nervous system Flashcards
what does the nervous system enable animals to do
enables animals to be sensitive to their environment and respond appropriately
why do animals need to be sensitive to their environment?
-to find food
-find a mte
-recognise and avoid potential threats like predators
how do animals detect changes in their stimuli?
using specific recepters found in sense organs
what are stimuli
an environment
examples of where receptors are found
retina - light
skin - pressure/touch
proteins such as those which detect glucose or insulin
all receptors are what of energy?
transducers
what is a transducer of energy
convert one form of energy into another. in the nervous system, information is carried in the form of electrical energy
5 sense organ receptors
-vision - retina, eyes
-hearing - ears
-smell - nose
-taste - tongue
-touch and temperature - skin
example of effectors
muscle and glands
eg. salivary glands
what are effectors
things that brings response to change in the environment
what response does the muscle and gland do
muscle - contracts and brings about movement
glands- secretes a hormone and / or chemicals
what are nervers
a collection of many long thin nerve cells called neurones. information travels along neurones as electrical impulses
what do sensory neurones do
carry impulses from receptors to relay neurones
found in the PNS
what do relay neurones do
carry impulses from the sensory neurones to the motor neurones
found in the CNS - central nervous system: Spinal chord and brain
what do motor neurones do
carry impulses from relay neurones to an effector (muscle or glands)
found in the PNS
function of cell body
where the nucleus and cytoplasm is found
function of dendrites
recieve electrical impulses from receptors or other neurones. found at the top of a neurone
function of axon
long and thin to transmit electrical impulses
funciton of myelin sheath
fatty material that surrounds an axon which speeds up the conduction of electrical impulses
function of nerve endings
fine branches of the axon that connects to the dendrites on a neurone or an effector
what does the CNS act as in the nervous system
the co ordinator
what does the central nervous system contain
relay neurones, the brain and spinal chords
what does the PNS - peripheral neverous system conatain
sensory and motor neurones, nerves
what is a reflex
a rapid, automatic and protective response to a stimulus, which we have little to no control over these actions
examples of reflexes
moving away from a hot object
releasing saliva when food enters mouth
withdraw hand from sharp object
advantage of pupil reflex
pupil constricts when a bright light is shone into the eye
won’t damage retina where your receptors are
advantage of moving your hand when touching something hot
you won’t burn / scal your skin
what is involved in the reflex action
reflex arc, consisting of sensory, relay and motor neurones
reflex pathway in order
1) stimulant
2) receptor
3) sensory neurone
4) relay neurone
5) motor nuerone
6) effector
7) response
name two co-ordinators
brain and spinal chords
neurone that carries impulses to the central nervous system
sensory neurone
neurone which carries impulses away from central nervous system
motor neurone
structure that brings about the response
effector
what is a synapse
a gap between the nerve endings of one neurone and a dendrite of another.
how are electrical impulses carried across neurones?
electrical impulse travels down the first neurone, then chemical neurotransmitters are released and diffuse across the synapse.
they bind to the receptors on the membrane of the second neurone. electrical impulse then starts in second neurone
advantages of electrical impulses being carried to multiple motor neurones from the relay neurone
allows lots of muscles to contract at the same time.
what does a higher level of chemical neurotransmitters released in a synapse mean? and what about the opposite
increased amount of chemical: stronger contractions
decreased amount of chemical: weaker contractions / limited movement
describe how neurones etc can help to coordinate a reflex action
receptor detects the stimulus then sends electrical impulses to sensory neurones. sensory neurones then synapse with relay neurones in the spinal chord (if it says spinal chord, if it says brain, say brain) which is the coordinator. relay neurones synapse with motor neurones which carries impulses away from the Spinal chord (or brain). effector receives these electrical impulses from motor neutrones and brings about the response
why does repeating the test give more valid results than doing the test once
keeps results consistent
the brain is the what in the nervous system
main co-ordinator
KNOW HOW TO LABEL BRAIN
KNOW HOW TO LABEL BRAIN
function of cerebral cortex
controlls intelligence, consciousness, memory and language
function of cerebellum
coordinates muscular activity and keeps you balanced
function of hypothalamus
regulates body functions like regulating body temperature
function of medulla
controlls unconscious activity eg, heart rate
function of pituitary glands
produces many hormones, involved in homeostatis
why can surgeons perform on someones brain whilst they are concious?
brain has no pain receptors
suggest how an fMRI scanner could help to find out more about the brain damage a person has
you can ask the patient to perform different tasks whilst taking the scan to see which part of the brain is active. you can compare it to a person without brain damage and use it with children and those with parkinsons disease.
advantages of MRI
it scans soft tissues which X-Rays cannot be used for
areas of brain damage, disease or unusual brain activity can be located. results can be used in research
