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Learn about the nervous system's role in interpreting information, maintaining homeostasis, and producing responses. Explore neuron structure and types, nerve impulses, and cellular components.
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Nervous System • the nervous system receives and interprets information from the internal and external environment and produces a response that allows the organism to maintain Homeostasis
it works closely with the Endocrine system but it produces a quicker response than hormones do. • there are 5 key parts to the functioning of the nervous system:
1. Reception of sensory information by receptors. • 2. Transmission of this information via Sensory neurons. • 3. Interpretation of the information by the brain.
4. Transmission of a response by a Motor Neuron. • 5. Response produced by Effectors: • organs, muscles and glands
THE NEURON • a neuron is a nerve cell with special membranes that produce electrical impulses • a neuron is composed of the following parts:
Dendrites • Short extensions from the cell body that receive stimulus information from receptor cells or other neurons and deliver it to the cell body.
Cell Body • contains the major cell organelles • acts as a bridge, allowing conduction of information between dendrites and axons
Axon • a long thin extension of the cell body responsible for conducting nerve impulses away from the cell body. • axons in the PNS, are coated with MYELIN an insulating material that increases the speed of nerve impulses
Myelin, a fatty protein coat is made from SCHWANN CELLS • tiny spaces located between the areas of myelin are called NODES OF RANVIER, impulses jump from one node to the next increasing their speed.
axons in the PNS are also coated with a membrane called the NEURILEMMA, this promotes the regeneration of damaged axons.
axons end in nodules called SYNAPTIC KNOBS; they contain neurotransmitter chemicals that allow conduction across the synapse.
Draw a labeled motor diagram. • Under the diagram, explain neurilemma and the difference between white and gray matter. (Nelson Textbook: Page 409-410)
TYPES OF NEURONS • three types: • 1. Sensory Neuron: conducts impulses from sensory receptors (touch, temperature, etc.) towards the brain or spinal cord.
2. Interneurons: act as a relay station between sensory and motor neurons; normally found in the brain and spinal cord.
3. Motor Neurons: conduct impulses from the interneurons to the effectors • neurons conduct impulses or ACTION POTENTIALS in one direction only, from dendrites to the synaptic knobs (Axon Terminal).
neurons can transmit their impulse to another neuron or to a muscle • the point where a neuron comes in contact with another neuron is called a SYNAPSE
the point where a neuron comes in contact with a muscle is called a NEUROMUSCULAR JUNCTION
Handout (Diagram Booklet) • Cells of the Nervous System