KEY TERMS & DEFINITIONS Flashcards
(39 cards)
What part of a nerve cell (neurone) is a dendrite and what does it do?
Dendrites are the branches at the end of the cell body (soma)
They receive neurotransmitters
What is a Soma?
The cell body of a neuron
Contains mitochondrion DNA
What does the nucleus of a neuron contain?
Genetic material
What is the axon of a neuron?
What does it do?
An extension of the cell body
Electrical impulses travel along the axon
What is the Myelin sheath? What does it do?
It is a fatty layer surrounding the axon
It speeds up transmission of electrical impulses and ensures that the transmission happens at a consistent speed so the body reacts quickly to a stimulus
What is the Myelin sheath made of?
Schwanns cells
What are the gaps between the myelin sheath called? What do they do?
Node of ranvier
Help to strengthen connection
Where do you find axon terminal buttons in a neurone and what do they do?
They are located at the end of the neuron (other end of the axon)
They are transmitters
What are the two types of neurotransmitters?
Excitatory and Inhibitory
What do excitatory neurotransmitters do?
They cause a neuron to fire
Excitatory neurotransmitters “excite” the neuron and cause it to fire chemical messages
This increases the likelihood of an action potential
What do inhibitory neurotransmitters do?
They prevent neuron from firing
They block or reduce the transmission of nerve signals, preventing neurons from firing. They act as “off switches” in the nervous system, promoting relaxation, sleep, and filtering out unnecessary excitatory signals.
What are endorphins?
A neurotransmitter in the body that naturally acts as a painkiller physically and psychologically
It can also trigger an increase in dopamine levels
What does heroin do?
Heroin binds to receiver receptor sites
It triggers the endorphins that released dopamine
What does serotonin do?
It is a neurotransmitter that carries signals between nerve cells
It is linked to mood
What are SSRIs
That a type of antidepressant that block the reuptake of serotonin
By blocking this reuptake, SSRIs increase the amount of serotonin available in the synaptic cleft, (the space between nerve cells where communication occurs.)
What is dopamine?
A neurotransmitter associated with reward it creates a feeling of pleasure and desire to repeat the activity triggering it
Lots of drugs causing increase in dopamine therefore becoming addictive
What are synaptic vesicles and where are they found?
Organelles found in the presynaptic terminal of a synapse which are filled with neurotransmitters
What do the synaptic vesicles do?
They release the neurotransmitters through the terminal into the synaptic cleft
What is the synaptic cleft?
The gap between the pre-synaptic terminal and the post-synaptic terminal of a synapse
What do autoreceptors do and where are they found in a synapse?
They are found on the presynaptic terminal
They detect, control and regulate the release of neurotransmitters into the synaptic cleft
What are the receptor sites in a synapse and where are they found?
They are found on the postsynaptic terminal
They are all specific to each neurotransmitter released from the presynaptic terminal and do slightly different things (think of it like enzymes lock and key)
Resting-potential into action-potential in the post synaptic terminal
In a postsynaptic terminal, the resting potential is the stable, negative electrical charge difference across the cell membrane when the neuron is not transmitting a signal, typically around -70mV. The action potential is a rapid change in membrane potential, from negative to positive, triggered by an excitatory input, causing a brief reversal of the electrical charge difference
Things that trigger a rise dopamine levels - why is this?
- Eating high calorific food
- Making a ‘good’ decision
- Exercising
- Sex
(it is an evolutionary instinct for survival)
