Unit Three - Key Area 4 Flashcards
What are neurons?
Neurons are cells within the nervous system that transmit information to other nerve cells, muscle, or gland cells.
What is a neuron made up of?
axon, dendrites and a cell body
What is the myelin sheath?
Myelin sheath insulates the axon and increases the speed of impulse conduction.
What do glial cells do?
Glial cells produce the myelin sheath and support neurons.
How does a loss of co-ordination occur?
when certain diseases destroy the myelin sheath
What does myelin enable?
Myelin enables nerve cells to transmit information faster and allows for more complex brain processes
Why is the myelination process important?
The myelination process is vitally important to a healthy central nervous system functioning.
What happens at a synaptic cleft (synapse).
Neurons connect with other neurons or muscle fibres
What do neurotransmitters do?
relay impulses across the synaptic cleft
Where are neurotransmitters stored?
in vesicles in the axon endings of the pre-synaptic neuron.
Describe the process of neurotransmitters at a synaptic cleft
They are released into the cleft on arrival of an impulse. They diffuse across the cleft and bind to receptors on the membrane of the postsynaptic neuron.
The electrical impulse changes to a chemical impulse as it is carried across the synaptic cleft.
What do receptors determine?
whether a signal is excitatory or inhibitory.
What happens in the process of summation?
A series of weak stimuli can combine to reach the firing threshold in the post-synaptic neuron
What are endorphins?
Endorphins are neurotransmitters that stimulate neurons involved in reducing the intensity of pain.
What are increased endorphins levels linked to?
The feelings of pleasure obtained from activities such as eating, sex and prolonged exercise.
When does endorphin production increase?
In response to severe injury, prolonged and continuous exercise, stress and certain foods.
What is dopamine?
A neurotransmitter that induces feelings of pleasure and reinforces particular behaviour by activating the reward pathway of the brain.
What does the reward pathway involve?
neurons which secrete or respond to dopamine.
When is the reward pathway activated?
The reward pathway is activated when an individual engages in a behaviour that is beneficial to them, for example when eating when hungry.
What are agonists?
Agonists are chemicals that bind to and stimulate specific receptors mimicking the action of a neurotransmitter at a synapse.
What are antagonists?
Antagonists are chemicals that bind to specific receptors blocking the action of a neurotransmitters at a synapse.
How can other drugs act on neurotransmitters?
other drugs act by inhibiting the enzymes that degrade neurotransmitters of by inhibiting reuptake of the neurotransmitter at the synapse causing an enhanced effect.
