Neurotransmitters Flashcards
What is a neurotransmitter?
A chemical messenger which carries, boosts and balances signals between neurones and other cells in the body
What is at the end of each neurone?
A synapse
What is released from an axon terminal?
Neurotransmitters are released after action potential has reached the synapse
What happens when the electrical signal reaches the end of the neuon?
It triggers a release of vesicles which contain the neurotransmitters.
What is excitatory neurotransmitters?
Have a excitatory effect on the neurone – increasing the chance of the neurone firing on an action potential
What is inhibitory neurotransmitters?
Have a inhibitory effect on the neuron e- decreasing the chance of the neurone firing on an action potential
What is a modulatory neurotransmitters?
Affect a large number of neurones at one time
How is resting potential created?
By a sodium potassium pump (transport protein).
Sodium potassium pump moves large number of sodium (Na+) ions outside the cell, causing it have a positive charge.
The sodium potassium pump then moves potassium (K+) ions into the cells cytoplasm, making the cytoplasm negatively charged
When does resting potential occur?
When a neurone is inactive - not being used
What happens when a stimulus reaches a resting neurone?
the neuron transmits the signal as an impulse called action potential
Explain the 5 step process of action potetional (in a neuone)
1) the stimulus causes sodium channels in the neurones membrane to open, allowing sodium ions that were on the outside into the centre of the cell
- 2) Sodium ions keep being let into the centre of the cell until the electrical potential of the cell changes to the outside being negatively charged and the inside being positively charged. If the stimulus signal is strong enough to cause the voltage to rise completely, action potential will be triggered
- 3) This high voltage causes the sodium channels to close and the potassium channels to open. So there is a lot of sodium and potassium ions inside the cell., The potassium channel opening allows all the potassium ions to move to the outside of the membrane.
- 4) There are more potassium ions on the outside of the membrane than there is sodium ions on the inside of the membrane – this causes the cells potential to drop a little lower than its resting potential
- 5) the sodium potassium pump will start working again, to move sodium ions to the outside of the cell, and potassium ions to the inside of the cell – returning the neurone to its resting state
When does action potential occur?
When a stimulus is detected
How is resting potential created?
By a sodium potassium pump (transport protein).
Sodium potassium pump moves large number of sodium (Na+) ions outside the cell, causing it have a positive charge.
The sodium potassium pump then moves potassium (K+) ions into the cells cytoplasm, making the cytoplasm negatively charged
