The Role of the CNS & Neurotransmitters in Human Behaviour

Question 1

Describe is the Central nervous system (CNS)

*describe question usually just wants you to mention the components in side of it

Answer 1

• made up of brain and spinal cord
• responsible for sending, receiving, and interpreting information from all parts of the body
• monitors and coordinates internal organ function and responds to changes in the external environment
• 2 system = CNS/PNS (peripheral nervous system)
• CNS = brain and spinal cord
• PNS = somatic (voluntary control) via skeleton muscle & automatic (involuntary control) e.g. heartbeat, blood flow

Question 2

Describe what the role of CNS is

Answer 2

• Pass messages from the brain to diff parts of the body and back (vice versa)
• Takes info from your environment
• Something happens that needs to be acted upon
• Communicates to the brain to know what to do and passes the messages back to act
• For example: if a ball comes to you, your body will ask the brain on what to do and the brain formulates a plan and sends the messages back on what to do and the appropriate body part will act to the plan to not get hit by the ball
• The whole premise is basically its sending messages around the body (can talk about transmitters, dendrites, synapse etc but don’t go too far-off topic)

Question 3

Identify and Define the main neurons

Answer 3

Motor- transmits info into to the muscle’s and glands

Inter - responsible for communicating among the neurons. Can combine multiple info to make a coherent image for what is trying to be conveyed

Sensory - carries the info from the sensory receptor

Question 4

Describe how does the neuron function

Answer 4

1. Dendrites- receive the info from other neurons, some receptors on it are designed to receive chemical neurotransmitters
2. soma (cell body) – signals received which causes an electrical change and are interpreted in the soma (contain nucleus - like the DNA for it). Takes all info and puts it together in the axon hillock
3. Axon Hillock – if signal is strong enough then sends it the axon
4. Axon – covered in myelin to help the signal from degrading
5. 5 Axon - axon terminals (synaptic buttons) once reached cause a release of neurotransmitters
6. purple structures (the things on the end of the axon terminals) = dendrites of another neuron and when neurotransmitters release from axon terminal they interact of the dendrites of the other neuron and repeats the whole over again

Question 5

Define Action potential

Answer 5

the method to how the nerve impulses passes down the axon of the neuron to stimulate the release of neurotransmitters

which is a tiny electrical impulse occurs when their is a change in electrical potential

Question 6

What is depolarization and how does it link to action potential

Answer 6

• depolarization current creates electrical activity which activates action potential
• reach -55mV = ion channels open to make neuron positive
• this is a threshold & not reached causes no action potential to fire = outside neuron is positive hence rush into the neuron making it more positive (depolarized)
• 40mV = electrical impulse to fire along a neuron to the axon terminal

Question 7

Explain Hyperpolarization and How it returns to the resting state

Answer 7

1. some channels can take longer & when opened potassium rushes out reversing depolarization
2. 1 around the same time sodium channel open causing potential to go back toward -70mV (*repolarization)
3. this action goes past -70mV (hyperpolarization) due to channels stay open too long
4. 2 gradually the ion concentration go back to resting levels an the cell return to -70mV

Question 8

Describe how does Synaptic transmission function

Answer 8

postsynaptic neuron (receiving the signals)

Presynaptic neuron (signal is initiated):
neurotransmitters (chemical signal) packages in vesicles (contain thousands of neurons like a bus) when stimulates by the action potential cause vesicles to fuse with presynaptic membrane and release is contents in synaptic cleft

Once in synaptic cleft, neurotransmitters interact with receptors of postsynaptic membrane and cause a reaction on the postsynaptic cell which involves increasing the likelihood the postsynaptic cell will become activated and fire an action potential or decreasing it

Question 9

How are neurotransmitters molecules cleared from the synaptic cleft (the gap between the synapse)

Answer 9

• drift away called diffusion - goes back into the presynaptic neuron called reuptake (being recycled and reused)
• enzymes break down the neurotransmitters within the synaptic cleft and the component parts can be sent back into the presynaptic neuron