Unit 13 nervous system


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Unit 13 nervous system

  1. 1. The Nervous System
  2. 2. I. The Nervous System <ul><li>A. Two main divisions : </li></ul><ul><li>The Central Nervous System (CNS) </li></ul><ul><li>The Peripheral Nervous System (PNS) </li></ul>
  3. 4. B. The CNS <ul><li>1. Two main parts: </li></ul><ul><li>The Brain : the main switch where impulses originate and flow. </li></ul><ul><li>The Spinal Cord : the link between the brain and the rest of the body. </li></ul>
  4. 5. C. The Brain <ul><li>1. MAJOR DIVISIONS </li></ul><ul><ul><li>Cerebrum : part of the brain responsible for all voluntary activities of the body. </li></ul></ul><ul><ul><ul><li>Lobes </li></ul></ul></ul><ul><ul><ul><ul><li>Frontal - personality </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Temporal - auditory </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Parietal – integrates senses </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Occipital – visual area </li></ul></ul></ul></ul>
  5. 6. <ul><ul><li>Cerebellum : part of the brain that coordinates and balances the actions of muscle </li></ul></ul><ul><ul><li>Brainstem : structure that connects the brain with the spinal cord; controls involuntary functions ex. breathing, heart rate coughing; coordinates and integrates all the information coming into the brain. </li></ul></ul>
  6. 7. Lobes of the Brain temporal frontal parietal occipital Central Nervous System brain spinal cord cerebellum brainstem medulla oblongata Page 35 in UP
  7. 8. D. The PNS <ul><li>1. Two major divisions </li></ul><ul><li>Sensory : transmits impulses from the sense organs to the CNS </li></ul><ul><li>Motor : transmits impulses from the CNS to the muscle or glands </li></ul>
  8. 9. E. Motor Divisions in the PNS <ul><li>Autonomic : regulates involuntary activities. </li></ul><ul><ul><li>Sympathetic nervous system : stimulates fight-or-flight reactions; gas pedal </li></ul></ul><ul><ul><li>Parasympathetic nervous system : stimulates calmer functions such as digestion; break </li></ul></ul><ul><li>Somatic : regulates activities under conscious control such as muscle movement and reflexes. </li></ul>
  9. 10. F. Neurons <ul><li>Cells that carry messages throughout the nervous system. </li></ul><ul><li>Types </li></ul><ul><li>Sensory Neurons: carry impulses from the sense organs to the brain and spinal cord. </li></ul><ul><li>Motor Neurons: carry impulses from the brain and spinal cord to muscles or glands. </li></ul><ul><li>Interneurons: (association) connect sensory and motor neurons and carries impulses between them. </li></ul>
  10. 11. motor neuron sensory neuron
  11. 14. <ul><li>3. Parts of a motor neuron </li></ul><ul><ul><li>cell body </li></ul></ul><ul><ul><li>nucleus </li></ul></ul><ul><ul><li>dendrites </li></ul></ul><ul><ul><li>axon </li></ul></ul><ul><ul><li>myelin sheath (schwann cells) </li></ul></ul><ul><ul><li>motor end plate </li></ul></ul><ul><ul><li>motor end brush </li></ul></ul>
  12. 15. cell body nucleus axon myelin Effector (muscle) motor end plate end brush { dendrite cytoplasm Page 32
  13. 16. G. Impulses moves along a neuron <ul><li>Resting Potential : the difference in charge across a nerve cell membrane resulting from the negative charge on the inside and the positive charge on the outside = polarized </li></ul><ul><li>Threshold : A minimum level of a stimulus required to activate a neuron. </li></ul>
  14. 18. <ul><li>Action Potential : changes in membrane potential that characterize a nerve impulse. the depolarization and repolarization of the membrane. </li></ul><ul><ul><li>Myelin : substance composed of lipids and protein than forms an insulated sheath around an axon. It increases the rate of the impulse. </li></ul></ul>
  15. 19. depolarization depolarization repolarization repolarization depolar.
