Endocrine System

  1. Endocrine System
    • Major Control System
    • Ductless glands; produce hormones
    • Diffuse into blood
    • Slow initial effects, but long persist much longer
    • Hormones act on specific targets
    • Regulated by negative feedback
  2. Endocrine system VS Nervous system
    • Endocrine:
    • Hormones
    • Targets cells with receptors
    • Changes metabolic activity 
    • Slower onset
    • Widespread effects 
    • Slow recovery
    • Nervous:
    • Neurotransmitter
    • Targets neurons muscle, glands
    • Rapid onset 
    • Local and specific effects
    • Rapid recovery
  3. Function of Hormone
    • Modify activity of target cells
    • Targets have specific receptors for specific hormones
    • Distributed by blood
  4. Endocrine glands
    Ductless glands that secret hormones directly into blood stream
  5. Lipid-soluble hormone
    • Steroid Hormones
    • -Lipid derived from cholesterol 
    • -eg. testosterone
  6. Water-soluble Hormones
    • Peptide Hormone
    • Biogenic amines
  7. Peptide Hormone
    • Chains of amino acids 
    • Includes protein hormones (longer chains)
    • Most hormones 
    • eg. Growth hormone
  8. Biogenic Amines
    • Modified Amino acids 
    • eg. thyroid hormone
  9. Negative vs Positive feedback
    • Negative- Occurs when the end product acts to turn off or slow down the pathway
    • Positive- Occurs when the end product stimulates further pathway activity
  10. Location of hormone receptors
    • Intracellular- Cytoplasm, nucleus, (Hormone must be lipid-soluble)
    • Cell Surface- Cell membrane (Hormone must be water-soluble
  11. Organs of Endocrine System
    • Hypothalamus
    • Pituitary (anterior and posterior)
    • Thyroid Gland
    • Parathyroid Gland
    • Adrenal gland (cortex and medulla)
    • Pancreas
    • Pineal gland
    • Thymus
    • Gonads
  12. Hypothalamus
    • Controls anterior pituitary
    • -Releasing hormones stimulate secretion 
    • -Antagonistic inhibiting hormones
    • Secretes & stores hormones in posterior pituitary 
    • Neurally stimulates adrenal medulla (Master controller of ANS)
  13. Anterior Pituitary gland (Adenohypophysis)
    • Glandular/derived from epithelial tissue 
    • Within hypophyseal fossa, sell turcica of sphenoid
    • Attached to hypothalamus via infundibulum 
    • Divided into three regions
  14. Regions of Anterior Pituitary
    • Pars Distalis 
    • Pars intermedia 
    • Pars tuberalis
  15. Pars Distalis
    • Large, anterior portion
    • Source of most hormones
  16. Pars intermedia
    • Thin, between anterior and posterior pituitary 
    • Secretes melanocyte-stimulating hormone
  17. Pars tuberalis
    Wraps around infundibulum
  18. Hormones of Anterior Pituitary
    • Human Growth Hormone 
    • Prolactin
    • Thyroid Stimulating Hormone (TSH)
    • Adrenocorticotropic Hormones (ACTH)
    • Follicle-stimulatin hormone 
    • Luteinizing hormone 
    • Melanoctye-stimulating hormone
  19. Human Growth Hormone (Pituitary)
    • Secreted by: Somatotropic cells in pars distalis
    • Target: All/most body cells (esp bone and muscle)
    • Action: Stimulates liver, muscles, cartilage, bones, other tissues; Promotes growth and repair
  20. Prolactin (Pituitary)
    • Secreted: Mammotropic cells in pars distalis 
    • Target: Mammary glands
    • Action: Initates milk production
  21. Thyroid Stimulating Hormone (TSH)(Pituitary)
    • Secreted: Thyrotropic cells in pars distalis
    • Target: Thyroid Gland
    • Action: Stimulates production of thyroid Hormone
  22. Adrenocortropic Hormone (ACTH)(Pituitary)
    • Secreted: Corticotropic cells in pars distalis 
    • Target: Adrenal Cortex
    • Action: Controls production/Secretion of adrenal cortex hormones
  23. Luteinizing hormone (Pituitary)
