A&P Chapter 23 Nervous System


Published on

Published in: Health & Medicine
1 Comment
No Downloads
Total views
On SlideShare
From Embeds
Number of Embeds
Embeds 0
No embeds

No notes for slide

A&P Chapter 23 Nervous System

  1. 1. Chapter 23 A&P The Nervous System
  2. 2. Introduction <ul><li>The nervous system is the body’s information gather, storage center and control system. </li></ul><ul><li>It controls, directs and coordinates body functions. </li></ul><ul><li>The nervous system is divided into the central nervous system and the peripheral nervous system. </li></ul>
  3. 3. Objectives <ul><li>Identify the structures that make up the nervous system. </li></ul><ul><li>Explain how nerve impulses are transmitted. </li></ul><ul><li>State the functions of the central nervous system, the peripheral nervous system and the autonomic nervous system. </li></ul><ul><li>Identify disorders associated with the nervous system. </li></ul><ul><li>Lifespan considerations. </li></ul>
  4. 4. Neurons, Nerve Fibers, Nerves and Tracts
  5. 5. Neurons / Nerve Cell <ul><li>All nervous system tissue is made up of nerve cells, called neurons, and their supporting tissues called neuroglia. </li></ul><ul><li>These cells allow the body to interacts with its internal and external environments. </li></ul><ul><li>There are 3 types of neurons: motor (doers), sensory (sensors) and interneurons (communicators). </li></ul>
  6. 6. Motor Neurons <ul><li>Motor neurons cause muscles to contract and glands to secrete, and organs to perform their functions. </li></ul><ul><li>They can also inhibit these actions. </li></ul><ul><li>Motor neurons are also known as efferent meaning they carry messages away from the cell body to the muscles and organs. </li></ul>
  7. 7. Motor neuron <ul><li>Motor neurons have a nucleated cell body with process extending away from the cell body. </li></ul><ul><li>These nerve fibers are called axons and dendrites. </li></ul><ul><li>Dendrites carry impulses to the cell body and the axon carries impulses away from it. </li></ul>
  8. 8. Motor neurons <ul><li>Most axons are covered with a fatty insulating substance called the myelin sheath. </li></ul><ul><li>Axons with myelin sheath transmit impulses faster than those without. </li></ul><ul><li>Damage to unmyelinated cells is usually permanent. </li></ul><ul><li>The axon and dendrites allow neurons to communicate. </li></ul>
  9. 9. What does this mean? <ul><li>Hit your thumb with a hammer and the motor neurons allow you to pull back you hand. </li></ul><ul><li>Smell fresh baked bread and your mouth waters. </li></ul><ul><li>Dust in your eye causes you to blink. </li></ul>
  10. 10. Sensory neurons <ul><li>The second types of nerve cell is known as the sensory neuron or afferent neurons. </li></ul><ul><li>Sensory neurons have sensor receptors that allow transmission or impulses, or messages, to the central nervous system. </li></ul><ul><li>Therefore our ability to feel the hammer, smell the bread or feel the discomfort from the dust. </li></ul>
  11. 11. Interneurons <ul><li>Third type of nerve cell. </li></ul><ul><li>Found in the central nervous system and mediate impulses between the motor and sensory neurons. </li></ul>
  12. 12. Nerve fibers, Nerves and Tracts <ul><li>A nerve is a bundle of nerve fibers, located outside the brain and spinal cord, that connect various parts of the body. </li></ul><ul><li>Sensory nerves carry messages to the CNS (brain) and the motor nerves carry messages away from the CNS. </li></ul><ul><li>Groups of nerve fibers within the CNS are known as tracts. </li></ul>
  13. 13. Nerve Impulses <ul><li>Chemical neurotransmitters are stored in the axon terminals. </li></ul><ul><li>The space between neurons is called a synapse. </li></ul><ul><li>Information is received in the dendrite, passed through the cell body, travels down the axon and over the synapse to the next dendrite. </li></ul>
  14. 14. The Central Nervous System Brain Cerebrum Largest part of the brain Thought intelligence Cerebellum Regulates & Coordinates Body movement Brainstem Connects Cerebrum To spinal cord Spinal Cord Conducts info To & from the brain. Protected by Meninges Dura Matter Arachnoid Pia Matter
  15. 15. The Peripheral Nervous System <ul><li>The peripheral nervous system has 12 pairs of cranial nerves and 31 pairs of spinal nerves. </li></ul><ul><li>Peripheral nerves with special functions for the autonomic nervous system. </li></ul>
  16. 16. Cranial Nerves <ul><li>The cranial nerves conduct impulses between the brain and the head, neck, chest and abdomen. </li></ul><ul><li>Impulses for smell, vision, hearing, pain, touch, temperature and pressure, voluntary and involuntary muscles control. </li></ul>
  17. 17. Peripheral Nervous Stsyem <ul><li>Spinal nerves carry impulses from skin, extremities and internal body structure not supplied by cranial nerves. </li></ul>
  18. 18. Autonomic Nervous System <ul><li>Controls involuntary muscles and functions including heartbeat, blood pressure, intestinal contractions and glandular secretions. </li></ul>
  19. 19. Autonomic Nervous System <ul><li>Sympathetic </li></ul><ul><li>Speeds up functions </li></ul><ul><li>Stimulated with exercise </li></ul><ul><li>Stimulated with anger, excitement or fear. </li></ul><ul><li>Parasympathetic </li></ul><ul><li>Slows down functions </li></ul><ul><li>Activated with relaxation </li></ul><ul><li>Activated when under stimulated for too long </li></ul>
  20. 20. What happens with fear?
  21. 21. The Sensory System