Coordination Flashcards
definition of stimulus
change in environment that is detected by a receptor causing a response
definition of response
action resulting from perception of stimulus
three types of neurones
sensory/relay/motor
describe the structure of sensory neurone (6)
long myelinated axon cell body in the middle one side is myelin sheath other side is dendrone many mitochondria in cytoplasm of axon many vesicles for neurotransmission
describe purpose of sensory neurone
receptor to CNS
describe purpose of relay neurone
intermediate neurone
pass action potentials
describe structure of relay neurone (4)
long axon
pre synaptic terminal
cell body
dendrites
describe structure of motor neurone (8)
dendrites lead to cell body nucleus in cell body many mitochondria much RER long axon synaptic knobs schwann cells node of ranvier
describe the myelin sheath (5)
Schwann cells wrap around axon
to form myelin sheath;
insulate axon;
depolarisation occur at nodes of ranvier;
long local circuits;
action potentials move by saltatory conduction;
describe the reflex arc
Stimulus → receptor → sensory neurone → relay neurone → motor neurone → effector
describe the purpose of reflex arc (4)
fast for protection
automatic
same specific response
doesn’t pass CNS
describe the transmission of action potentials (10)
Na+ channels open; Na+ enters axon; depolarisation; Na+ channels close; K+ channels open; K+ move out of cell; repolarisation; local circuits; one way transmission; happens at nodes of ranvier;
what is the resting potential of axon
-60mV
how is the resting potential maintained (3)
active transport
sodium and potassium pump
sodium ions out and potassium ions in
against electrochemical gradient
what gradient causes the flow of Na+/K+
electrochemical gradient
how is the speed of conduction quick
jump from one node to the next (saltatory conduction)
faster in thin axons with less resistance
describe action potential in taste buds (6)
Na+ diffuse through microvilli
membrane depolarised
stimulates voltage gated calcium ions to open
calcium ions flood in cytoplasm
stimulate vesicles of neurotransmitter to perform exocytosis
stimulation above threshold = action potential passed