neurons

Question 1

what is a neuron?

Answer 1

located in our CNS. they transmit signals chemically and electrically and provide the nervous system with its primary means of communication.

Question 2

what are the 3 types of neurons?

Answer 2

sensory
relay
motor

Question 3

what is the structure of a sensory neuron?

Answer 3

long dendrites and a short axon

Question 4

what is the function of a sensory neuron?

Answer 4

found in receptors such as eyes, ears, tongue, skin and carry nerve impulses to the CNS. when these nerve impulses reach the brain, they are translated into sensations such as vision, hearing, taste and touch. however, not all sensory neurons reach the brain as some neurons stop at the spinal cord, allow ng for quick reflex actions.

Question 5

what is the structure of a relay neuron?

Answer 5

short dendrites and a short axon

Question 6

what is the function of a relay neuron?

Answer 6

they are found between sensory input and motor output response. relay neurons are found in the brain and spinal cord and allow sensory and motor neurons to communicate.

Question 7

what is the structure of a motor neuron?

Answer 7

short dendrites and long axons

Question 8

what is the function of a motor neuron?

Answer 8

are found in the CNS and control muscle movements. when motor neurons are stimulated, they release neurotransmitters that bind to the receptors on muscles to trigger response, which can lead to movement.

Question 9

what are the parts of a neuron?

Answer 9

dendrites
nucleus
cell body
axon
myelin sheath
Schwann cell
node of ranvier
axon terminal

Question 10

what is the function of the nucleus?

Answer 10

control centre of a cell, controls the cells chromosomal DNA

Question 11

what is the function of the dendrites?

Answer 11

recieves the nerve impulse or signal from adjacent neurons

Question 12

what is the function of the axon?

Answer 12

where electrical signals pass along

Question 13

what is the function of the myelin sheath?

Answer 13

insulates/protects the axon from external influences that might effect the transmission of nerve impulses down the axon

Question 14

what is the function of the node of ranvier?

Answer 14

speed up transmission of the impulse by forcing it to ‘jump’

Question 15

what is the function of the axon terminal?

Answer 15

terminal buttons send signals to adjacent cells

Question 16

what is the process of synaptic transmission?

Answer 16

• when the action potential reaches the presynaptic terminal, it triggers the synaptic vesicles to release neurotransmitters into the synaptic gap
• the neurotransmitters diffuse across the synaptic gap between the pre and post synaptic cells
• the neurotransmitters bind to the post-synaptic receptor sites on the membrane of the post synaptic neurons dendrite
• this stimulation of the post-synaptic receptors converts the chemical message back to an electrical impulse and the process of transmission begins again in the post-synaptic neuron
• the effects are terminated by a process called reuptake. the neurotransmitters are taken up by the pre-synaptic neuron where they are again stored in synaptic vesicles ready for later release.

Question 17

what is an excitory neurotransmitter and what effect does it have?

Answer 17

they have excitory effects on the neuron. this means they will increase the likelyhood that the neuron will fire an action potential

Question 18

what is an inhibitory neurotransmitter and what effect does it have?

Answer 18

they have inhibitory effects on the neuron. this means they will decrease the likelyhood that the neuron will fire an action potential