Physiology Unit 2

  1. What are endocrine organs?
    Endocrine organs are anything that secretes a hormone.
  2. Differentiate between primary and secondary endocrine organs
    • Primary endocrine organs are organs that their primary purpose is to secrete hormones
    • Secondary endocrine organs are organs that does something else as its primary function, but also does secrete hormones.
  3. Examples of Primary endocrine organs
    • Hypothalamus
    • pituitary gland
    • pineal gland
    • thytoid gland
    • parathyroid gland
    • thumus
    • adrenal gland
    • pancreas
    • gonads
  4. Examples of secondary endocrine hormones
    • Heart
    • liver
    • stomach
    • skin
    • small intestine
    • kidney
  5. Describe in general the functional relationship bt the hypothalamus and pituitary gland
    • They function together to regulate virtally every body system
    • Most hypothalamic hormones act on the pituitary
    • Pituitary gland containes two functionally and structurally different sections
    • - Anterior (adenohypophysis)
    • - Posterior (neurohypophysis)
  6. Anterior lobe of pituitary is AKA
  7. Posterior pituitary AKA
  8. Hypothalamic- ant. pituitary interactions
    • Hormones are secreted from neurosecretory cells in hypothalamus into blood
    • These hormones are then transported through the H-P portal system to the ant. pituitary
    • They stimulate the anterior pituitary to secrete hormones
  9. Hypothalamic-post pituitary interactions
    • - Oxytocin and ADH (aka vasopressin) are synthesized in the hypothalamus , packaged, and transported to neural endings in the post pit.
    • - Hormones are released from the post pit by exocytosis upon signal from another neuron
  10. Hypothalamic pituitary axis
    • Controlled by neg feedback system
    • The short loop feeds from the ant pituitary to the hypothalamus to prevent buildup of excess ant pituitary tropic hormone
    • The long loop feeds from the endocrine gland stimulated by the ant pit to the hypoth to inhibit secretion of tropic hormone.
    • Essentially they both limit their own secretion
    • Axis: Hypothalamus; tropic hormone 1 secretion --- anterior pit; tropic hormone 2 secretion--- endocrine gland; hormone 3 secretion--- target cell response
  11. Because the hormones in the posterior pituitary are released by neurons instead of endocrine glands, they are also called ______________
  12. - ID the hormones secreted by the post pituitary
    - Where they are produced
    - How they are tranported to the post pituitary
    - What is the stimulus for their secretion?
    • ADH (vasopressin) and oxytocin
    • They are synthesized in neurons originating in different regions of the hypothalamus
    • ADH is synth in the paraventricular nucleus
    • Oxcytocin is synth in the suraoptic nucleus
    • Following synthesis, these hormones are packaged into secretory vesicles and tranported to the neural endings in the post pit
    • The hormone is released by exocytosis when these neurons receive a signal, usually from other neruons
  13. How does the hypothalamus signal the anterior pituitary to release its hormones?
    • By the hypothalamic-pituitary portal system which is a series of 2 capillary beds
    • After the hypoth secretes tropic hormones into the capillary bed located there, these tropic hormones travel down the infundibulum to the pituitary gland via a protal vein, from which they enter a second capillary bed. The hypothalamic tropic hormones then stimulate or inhibit the release of hormones from the ant pituitary
  14. Describe the functional relationship b/t the hypothalamus and anterior pituitary
    The hypothalamus releases a tropic hormone that effects the release of another tropic hormone from the ant pituitary; this tropic hormone effects the release of a third hormone from another endocrine gland and this third hormone exerts effects on target cells throughout the body.
  15. The ant pituitary and hypothalamus secrete primarily ________ __________ which ____________________________________
    • tropic hormones
    • regulate the secretion of other hormones
  16. Identify the hormones that are secteted by the hypothalamus and the ant pituitary hormones that are secreted in response to each and the target locations
    • Prolactin releasing hormone (PRH)---- stimulates prolactin--- stimulates mammary glands
    • Prolactin inhibiting hormone (PIH) aka dopamine---- inhibits prolactin

    Thyrotropin releasing hormone (TRH)---- stimulates the release of TSH--- TSH then stimulates secretion of thyroid hormones by the thyroid

    • Corticotropin releasing hormone (CRH)--- stimulates the release of adrenocorticotropic hormone (ACTH)---ACTH then stim secretion of other hormones by the adrenal cortex
    • Growth hormone releasing hormone (GHRH)--- stimulates secretion of GH --- GH regulates growth and energy metabolism but also fuction as a tropic hormone by stimulating the secretion of insulin-like growth factors (IGFs) by the liver

    Growth hormone inhibiting hormone (GHIH) aka somatostatin--- inhibits release of GH

    Gonadotropin releasing hormone (GnRH)---- stim both FSH and LH--- LH stimulates ovulation and secretion of sex hormones; FSH promotes development of reproductive cells (eggs and sperm) and stim secretion of estrogens and inhibin
  17. Which tropic hormones from the hypothalamus act on the ant pit?
    • PRH
    • PIH (dopamine)
    • TRH
    • CRH
    • GHRH
    • GHIH (somatostatin)
    • GnRH
  18. PRH (stimulates/inhibits) ___________
    Acts on...
    • Prolactin releasing hormone stimulates prolactin
    • (mammary glands- breasts)
  19. PIH (stimulates/inhibits) ___________
    Acts on...
    • Prolactin inhibiting hormone inhibits prolactin
    • (mammary glands- breasts)
  20. TRH (stimulates/inhibits) ___________
    Acts on...
    • Thyrotropin releasing hormone stim TSH
    • (thyroid- releases thyroid hormones)
  21. (CRH) (stimulates/inhibits) ___________
    Acts on...
    • Corticotropin releasing hormone stimulates adrenocorticotropic hormone ACTH
    • (adrenal cortex- releases cortisol)
  22. GHRH (stimulates/inhibits) ___________
    Acts on...
    • Growth hormone releasing hormone stimulates GH
    • (Liver and other cells throughout the body- releases insulin like growth factors IGF)
  23. GHIH (stimulates/inhibits) ___________
    Acts on...
    • Growth hormone inhibiting hormone inhibits GH
    • (liver and other cells throughout the body)
  24. (GnRH) (stimulates/inhibits) ___________
    • Gonadotropin releasing hormone stim LH and FSH
    • (gonads- FSH promotes development of sex cells and stimulates the secretion of inhibin in both males and females; LH stimulates secretion of androgens in males and secretes estrogens and progesterone in females)
  25. **Describe the control of blood hormone levels (2 ways)
    • Rate of hormone secretion
    • - **Inhibition negative feedback
    • - Circadian rhythms- mechanism not well understood, but rhythm depends on neural and endocrine input
    • Carrier protien binding
    • - Lipophilic hormones are transported this way which increases the half-life of the hormones
    • -**Only the concentrations of unbound hormones affects the binding of hormone receptor. (active pool)
    • Clearance rate
    • - aka hormone metabolism
    • - most hormones are metabolized by the target cell itself
    • - hormones are degraded by enzymes located in lysosomes
  26. Antagonistic hormone interactions
    two hormones have oppposite effects
  27. Additive hormone interactions
    • two hormones have the same effect and the net effect equals the sum of the individual effects
    • - epinepherine and norepinepherine
  28. Synergistic hormone interactions
    two hormones that have the same effect and the net effect is greater than the sum of the individual effects
  29. Permissive hormone interactions
    • one hormone is neeeded for another hormone to exert its actions
    • - parathyroid secretes parathyroid hormone and activates calcitriol
Card Set
Physiology Unit 2
Chapter 6 Objectives