Endocrine System

  1. Direct Communication:
    • exchange of ions and molecules between adjacent cells across gap junctions
    • occurs between 2 cells of same type
    • highly specialized and rare
  2. Paracrine Communication
    • uses chemical signals to transfer info from cell to cell within single tissue
    • most common form of intercellular communication
  3. Endocrine communication
    • endocrine cells release chemicals(hormones) into bloodstream
    • alters metabolic activities of many tissues and organs simultaneously
  4. Endocrine system
    • regulates long term processes: growth, developement, reproduction
    • uses chemical (hormone) messengers to relay info between cells
  5. Synaptic communication
    • occurs across synaptic cleft
    • chemical mediator is a neurotransmitter
    • (muscle contraction)
  6. Target cells
    specific cells that possess receptros needed to bind and read hormonal messages
  7. Hormones
    • stimulate synthesis of enzymes/structural proteins
    • increase/decrease rate of synthesis
    • turn existing enzyme/membrane channel on or off
  8. Two classes of Hypothalamic Regulatory Hormones
    • Releasing hormones
    • Inhibiting hormones
  9. Releasing Hormones
    stimulate synthesis and secretion of one/more hormones at anterior lobe
  10. Inhibiting hormones
    prevent synthesis and secretion of hormones from anterior lobe
  11. Anterior Lobe
    • aka Adenohypophysis
    • divided into 3 regions: pars distalis, intermedia, tuberalis
  12. Thyroid Stimulating Hormone
    secretion of thyroid hormones
  13. Adrenocorticotropic hormone
    secretion of glucocorticoids (cortisol, corticosterone)
  14. Follicle Stimulating Hormone
    • secretion of estrogen, follicle developement
    • stimulation of sperm maturation
  15. Luteinizing Hormone
    • ovulation, formatio of corpus luteum
    • secretion of progesterone
    • secretion of testosterone
  16. Prolactin
    mammary glands for production of milk
  17. Growth hormone
    growth, protein synthesis, lipid mobilization and catabolism
  18. Melanocyte-Stimulating hormone
    increased melanin synthesis in epidermis
  19. Antidiuretic Hormone
    reabsorption of water, elevation of blood volum and pressure
  20. Oxytocin
    • labor contractions, milk ejection
    • contraction of ductus deferens and prostate gland
  21. Relationship between anterior pituitary and hypothalamus
    • 1. When stimulated, hypothalamic neruons secrete releasing/inhibiting hormones into primary capillary plexus
    • 2. hypothalamic hormones travel through portal veins to anterior pituitary either stimulating/inhibitng hormones
    • 3. Anterior pituitary hormones secreted into secondary capillary plexus
  22. Relationship between posterior pituitary and hypothalamus:
    • 1. Hypothalamic neurons synthesize oxytocin and ADH
    • 2. Oxytocin and ADH are transported along hypothalamic-hypophyseal tract to posterio pituitary
    • 3. Oxytocin and ADH are stored in axon terminals
    • 4. Oxytocin and ADH release into blood when hypothalamic neurons fire
  23. Effects of Thyroid Hormones:
    • 1. Elevates rates of oxygen consumption and energy consumption in children
    • 2. increased heart rate and force of contraction, rise in BP
    • 3. increased sensitivity to sympathetic stimulation
    • 4. maintenance of normal sensitivity of respiratory center to changes in oxygen and CO2 concentrations
    • 5. Stimulation of red blood cell formation and thus enhanced oxygen delivery
    • 6. Stimulation of activity in other endocrine tissues
    • 7. Accelerated turnover of minerals in bone
  24. Follicular/Epithelium
    increases energy, oxygen consumption, growth, development
  25. C cells
    decreases Calcium concentrations in body fluids
  26. Parathyroid (Chief) cells
    increases Calcium concentrations in body fluids
  27. Zona Glomerulosa
    • Mineralcorticoids
    • Aldosterone: regulate electrolyte concentration in extracellular lfuids particularly of Sodium and Potassium
  28. Zona Fasciculata
    • Glucocorticoids
    • cotisol: influence energy metabolism of most body cells and help us resist stressors , adapt to food intake by keeping glucose levels constant
    • inhibits activites of white blood cells: anti-infammatory effect
    • *Inhibitory: Corticotopin releasing hormone and ACTH
  29. Zona Reticularis
    • network of endocrine cells
    • Produces androgens
  30. Suprarenal Medulla produces _____ and ______ and what are the % of the secretions?
    • epinephrine: 75-80%
    • norepinephrine: 20-25%
  31. Cushions Syndrome
    • Too much cortisol
    • buffalo hump, round face
    • tendency to bruise and poor wound healing
  32. Kidneys Hormonal Effects
    • Stimulates red blood cell production
    • " calcium and phosphate absorption
    • Calcium release from bone
  33. Heart Hormonal Effects
    • increase water and salt loss at kidneys
    • decrease thirst
    • suppress secretion of ADH and aldosterone
  34. Thymus
    coordinate and regulate immune response
  35. Adipose Hormonal Effects
    suppression of appetite; permissive effects on GnRH and gonadotropin synthesis
  36. Steroid Hormones
    • Adrenal Cortex layes
    • Estrogen
    • Progesterone
    • Calcitrol from Kidney
    • Calciferol from skin
  37. Steroid Hormones attach to segment of ____ which undergoes transciption and ____ results in new protein being made.
  38. Humoral Control
    • cells of gland monitor blood levels and secrete hormone in response to decrease
    • ex: parathyroid-Calcium levels
    • pancreas-Glucose
  39. Neural Control
    • hormones release by nerve stimulation
    • ex: adrenal Medulla-epinephrine
  40. Hormone Stimuli
    • most hormones release hormones in response to other hormones attaching to target cells on their glands
    • ex: anterior pituitary: releasin and inhibin from hypothalamus
Card Set
Endocrine System
Endocrine System