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  • 1. Endocrine Glands Hypothalamus Pineal gland Pituitary gland Thyroid gland Parathyroid glands Adrenal glands Pancreas Ovary (female) Testis (male)

2. Chemical Classification of Hormones

  • Aminehormones are derived from tyrosine or tryptophan
    • Include NE, Epi, thyroxine, melatonin
  • Polypeptide/proteinhormones are chains of amino acids
    • Include ADH, GH, insulin, oxytocin, glucagon, ACTH, PTH
    • Glycoproteins include LH, FSH, TSH
  • Steroidsare lipids derived from cholesterol
    • Include testosterone, estrogen, progesterone & cortisol

3. Water Solubility

  • Polar
    • water soluble. Cannot pass through cell membrane
    • Polypeptides, glycoproteins, most amines
  • Nonpolar (lipophilic)
    • Insoluble in water but soluble in lipid
    • Can pass through cell membrane
    • Steroids and thyroid hormone

4. Common Aspects of Neural & Endocrine Regulation

  • Target cells withreceptorproteins that combine with the regulatory molecule
  • The binding causes a specific sequence of changes in target cell ( Signal transductionleads toresponse )
  • There exists mechanisms to quickly turn off the action of the regulator
    • rapid removal or chemical inactivation
    • There is an OFF switch as well as an ON switch

5. Mechanisms of Hormone Action 6. Lipophilic hormones

  • Pass through cell membrane
  • Bind to intracellular receptors
  • The hormone-receptor complex acts as a Transcription factor. It activates a gene to make an mRNA from which an enzyme protein is made. This enzyme will in some way change the metabolism of the target cell.

7. Hormones That Bind to Nuclear Receptor Proteins

  • Lipid hormones travel in blood attached to carrier proteins
    • They dissociate from carriers to pass thru plasma membrane of target
      • Receptors are located in the cytoplasm or nucleus

8. Polar hormones

  • Water soluble hormones use cell surface receptors because cannot pass through plasma membrane
    • Actions are mediated by 2nd messengers
    • Hormone is extracellular signal; 2nd messenger carries signal from receptor to inside of cell
  • Some second messengers include:
    • cAMP
    • Phospholipase C
    • Tyrosine kinase
    • Calcium ions

9.

  • Mediates effects of many polypeptide & glycoprotein hormones
  • Hormone binds to receptor causing dissociation of a G-protein subunit

Adenylate Cyclase-cAMP 10. Hypothalamus 11. Hypothalamus

  • Hypothalamus produces ADH and Oxytocin that are transported to the posterior pituitary for release. (more on these later)
  • Controls the pituitary gland via a variety of releasing and inhibiting factors.
    • TRH thyrotropin releasing hormone
    • GHRH growth hormone releasing hormone
    • CRH corticotropin releasing hormone
    • Prolactin inhibiting hormone
    • Etc. etc.

12. Pituitary Gland 13. Pituitary Gland

  • Pituitary gland is located beneath hypothalamus

14. Posterior Pituitary

  • Stores & releases 2 hormones produced in hypothalamus:
    • Antidiuretic hormone( ADH/vasopressin ) which promotes H 2 0 conservation by kidneys
    • Oxytocinwhich stimulates contractions of uterus during parturition & contractions of mammary gland alveoli for milk-ejection reflex

Hypothalamus Neurosecretory cells of the hypothalamus Axon Anterior pituitary Posterior pituitary HORMONE ADH Oxytocin TARGET Kidney tubules Mammary glands, uterine muscles 15. Anterior Pituitary

  • Secretes 6trophichormones that maintain size of targets
    • High blood levels cause target to hypertrophy
      • Low levels cause atrophy

16. Anterior Pituitary

  • Growth hormone ( GH ) promotes growth, protein synthesis, & movement of amino acids into cells
  • Thyroid stimulating hormone( TSH ) stimulates thyroid to produce & secrete T 4& T 3
  • Adrenocorticotrophic hormone( ACTH ) stimulates adrenal cortex to secrete cortisol, aldosterone

17. Anterior Pituitary

  • Follicle stimulating hormone( FSH ) stimulates growth of ovarian follicles & sperm production
  • Luteinizing hormone( LH ) causes ovulation & secretion of testosterone in testes
  • Prolactin( PRL ) stimulates milk production by mammary glands

18. Anterior Pituitary

  • Other hormones/products of the pituitary gland include:
    • MSH- influences skin pigmentation in some vertebrates and fat metabolism in mammals
    • Endorphins -inhibit the sensation of pain

19. Pituitary Regulation

  • Release of A. Pit. hormones is controlled by
    • Hypothalamicreleasing&inhibiting factors
    • Feedbackfrom levels of target gland hormones
    • Higher brain centers (via the hypothalamus)

20. Anterior Pituitarycontinued

  • Releasing & inhibiting hormones from hypothalamus are released from axon endings into capillary bed inmedian eminence
    • Carried byhypothalamo-hypophyseal portal systemdirectly to another capillary bed in A. Pit.
      • Diffuse into A. Pit. & regulate secretion of its hormones

21. Feedback Control of Anterior PituitaryTarget glands produce hormones that feedback to regulate the anterior pituitary and the hypothalamus 22. Higher Brain Function & Anterior Pituitary Secretion

  • Hypothalamus receives input from higher brain centers that can affectPituitary secretion
    • E.g. psychological stress affects circadian rhythms, menstrual cycle, & adrenal hormones

23. Adrenal Gland 24. Adrenal Glands

  • Sit on top of kidneys
  • outer cortex
  • inner medulla

25. Adrenal Glands

    • Adrenal Cortex
      • Mineralocorticoids
        • Aldosteronewhich stimulate kidneys to reabsorb Na +and secrete K
      • Glucocorticoids
        • Cortisolwhich inhibits glucose utilization & stimulates gluconeogenesis. Inhibits inflammation, Supresses the immune system

26. Adrenal Medulla

  • Secretes Epinephrine and Norepinephrine
    • "fight or flight" response
      • causes:
        • Increased respiratory rate
        • Increased HR & cardiac output
        • General vasoconstriction which increases venous return
        • Glycogenolysis & lipolysis
        • Etc, etc, etc

27. Stress 28. Diseases associated with Adrenal hormone levels

  • Cushings disease
    • Hyperadrenocorticism
      • widened face with acne and flushing
      • fatty deposits over back of neck
      • stretch marks, easy bruising, hair overgrowth
      • diabetes mellitus
      • muscle loss and fatigue
      • depression and psychosis
      • moon-like face,
  • Addisons disease
    • Hypoadrenocorticism
      • Hyperpigmentation, weight loss

29. Thyroid Gland 30. Thyroid Gland

  • Is located just below the larynx
  • Secretes T 4& T 3which set BMR & are needed for growth, development
  • Also secretes Calcitonin which lowers blood calcium levels

31.

  • Hypothyroidism

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