neurones communications mod 5 (laake booklet) Flashcards
where are chemoreceptors found and their function?
- in carotid arteries
- detect increase or decrease in blood ph
where are the baroreceptors found and their function?
- in blood vessels
- detect increase or decrease in pressure
what are receptor cells?
specialised cells which respond to a specific stimulus by initiating action potential
sensory receptor in nose?
olfactory cells
sensory receptor in retina
rods and cones
what receptor detects change in muscle length?
proprioreceptors
why would the response not continue to increase if a stimulus is constant?
receptor only detects changes in environments
what is sensory adaptation?
sensory receptors in the brain reduce their sensitivity to a continuous, unchanging stimuli.
what is habituation?
animal may learn to ignore a stimulus which is used to elicit stronger response -> due to repeat exposure
whats in the PNS (peripheral nervous system)
sensory and motor neurones
CNS
brain + spinal cord
what is the somatic nervous system? (THINK ‘S’)
voluntary/involuntary movement from skeletal muscles via motor neurone
what is the sympathetic nervous system
flight/fight response w/ noradrenaline
parasympathetic nervous system (+enzyme present)
relaxing responses e.g. REST AND DIGEST w/ enzyme * ACETYLCHOLINE + VAGOUS NERVE
what is neurone resting potential
-65mv
what is neurone threshold potential
-55mv
what is a change in electrical potential of membrane generated in response to stimulus called?
receptor potential
what is the magnitude of action potential?
+40mv
what happens when vibration is applied to a pacinian corpuscle…
lamellae are compressed and deformation causes NA+ channels to open
depolarisation is…
the entry of sodium ions (NA+)
what is a monosynaptic reflex
one synapse in the reflex arc e.g. sensory -> motor
what fraction of peripheral neurones are myelinated?
1/3
what is the myelin sheath made up of
schwaan cells
how is the myelin sheath kept alive?
schwaan cell nucleus and cytoplasm
function of myeline sheath
prevents ion movement across neurone membrane so it only occurs at nodes of ranvier so impulse jumps from node to node = rapid conduction
conduction of impulse in myelinated neurones
saltatory