  16. 20. a b c d e f g h <ul><li>synapse </li></ul><ul><li>neurotransmitter </li></ul><ul><li>axon terminal </li></ul><ul><li>myelin </li></ul><ul><li>axon </li></ul><ul><li>cell body </li></ul><ul><li>dendrite </li></ul><ul><li>receptor </li></ul>answers Identify the parts of the neuron What direction does the impulse travel? Page 34
  17. 21. H. Stimulation of a neuron <ul><li>Receptors : special sensory neurons in sense organs that receive stimuli from the external environment. </li></ul><ul><li>Effectors : muscle or glands that bring about a coordinated response. </li></ul>
  18. 22. <ul><li>Synapses : points of near contact which impulses are chemically passed from one neuron to another. </li></ul><ul><li>Neurotransmitters : chemicals located within vesicles that are used by the neuron to signal another. </li></ul><ul><ul><li>Example = acetyl choline, </li></ul></ul>
  19. 23. I. Simple Reflex Arc <ul><li>Sensory neuron : neuron that carries impulses from the sense organs to the brain and/or spinal cord. </li></ul><ul><li>Interneuron : (association) cell that connects sensory and motor neurons and carries impulses between them. </li></ul><ul><li>Motor neuron : neuron that carries impulses from the brain and/or spinal cord to muscles and glands. </li></ul>
  20. 25. sensory neuron cell body (sensory neuron) receptors synapse synapse motor neuron effector (muscle) association neuron Label the diagram Page 33
  21. 26. More on the brain…. <ul><li>The human brain has a continuous electrical activity </li></ul><ul><li>Can be recorded by an electroencephalogram (EEG) </li></ul><ul><li>Used to diagnose diseases of the brain, such as epilepsy, brain </li></ul><ul><li>tumors, stroke and </li></ul><ul><li>sleep disorders </li></ul>
  22. 27. EEG activity…. <ul><li>Changes in different situations </li></ul>
  23. 28. What is “brain death?” <ul><li>Irreversible cessation of all brain activity for a period of 24 hours, so that cardiopulmonary functions must be artificially maintained </li></ul><ul><li>Criteria: </li></ul><ul><ul><li>Deep, irreversible coma </li></ul></ul><ul><ul><li>Absence of spontaneous movements </li></ul></ul><ul><ul><li>Lack of response to most painful stimuli </li></ul></ul><ul><ul><li>Lack of respiration when disconnected from ventilator for three minutes </li></ul></ul><ul><ul><li>Absence of brain waves </li></ul></ul><ul><ul><li>Lack of cranial reflexes </li></ul></ul>
  24. 29. J. Diagnostic Techniques <ul><li>A. MRI – magnetic resonance imaging; computer controlled radio waves and very big magnets, 25,000 times stronger than the earth’s atmosphere; can’t use with </li></ul><ul><li> pacemakers </li></ul><ul><ul><li>Page 25 in Unit 13 packet </li></ul></ul><ul><ul><ul><li>Diagram </li></ul></ul></ul><ul><ul><ul><li>Machine types </li></ul></ul></ul><ul><ul><ul><li>Images – knee, brain </li></ul></ul></ul><ul><ul><ul><li>Image series of head </li></ul></ul></ul><ul><ul><li>Images tissues and not bones or teeth </li></ul></ul>
  25. 31. open standing knee
  26. 34. <ul><li>B. CT – computerized tomography </li></ul><ul><ul><li>Page 27 in Unit 13 packet </li></ul></ul><ul><ul><ul><li>Machine </li></ul></ul></ul><ul><ul><ul><li>Images – kidney </li></ul></ul></ul><ul><ul><li>Series of x-ray images, can produce 3-d images; analysis on the basis of tissue density, bone – white, gas and liquids – black, tissue various forms of grey </li></ul></ul><ul><ul><li>Used to diagnose tumors </li></ul></ul><ul><li>C. Sonogram </li></ul><ul><ul><li>Page 26 in Unit 13 packet </li></ul></ul><ul><ul><li>First used in WWII to locate submerged objects </li></ul></ul><ul><ul><li>Uses ultra sound to image internal organs </li></ul></ul>