane to ions
-difference in ion concentration across the membrane
What does the sodium potassium pump do?
moves 2 potassium in and 3 sodium out
when does an action potential occur?
when a stimulus of sufficient strength depolarises the cell
What does an action potential cause?
opens sodium channels so the inside of the cell becomes more positive
What is repolarisation?
returning to resting membrane potential
-potassium leaves the cell rapidly and sodium channels close
What is the all-or-nothing law?
once a nerve impulse is initiated, it travels the length of the neuron
What does the membrane potential depolarise from?
-70mv to 30mv
What do excitatory postsynaptic potentials (EPSP) promote?
neural depolarisation in two ways, temporal and spatial summation
What is temporal summation?
rapid, repetitive excitation from a single excitatory presynaptic neuron
what is spatial summation?
summing EPSP from several different presynaptic neurons
What do inhibitory postsynaptic potentials (IPSP) cause?
hyperpolarisation (more negative resting potential) so it resists depolarisation
What are the joint proprioceptors?
-free nerve endings- touch and pressure
-Golgi type receptors
-Parcinian corpuscle
What are the muscle proprioceptors (mechanoreceptors)?
-muscle spindles
-Golgi tendon organ
What is proprioception?
The sense of the body’s position in space based on specialised receptors that reside in the muscle, tendons and joints
What are proprioceptors?
sensors that provide information about joint angle, muscle length and tension which is integrated to give information about the position of the limb
What do muscle spindles respond to?
change in muscle length
What do muscle spindles consists of?
-intrafusal fibres
-gamma motor neurons
-stretch reflex
What is the function of muscle spindles?
assist in the regulation of movement and maintain posture
What is the role of the Golgi Tendon Organ (GTO)?
monitor force development in muscle preventing muscle damage during excessive force generations
What does the stimulation of GTO result in?
reflex relaxation in muscle- inhibitory neurons send inhibitory postsynaptic potentials to muscle alpha motor neurons
What are muscle chemoreceptors sensitive to?
changes in the chemical environment surrounding a muscle i.e. changes in pH, CO2 and K
What are muscle chemoreceptors important for?
regulation of cardiovascular and pulmonary responses
What are the different types of motor units?
-Type 1(smallest, slowest)
-Type IIA(fast, fatigue resistant)
-Type IIX (fast, fatigable)
What muscle fibre type is recruited first?
Type I–> Type IIA –> Type IIX
What is the cerebrum/cerebral cortex responsible for?
-reception of sensory inputs
-organisation of movement
-storage of learned experiences
What is the cerebellum responsible for?
control of movement and integration of sensory information
What is the brainstem responsible for?
cardiorespiratory function, locomotion, muscle tone, posture, receiving information from special senses
Where is the brainstem?
Midbrain
What are the functions of the brainstem?
body movement
controlling responses to sight
eye movement
pupil dilation
hearing
What is the medulla oblongata involved in?
control of automatic function, relaying signals between brain and spinal cord and coordination of body movements
What is the pons involved in?
sleep
control of automatic function
relays sensory information between cerebellum and cerebrum
