Neurons

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Neuron Objectives

Identify the parts of a neuron in a drawing or microscopic image, including the dendrites, cell body, axon, and myelin.
Explain what occurs at a synapse when one neuron communicates with another neuron.
Describe the path information takes through nerves in a reaction test that requires a subject to see and respond to a falling object.

We are beginning this section with neurons, the cells that connect together and communicate.

Neurons are the connected cells that communicate information rapidly around the body. Signals enter the ___, travel through the ___ ___, down the long ___, and out the ___ ___.

Neurons connect together at the synapse, where the axon terminal of one neuron contacts the dendrite of the next neuron. Movement of calcium causes neurotransmitters to spill into the gap between neurons, and causes sodium to move into the next neuron.

This is another example of why calcium and sodium are important to organ function.

In this model of a synapse, identify the axon terminal with a mitochondrion, vesicles of neurotransmitters, small dots representing calcium and sodium, and the next neuron’s dendrite.

Fat plays a role in nervous system function. Why is myelin important?

The glial cells that wrap around a neuron’s axon are called Schwann cells and they produce layers of myelin that insulates the axon.

In this longitudinal cut of a nerve, look for the axons and their myelin.

This is a transverse view of a nerve, which is a bundle of _____. What are the circles with “dots” inside of them?

Large blood vessels and nerves often run along each other. Identify the artery, vein, and nerves in this microscopic image.

If you catch something that is falling, the eye has to receive information on the object, send it to the brain, the brain has to process the information, send a signal through the spinal cord, and out motor nerves to skeletal muscle that contact so you can grab the object.

Reaction time is a fun activity to model if you have an assistant available.

The next section examines reflex responses that are hard-wired automatic responses to specific stimuli.

Check your knowledge. Can you:

identify the parts of a neuron in a drawing or microscopic image, including the dendrites, cell body, axon, and myelin?
explain what occurs at a synapse when one neuron communicates with another neuron?
describe the path information takes through nerves in a reaction test that requires a subject to see and respond to a falling object?