The Anatomy of a Synapse and Neuron
Neurons form elaborate networks through which nerve impulses—action potentials—travel. Each neuron has as many as 15,000 connections with neighboring neurons.
Neurons do not touch each other; instead, neurons interact at contact points called synapses: a junction within two nerve cells, consisting of a miniature gap which impulses pass by a neurotransmitter. A neuron transports its information by way of a nerve impulse called an action potential.
The action potential can originate in the cell body when it has received a stimulus, then it moves down the axon of that neuron. When an action potential arrives at the synapse, it stimulates the release of neurotransmitters. These neurotransmitters are released into the synaptic cleft to bind to the receptors of the adjacent cell.
Color the Neurons
Color the cell body and the dendrites blue.
Color the axon (and myelin sheaths) red .
Highlight the synapse with yellow.
Use an arrow to show movement of the action potential.
On a cellular level, the neuron cell has vesicles that contain neurotransmitters. Each neurotransmitter can carry a different type of message. Some neurotransmitters, like serotonin, regulate appetite, sleep, and mood.
1. The junction between two communicating neurons is called the:
2. A nerve impulse traveling down a neuron is called an:
3. Where does the action potential originate from?
4. Chemicals released at the end of a neuron are called:
5. What organelles store neurotransmitters?
6. What neurotransmitters is associated with sleep and mood?
The image below shows how seratonin is released from the neuron and how a drug called SSRI (selective seratonin re-uptake-inhibitors) is used to treat mood disorders. The neuron, like most cells of the body has mitochondria which provide the energy the cell needs to function.
The axon area contains the vesicles that store the neurotransmitters. They cross the synaptic cleft and land on the receptors of the dendrites of the next neuron.
The neurotransmitters are returned to the original cell through transporters, a process called re-uptake. As long as the neurotransmitter remains in the cleft, the receptors will continue to be stimulated. Certain drugs, called SSRI's can block the re-uptake process, which leaves seratonin active for longer. This has an effect of elevating the person's mood or reducing anxiety and can be used to treat anxiety and depression.
Color the Neuron
- mitochondria (A) orange
-
axon on the nerve cell (X) blue.
- neurotransmitters (E) red
- vesicles (B) pink
- receptors (D) green
- dendrite (Y) yellow
- transporter (reuptake area) purple
- inhibitor (F) brown
Identify each of the letters:
A ___________________
B
___________________
C ___________________
D ___________________
E ___________________
F ___________________
X ___________________
Y ___________________
Questions:
8. Where do neurotransmitters land? ________________________
9. What happens if the reuptake transporter is blocked? ______________________
10. What do SSRIs treat? ___________________________________________