Endocrine System Overview Quiz

Study Notes

Hormones and Their Functions

Hypothalamus Hormones:
- GHRF: Stimulates secretion of growth hormone (GH).
- Somatostatin: Inhibits secretion of GH.
- Thyrotropin-releasing factor (TRF): Stimulates secretion of thyroid-stimulating hormone (TSH).
- Corticotropin-releasing factor (CRF): Stimulates secretion of TSH.
- Prolactin-inhibiting factor (PIF): Inhibits prolactin secretion.
- Gonadotropin-releasing hormone (GnRH): Stimulates secretion of follicle-stimulating hormone (FSH) and luteinizing hormone (LH).
Pituitary Gland Hormones:
- TSH: Stimulates thyroid gland and regulates cell proliferation.
- ACTH: Stimulates adrenal cortex.
- FSH: Promotes follicle growth.
- LH: Induces ovulation and testosterone release (interstitial cell-stimulating hormone, ICSH).
- GH: Supports cell growth, division, metabolism, and protein synthesis; disorders include dwarfism (low GH), gigantism (high GH in childhood), and acromegaly (high GH in adults).
- Prolactin (LTH): Stimulates lactation and breast development.
- MSH: Promotes melanin production.
- ADH (Vasopressin): Aids water reabsorption, increases blood volume, and blood pressure; deficiency leads to diabetes insipidus.
- Oxytocin: Triggers labor and lactation; excessive levels can lead to complications such as uterine wall rupture.

Glandular Hormones and Disorders

Pineal Gland:
- Melatonin: Regulates biological clock, sleep cycles, and gonadal development.
Thyroid Gland:
- T3 and T4: Crucial for maintaining basal metabolic rate (BMR), glucose metabolism, and overall physical growth; disorders include hyperthyroidism (high levels), hypothyroidism (low levels), and developmental disorders like cretinism (children) and myxedema (adults).
- Calcitonin: Lowers blood calcium levels; dysfunction can lead to hypercalcemia or hypocalcemia.
Parathyroid Gland:
- Parathyroid hormone (PTH): Increases blood calcium levels; disorders include hypercalcemia (excess PTH) and hypocalcemia (insufficient PTH).
Thymus Gland:
- Thymosin: Facilitates maturation of T-lymphocytes (white blood cells).
Pancreas:
- Insulin: Lowers blood sugar levels; insufficient insulin results in diabetes mellitus.
- Glucagon: Increases blood sugar levels; low glucagon can lead to hypoglycemia.
Adrenal Gland:
- Epinephrine and norepinephrine: Enhance heart rate, blood pressure, and glucose levels; can cause hypertension and aggressive behavior when elevated.
- Aldosterone: Promotes reabsorption of sodium and chloride.
- Androgens: Influence secondary sexual characteristics; excess can cause masculinization in females.
- Cortisol: Reduces inflammation and pain, aids glycogen metabolism; disorders include Addison’s disease (low cortisol) and Cushing syndrome (high cortisol).
Ovaries:
- Estrogen: Promotes secondary sexual characteristics; low levels can lead to sterility and high levels are associated with fibroids and polycystic ovaries.
- Progesterone: Prevents ovulation and maintains pregnancy; low levels can trigger early menstruation and increase miscarriage risk.
Testes:
- Testosterone: Essential for male reproductive organ development, secondary sexual traits, libido, and normal sperm production; deficiencies lead to feminine characteristics and male sterility.

Kidneys

Renin: Monitors blood pressure.
Calcitriol: Increases intestinal absorption of calcium.
Erythropoietin (EPO): Stimulates red blood cell production in response to low oxygen levels or bleeding.