B5: Nervous response Flashcards
(16 cards)
what is a stimulus
a detectable change in an organism’s enviornment
what are the sensory organs and what do they detect?
eyes - light intensity
skin - temp. and pressure
tongue - chemical changes
nose - chemicals in air
ears - sound waves
what are receptors, and what is their job?
they are specialised cells that detect a stimulus. they then convert the stimulus into and electrical signal in the nerve cell
what are effectors?
they carry out the response. they are usually a muscle which contracts, or a gland, which secretes chemical messengers - hormones
what does your automatic control system do?
it keeps your internal environments stable using a mechanism called negatice feedback
give the flowchart for a nervous reponse
stimulus
receptors
coordination centre:
sensory neurones
central nervous system
relay neurones
motor neurones
effector
reponse
give an example of a nervous reponse
a person saw a flash of light and blinked in response.
stimulus - flash of light
receptors - light receptors in eye
(goes along spinal cord)
effector - muscle in eyelid
response - muscle contraction of eyelids to cover eyes
what is a specialised nerve cell called?
a neurone
what is a neurone adapted to do?
carry electrical impulses from one place to another
what is a bundle of neurones called?
a nerve
give some of the features and functions of a neurone
long fibre - axon - to carry electrical impulses
axon insulated by myelin sheath (fatty layer) to speed up impulses
branches, dendrons, which branch off furhter into dendrites to receive impulses from other neurones
what is a synapse?
the junction between two neurones across which electrical signals pass.
when a nerve impulse arrives at a synapse, what chemical is triggered to release?
neurotransmitters are released from the synaptic vessicles
what happens after the neurotransmitters are released?
they diffuse across the synaptic cleft and bind to the specific receptors on the next neurone, triggering another impulse.
how are impulses transferred ACROSS a neurone?
electrically
how are impulses transferred BETWEEN neurones?
chemically (neurotransmitters)
