CHAPTER 18

• What does the anterior pituitary produce?


  Several hormones that affect many body organs
• How do anterior pituitary hormones act?

  They act through second-messenger systems
• What regulates the anterior pituitary hormones?

  Hormonal stimuli, mostly through negative feedback
• What is TSH and its function?

  Thyroid hormone stimulating hormone; stimulates secretion of TH and growth of thyroid
• What does ACTH stimulate?

  Secretion of glucocorticosteroids such as cortisol
• What is the effect of high concentrations of ACTH?

  Increases skin pigmentation
• What does FSH stimulate in females?

  Secretion of estrogen and promotes follicle maturation
• What does FSH stimulate in males?

  Stimulates sperm production
• What is the function of LH?

  Stimulates ovulation and production of progesterone in ovaries
• What does LH stimulate in males?

  Secretion of testosterone and supports sperm cell production
• What is the role of GH?

  Stimulates widespread tissue growth and increases blood glucose levels
• What does MSH do?

  Increases melanin production in skin
• What is the function of prolactin?

  Stimulates milk production and prolongs progesterone secretion
• What disease is associated with TSH hypersecretion?

  Grave’s disease
• What disease is associated with ACTH hypersecretion?

  Cushing’s disease
• What is the result of FSH hyposecretion?

  Sterility
• What is the result of LH hyposecretion?

  Sterility
• What is the result of GH hyposecretion?

  Pituitary dwarfism
• What is the result of GH hypersecretion?

  Giantism or acromegaly
• What is the result of prolactin hypersecretion?

  Galactorrhea, amenorrhea, sterility, impotence
• What is the function of ADH?

  Increases water retention and constricts blood vessels
• What does oxytocin stimulate?

  Uterine contraction and milk let-down
• Where are ADH and oxytocin produced?

  They are produced by the hypothalamus
• What is the location of the thyroid gland?

  At the base of the throat, just inferior to Adam’s apple
• What is the structure of the thyroid gland?

  Consists of two lobes joined by a central mass of isthmus
• What are the active hormones produced by the thyroid gland?

  Thyroxine and triiodothyronine
• What is the role of thyroxine?

  Controls the rate at which glucose is oxidized and converted to energy
• What is the role of triiodothyronine?

  Similar to thyroxine, it also regulates metabolism
• What condition results from iodine deficiency?

  Goiter, an enlargement of the thyroid gland
• What is cretinism?

  Dwarfism resulting from hyposecretion of thyroxine
• What is myxedema?

  Hypothyroidism characterized by physical and mental sluggishness
• What is Graves' disease?

  Hyperthyroidism
• What is exophthalmos?

  Bulging of the eyes due to hyperthyroidism
• What are the major endocrine organs?

  • Pituitary Gland
  • Hypothalamus
  • Thyroid Gland
  • Parathyroid Gland
  • Adrenal Glands
  • Pancreas
  • Gonads (Ovaries and Testes)
  • Pineal Gland
  • Thymus
• What is the difference between endocrine and exocrine glands?

  Endocrine glands are ductless and release hormones into the bloodstream, while exocrine glands have ducts and secrete substances outside the body.
• What is endocrinology?

  The scientific study of hormones and endocrine organs
• How does the endocrine system act compared to the nervous system?

  The endocrine system acts more slowly using chemical messengers called hormones.
• What is the function of the hypothalamus in relation to the pituitary gland?

  The hypothalamus synthesizes releasing and inhibiting hormones that control the anterior pituitary gland.
• What hormones are stored and released by the posterior pituitary gland?

  Oxytocin and antidiuretic hormone (ADH)
• What is the role of oxytocin during childbirth?

  Stimulates powerful contractions of the uterine muscle