nervous system Flashcards
defenition of nervous system
system of nervous tissue that detects, relays and co-ordinates information about an organism’s internal and external environment.
name of nerve cells
neurones
what do neurones do
convey information in the form of nerve impulses
what type of responses do neurones produce
rapid, localized response.
2 functions of the nervous system
- collect, process and respond to information in the environment
- co-ordinate the working of different organs and cells
what is the actual name for the CNS
Central Nervous System
what in the CNS
brain + spinal cord
what does CNS do
passes messages to and from the brain and connects nerves to the PNS
what makes up the PNS
All the nerves and nerve cells outside your central nervous system
actual name of PNS
Peripheral Nervous System
function of PNS
relay information to and from your brain and spinal cord to the rest of your body
PNS consists of how many pairs of what
12 pairs of cranial nerves
what is the PNS sub divided into
somatic nervous system (SNS)
autonomic nervous system (ANS)
in a labelling what would you label as being the CNS
brain
spinal cord
in a labelling what would you label as being the PNS
Spinal Nerves
Nerve
what is the full name of SNS
somatic nervous system
what type of control is SNS
voluntary control
what does SNS allow you to do
move your arms and legs
full name of ANS
autonomic nervous system
what type of control is ANS
not under conscious control
what does ANS let us do
governs vital functions in the body such as breathing, heart rate, digestion, sexual arousal and stress responses
2 neurone types we have to learn
sensory
motor
what do sensory neurones do
Carry messages from the peripheral sense organs to the CNS
what do motor neurones do
Convey electrical impulses from the CNS to effector organs (e.g. muscles, glands)
where does the sensory neurones carry impuleses
from the receptors to the central nervous system
where does the motor neurones carry impulses
from the CNS to the muscle (effector)
how many bits are there on a motor neurone
8
what are the bits of a motor neurone
dendrites
nucleus
cellbody
axon
schwann cell
myelin sheath
node of ranvier
axon terminal
function of dendrites
receive signals from other cells
function of cell body
organises and keeps the cell functional
function of nucleus
controls the entire neurone
function of axon
transfers signals to other cells and organs
function of myelin sheath
increases the speed of the signal
function of schwann cell
produces the myeliin sheath
function of nodes or ranvier
allow diffusion of ions
function of axon endings / terminals
forms junctions with other cells
function of synaptic end bulbs
responsible for transmission of impulse from axon to muscle fiber through the synapse
what is ANS split into
Sympathetic nervous system: Fight or flight – for emergencies
Parasympathetic nervous system: Rest and digest – maintains and st0res energy
what do reflexes do
Produce fast response to stimulus
what happens in reflex arch
1 – Receptors detect stimulus
2 – Sensory neurons conduct impulse to the CNS
3 – Sensory neurons enter the spinal cord
4 – Sensory neuron synapses with relay neuron
5 – Relay neuron synapses with motor neuron
6 – Motor neuron carries impulse to effector.
what are neurotransmitters
brain chemicals that communicate information throughout our brain and body. They relay signals between neurones.
what exists between neurotransmitters
synaptic cleft
what do neurotransmitters react with
receptors on the membrane of the postsynaptic cell,
what does the neurotransmitters reacting with do
causes ionic channels on the membrane to open or close
neurotransmitters defenition
chemical secreted in response to an action potential which carries chemical signal across synapse
this singal going from one neurone to the next creates a new action potential
steps of neurotransmission
opening and closing of voltage-ion chanels which causes brief reversal of the resting membrane potential to create an action potential
what happens when action potential moves down axon
polarity changes in the mmebrane
what happens when the signal reaches the axon terminal
stimulates other neurons
what is an action potential
movement of charge along the axon of a wave - wave depolarisation
what ions are involved in nerve impulses
sodium
potassium
what happens to the axon after an action potential has happened
repolarises to be + outside and - inside
how do neurone signal cross the synapse gap
use of neurotransmitters
synapse dull thingy
1.An electrical impulse travels along an axon.
- triggers the nerve-ending of a neuron to release neurotransmitters.
3.These chemicals diffuse across the synapse (the gap) and bind with receptor molecules on the membrane of the next neuron.
4.The receptor molecules on the second neuron bind only to the specific chemicals released from the first neuron. This stimulates the second neuron to transmit the electrical impulse.
what happens to neurotrasmitters after theyrre used
destroyed
extra bit yn reflex arc compared i just reflex
relay neuron
what does relay neuron mean
signal doesnt have to go to the brain - quicker response
effect of enzymes
stops muscles and nerves from overstimulating
cholinestrate - inhibitor
what can you use to stop twitches
inhibitors
effect of cholinestrase
group of medicine that block the breakdown of acetylcholine
factors that can effect synaptic transmission
cholinesterase
active transport of Ca+ out of synaptic knob
reabosorption of neurotransmitter molecules
what chemicals affect synaptic transmission
nicotine
caffeine
organophosphate insecticides
curare
how does nicotine affect synaptic transmission
stimulates CNS
how does caffine affect synaptic transmission
stimulates
how does organophosphate affect synaptic transmission
inhibitor
how does curare affect synaptic transmission
inhibitor
why is reflex arc good
quick response
what makes the myelin sheath
schwann on top
axon middle
node of ranvier is bottom
