Endocrine System Hormones and Functions

Endocrine Glands, