Bio: Neurotransmission Flashcards
Neurons
Nerve cells
Neurotransmitter
A neurotransmitter is a chemical messenger that carries signals between neurons. Neurotransmitters are released from the terminal buttons at the end of an axon after the action potential has sent an electrical charge down the neuron. The neurotransmitter then crosses the synaptic gap to reach the receptor site on another neuron.
Excitatory Function
These types of neurotransmitters increase the likelihood that the neuron will fire an action potential. It is also when a drug attaches to a receptor site for a neuron and activates the neuron as if the neurotransmitter was sending a message.
Inhibitory Function
When a neurotransmitter decreases the likelihood that the neuron will fire an action potential. It may also be when a drug attaches to a receptor site for a neurotransmitter and blocks the transmission across the synapse.
Soma
The main cell body of a neuron
Axon
The long, threadlike part of a nerve cell that transfers the nerve impulse
Terminal Buttons
Tiny bulblike structures at the end of the dendrites, which contain neurotransmitters that carry the neuron’s message into the synapse.
Synaptic Gap
The space between 2 nerve cells
Dendrite
The branched projections of a neuron that receive the message from the terminal buttons of the previous nerve cell.
Receptor Site
Areas on the dendrite where the neurotransmitters bind in order to pass along the signal
Re-uptake
The reabsorption of a neurotransmitter by the terminal buttons of the pre- synaptic neuron after it has performed its function of transmitting neural impulses. This prevents further activity of the neurotransmitter.
Serotonin
A neurotransmitter that works to regulate mood, appetite, and sleep. Low levels of serotonin have been linked to Clinical Unipolar depression and high levels of aggression. High levels of serotonin have been linked to
hallucinations.
Dopamine
A neurotransmitter that helps control the brain’s reward and pleasure centers. Dopamine also helps regulate emotional responses. Dopamine deficiency results in Parkinson’s Disease, and people with a lower number
of dopamine receptor sites may be more prone to addiction.
Acetylcholine (ACh)
The most common neurotransmitter. Acetylcholine receptor sites are found in the hippocampus. It appears that acetylcholine plays a key role in memory consolidation from STM to LTM.
Agonist
Chemicals that enhance the action of a neurotransmitter.
Antagonist
A chemical or drug that blocks or inhibits the action of the neurotransmitter, usually by binding at the receptor site so the neurotransmitter cannot.
Scopolamine
A drug that acts as an antagonist to ACh
MAO-A (Monoamine
Oxidase A)
An enzyme that helps break down neurotransmitters (like dopamine, norephinephrine, and serotonin) that remain in the synaptic gap after binding and re-uptake has occurred.
Neurotransmitter SAQ intro
Introduction:
- Neurotransmitters are chemicals that carry the electrical impulses between neurons in the brain and body
- they act within the gap between two neurons, the synapse
- very fast process
- starts in dendrites that branch out form the cell body and receive electrochemical impulses from a nearby neuron
- the impulse passes down the axon as an action potential, down to the terminal buttons, which contain tiny sacs filled with a neurotransmitter called a synaptic vesicle.
- the neurotransmitter is then released into the synapse between the neurons
- synapses can be excitatory or inhibitory, which means they can either instruct the receiving neuron to fire or not to fire respectively.
- each nuerotransmitter can act in either an excitatory way or an inhibitory way
- neutrotransmitters are affected by chemicals that bind to receptor sites, agonists which increase the neurotransmitter effect, or antagonist, which reduce their effect
