Biology 30 Unit 1: The Nervous System I ntro R ecap

1. Biology 30 Unit 1: The Nervous System Intro Recap

2. The Nervous system has two main divisions: The Central Nervous System (CNS) and The Peripheral Nervous System (PNS)

3. The CNS consists of the nerves of the brain, and the spinal cord. The CNS acts as a coordinating center for incoming and outgoing information.

4. The PNS consists of nerves that carry information between the organs of the body and the CNS. The PNS can be further divided into somatic and autonomic nerves.

5. The somatic nervous system controls the skeletal muscle, bones, and skin. The autonomic nervous system controls the internal organs of the body.

6. There are two main types of nerve cells: Glial cells (neuroglial cells)are non-conducting cells important for the structural support and metabolism of the nerve cells. Neurons are the functional units of the nervous system.

7. The anatomy of a neuron: Dendrites receive information, either from the environment or from other neurons. Axons are extensions of the cytoplasm that conduct nerve impulses away from the cell body. The axon carries nerve impulses toward other neurons or to effectors. Most nerves are comprised of many axons held together by connective tissue.

8. Many axons are covered with a white coat of fatty protein called the myelin sheath, which acts as insulation for the neurons. Why do you think this is important? The myelin sheath is formed by special glial cells called Schwann cells. The spaces between the Schwann cells are called the nodes of Ranvier. What is the purpose of these spaces?

9. All nerve fibres found within the peripheral nervous system have a thin outer membrane called the neurilemma, which surrounds the axon. The neurilemma is formed by the Schwann cells and promotes the regeneration of damaged axons.