Cells of the Nervous System: The Neuron Flashcards
Each structural component of the neuron has an important function. Overall structure of the cell can vary depending on location and function of the neuron.
What are the 2 major cell types within the nervous system?
Neurons and Neuroglia
What are neurons?
Neurons are the basic units of the brain
What is the main function of neurons?
To send electrical signals over short and long distances in the body, and they are electrically and chemically excitable.
What is the function of the neuron dependent on?
The structure of the neuron
What does the typical neuron consist of? (5)
dendrites, cell body, axon (including axon hillock), and presynaptic terminal.
What is the estimated number of neurons in an adult human brain?
Close to 86 billion neurons
Compared to how the rest of the body, what is the percentage of neurons?
About 0.2%
What are some unique characteristics of the neuron? (4)
- Neurons are electroactive
- Neurons are specialized for rapid communication
3.Neurons are “forever” cells - Neurons can change
What does being electroactive mean?
They are charged cells that can change their charge
Why can Neurons change?
Because of the plasticity of the brain.
Describe how dendrites look.
They are processes that branch out in a tree-like fashion from the cell body.
What is the main target for incoming signals received from other cells.
Dendrites
What are the small protrusions along the branches of the dendrites?
Dendritic Spines
True or False: Many cells lack spines
True. However, they are still capable of permanently changing.
What is thought to underlie the reason that we can learn new facts or maintain memories about our childhood over a long period of time?
Dendritic plasticity
Where does the information that arrives through the dendrites of a neuron eventually filter into?
The cell body or the soma of the neuron
What is the main output extension of the neuron?
The axon
Where are is the axon hillock located?
Where the cell body transitions into the axon
What is it called when several axons bundle and travel together?
Nerves
What is the electrical signal an axon transmits called?
Action potential
Where is the largest axon in the body located?
In the sciatic nerve that runs from the posterior end of the spinal cord down the leg to control the muscles of the big toe.
Where is the action potential transmitted from?
The axon hillock
How is a neurotransmitter released?
The axon releases the action potential from the axon hillock to the presynaptic terminal where the electrical signal will result in the release of a neurotransmitter to communicate with the next cell.
What is the myelin sheaths?
A fatty substance the wraps around portions of the axon and increases action potential speed.
What are the breaks between the myelin segments called?
Nodes of Ranvier
