The cells of the nervous and neurotransmitters at synapses Flashcards
What are the three types of neuron?
Sensory, inter and motor
Cell body consist of ?
Nucleus so it is the control centre
What does the axon consist of
Single nerve fibre that carries nerve impulses away from a cell body
What do dendrites do?
They pass impulses towards the cell body
What are axons surrounded by?
The myelin sheath
What is the myelin sheath?
A layer of fatty material which insulates the axon, greatly increasing the speed of impulse conduction
What is Myelination?
The development of myelin and continues from birth to adolescence
What can destroy the myelin sheath which results in a loss in coordination
Certain diseases
What produces the myelin sheath and supports neurons
Glial Cells.
What functions does the synaptic cleft carry out?
It acts as a switch and may allow or prevent signals passing from one neuron to the next
How are messages relayed across the synaptic cleft
By neurotransmitters
What are endorphins
Neurotransmitters that stimulate neurones involved in reducing intensity of pain by combining with receptors synapses and blocking transmission of pain signal.
What are endorphins produced by?
Hypothalamus
What is dopamine
A neurotransmitter that induce feeling of pleasure by stimulating the reward pathway which reinforces certain behaviour to satisfy a need that is beneficial such as hunger or thirst.
Neurotransmitter related diseases such as Alzheimer’s schizophrenia and depression can be treated by?
Agonists and Antagonists.
What are agonists?
They bind to and stimulate specific receptors on the postsynaptic neurone mimicking action of naturally occurring neurotransmitters triggering normal cellular response
Antagonists
Bind to specific receptors to on postsynaptic neurone and blocking the action of the neurotransmitter inhibiting normal cellular response
What do inhibitors do?
Act by preventing the removal of the neurotransmitter (by degrading enzymes or preventing re-uptake) causing an enhanced effect
What can act like agonists and antagonists?
Recreational drugs
How to recreational drugs work
They affect transmission at synapses in the brain altering an individuals mood, cognition, perception, behaviour
What do many recreational drugs affect?
They affect the neurotransmission in the reward circuit of the brain causing them to be overstimulated
How is drug addiction caused
By repeated use of drugs that act as antagonists.
What do antagonists do?
They block specific receptors causing the nervous system to compensate by increasing both the number and sensitivity to of these receptors.
How is drug tolerance caused?
By repeated use of drugs that act as agonists.
What do agonists do?
Stimulate specific receptors causing the nervous system to compensate by decreasing both the number and sensitivity of these receptors
