Animal Hormones part 2

  1. largest endocrine gland
    thyroid gland

    • high rate of blood flow
    • anterior & lateral sides of trachea
  2. The thyroid follicles are lined with __ that secrete T3 & T4.
    follicular cells

    (page 32 on slides)
  3. __ regulates cell metabolism by acting as a transcription factor for many genes.
    Thyroxine
  4. The anterior pituitary secretes __, which activates the follicles to produce __.
    • thyroid-stimulating hormone (TSH);
    • thyroxine
  5. steps in releasing T3 & T4
    • 1. Paraventricular nucleus in hypothalamus releases thyrotropin-releasing hormone near the infundibulum to the portal system towards the anterior pituitary.
    • 2. The anterior pituitary then releases thyrotropin (TSH) to the bloodstream to the thyroid gland.
    • 3. TSH activates follicles to produce thyroxine (as thyroglobulin), which becomes T3 & T4 with the addition of iodine.
    • 4. This cranks up metabolism.

    If T3 & T4 get too high, negative feedback occurs, which then causes the anterior pituitary to stop releasing TSH to maintain homeostasis.
  6. Thyroxine begins as a glycoprotein, __ and becomes T3 & T4 with the addition of __
    thyroglobulin; iodine
  7. __ is a disease that results from an enlarged thyroid gland.
    Goiter
  8. Hypothyroidism (thyroxine deficiency) is the result of __. The most common cause is __ - follicle cells can't produce thyroxine.
    • low circulating thyroxine;
    • iodine deficiency
  9. Hypothyroidism results from reduced levels of __ & increased levels of __
    • T3 & T4 (reduced thyroxine);
    • thyrotropin-releasing hormone & TSH

    Reduced levels of T3 or T4 causes the hypothalamus to release more thyrotropin-releasing hormone & the anterior pituitary to release more TSH, but since thyroglobulin is still produced but not converted efficiently to T3 or T4, the thyroid still enlarges. The solution would be to consume more iodine.
  10. Hyperthyroidism (thyroxine excess) is often caused by __. __ activates __ receptors on follicle cells & increases thyroxine.
    • autoimmune disease;
    • Antibody-binding (Effector B cells release antibodies that mimic TSH);
    • TSH
  11. Hyperthyroidism results from reduced levels of __ & increased levels of __
    • thyrotropin-releasing hormone & TSH
    • T3 & T4 (increased thyroxine)

    Antibodies mimicking TSH causes increased levels of T3 and T4.This causes the hypothalamus to stop releasing thyrotropin-releasing hormone, which causes the anterior pituitary to stop releasing TSH. Thyroid still remains stimulated by antibodies mimicking TSH and grows bigger. The solution would be to suppress the immune system.
  12. Cortisol is released from the __ layer of the adrenal cortex.
    zona fasciculata
  13. steps in releasing cortisol
    • 1. Paraventricular nucleus in hypothalamus releases corticotropin-releasing hormone near the infundibulum to the portal system towards the anterior pituitary.
    • 2. The anterior pituitary then releases corticotropin (ACTH) to the bloodstream to the adrenal cortex.
    • 3. From the zona fasciculata layer, cortisol is released.

    A negative feedback occurs after cortisol is released for the hypothlamus to stop releasing CRH & the anterior pituitary to stop releasing ACTH
  14. functions of cortisol
    • stress response (anger/fear)
    • increases blood glucose levels by inhibiting glucose uptake into muscle and fat cells
    • blocks immune system reactions
    • increases cardiac muscle contractions
Author
sophathida
ID
325751
Card Set
Animal Hormones part 2
Description
Week 6
Updated