Histo Lecture 20

  1. Hypothalamus control pituitary secretion via releasing these 4 hormones
    • TRH
    • GnRH
    • CRH
    • GHRH
  2. Thyroid hormones require what for synthesis?
  3. T3 & T4 stimulate transcription of:
    numerous genes
  4. What is the major form of thyroid hormone used for transport in the blood?
  5. What is the most potent form of thyroid hormone?
  6. How do you get goiters?
    Lack of iodine. Results in high levels of TSH and constant stimulation of thyroid gland
  7. What disease can cause goiters?
    Graves' disease
  8. What are some actions of thyroid hormone?
    • Increased oxygen consumption which ups BMR
    • Stimulates glucose absorption in GI tract
    • Stimulates lipolysis and proteolysis
    • Stimulates muscle uptake/use of glycogen
    • Increased CO
  9. _______ is required for normal growth to adult stature
  10. How does TH promote normal growth?
    • Promotes bone formation
    • Promote ossification, bone maturation, fusion of epiphyseal plates
    • Necessary for prenatal CNS development
    • Increases GI motility
    • Maintains sexual function
    • Promotes growth of cartilage, teeth, hair, nails, and epidermis
  11. What are some other stimuli of TRH-TSH-TH?
    • Exposure to cold
    • Excitement
    • Anxiety
  12. Increased levels of TH create negative feedback for what hormones?
    TSH and TRH
  13. What releases growth hormone?
    Pituitary gland
  14. How is GH released?
    pulsatile with secretory bursts every 2 hours
  15. How does GH act?
    Directly on target tissues or stimulates liver production of somatomedins (IGF-1)
  16. What are some conditions that stimulate secretion of GH?
    • Starvation/fasting
    • Trauma
    • Puberty hormones
    • Exercise
    • Excitement
    • Deep sleep
  17. What are some inhibitors of GH?
    • Negative feedback on hypothalamus
    • Somatostatin
    • Somatomedin
    • Increased levels of blood glucose and fatty acids
    • Obesity
    • Aging
  18. Somatomedin has a feedback loop on:
    Hypothalamus and pituitary
  19. GH has multiple metabolic affects on:
    Muscle, liver, adipose tissue, and bone
  20. What are the general actions of GH?
    • Linear growth
    • Protein synthesis
    • Organ growth
    • Carbohydrate and lipid metabolism
  21. What is the Diabetogenic effect?
    • Increases insulin resistance
    • Reduces glucose uptake and utilization
    • Increases lipolysis in adipose tissue
  22. What happens when growth hormone increases protein synthesis?
    • Stimulates increased protein and nucleic acid synthesis
    • Promotes tissue growth
    • Increased lean body mass, increased organ size
  23. What are the two sections of the adrenal gland?
    • Adrenal medulla
    • Adrenal cortex
  24. What does the adrenal medulla release?
    Releases catecholamines
  25. What does the renal cortex release?
  26. What are the three zones of the adrenal gland?
    • Zona glomerulosa
    • Zona fasciculata
    • Zona reticularis
  27. What is the Zona Glomerulosa?
    • Outer most layer
    • secretes mainly aldosterone
    • controlled by angiotensin II and extracellular fluid volume
  28. What is the Zona Fasciculata?
    • Secretes gluccocorticoids
    • Controlled by ACTH (pituitary) and CRH (hypothalamus)
  29. What is the Zona Reticularis
    • Secretes androgens
    • Controlled by ACTH (pituitary) and CRH (hypothalamus)
  30. The adrenal medulla is under direct neural control of what?
    Sympathetic nervous system as part of the "fight or flight" response
  31. What causes cortisol secretion?
    • Trauma, infection, debilitating dieases
    • Intense heat/cold, surgery, full restraint
  32. What are some actions of cortisol?
    • Increases gluconeogenesis and glycogen storage in the liver
    • Increases mobilization of fats from adipose
    • Reduces inflammatory processes; speeds resolution of inflammation
    • Maintains vascular responsiveness to EPI and NOREPI
    • Inihibits bone formation
    • Increases GFR
  33. What are some cortisol actions on sleep?
    • Decreases REM sleep, increases slow wave sleep
    • Increases wake time (burst of release just prior to waking up)
  34. Aldosterone is the major ________
  35. What is aldosterone released in response to?
    low ECF, low BP mainly due to renin-angiotensin II system and serum K+
  36. How does Aldosterone affect ECF and BP?
    Enhances sodium reabsorption in GI tract and from sweat and saliva
  37. What controls release of aldosterone?
    Hypothalamic-pituitary axis
  38. Where are androgens secreted?
    Zona Reticularis
  39. What androgens important for in females?
    Axillary and pubic hair and for libido
  40. What regulates blood calcium and phosphate levels?
    PTH and calcitonin
  41. PTH secretion is stimulated by what?
  42. What releases calcitonin?
    Thyroid gland
  43. Vitamin D is necessary for what?
    bone deposition and resorption
  44. Vitamin D increases calcium absorption where?
  45. What are the three cells types of the Islets of Langerhans?
    • alpha cells - glucagon
    • beta cells - insulin
    • dela cells - somatostatin
  46. What are some islet characteristics?
    • Gap junctions between cell types to allow communication
    • Blood flow allows cells of islets to recognize secretion levels
    • Adrenergic and cholinergic input
  47. What sitmulates insulin secretion?
    • Increased blood glucose concentration
    • Increased amino acid & fatty acid concentration
    • Release of glucagon
    • GH, cortisol, K+
    • Obesity
    • Parasympathetics
  48. What inhibits secretion of insulin?
    • Decreased blood glucose concentration
    • Fasting
    • Exercise
    • Sympathetics
  49. What does the presence of insulin increase?
    • Glucose uptake into cells
    • Glycogen formation
    • Protein synthesis
    • Fat deposition
    • K+ uptake into cells
  50. What does the presence of insulin decrease?
    • Glycogenolysis
    • Gluconeogensis
    • Lipolysis
  51. What stimulates secretion of glucagon?
    • Fasting
    • Decreased blood glucose
    • Increased amino acid
    • CCK
  52. What inhibits secretion of glucagon?
    • Insulin
    • Somatostatin
    • Increased fatty acid
  53. What does glucagon increase?
    • Glycogenolysis
    • Gluconeogenesis
    • Lipolysis
  54. What is the general function of glucagon?
    Liberate stored nutrients for energy utilization
  55. What does somatostatin do?
    • Provides over-riding control of glucagon and insulin secretion
    • Inhibits release of insulin and glucagon
  56. What stimulates release of somatostatin?
    • Ingestion of a meal
    • GI hormones
    • Glucagon
    • Sympathetic system
  57. What inhibits release of somatostatin?
Card Set
Histo Lecture 20
Endocrine Organs and Hormones