central nervous system

Question 1

what is the central nervous system?

Answer 1

the brain and spinal cord are referred to as the CNS. This is the central processing and control point for all human behaviour.

Question 2

what is the structure and function of neurons?

Answer 2

the central nervous system includes the brain and spinal cord. Neurons carry electrochemical ‘messages’ around the brain and body. They are the body’s communication system.
Structure:
* dendrites
* nucleus
* cell body
* node of Ranvier
* axon
* mylein sheeth
* schwann’s cells
* axon terminals
* terminal buttons

Question 3

describe dendrites

Answer 3

branches at the top end of a neuron that recieve messages from other neurons

Question 4

describe axons

Answer 4

a long branch from the cell body that passes electrical impulses down to the end of the neuron to allow it to communicate with others

Question 5

describe terminal buttons

Answer 5

the very end of a neuron where the nerve impulse becomes a chemical message that can be passed to the dendrite of another neuron

Question 6

describe vesicles

Answer 6

tiny sacs that contain molecules of neurotransmitter chemicals

Question 7

function of neurotransmitters

Answer 7

neurotransmitters allow electrochemical impulses to cross synpases between the neurons.

Question 8

what is the lock and key mechanism?

Answer 8

there are receptors on the dendrite of the next neuron. the receptor has to be the right shape for the neurotransmitter to pass on to the next neuron.

Question 9

explain process of synpatic transmission

Answer 9

• when the action potential reaches axon terminal, the vesicles travel to the outer membrane of the terminal buttons
• neurotransmitters will be released from vesicles in the synaptic gap
• receptors on the dendrites are designed to bind to and absorb a specific neurotransmitter. this uses lock and key mechanism - if neurotransmitter fits the receptor the message is sent. if not then the message is not passed on
• neurotransmitters are reabsorbed in to pre-synaptic neuron so they can be reused
• excess neurotransmitters that are not reabsorbed are broken down by enzymes

Question 10

what is noradrenaline?

Answer 10

• produces fight or flight response
• sleeping - dreaming
• learning
• attention
• emotion, especially mood control

Question 11

what is dopamine?

Answer 11

• responsible for posture and control of movement - linked to Parkinson’s
• dependency behaviour - addiction
• cognitive functions
• emotion

Question 12

what is serotonin?

Answer 12

• responsible for mood control - happiness and good mood
• sleep - wakefulness
• regulates body temperature

Question 13

what is GABA?

Answer 13

• Gamma-AminoButyric Acid
• an inhibitor that blocks rather than taking a message on
• it calms nerves that are firing so producing feelings of relaxation. low levels are associated with anxiety

Question 14

what are the contact points between neurons?

Answer 14

synapses

Question 15

what is sent across the synaptic gap?

Answer 15

chemical messengers called neurotransmitter

Question 16

what happens if the neurotransmitter isnt accepted into the next neuron?

Answer 16

it is reabsorbed by pre-synaptic neuron

Question 17

describe ‘neuron’

Answer 17

fundamental units of the brain and nervous system, responsible for receiving sensory input and sending electrical impulses between the brain and body to transfer messages