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Nervous system

Nervous system. Nervous system. Nervous system consists of the brain, spinal cord, and nerves. Nervous tissue consists of neurons; whereas the brain and spinal cord contain all parts of neurons, nerves contain only axons. Nervous tissue. dendrite. nucleus. astrocyte. cell body.

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Nervous system

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  1. Nervous system

  2. Nervous system • Nervous system consists of the brain, spinal cord, and nerves. • Nervous tissue consists of neurons; whereas the brain and spinal cord contain all parts of neurons, nerves contain only axons.

  3. Nervous tissue dendrite nucleus astrocyte cell body Microglia Oligodendrocyte axon

  4. Neurons • Motor Neurons • Accept nerve impulses from the Central nervous system (CNS) • Transmit them to muscles or glands • Sensory Neurons • Accept impulses from sensory receptors • Transmit them to the CNS • Interneurons • Convey nerve impulses between various parts of the CNS

  5. CNS & PNS • Central nervous system = Brain + Spinal cord • Peripheral nervous system = Cranial nerves + Spinal nerves (gather info from sensors and conduct decisions to effectors)

  6. Nerves • Structures containing many long fibers with myelin sheath (axons / dendrites) • Nerves do not contain cell bodies

  7. Brain • Cerebrum • Diencephalon • Cerebellum • Midbrain • Pons • Medulla Brain stem

  8. Cerebrum • Cerebral Cortex A thin but highly convoluted outer layer of gray matter • 4 lobes: frontal lobe; temporal lobe; parietal lobe; occipital lobe • White matter The rest of cerebrum except cerebral cortex • Responsible for higher mental capabilities

  9. Diencephalon • A region encircling the 3rd ventricle • Consists of hypothalamus + thalamus + pineal gland • Hypothalamus forms floor of the 3rd ventricle • Thalamus located in the sides and roof of the 3rd ventricle • Pineal gland secretes melatonin • Helps integrate mental functions, primitive emotion and sleep

  10. Cerebellum • Separated from the brain stem by the 4th ventricle • Receives sensory input from the eyes, ears, joints, and muscles • Sends motor impulses out the brain stem to the skeletal muscles • Helps maintain balance and produce smooth movements

  11. Brain stem • Contains the midbrain, the pons, and the medulla oblongata • Midbrain • Acts as a relay station for tracts passing between the cerebrum, and the spinal cord or cerebellum • Pons • Helps regulate breathing and head movements • Medulla oblongata • Contains reflex centers for vomiting, coughing, sneezing, hiccuping, and swallowing

  12. Spinal cord • The center for many reflex actions (involuntary and predictable response to a given stimulus) • Contains white and butterfly-shaped gray matter

  13. Spinal reflexes • A reflex is an involuntary and predictable response to a given stimulus. • The brain is not involved in formulating the response.

  14. dorsal ventral

  15. Experiment • Dissecting sheep brain, observing structure of brain • Observing prepared slides and learning the structure of spinal • Spinal Reflexes page 432

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