Keywords - nervous coordination and muscle Flashcards
Action Potential
change that occurs in electrical charge across membrane of an axon when it is stimulated + a nerve impulse passes
Axon
process extending from a neurone that conducts action potentials away from cell body
Depolarisation
temporary reversal of charges on cell surface membrane of a neurone that occurs when nerve impulse is transmitted
Neurone
nerve cell, made up of cell body, axon + dendrites, which is adapted to conduct action potentials
Neurotransmitter
group of chemicals (eg. acetylcholine) released by neurones. They diffuse across the synapse between adjacent neurones + so pass an impulse from one neurone to the next or between neurones and muscles
Repolarisation
return to resting potential in the axon of a neurone after an action potential
Resting potential
difference in electrical charge maintained across membrane of axon of a neurone when not stimulated
Sodium-potassium pump
protein channels across cell surface membrane that use ATP to move Na ions out of cell in exchange for K ions in
Voltage-gated channel
protein channel across cell surface membrane that opens + closes according to changes in electrical potential across membrane
Actin
thin filament protein which, together with myosin, is involved in contraction within cells (muscle)
Myosin
thick filament protein which, together with actin, is involved in contraction of skeletal muscle cells
Neuromuscular junction
point where a motor neurone meets a skeletal muscle fibre
Tropomyosin
protein in muscle which forms a fibrous strand around actin filaments, preventing myosin from binding during relaxation
Sarcomere
section of myofibril between two Z-lines that forms the basic structural unit of skeletal muscle
