Key Area 3.3 Flashcards
What are neurons?
Nerve cells
What are neurons made up of?
A cell body, and fibres called dendrites and axons.
What are the three types of neuron?
Sensory, inter, motor
What is myelination?
The covering of neuron fibres with a myelin sheath which insulates them, increasing the speed of nervous impulses. This process continues from birth to adolescence
What do glial cells do?
Physically support neurons and produce the myelin sheaths
How do glial cells remove debris?
Phagocytosis
What are synapses?
Gaps between neurons
What are found in pre synaptic neurons?
Synaptic vesicles containing neurotransmitters
What to nervous transmissions between neurons rely on?
Neurotransmitters secreted into the synaptic cleft
What to receptors in the post synaptic membrane respond to?
Neurotransmitters
Why must neurotransmitters be removed from the synaptic cleft?
To maintain sensitivity.
How are neurotransmitters reused?
By being broken down by enzymes or being tea sores into the pre synaptic membrane
What do receptors determine?
Whether a signal is excitatory or inhibitory
What can synapses filter out?
Weak stimuli resulting from insufficient secretion of neurotransmitters
What are neural pathways?
Routes taken by impulses though the nervous system
What happens in converging neural pathways?
impulses from several neurons are passed to a single neuron.
What happens in diverging neural pathways?
Impulses from one neuron are passed to several others.
What happens in reverberating neural pathways?
Impulses are recycled round loop like pathways.
Why are new neural pathways created?
To bypass areas of brain damage, to suppress reflexes or in response to sensory impulses
What does creation of new neural pathways do?
Gives plasticity of response of response
What are endorphins?
Neurotransmitters that stimulate neurons involved in reducing intensity of pain, creation of euphoria, appetite modulation and release of sex hormones
When does endorphin production increase?
In response to severe injury, prolonged and continues exercise, stress and certain foods
What does dopamine do?
induced the feeling of pleasure and reinforced particular behaviour in the reward pathway.
What do agonist drugs do?
act like neurotransmitters and can enhance transmission.
What do antagonistic drugs do?
Bind to specific receptors, blocking the action of a neurotransmitter.
What can certain drugs inhibit?
Enzymes that degrade neurotransmitters or inhibit their reabsorption
What can recreational drugs do?
Mimic neurotransmitters, resulting in mood change, alteration of perception and changes in cognition and behaviour.
What do recreational drugs affect?
Neurotransmission in the reward pathway.
What is sensitisation?
An increase in the number and sensitivity of receptors as a result of exposure to antagonistic drugs- this can lead to drug addiction.
What is desensitisation?
A decrease in the number and sensitivity of receptors as a result of exposure to agonistic drugs- this can lead to drug tolerance.
