physiology test #2 topic 6

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physiology test #2 topic 6
2013-09-24 19:44:44

Central nervous system
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  1. Central nervous system
    Brain and Spinal Cord
  2. Peripheral Nervous System
    • Afferent Division (sends info to CNS)
    • Efferent Division (receives info from CNS)
  3. Efferent Division leads into the
    • Somatic Nervous system
    • Autonomic nervous system
  4. Autonomic nervous system leads into the
    Sympathetic nervous system and the Parasympathetic nervous system
  5. Three classes of neurons
    • Afferent neurons
    • efferent neurons
    • interneurons
  6. Afferent neurons
    • have sensory receptors
    • axon terminals in CNS
    • send info to CNS from body
  7. efferent neurons
    • cell body in CNS
    • axon terminals in effector organ
    • send info from CNS to body
  8. Interneurons
    • a)  lie within CNS
    • b)  some connect afferent neurons and efferent neurons
    • (1) integrate peripheral responses and peripheral
    • information

    • c) some connect other interneurons
    • (1) responsible for activity of the “mind”, i.e., thoughts,

    • emotions, motivation, etc.
    • d) 99% of all neurons are interneurons
  9. The brain
    Gross structure and Associated functions
  10. Brain Stem
    • 1. critical connecting link between entire brain and spinal cord
    • 2. cranial nerves 3-12 emerge from brain stem
    • 3. integrative functions: sleep/wake cycle control, cardiovascular control, respiratory control, digestive control, regulation of muscle reflexes, arousal and activation of cerebral cortex
  11. Cerebellum- "little brain"
    • 1. important for motor control... does not initiate but involved with coordination, precision and accuracy of voluntary muscle activity
    • 2. maintenance of balance
    • 3. enhancement of muscle tone
    • 4. damage- ability to carry out movement but without coordination, is misdirected and may have inapporiate force
  12. Hypothalamus
    • 1. regulation of many homeostatic functions and associated behaviors
    •  - body temp, thirst and urine output, food intake, uterine contraction and milk production
    • 2. link between nervous and endocrine systems via Pituitary Gland
    • - smooth and cardiac muscle control, exocrine gland control
    • 3.involved in emotion and basic behavior patterns
  13. Thalamus
    • 1. Relay station and filter for all input to the cerebral cortex
    • 2. crude awareness of sensation
    • 3. some degree of consciousness
    • 4. role in motor control
  14. Cerebrum
    • 1. Basal nuclei
    • - inhibition of muscle tone, coordination of slow sustained movement, suppression of useless movement patterns
    • 2. Cerebral cortex
    • - sensory perception, voluntary control of movement, language, personality, consciousness and sophisticated mental events (thinking, memory, etc)
  15. Limbic system
    • 1. Not a separate structure
    • 2. Includes interconnected portions of 
    •     - cerebral cortex, basal nuclei, thalamus, hypothalamus
    • 3. involved in generating emotions and formulating memories
  16. Neural basis of some human behaviors
    • language and speech
    • emotions
    • memory
  17. Language and speech
    processed in multiple areas of cerebral cortex
  18. Emotions
    • a. generated by the limbic system which attaches "feelings" to basis survival-ralted programs of the brainstem including feeding, aggression and sexuality 
    • b. at birth primates have sufficient emotional circuits to bond to a caretaker, to recognize a face, have visual and vocal interactions with caretaker. As a child develops and emotional memories laid down more complex emotions become possible.
  19. memory: short term
  20. in frontal lobes of cortex, rely on rapid changes in strength of existing nerve connections
  21. memory: long term
  22. involves limbic system and requires new connections among neurons; this is accomplished by practice and consolidation
  23. Support of the brain
    Glial cells
  24. Four types of glial cells
    • 1. Astrocytes
    • 2. Microglia
    • 3. Oligodendrocytes
    • 4. Schwann Cells
  25. 90% of cells in CNS are not neurons but are
    glial cells
  26. Glial cells only occupy _____ percent of brain volume
  27. Glial cells do not
    initiate or conduct nerve impulses
  28. Glial cells support
    CNS neurons physically, metabolically and homeostatically
  29. Brain carefully shielded from harmful blood changes
    prevents changes in blood ions and molecules from adversely affecting brain
  30. A normal capillary has pores in its walls for..
    easy passage of materials
  31. Brain _______ have tight junctions that prevent ____________.
    Capillaries, passage of materials
  32. Only small lipid soluble substances can...
    diffuse through capillary membrane
  33. All other molecules must be transported into brain by...
    carrier proteins
  34. The brain can only make ATP:
    • from glucose (no other sugars or fats)
    • in the presence of 02
  35. What is the brain dependent on
    constant supplies of glucose and O2.
  36. 4-5 min without O2 or 10-15 min without glucose =
    brain damage and then death
  37. Spinal Cord structure
    • 1. Whole cord (Figs 9.6 & 9.7)
    • a) 31 pairs of nerves

    • 2. Cross section (Fig 9.8)
    • a) gray matter
    • (1) cell bodies, dendrites, short interneurons, glial cells

    • b) white matter
    • (1)  mylenated axons organized into tracts (bundles of axons)
    • (2)  some are ascending (to brain) and some aredescending (from brain)
    • (3)  like packaged phone lines
  38. Spinal cord function
  39. 1. Carries and supports neurons (both afferent and efferent) between brain and body (Fig 9.8)
    2. Reflex Arc (Fig 9.18, 9.20)
  40. a) Reflex for neural pathways (ex: knee-jerk reflex, papillary
    light reflex, etc.)