neurons and synaptic transmission- biopsychology

Question 1

what are the types of neurons

Answer 1

sensory, relay and motor

Question 2

what is the structure of a neuron

Answer 2

vary in size from less than mm to up to m long but share all same structure
cell body includes nucleus which contains genetic material of the cell, branchlike structures called dedrites protude from the cell body, carry nerve impulses from neighbouring neurons towards body
axon carries impulses away from cell body down to length of neuron, covered in fatty layer of myelin sheath that protects the axon and speeds up electrical transmission of impulse, myelin sheath would have reverse effect and slow down electrical impulse is was continuous so it is segmented by gaps called nodes of ranvier which sppeed up transmission of impulse by forcing it to jump across gaps along axon
terminal buttons communicate with next neuron in the chain across gap known as synapse

Question 3

what is the location of neurons

Answer 3

cell bodies motor neurons may be in central nervous system but they have long axons which form part of peripheral nervous system, sensory neurons located outside cns in the pns and clusters known as ganglia, relay neurons make up 97% of all neurons and most found in the brain and visual system

Question 4

what is the electrical transmission

Answer 4

neuron in resting state inside of the cell is negatively charged compared to the outside, when neuron activiated by stimulus, the inside of cell becomes positively charged for split second causing action potential to occur which creates electrical impulse that travels down the axon towards the end of the neuron

Question 5

what is chemical transmission

Answer 5

neurons communicate with each other within groups known as neural networks
each neuron seperated from the next by small gap called synapse
signals within neurons trasnmistted electrically, signals between neurons transmitted chemically across synapse
electrical impulse reaches end of the nruon (presynaptic terminal) triggers release of neurotransmitter from tiny sacs called synaptic vesicles

Question 6

what are neurotransmitters

Answer 6

chemicals that diffuse across synapse to next neuron in the chain, once neurotransmitter crosses the gap it is taken up by postsynapstic receptor site on dendrites of next neuron
chemical message converted back to electrical impulse and prcess of transmission begins again in other neuron
direction of travel can only be one way because they are released from presynaptic neuron terminal and received by postsynaptic neuron
each neurotransmitter has own specific molecular structure that fits into postsynaptic receptor site
have specialist functions- acetylcholine found at each point where motor neuron meets muscle and upon release cause muscles to contract

Question 7

what is extinction and inhibition

Answer 7

neurotransmitters have either excitatory or inhibitory effect on neighbouring neuron
neurotransmitter serotonin causes inhibition in receiving neuron resulting in neuron becoming more negatively charged and less likely to fire
adrenaline which is both hormone and neurotransmitter causes excitation of postsynaptic neuron by icnreasing positive charge and making it more liekyl to fire

Question 8

what is summation

Answer 8

whether postsynaptic neurons fires decided by process summation
excitatory and inhibitory influences summoned if net effect on postsynaptic neuron is inhibotory then the postsynaptic neuron less likely to fire, if net effect is excitatory it is more likely to fire, once electrical impulse created travels down the neuron
action potential of postynaptic neuron only triggered if the sum of excitatory and inhibitory signals at any one time reaches threshold