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Endocrine System - Anatomy & Physiology

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Terms in this set (22)

  • What are the two main types of glands in the endocrine system?
    Exocrine glands (ducted) and endocrine glands (ductless, secrete hormones into interstitial fluid and blood).
  • How do hormones affect target cells?
    Hormones bind to specific glycoprotein receptors on target cells, affecting only those cells with the correct receptors.
  • What is down-regulation in hormone activity?
    A decrease in the number of hormone receptors to reduce sensitivity when hormone levels are high.
  • What is up-regulation in hormone activity?
    An increase in the number of hormone receptors to increase sensitivity when hormone levels are low.
  • What are the two categories of hormones based on their solubility?
    Lipid-soluble hormones (steroids, thyroid hormones, nitric oxide) and water-soluble hormones (amines, peptides, proteins).
  • How do lipid-soluble hormones act on target cells?
    They diffuse through the plasma membrane and bind to intracellular receptors, affecting gene transcription.
  • How do water-soluble hormones act on target cells?
    They bind to receptors on the plasma membrane, activating second messenger systems like cAMP.
  • What is the role of the hypothalamus in the endocrine system?
    It links the nervous and endocrine systems and controls the pituitary gland via releasing and inhibiting hormones.
  • What are the two lobes of the pituitary gland?
    The anterior pituitary (adenohypophysis) and the posterior pituitary (neurohypophysis).
  • Name three hormones secreted by the anterior pituitary.
    Human growth hormone (hGH), thyroid-stimulating hormone (TSH), and adrenocorticotropic hormone (ACTH).
  • What hormones does the posterior pituitary release?
    Oxytocin (OT) and antidiuretic hormone (ADH), both produced by the hypothalamus.
  • What is the function of oxytocin?
    Stimulates uterine contractions during labor and milk ejection from mammary glands.
  • What is the function of antidiuretic hormone (ADH)?
    Decreases urine production by promoting water reabsorption in kidneys and increases blood pressure by constricting arterioles.
  • What hormones are produced by the thyroid gland?
    Thyroxine (T4), triiodothyronine (T3), which increase metabolic rate, and calcitonin, which lowers blood calcium.
  • What is the role of parathyroid hormone (PTH)?
    Increases blood calcium by stimulating osteoclast activity and decreasing phosphate levels.
  • What are the three zones of the adrenal cortex and their functions?
    Zona glomerulosa (mineralocorticoids), zona fasciculata (glucocorticoids), zona reticularis (androgens).
  • What hormones are secreted by the adrenal medulla?
    Epinephrine and norepinephrine, which intensify sympathetic 'fight or flight' responses.
  • What are the main endocrine cells in the pancreas and their secretions?
    Alpha cells secrete glucagon, beta cells secrete insulin, delta cells secrete somatostatin, and F cells secrete pancreatic polypeptide.
  • What hormones do the ovaries produce?
    Estrogens, progesterone, inhibin, and relaxin, regulating the menstrual cycle, pregnancy, and secondary sex characteristics.
  • What hormone do the testes produce?
    Testosterone, which regulates sperm production and maintains male secondary sex characteristics.
  • What is the function of the pineal gland?
    Secretes melatonin, which helps regulate the biological clock and promotes sleepiness.
  • What hormones are produced by the thymus?
    Thymosin, thymic factor, and thymopoietin, all involved in T cell maturation.