central nervous system (neuron, NTs & synapses)

Question 1

what are the two main parts of the nervous system?

Answer 1

central nervous system and peripheral nervous system

Question 2

what does the cns consist of?

Answer 2

• brain and spinal cord
• brain is within the skull and spinal cord is within the vertebrae

Question 3

what is the cns?

Answer 3

• the central processing and control point for all human behaviour

Question 4

what is the process of the cns?

Answer 4

• brain processes all incoming info from senses and is responsible for controlling behaviour that may result from this info

Question 5

what does the spinal cord do?

Answer 5

• connects brain to rest of body, and allows messages to be passed from body to brain, and also from brain to other parts of body in order to get them to respond

Question 6

what are the cell in the cns called? what do they do?

Answer 6

• neurons
• these cells communicate with around 1000 other cells at a time in a huge network

Question 7

what cells are neurons?

Answer 7

• cells that receive and transmit messages, passing messages from cell to cell

Question 8

how is a neuron structured?

Answer 8

• at one end, a neuron has dendrites which are finger-like structures surrounding a cell body, and form a structure that is tree-like.
• from the cell body, there is also a long extension coming from the axon hillock
• this long extension is called an axon and can be up to a metre long in humans
• the axon ends at an axon terminal
• the axon is where the electrical signal from the cell body travels
• the axon terminal has more than one ‘branch’ and at the end of each branch is a terminal button
• he axon is protected by the myelin sheath which surrounds it to form an insulation layer
• to speed up the messages there are places in the myelin sheath where it thins, called node of ranvier

Question 9

what is the neuron made up of and what does it lead to?

Answer 9

• neurons are made up of a cell body sending an electrical signal down an axon, which is protected by a myelin sheath
• the myelin sheath has breaks in it, where the axon is not protected, and these breaks are called the nodes of ranvier
• the electrical signals arrives at the axon terminal and the signal triggers the release of neurotransmitters into the synaptic gap
• the synaptic gap separates the terminal buttons of one neuron from the dendrites of another neuron
• if the dendrites have receptors that ‘match’ the chemical composition of the released neurotransmitter, the signal continues with the neurotransmitter sending a message to the cell body of the other neuron, which triggers an electrical impulse called the action potential down the axon of that neuron and so on