bio 15

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bio 15
2012-11-06 19:55:56

feeding and drinking
Show Answers:

  1. 2 ways in which hypothalamus activiates the adrenals

  2. where are the adrenal glands located?
    just above the kidneys
  3. 2 portons of adrenal glands
    cortex and medulla
  4. (adrenal glands)What does cortex secrete?
    hormones cortisol, androgens, and estrognes

  5. (adrenal glands) what does the medulla secrete?
    secretes norepinephrine and epinephrine

  6. when does negative feedback occur?
    when the system responds in an opposite direction to the perturbation

    *maintains homeostasis
  7. (result of activation of adrenals) Cortisol
    -increases blood presusre

    -increases blood sugar level

    -Supresses immune function
  8. (result of activation of adrenals) Epineprine and norepinphrine
    -increase heart rate

    -increase blood pressure
  9. Chronic stress and health
    -chronic stress can hamper ones body
  10. (health) Immune system is responsible for...
    • protecting us against foreign agents
    • *bacteria
  11. (stress can effect immune activity) Short term stressors
    • can enhance immune function
    • *public speaking, athletic contest
  12. (stress can effect immune activity) Long term stressors
    • can depress immune function
    • *unemployment, over-crowding)
  13. example of restraint stress on health
    -increase in circulating levels in glucocorticoids (cortisol)

    -chronic elevations in glucocoricoids will suppress immune fucntion and allow the abcteria to increase and promotoe stomach ulcers
  14. Control reduces...
  15. predictability reduces
  16. What is the hippocampus capable of generating?
    new, functioning neurons called neurogenesis
  17. (stress effects) Stress and Neurogenesis
    • -stress appears to reduce neurogenesis
    • *ex) fox odor exposure to rats, reduced the birth of new cells in hippocampus

    • -*effect is likely mediated by glucocorticoids
    • ***removal of adrenal glands eliminates the effect of stress on nuerogenesis
  18. Hippocampus is critical for...
    -learning and memory as well as providing negative feedback to the HPA axis

    -they also contain neurons that express glucocorticoids receptors
  19. Ghrelin hormone
    -stomach hormone

    -it has been linked to hunger
  20. Ghrelin and feeding behavior
    -ghrelin levels rise and peak before the onset of a meal

    • -ghrelin levels fall after meal consumption
    • *data indicates that there is correlation between ghrelin levels and feeding behavior
  21. When animals get injected with ghrelin...
    they eat
  22. (sections of hypothalamus) Supraoptic nucleus and paraventricular nucleus
    make and package oxytocin and vasopressin
  23. (sections of hypothalamus) medial preoptic nucleus
    -male sexual behavior
  24. (sections of hypothalamus) Ventromedial nucleus
    female sexual behavior
  25. (sections of hypothalamus) Arcuate nucleus
    -feeding behavior
  26. (arcuate hypothalamus-ghrelin) Ghrelin acts on and excites 2 neurons that stimulate feeding behavior
    -Agrp and

  27. Satiety means...
  28. Characteristics of OB/OB mouse
    -ate voraciously

    -incredibly obese
  29. (hormones and feeding-satiety) experiment D
    -2 lean mice

    • *normal insulin
    • *normal blood sugar
    • * <fat pad size
  30. (hormones and feeding-satiety) experiment c, OB/OB + lean
    • Obese
    • - < food intake
    • - < insulinemia
    • - < blood sugar

    • Lean
    • -no change
  31. (hormones and feeding-satiety) experiemtn A, DB/DB + lean
    • DB
    • - >body weight
    • - > adipose tissue mass

    • lean
    • - < food intake
    • - < insulimenia
    • - < blood sugar
    • ***death by starvatiion
  32. (experiments on hormones and feeding) OB/OB mice
    failed to make and release leptin
  33. (experiments on hormones and feeding) db/db mice
    failed to express leptin receptors but made leptin
  34. Leptin deleivered to the periphery or the central nervous system ...
    decreases feeding and body weight
  35. 2 sets of hormones in arcuate hypothalamus

  36. (arcuate hormones) Leptin
    • -works on the other set of neurons to shut off feeding behavior
    • *inhibits
  37. (arcuate hormones) Ghrelin
    stimulates feeding behavior
  38. (more to it than ghrelin and leptin) 3 other reasons for feeding?
    -neural signals


  39. (more to it than ghrelin and leptin) 3 other hormones associated with satiety

    - insulin

  40. (more to it than ghrelin and leptin) 3 other reasons that make satiety happen?
    -neural signals

    - stomach stretching

    -other hormones in play besides leptin
  41. (body fluid homeostasis) What organ carefully monitors blood pressure and sodium levels?
  42. (body fluid homeostasis) if our body fluid becomes too concentrated...
    • we drink more water
    • and concentrate our urine
  43. (body fluid homeostasis) If our body become too diluted...
    we are drive to consume sodium
  44. (body fluid homeostasis) Our kidneys carefully monitor...
    • osmolarity
    • *osmoles of solute/liter of solution
  45. (body fluid homeostasis) Changes in blood pressure can trigger...
    the release of enzymes and hormones
  46. if perfusion of kidney decreases...
    juxtaglomerular cells secrete renin