BMS100 - Chapter 11: The Endocrine System
    Introduction (p. 277)
  1. The endocrine system is a network of glands that secrete (produce & release) hormones.
  2. Hormones travel in the bloodstream and affect the function of “target cells.”
  3. Target cells have receptors that allow them to respond to specific hormones.
  4. (Exocrine glands, such as sweat glands, etc., secrete through ducts onto a surface or into a cavity.)
    Thyroid Gland (p. 286)
  1. located in neck; contains many microscopic "follicles"
  2. follicular cells "trap" iodine and use it to produce thyroid hormone precursors
  3. the follicles store thyroid hormone precursors
  4. thyroid hormones (thyroxine etc., or “T3 & T4”)
    1. increase metabolic rate (calorie consumption & heat production)
    2. necessary for normal development and function of nervous system
    Parathyroid Glands (p. 288)
  1. on posterior surface of thyroid gland
  2. nerve and muscle function, including heart function, require a precise blood calcium concentration
  3. parathyroid hormone (PTH) increases blood calcium level (if necessary)
    1. PTH promotes calcium absorption in small intestine (how calcium enters the body)
    2. PTH stimulates osteoclasts, cells that break down the bone matrix (where calcium is stored in the body)
    3. PTH prevents calcium loss in kidneys (how calcium leaves the body)
    Adrenal Glands (p. 288)
  1. located atop the kidneys; each adrenal gland consists of a cortex and a medulla
  2. activation is associated with stress (injury, need for extreme physical performance, etc.)
  3. adrenal medulla
    1. secretes epinephrine (= adrenaline) and norepinephrine
    2. effects of epinephrine: increased heart rate, blood pressure, & blood glucose; dilates air passages; etc.)
  4. adrenal cortex produces several steroid hormones
    1. aldosterone causes the kidneys to conserve sodium ions and water (maintain blood volume)
    2. cortisol causes breakdown of fat and protein and increases the blood concentrations of glucose, amino acids and fatty acids
    Pancreas (p. 292)
  1. is both an endocrine gland (secretes hormones) and an exocrine gland (secretes digestive juices)
  2. pancreatic islets = patches of endocrine tissue among the exocrine structures
  3. some hormones of the pancreatic islets
    1. insulin
      1. release is triggered by high blood sugar level
      2. insulin enhances movement of glucose into cells, stimulates carbohydrate and fat storage inside cells, and promotes protein synthesis
      3. result: lowered blood sugar level
    2. glucagon
      1. release is triggered by low blood sugar level
      2. glucagon stimulates the liver to produce glucose
      3. result: elevated blood sugar level
    Pituitary Gland (p. 282)
  1. has an "anterior lobe" and a "posterior lobe"
  2. the hypothalamus controls most pituitary secretions
  3. hormones of anterior pituitary
    1. growth hormone (GH or hGH) stimulates cells to absorb amino acids, produce protein, and enlarge and divide
    2. “tropic hormones” (4) that stimulate other glands (thyroid, gonads, adrenal)
    3. others (stimulate milk production, etc.)
  4. hormones of posterior pituitary
    1. antidiuretic hormone (ADH) reduces the volume of water that the kidneys excrete
    2. oxytocin stimulates uterine contractions and milk ejection
Chapter 11 Questions at OLC - 1, 2, 3, 4, 7, 8, 9, 10, 11, 18, 25, 28, 32, 34, 37, 38, 40
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Fall 2010