5/10 Nervous system revised
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Transcript of 5/10 Nervous system revised
The Nervous System
Role of the nervous system
• respiratory center• defense (ex: pain stimuli)• relay information (ex: hunger, full bladder)
Functions of the nervous system
• receives information • interprets the information• makes the body respond or react
Nerve cell
Structure and Functions –Nerve cell
• also called neuron• scattered throughout the body• born with all the neurons that you would need
(none grows or regenerates)
Parts of a neuron
• dendrites• axon• nucleus• cytoplasm• interneurons*
*HW: 1) What are interneurons? 2) What is a soma/perikaryon?
Axon
• threadlike structure• carries impulses away from the nerve cell
body• may have a myelin sheath (myelinated)
Dendrites
• looks like fibers branching out• receives impulses or stimuli
Afferent or Efferent? Sensory or Motor?
• Pick up information, sends it to CNS• From CNS, sends out orders
Structure and Functions- Neuroglia
• Also called glia• Does not transmit impulses• For protection and nourishment
Kinds of Glia
• Astrocytes –pass nutrients between blood capillaries and neurons
• Microglia – engulf foreign materials and bacteria
• Oligodendroglia, Schwann cells*- insulate axons of neurons
*HW: Are oligodendroglia and Schwann cells the same thing?
Central nervous system
• brain• spinal cord
Brain
• cerebrum• cerebellum• brain stem• diencephalon
Spinal Cord
Peripheral Nervous System
• cranial nerves• spinal nerves• peripheral nerves
Autonomic Nervous System
• Sympathetic • Parasympathetic
• (I) O• (II)* O• (III) O• (IV) T• (V) T• (VI) A• (VII) F• (VIII) A• (IX) G• (X) V• (XI) S• (XII) H
– Olfactory (I) – sensory (olfactory)– Optic (II) – not a true nerve– Oculomotor (III) – motor (extrinsic eye muscles)– Trochlear (IV) – motor (extrinsic eye muscles)– Trigeminal (V) – sensory &motor (skin of head, teeth, jaws)– Abducens (VI) – motor (extrinsic eye muscles)– Facial (VII) – sensory (taste buds) & motor (2nd hyoid arch)– Auditory (VIII) – aka octaval; sensory (inner ear)– Glossopharyngeal (IX) – sensory (taste buds, gill pouches) & motor (3rd hyoid
arch)– Vagus (X) – sensory & motor (mouth, pharynx, viscera)– Spinal Accessory (XI) – motor (mastoids, trapezius)– Hypoglossal (XII) – motor (hyoid and tongue muscles)