neuronal communication

Created by

Evie squires

Cards (56)

role of mechanoreceptor
pressure and movement
role of chemoreceptor
chemicals
roles of thermoreceptors
heat
roles of photoreceptors
light
what is a transducer
a receptor that converts mechanical energy to electrical energy. if threshold value is exceeded action potential is produced
how do the pacinian corpuscles work
normally: sodium channels closed and it had testing potential.
when pressure is applied:
- lamellae mem stretched Na+ channels widen
- Na+ diffuses in.
- Neurone more + on inside so changes potential and becomes depolarised.
- generator potential produced and if large enough becomes action potential
what does self-propagating mean
does need a trigger - just does it
the nervous impulse during resting:
- Sodium potassium pump uses active transport to pump K+ (2) into axon and Na+ (3) out.
- overall axon becomes - so electrochem gradt
- most channels closed but some Na+ diffuses back in down elec gradt
- more K+ diffuses out of axon as some gates are open and mem more permeable to K+
- the - charge inside mem means K+ don't move back in so stays polarised
the nervous impulse during action potential:
- stimulus causes Na+ channels to open
- Na+ moves into axon down electrochem gradt
- mem is depolarised and triggers Na+ channels to open down the axon
the nervous impulse during refractory:
- behind action pot Na* channels close
- K+ channels open so K+ goes out down gradt
- so much + leaves so axon becomes extra -
- becomes hyperpolarised
- Sodium potassium starts again
- repolarised
why does the cell body of a neurone contain lots of mitochondria and endoplasmic reticulum's
to produce neurotransmitters
what is the role of the dendrons
transmit impulses to cell body
what is the role of the axon
transmit impulses away from cell body
what is the general path of an impulse
receptor > sensory > relay > motor > effector
what is the difference between a myelinated and non-myelinated neuron
- covered axons by myelin sheath
- made of plasma membrane to insulate to increase speed of transmission
what is the node of ranvier
between each myelin sheath where the impulse jumps over
factors effecting action potential:
diameter of axon - faster if wider bc less resistance
temp - more temp = more diffusion of NT after 40degrees bonds disrupted
myelin sheath - if present = faster
what is it called when AP jumps at Nodes of Ravier
Saltarory conduction
what is the all or nothing principal
a certain level of stimulus will always tigger. If it meets it AP will generate, if it doesn't it doesn't. Larger stimulus will only increase frequency
what is the role of the presynaptic neurone
makes and releases NT when AP reaches synaptic knob.
why does the the postsynaptic neurone swell up
bc it contains mitochondria (for ATP) and Endoplasmic reticulum (to make NT) and vesicles(to store NT)
what is a cholinergic synapse
A synapse that uses acetylcholine as its neurotransmitter.
what is a neuromuscular synapse
synapse between neuron and muscle fiber
what is the difference between summation special and summation temporal synapses
special - several neurone releases NT through cleft
temporal - single neurone releases NT through cleft
What are inhibitory synapses
Synapses which make it less likely that a new action potential will be created on the post-synaptic neurone >> bc Cl- channels can be made to open so Cl- diffuses inn
How do synapses work?
1. AP arrives at presynaptic neurone
2. Ca+ channels open and Ca+ enters knob
3. triggers vesicles with NT inside to fuse w presynaptic mem
4. acetycholine released into cleft
5. NT fuse w receptors on Na+ channels so they open and Na+ diffuses in
6. influx generates new AP in postsynaptic
7. acetylcholine esterase splits NT back into Cl- and ethanoic acud and they diffuse back
6. ATP released by mitochondria to recombine acetycholine stored back in vesicles
7. Na+ channels close again
what is the difference between the sympathetic and the parasympathetic, autonomic nervous system
>sympathetic - stimulates effectors, speeds up activity, strenuous exercise, fight or flight
>parasympathetic - inhibits effectors, slows down activity, controls normal conditionsSee an expert-written answer!We have an expert-written solution to this problem!
what's the role of the cerebrum
receives sensory info and interprets with respect to previous activities. left side controls right side of body and vise versa.
4 parts: frontal, pariental, occipital, temporal lobe
What is the role of the frontal lobe?
short term memory and voluntary movements
what is the role of the pariental lobe
process's sensory info
What is the role of the occipital lobe?
vision
What is the role of the temporal lobe?
visual memories and language
cerebellum function
controls muscular balance but doesn't initiate it
Receives muscular information from muscles and balance information from ears
What is the role of the medulla oblongata?
contains regulatory centres of nervous system
also controls reflex actions - coughing etc
what is the role of the hypothalamus
controls autonomic nervous system
has 2 centres for each system - sympathetic/parasympathetic. controls behaviour, plasma conc and produces hormones
What is the role of the pituitary gland?
To control the release of hormones from all the other endocrine glands in the body
Anterior and posterior parts
knee jerk reflex
A spinal reflex below the patella
patellar tendon is stretched
causes extensor muscles in the thigh to contract
relay neuron inhibits motor neurone in flexor
so relaxes - causing a kick.
blinking reflex
a crainial reflex
Either a corneal reflex to protect the cornea or an optical reflex to protect the lens and retina from bright light
- stimulus triggers impulse along sensoryN, passes a long relay to lower brain stem, impulses sent along motor neuron to initiate response
why are reflexes important
they help us survive and protect ourselves
they are immediate so no thinking is needed so brain is not overloaded
they are fast
they are effective from birth
slow twitch muscle fibres function
slow , long contractions for endurance exercise less powerful