Nervous System: Anatomy, Function, and Neurons, Study notes of Neurobiology

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Nervous System

Function:

It regulates and coordinates many of the other systems. It controls memory and logical thought, and it gives the body the ability to react or respond to both internal and external stimuli.

Peripheral Nervous System (PNS) All of the nerves outside of the brain and spinal cord.

Afferent- transmits nerve impulses (action potentials) from the sense organs to the CNS. Efferent- transmits impulses from the CNS to the muscles and glands (effectors).

NERVOUS TISSUE

Neurons (nerve cells) Receive and transmit action potentials.

Sensory (afferent) neurons transmit impulse from the sense organs to the CNS.

Cell body- The portion of the cell that contains the nucleus. Also contains nissl bodies, patches of rough ER.

Dendrites- Cell extensions that transmit impulses toward the cell body.

Axons-

Cell extension that carries impulses away from the cell body. Collateral axons may form branches off the axon.

Neuroglia (glial cells) Very abundant. Serve to support the CNS. Can also produce cerebrospinal fluid, help remove bacteria from the CNS, and protect and insulate the axons of many neurons. Examples: Neurolemmocytes or Schwan cells(PNS), Oligodendrocytes(CNS). Both produce myelin on axons of neurons.

Ganglion- A bundles of nerve cell bodies.

Cortex- Gray matter at the surface of the brain.

Nerves- Bundles of white matter (axons with myelin) in the PNS.

Nerve Impulses

Resting potential- A neuron that has a more positive charge on the outside of the cell compared to the inside of the cell (polarized).

Action potential- A reversal in the polarity (depolarization) of the neuron. Sodium ions rush into the cell so the inside is now more positive than the outside of the cell.