Nervous System Flashcards
Organization of the nervous system
In 2 parts:
Central Nervous System - brain and spinal cord
Peripheral Nervous System - spinal and cranial nerves
Divisions of the PNS
Afferent - conducts towards the CNS
Efferent - conducts away from the CNS
Somatic Division of the PNS
Nerves that supply the skeletal muscles. Usually under conscious control
Autonomic Division of the PNS
Nerves that supply smooth muscle, heart muscle, and glands. Not under conscious control. 2 parts: parasympathetic and sympathetic
3 Functions of the Nervous System
- Monitor (Sensory Input)
- Integration
- Response (Motor Input)
Nerve
A bundle of neuronal processes found in the PNS
Nerve Tract
The same as the nerve, a bundle of neuronal processes, but found in the CNS
Ganglion
A collection of cell bodies and synapses which is found in the PNS
Nucleus
A collection of cell bodies and synapses found in the CNS
Center
A synaptic area in the CNS with a specific function (vision center, speech center, etc)
Gray Matter
A general term for unmyelinated nervous tissue.
White Matter
A general term for myelinated nervous tissue
Neurons
The structural and functional units of the nervous system, they conduct actions potentials. They are long lived, amitotic (don’t divide) and have a high metabolic rate.
Structure of a Neuron
Have 3 general regions: input region, conducting region, and output region. Consist of a cell body and one or more slender processes.
Plasma Membrane of the Neuron
This is the site of electrical signaling
Nissl Bodies
Condensations of the rough ER. Composed mainly of RNA and proteins, and function in protein synthesis.
Dendrites
Highly branched cell processes. They are the receptive regions of the neuron. They conduct signals toward the cell body and contain Nissl bodies
Axons
Processes that generate and conduct the AP away from the cell body. Do not contain Nissl bodies, rough ER, or Golgi apparatus. Have a plasma membrane called an axolemma.
Axon Hillock
The region of the cell body which extends into the axon. It is here that the AP is initiated.
Collaterals
Branching of the axons along it’s length.
Telodendria
The terminates of the axon. Each axon can have 10,000 or more. Here is where the neurotransmitter is released.
Myelin Sheath
A white envelope which surrounds the axons of many nerve cells. Made mostly of a white lipid known as myelin. It protects, insulate, and increases the speed of the AP.
Myelination in the PNS
The sheath is formed by Schwann cells which wrap around the axons many times creating many layers of membrane.
Satellite Cell
Regulate the chemical environment of the cell.