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2012-07-20 10:35:27

MCAT Biology
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  1. Growth Hormone (hGH)
    ANTERIOR PITUITARY: increases bone and muscle growth, increases cell turnover rate, rate of mitosis & protein synthesis. 

    Lowers blood glucose and oxidizes fatty acids for energy instead. Lowers the breakdown of protein.
  2. Prolactin

    Normally inhibited by progesterone and estrogen.
  3. Thyroid-stimulating hormone (TSH)
    ANTERIOR PITUITARY -> THYROID: increases synthesis and release of thyroid hormone (tropic)

    Experiences negative feedback effect from T3 and T4  
  4. Adrenocorticotropic hormone (ACTH)
    ANTERIOR PITUITARY -> ADRENAL GLAND: increases growth and secretory activity of adrenal cortex

    Stimulated by stress
  5. Luteinizing hormone
    ANTERIOR PITUITARY -> OVARY/ TESTES: ovulation or testosterone synthesis
  6. Follicle-stimulating hormone (FSH)
    ANTERIOR PITUITARY -> OVARY / TESTES: follicle development or spermatogenesis
  7. Antidiuretic hormone (ADH, vasopressin)
    POSTERIOR PITUITARY -> KIDNEY: water retention

    Increase BP
  8. Oxytocin
    POSTERIOR PITUITARY -> BREAST & UTERUS: milk letdown and uteral contractions
  9. Thyroid hormone (TH, thyroxine)
    THYROID: in the child it is necessary for physical and mental development; in the adult, it increases metabolic rate and temperature

    *Increase the transcription of many genes in many cells in the body
  10. Calcitonin
    THYROID C CELLS -> BONE, KIDNEY, SMALL INTESTINE: lowers serum [Ca2+] by decreasing osteoclast acivity
  11. Parathyroid hormone (PTH)

    Stimulates osteoclast proliferation and Ca2+ resorption
  12. Thymosin
    THYMUS: is involved in T-cell development during childhood.
  13. Epinephrine & Norepinephrine
    • ADRENAL MEDULLA: sympathetic stress response (rapid)
    • Vasoconstrictors of  internal organs and skin but vasodilators of skeletal muscles
  14. Cortisol (glucocorticoid)
    • ADRENAL CORTEX--->results in a longer-term stress response;
    • increased blood [glucose]; stimulates gluconeogenesis in the liver;
    • increased protein catabolism;
    • increased fat catabolism
    • decreased inflammation and immunity

    Steroid (glucocorticoid)
  15. Aldosterone (mineralocorticoid)
    • ADRENAL MEDULLA--> KIDNEY-->Increased Na+ reabsorption to increase blood pressure, K secretion
    • Steroid hormone
  16. Sex steroids
    ADRENAL CORTEX: not normally important, but an adrenal tumor can overproduce these, causing masculinization or feminization.
  17. Insulin
    BETA CELLS OF THE ISLETS OF LANGERHANS IN THE PANCREAS: decreases blood [glucose]; increases glycogen and fat storage; it is activated at high blood [glucose] and is absent or ineffective in diabetes melitus

    Bonds to membrane receptors to exert action and increase permeability to cells to glucose
  18. Glucagon
    ALPHA CELLS OF THE ISLETS OF LANGERHANS IN THE PANCREAS: secreted at low blood [glucose] and results in an increase in blood [glucose] and decrease in glycogen and fat storage

    Stimulates glycogenolysis and glunegenesis in the liver
  19. Somatostatin (SS)
    SIGMA CELLS OF THE ISLETS OF LANGERHANS IN THE PANCREAS: inhibits many digestive processes
  20. Testosterone
    TESTES: male characteristics; spermatogenesis
  21. Estrogen
    OVARIES / PLACENTA: Female characteristics, endometrial growth
  22. Progesterone
    OVARIES / PLACENTA: leads to endometrial secretion, pregnancy
  23. Atrial natriuretic factor (ANF)
    HEART -> KIDNEY: increases urination to decrease blood pressure
  24. Erythropoeitin
    KIDNEY -> BONE MARROW: increases RBC synthesis
  25. Regulation of [Ca2+]
    Parathyroid hormone and Calcitonin
  26. Regulation of blood [glucose]
    Insulin and Glucagon
  27. Milk production and letdown
    Oxytocin and Prolactin
  28. Secreted by the Pancreas
    Glucagon (alpha) & Insulin (beta) & Somatostatin (sigma)
  29. Involved in Pregnancy Prepping
    Oxytocin, Prolactin, Progesterone, Estrogen, LH, FSH
  30. Regulation of B.P.
    Atrial natriuretic factor (ANF) & Aldosterone
  31. Hormones that increase blood [glucose]
    Glucagon (polypeptide derivative), Epinepherine (amino acid derivative), Cortisol (steroid / glucocorticoid)
  32. Difference between endocrine and exocrine glands
    Exocrine glands: release enzymes into environment through ducts

    Endocrine glands: release hormones directly into body fluids, are not released directly to tissues but are released into the general circulation
  33. What kind of gland is the pancreas?
    It is both an endocrine AND an exocrine gland
  34. How do hormones exert their actions on cells?
    By binding to specific cellular receptors, which are found either on the membrane OR within the cell
  35. What are the three types of hormones?
    • 1. Peptide 
    • 2. Steroid
    • 3. Tyrosine derivatives
  36. Where are protein hormones synthesized and how are they processed?
    • 1. Synthesized by the ER as a preprohormone 
    • 2. Cleaved into a prohormone in the ER lumen
    • 3. Sent to Golgi where they are cleaved & modified
    • 4. Secreted into blood stream via exocytosis
  37. Receptors of protein hormones
    May be an ion channel or a second-messenger pathway instigator once hormone binds
  38. What are the steroid hormones?
    1. Aderal cortex - cortisol (glucocorticoid) & aldosterone (mineralcorticoid)

    2. Gonads/placenta - estrogen, progesterone, testosterone
  39. How do steroid hormones exert their actions?
    Require a protein transport to be carried through blood stream. 

    • Freely diffuse through plasma membrane because nonpolar.
    • Combine with a cytosolic receptor to diffuse into the nucleus, where they act at the transcription level.

    Steroids usually affect the synthesis of proteins within the target cell.
  40. What are the tyrosine derivative hormones?
    Thyroid: T3 & T4

    Adrenal Medulla: Catecholamines epinephrine & neuroepinephrine
  41. Where in the cell are tyrosine derivative synthesized?
    Via cytosolic enzymes or on the rER.
  42. Solubility to tyrosine derivatives
    Tyroid hormones = lipid soluble, have long latent period

    Catecholamines: water soluble, act though cAMP
  43. Key for hormone questions
    Remember that hormones RESPOND to irregularities in the body if they arise --- they don't create them! 

    Think about the physiological situation and then think about how the body would then respond to it via hormone release to compensate.
  44. Adrenal ctx vs Adrenal medulla
    Ctx: steroid hormone secretion 

    Medulla: catecholamine secretion
  45. Hormones the thyroid gland secretes
    • 1. T3 & T4
    • 2. Calcitonin