The Nervous System Flashcards
what are the 2 systems that coordinate the body enabling it to respond to stimuli
the endocrine+ nervous systems
differences between the nervous system and the endocrine system
Nervous:
electrochemical message
carried in neurons
fast-acting
short term effects
endocrine
chemical message
carried in blood
slow acting
long lasting effects
how many sections does the NS have
2
what does CNS stand for
central nervous system
what does PNS stand for
peripheral nervous system
what the CNS composed of
brain + spinal cord
how does the PNS work
carries messages between CNS + body
what is a neuron
a nerve cell
what do neurons do
carry electrochemical messages between CNS + PNS
what are the steps involved in responding to stimuli
Reception
transmission
integration
response
reception
stimulus is detected by sense organs
transmission
message passes alongs neurons to CNS
integration
message is sorted + response is decided in CNS
response
carried out by effector muscles stimulated by neurons
what does a sensory neuron do?
carries messages from sense organ to the CNS
what does a motor neuron do?
carries messages form the CNS to a muscle or gland
what does an interneuron do?
carries messages between sensory and motor neurons
function of cell body
contains nucleus and mitochondria
produces neurotransmitters
function of nucleus
control centre
function of dendrites
fibres that receive and carry impulse to the cell body
function of axons
carry impulse away from cell body
function of schwann cells
produce myelin sheath
function of myelin sheath
insulates electrical impulse
speeds up impulse
function of neurotransmitter swellings
release neurotransmitter to carry impulse across synapse
impulse
electrochemical message carried in neurons
movement of nerve impulse
inside of a neuron is positively charged and outside is negative. as the impulse passes through the axon, the charge changes and then changes back after the impulse has passed through
resting neuron
neuron not carrying an impulse
threshold
is the minimum stimulation required to send a message along a neuron
the all or nothing law
states that is the threshold is reached an impulse is carried but if the threshold is not reached no impulse is carried
refractory period
the short time length after an impulse passes through to allow the neuron to recover so that another impulse can pass through
synapse
region between 2 neurons
synaptic cleft
tiny gap between neurons give
give an example of a neurotransmitter
dopamine
neurotransmitter
a chemical that carries a nerve message across a synapse
give a detailed account of how neurotransmitters work
neurotransmitter is released when the impulse arrives at the synapse
the neurotransmitter travels across the synapse and combines with receptors
impulse is generated in the next neuron
enzymes break down neurotransmitters
the products are reabsorbed
protection of the brain
the skull
3 membranes- meninges with fluid in between called cerebrospinal fluid
what does cerebrospinal fluid do
acts as a shock absorber
function of cerebrum
controls voluntary muscles
receives impulses from sense organs
function ofcerebellum
controls muscular coordination and balance
function of medulla oblongata
controls involuntary actions ie breathing ect
function of thalamus
sends messages to different parts of the brain
function of hypothalamus
controls internal environment of the body
function of pituitary gland
part of the endocrine system
name a nervous system disorder
Parkinson’s disease
cause of Parkinson’s disease
body fails to produce dopamine
treatment for Parkinson’s disease
no cure
symptoms can be alleviated by physiotherapy or drugs that mimic dopamine
prevention of Parkinson’s disease
no known preventative measures
composition of the spinal cord
nerve tissue surrounded by vertabrae
function of spinal cord
relays messages to/from the brain to the PNS and controls reflex actions
where is the spinal cord located
neutral canal of the spine surrounded by meninges
white matter
part of the CNS that contains axons only
grey matter
part of the CNS that contains cell bodies and dendrites
function of central canal
contains cerebrospinal fluid
function of dorsal route
carries sensory neurons into spinal cord
ventral route
carries motor neurons out of spinal cord to effector muscles
reflex action
automatic involuntary response to a stimulus
reflex arc
the nerve pathway of a reflex action
mechanism of reflex arc
stimulus is detected by a receptor
sensory neurons carry impulse to spinal cord through dorsal root
in the spinal cord an impulse is carried to motor neuron via interneuron
another neuron takes impulse to brain
motor neuron carries impulse to effector muscle
PROCESS IS NOT CONTROLLED BY BRAIN!!!
benefit of reflexes
allows you to respond quickly to danger protecting the body
