Fundamentals of endocrinology

• What is the overview of the endocrine system?

  • The endocrine system consists of glands that secrete hormones.
  • Hormones regulate various bodily functions.
  • It plays a crucial role in maintaining homeostasis.
• Which two structures are primarily discussed in the context of the endocrine system?

  The hypothalamus and pituitary gland are primarily discussed.
• What is the role of the hypothalamus in the endocrine system?

  The hypothalamus regulates the pituitary gland and maintains homeostasis.
• What are the major axes of the anterior pituitary?

  • Gonadotrophin axis
  • Growth axis
  • Prolactin axis
  • Thyroid axis
  • Adrenal axis
• What does GnRH stand for?

  GnRH stands for gonadotrophin-releasing hormone.
• What is homeostasis?

  Homeostasis is the maintenance of a stable internal environment in the body.
• What are some examples of homeostasis?

  • Regulation of body temperature
  • Maintenance of blood glucose levels
  • Control of pH levels in the blood
• What are feedback loops in the context of homeostasis?

  Feedback loops are mechanisms that regulate physiological processes to maintain homeostasis.
• What gland is discussed in relation to thyroid function?

  The thyroid gland is discussed in relation to thyroid function.
• What hormones does the thyroid synthesize?

  • Triiodothyronine (T3)
  • L-thyroxine (T4)
  • Calcitonin
• What is the difference between free and bound thyroid hormones?

  Only free hormones are available for action in target tissues.
• What is the role of iodine in thyroid hormone production?

  Iodine is required for the production of T3 and T4 hormones.
• What are the physiological effects of thyroid hormones?

  • Increases heart rate and cardiac output
  • Increases bone turnover and resorption
  • Maintains normal respiratory drive
  • Increases gut motility
  • Enhances muscle contraction and relaxation
  • Increases hepatic gluconeogenesis and intestinal glucose absorption
  • Increases lipolysis and cholesterol metabolism
  • Enhances catecholamine sensitivity
• What is thyroid pathology?

  Thyroid pathology refers to diseases and disorders affecting the thyroid gland.
• What are the main structures of the adrenal glands?

  • Capsule
  • Outer Cortex (with zones: Glomerulosa, Fasiculata, Reticularis)
  • Inner Medulla
• What does the adrenal cortex produce?

  The adrenal cortex produces different classes of steroids in different zones.
• What is aldosterone classified as?

  Aldosterone is classified as a mineralocorticoid.
• What is Cushing’s Syndrome?

  Cushing’s Syndrome is characterized by increased circulating glucocorticoids, particularly cortisol.
• What is a pheochromocytoma?

  A pheochromocytoma is a tumor in the adrenal medulla that secretes catecholamines.
• What effect does LH have on testosterone production?

  LH stimulates testosterone production from Leydig cells of the testis.
• What role does FSH play in male reproduction?

  FSH stimulates Sertoli cells to produce mature sperm and inhibins A and B.
• How does inhibin affect FSH secretion?

  Inhibin feeds back to the pituitary to decrease FSH secretion.
• How does the menstrual cycle relate to GnRH activity?

  The menstrual cycle depends on the activity of hypothalamic GnRH, which stimulates LH and FSH release.
• What is the role of FSH in female reproduction?

  FSH stimulates follicular development and the activity of aromatase in ovarian granulosa cells.
• What are some disorders of sex and reproduction?

  • Hypogonadism
  • Gynaecomastia
  • Polycystic Ovary Syndrome
  • Hirsutism
• What factors affect growth hormone release?

  Factors affecting growth hormone release include sleep, exercise, and stress.
• What is the function of ADH (anti-diuretic hormone)?

  ADH leads to water reabsorption in the kidneys and decreases diuresis.
• What happens at high concentrations of vasopressin?

  At high concentrations, vasopressin causes vasoconstriction.
• What is the role of oxytocin in the endocrine system?

  Oxytocin is involved in childbirth and lactation.
• What are hormones?

  Hormones are messenger chemicals that travel in the blood between organs and tissues, regulating many processes.
• What is a hormone axis?

  A hormone axis is a system that controls the amount of a hormone in the system.
• What can result from too much or too little of a hormone?

  Too much or too little of a hormone can have significant consequences.
• Which two structures in the brain control most hormones in the body?

  The hypothalamus and the pituitary gland control most hormones in the body.
• Where is the hypothalamus located in relation to the pituitary gland?

  The hypothalamus sits above the pituitary gland.
• How does the hypothalamus control the pituitary gland?

  The hypothalamus releases hormones that stimulate the pituitary gland, which then releases hormones in response.
• What hormones are released by the hypothalamus?

  • Thyrotropin-releasing hormone (TRH)
  • Corticotropin-releasing hormone (CRH)
  • Gonadotropin-releasing hormone (GnRH)
  • Growth hormone-releasing hormone (GHRH)
  • Somatostatin (growth hormone-inhibiting hormone, GHIH)
  • Dopamine (prolactin-inhibiting hormone, PIH)
• What is the function of Thyrotropin-releasing hormone (TRH)?

  TRH stimulates thyroid-stimulating hormone secretion by the pituitary.
• What does Corticotropin-releasing hormone (CRH) stimulate?

  CRH stimulates adrenocorticotropic hormone secretion by the pituitary.
• What is the role of Gonadotropin-releasing hormone (GnRH)?

  GnRH stimulates luteinising hormone (LH) and follicle-stimulating hormone (FSH) secretion by the pituitary.
• What does Growth hormone-releasing hormone (GHRH) stimulate?

  GHRH stimulates growth hormone (GH) secretion by the pituitary.