topic 9 9.4 mammalian nervous system

central nervous system

brain and spinal cord produces stimuli and propagates impulses

peripheral nervous system

all neurons that are not in the central nervous system

two divisions of central nervous system

automatic and somatic (voluntary)

two divisions of automatic nervous system

sympathetic and parasympathetic

sympathetic nervous system

stimulates fight or flight response

neurotransmitter is noradrenaline

ganglia located near CNS

parasympathetic nervous system

inhibits effectors rest/digest

neurotransmitter acetylcholine

ganglia located far from CNS

gray matter

cell bodies dendrites unmyelinated axons inner spinal cord

white matter

myelinated axons outer spinal cord

cerebellum

controls exceution of movement balance and coordination

medulla oblongata

autonomous functions eg breathing and heart rate

cerebrum

voluntary activities eg speech and thought

hypothalamus

includes pituitary gland

osmoregulation and thermoregulation

resting potential

potential difference (voltage) across a membrane when not stimulated

how is a resting potential made pt 1

membrane is more permeable to K than Na

how is a resting potential made pt 2

sodium potassium pump actively transports 3Na out of cell and 2K into cell

how is a resting potential made pt 3

established electrochemical gradient cell contents more negative than outside environment

stages in action potential

depolarisation

repolarisation

hyperpolarisation

return to resting potential