Human Biology

1.41. Nerve Cells and Nerve Impulses http://www.ck12.org

• dendrite: Extension of the cell body of a neuron that receives nerve impulses from other neurons.


• motor neuron: Nerve cell that carries nerve impulses from the brain and spinal cord to organs, glands, and
  muscles.


• myelin sheath: Fatty layer that insulates the axon and allows the electrical signal to travel much more quickly.


• nerve: Bundle of nerve cells.


• nerve impulse: Electrical signal transmitted by the nervous system.


• neuron: Nerve cell.


• neurotransmitter: Chemical that carries a nerve impulse from one nerve cell to another at the synapse.


• node of Ranvier: Any gap within the myelin sheath exposing the axon.


• sensory neuron: Nerve cell that carries nerve impulses from the sense organs and internal organs to the brain
  and spinal cord.


• synapse: Place where the axon of one neuron meets the dendrite of another.

Summary

• Neurons, or nerve cells that carry nerve impulses, are made up of the cell body, the axon, and several dendrites.


• Signals move across the synapse, the place where the axon of one neuron meets the dendrite of another, using
  chemicals called neurotransmitters.

Practice

Use the resource below to answer the questions that follow.

• Neuronsat http://www.youtube.com/watch?v=jOkp68kUQvc (3:16)

MEDIA

Click image to the left for more content.

1. What are the three types of neurons?


2. What neurons are most abundant in our brain?


3. What is the function of sensory neurons? Where do they send information?


4. What is the function of motor neurons? Where do they send information?

Review

1. Describe a neuron and identify its three main parts.


2. Explain how one neuron transmits a nerve impulse to another neuron.