Nerves key words Flashcards
Action potential
The change in potential difference across the neurone membrane of the axon when stimulated
All or nothing
Refers to the fact that a nerve either conducts an action potential or it doesn’t
Depolarizations
A change in the potential difference from negative to positive across the membrane of a neurone
Hyperpolarized
A membrane which is more highly polarized than its usual resting potential
Myelin sheath
Membrane rich in lipid which surrounds the axon of some neurons, speeding up impulse transmission. Consists of many layers of Schwann cells
Neurone
Specialized cell which transmits impulses in the form of action potentials
Polarised
A membrane with a potential difference across it
Refractory period
The potential difference from positive back to negative across the membrane of a neurone
Resting potential
The potential difference across the membrane of an axon of a neurone at rest
Sensory receptor
Specialised cell which detects a stimulus
Summation
Build up of a neurotransmitter in a synapse to sufficient levels to stimulate an action potential
Threshold potential
A potential difference which needs to be reached for voltage gated sodium ion channels to open and create an action potential
Synapse
Junction between two neurons
Synaptic knob
End of axon - bulbous
Synaptic cleft
Gap between neurons/target cell
