neurones and synaptic transmission

Question 1

what % of neurons are located in the brain?

Answer 1

80%

Question 2

what do neurons do?

Answer 2

they transmit signals electrically and chemically

Question 3

what are the three types of neurons?

Answer 3

sensory
relay
motor

Question 4

what are sensory neurons?

Answer 4

messages from the PNS t the CNS

Question 5

how are sensory neurons adapted for their function?

Answer 5

long dendrites and short axons

Question 6

what are relay neurons?

Answer 6

connect the sensory neurons to motor or other neurons

Question 7

how are relay neurons adapted for their function?

Answer 7

short dendrites

short axons

Question 8

what are motor neurons?

Answer 8

connect CNS to effectors e.g. muscles or glands

Question 9

how are motor neurons adapted for their function?

Answer 9

short dendrites

long axons

Question 10

what is the basic structure of a neuron?

Answer 10

cell body with nucleus
dendrites extending from body carrying nerves impulses away from neighbouring neurons to cell body

axon carrying impulse away from cell body down neuron

axon covered w/ myelin sheath protect axon and speed up elec impulse

nodes of ranvier ensure that impulses have speed as it is a gap

terminal buttons communicate with next neuron across synapse

Question 11

list all the steps of a neurone

Answer 11

1.cell body with nucleus

dendrites carry nerve impulses away from neighbouring neurons to cell body
axon carrying impulse away from cell body down neuron

axon covered w/ myelin sheath protect axon and speed up elec impulse

nodes of ranvier ensure that impulses have speed as it is a gap

terminal buttons communicate with next neuron across synapse

Question 12

when a neuron is in it’s resting state it is… until it is activated with a stimulus

Answer 12

negative

Question 13

when a neuron becomes positively charged for a split second, this causes an ….

Answer 13

action potential creating electrical impulse that travels down the axon towards the end of the neuron

Question 14

define synaptic transmission

Answer 14

process where neighbouring neurons communicate with each other through chemical messages across the synaptic cleft

Question 15

what are the 6 steps of synaptic transmission?

Answer 15

info passed down axon, called action potential needing to transferred to another neuron

needs to cross through synaptic cleft between pre-syn neuron and post-syn neuron

in the axon terminal located at end of neuron is synaptic vesicles containing neurotransmitters

action potential reaches synaptic vesicles, open up calcium channels which move vesicles to membrane to release into synaptic cleft

neurotransmitters carry signals across syn cleft, binding to receptor sites of post-syn cell

neurotransmitter either has has an excitatory or inhibitory effect

Question 16

list the steps of synaptic transmission

Answer 16

info passed down axon, called action potential needing to transferred to another neuron

needs to cross through synaptic cleft between pre-syn neuron and post-syn neuron

in the axon terminal located at end of neuron is synaptic vesicles containing neurotransmitters

action potential reaches synaptic vesicles, open up calcium channels which move vesicles to membrane to release into synaptic cleft

neurotransmitters carry signals across syn cleft, binding to receptor sites of post-syn cell

neurotransmitter either has has an excitatory or inhibitory effect

Question 17

what is an excitatory and inhibitory neurotransmitter?

Answer 17

excitatory - increase positive charge, increase action potential and more likely to fire e.g. adrenaline
inhibitory - negative charge, decrease action potential, less likely to fire e.g. serotonin