Neurons And Synaptic Transmission

Question 1

What is the cell body

Answer 1

Includes a nucleus
Contains genetic material of the cell

Question 2

What are dendrites

Answer 2

Branch like structures - project from the cell body
Carry impulses from other neurons to cell body

Question 3

What is the axon

Answer 3

Carries the impulses away from the cell body down the length of the neuron

Question 4

What is the myelin sheath

Answer 4

A layer covering the axon to protect it and sped up electrical impulse

Question 5

What are nodes of ranvier

Answer 5

Segments the myelin sheath
Speed up the transmission of the impulse by forcing it to jump across gaps along the axon

Question 6

What are terminal buttons

Answer 6

At the end of an axon
Communicate with the next neuron across a synaptic gap using neurotransmitters

Question 7

Function of a sensory neuron

Answer 7

Carry messages from the PNS to the CNS - only transmit messages - unipolar
Tell brain about external and internal environment by processing info from one of 5 sets of sensory receptors which are converted into neural impulses
Impulses translated into sensations in the brain so we can react properly

Question 8

What is the structure of a sensory neuron

Answer 8

Long dendrites
Short axons

Question 9

Function of relay neuron

Answer 9

Allow sensory and motor neurons to communicate and connect with each other
Send and receive info from many sources - multipolar
Only carry messages from one part of the CNS to the other

Question 10

Structure of relay neuron

Answer 10

Short dendrites and axons

Question 11

Function of motor neuron

Answer 11

Connects CNS to effectors (eg muscles and glands)
Multipolar -send and receive info from many sources
Protect axons outside CNS to directly or indirectly control muscles and glands
Form synapses with muscles - release neurotransmitters when stimulated to trigger response in the muscles - contract / relax

Question 12

Structure of motor neuron

Answer 12

Short dendrites and long axons

Question 13

The process of synaptic transmission

Answer 13

1. Dendrite picks up message - sends an impulse through cell body and along the axon to terminal buttons
2. Action potential arrives at terminal buttons - needs to cross synaptic gap to reach another neuron
3. End of terminal button - synaptic vesicle - contain and store NTs - are chemical messengers that convert the impulse to chemical message that ranchers to next neuron
4. Impulse travelling to end of neuron reaches synaptic vesicle - release NTs that then cross the synaptic gap
5. As the NT diffuses across the synaptic gap it binds to specialised receptors on the surface of the next cell that match that particular cell
6. Cell is activated - receptor molecules produce either an excitatory effect or inhibitory effect - post synaptic level
7. Synaptic transmission completed by process called reuptake - NT is taken back up by a presynaptic neuron

Question 14

What is a neurotransmitter

Answer 14

Chemicals released from the end of the brain calls
Allow brain cells to communicate with each other & relay messages to different areas and structures of the brain

Question 15

Neurotransmitters - excitation of post synaptic neuron

Answer 15

Create positive charge
Neuron more likely to fire
Rise in action potential = increase activity

Question 16

Neurotransmitters - inhibition of post synaptic neuron

Answer 16

Create negative charge
Neuron less likely to fire
Fall in action potential = decreased activity

Question 17

Summation

Answer 17

Excitatory and inhibitory influences are summed
Net effect of post synaptic neuron is inhibitory - neuron less likely to fire
Net effect of post synaptic neuron is excitatory - neuron more likely to fire

Question 18

Example of excitatory Neurotransmitter

Answer 18

Glumate
Adrenaline

Question 19

Example of inhibitory neurotransmitter

Answer 19

GABA
Serotonin