Semester Summative Assessment Study Guide/Honors Anatomy & Physiology

nervous system,

What are the functions of the Nervous System?

Detects impulses from senses, control center

Major organs are brain, spinal cord, senses nerves

 

Explain the structures a nerve impulse encounters as it travels through a neuron.

·      Dendrites: receive the nerve impulse from the senses or another neuron

·      Cell body: contains nucleus; transmits impulse to the axon

·      Axon: passageway for nerve impulse after the cell body; ends in axon terminals

·      Myelin Sheath: Insulates the axon, produced by Schwann cells; between this is the nodes of Ranvier, which increases the speed of the impulse.the axon,

2 Major Types of Nerve Cells

·      Nerve cells pass impulses throughout the body.

·      There are 2 major types of nerve cells:

·      Neurons (make up 10% of the NS)

·      Neuroglia (“nerve-glue”, make up 90% of the NS

Review the nerve synapse:

1.     The nerve impulse travels down the axon

2.     The impulse reaches the axon terminal

3.     The electrical signal cannot jump the gap by itself

4.     Chemicals called neurotransmitters are released

5.     Neurotransmitters move across the synaptic cleft

6.     They attach to receptors on the next neuron

7.     Channels open in next neuron

8.     A new action potential begins

9.     The nerve impulse continues