Role Of Central Nervous System And Neurotransmitters In Human Behaviour Flashcards
What are the 2 subsystems that the nervous system is made of? State what these 2 subsystems are made up of
- central nervous system= the brain and spinal cord
- peripheral nervous system= autonomic nervous system (involuntary actions- this is further split into the sympathetic NS and the parasympathetic NS) and the somatic nervous system (voluntary actions)
What is the role of the nervous system?
-made up of the brain, spinal cord and a complex network of neurones, its responsible for sending, receiving and interpreting information from all parts of the body. It monitors and coordinates internal organ function and responds to changes in the external environment.
How does the central nervous system work?
- CNS is made up of the brain and the spinal cord.
- the spinal cord receives information from our skin, joints, and muscles of the body
- the brain receives information directly from the ears, eyes, nose and mouth, as well as from the rest of the body via the spinal cord
- neurons receive and transmit messages in the brain in response to the information received.
- The brain makes a decision on the appropriate action needed, and sends a message to the body back through our spinal cord
- this action is carried out by nerve impulses (electrical signals passing through neurons through synapses)
Draw and label a neuron. Explain what each part of the neuron does.
- cell body = contains other materials (e.g mitochondria) that allows the cell to function
- dendrites = receives messages from other neurons in order to trigger an electrical impulse within the cell
- nucleus = houses neurons genetic material
- myelin sheath = layers of fatty deposit that provide an insulating layer to the axon to help speed up rate of message transmission
- node of ranvier = breaks in the axon, electrical impulses jumps each section of the axon
- axon = extension of the cell body that passes the electrical impulse away from the cell body towards axon terminals
- schwann’s cells
- axon terminals = forms terminals with other cells, passing nerve impulses from cell body to parts of the body they control
- terminal buttons = contain tiny vesicles that store neurotransmitters ready for the next stage of neural transmission
What is the function of motor neurons?
-carry signals from the CNS to effectors (muscles or glands)
What is the function of relay neurons?
Carry messages from one part of the CNS to another
What is the function of sensory neurons?
Carry signals from receptors to the spinal cord and brain
Explain the process of how neurons pass messages onto the next neuron.
- Neurons sends messages electrochemically (chemicals cause an electrical signal). And chemicals in the body are electrically charged= ions
- when a neuron is not sending a signal it is at rest and the inside of the neuron is negative, and outside is positive. The resting potential of a neuron is -70 mV
- an action potential (impulse) occurs when a neuron sends information down an axon, away from the cell body. It is an explosion of electrical activity that is created by depolarising current. This means a stimulus causes the resting potential (negative) to move towards becoming a positive charge.
- because there are many more positive ions on the outside, and the inside of the neuron is negative, positive ions rush into the neuron, making it positive and become depolarised, causing the electrical impulse to fire along a neuron to the axon terminal
- hyperpolarization is when the neurotransmitters are pushed out of the cell because the channels stay open a bit too long. Gradually the ion concentrations go back to resting levels and the cell returns to -70mV
Explain the stages of how synaptic transmission works.
- An action potential arrives as the axon terminal
- The action potential triggers the release of neurotransmitters from a vesicles, whose membrane will be recycled
- Neurotransmitter binds to the receptor sites on ion channels
- Ions cross the membrane through the open channels. This produces a synaptic potential in the postsynaptic neuron
- Neurotransmitter is removed from the synaptic cleft through the transporters, diffusion, and degradative enzymes
What is a neurotransmitter and what do they effect in the body?
- A chemical which relays signals across the synapses between neurons
- they have an effect on our emotions, cognition, and behaviour
Explain how neurotransmitters cross between neurons
- travel across the synaptic space between the terminal buttons of one neuron and the dendrites of other neurons which they bind to.
- the dendrites will only admit the neurotransmitter if they are the right shape to fit in the receptor sites on the receiving neuron. Often compared to a lock and key
What is an excitatory neurotransmitter effect?
Make the cell more likely to fire
What is an inhibitory neurotransmitter effect?
Make the cell less likely to fire
What happens if the receiving neuron is able to accept more then one neurotransmitter?
It will be influenced by the excitatory and inhibitory processes of each.
What happens if the excitatory effects of the neurotransmitter are greater than the inhibitory effects?
The neuron moves closer to its firing threshold and if it reaches the threshold, the action potential and the process of transferring information through the neuron begins.