    • Secreted: Gonadotropic cell in pars distalis 
    • Target: Gonads (ovaries/testes)
    • Action: Production of gametes & sex hormones
  24. Melaoncyte-stimulating hormone (Pituitary)
    • Secreted: Corticotropic cells in the pars intermedia
    • Target: Melanocytes 
    • Action: Appetite suppression
  25. Posterior Pituitary (Neurophypophysis)
    • Neural rather than glandular
    • Does NOT synthesize Hormones 
    • Consists of pas nervosa & infundibulum
    • Stores and releases two hormones produced by hypothalamus (transported by hypothalmo-hypophyseal tract)
  26. Oxytocin
    • Target:Uterus, mammary glands, smooth muscle in reproductive tract
    • Action: Muscle contraction, milk ejection
    • (synthesized by hypothalamus)
  27. Antidiuretic hormone/Vasopressin
    • Target: Kidney and walls of blood vessels 
    • Action: Conserves water, raises blood pressure
    • (synthesized by hypothalamus)
  28. Thyroid gland
    Two lobes, joined by isthmus
  29. Thyroid Hormone
    • Secreted: Follicular cells in thyroid 
    • Target: Most body cells 
    • Action: RAISE metabolic rate, influence development
  30. Calcitonin
    • Secreted: Parafollicular cells in thyroid
    • Target: Bone, kidney
    • Action: LOWER blood calcium, RAISE calcium deposition in bone
  31. Parathyroid Glands
    • Four small nodes 
    • Posterior thyroid
  32. Parathyroid Hormone
    • Secreted: Chief cells of Parathyroid
    • Target: Bone, small intestine, kidney
    • Action: Increases blood calcium, increase calcium absorption in small intestines, retuen Cato blood from forming urine
  33. Adrenal Glands
    • Superior kidney surface 
    • Two regions: 
    • -Cortex: Outer glandular; 3 zones, each secret different categories of steroid hormones; Helps regulate salt sugar and sex
    • -Medulla: inner, neural
  34. Hormones of Adrenal Cortex
    • Mineralocorticoids
    • Glucocorticoids
    • Gonadocorticoids
  35. Mineralocorticoids (Adrenal)
    • Secreted: Zona Glomerulosa
    • Target: Kidneys 
    • Action: Mineral homeostasis (increase blood Na& Water; decrease K+)
  36. Glucocorticoids (adrenal)
    • Secreted: Zona fasciculata
    • Target: Liver
    • Action: increase lipid & protein metabolism, increase blood glucose, reduce inflammation
  37. Gonadocorticoids (Adrenal)
    • Secreted: Zona reticularis
    • Target: gonads (testes and ovaries)
    • Action: Assist in growth of axillars and pubic hair; contributes to libido in females
  38. Epinephrine&Norepinephrine (Adrenal Medulla)
    • Secreted: Chromaffin cells
    • Target: Many body cells, various organs
    • Action: Intensify sympathetic responses
  39. Glucagon
    • Secreted: Alpha Cells of Pancreas
    • Target: Liver
    • Action: Glycogen breakdown, raising blood glucose
  40. Insulin
    • Secreted: Beta cell of Pancreas
    • Target: Liver, body cells 
    • Action: Promotes glucose transport into cells, decreasin blood glucose
  41. Somatostatin
    • Secreted: Delta Cells in Pancreas
    • Target: Alpha & Beta cells of pancreas
    • Action: Inhibits release of glucagon & insulin
  42. Pancreatic Polypeptide
    • Secreted: F cells 
    • Target: Pancreas, gallbladder 
    • Action: Inhibits digestive secretion
  43. Melatonin
    • Secreted: Pinealocytes of pineal gland 
    • Target:Hypothalamus
    • Action: Promotes sleepiness; may slow sexual maturation
  44. Thymus Gland
    • Deep to sternum; within mediastinum, superior to heart
    • Bilobed 
    • Larger in infants & children, atrophied in adults
  45. Thymosins & Thymopoeitin
    • Secretion: Thymus gland
    • Target: T cells of immune system
    • Action: Promotes development & immunocompetence
Author
michaelirby98
ID
242584
Card Set
Endocrine System
Description
Endocrine System
Updated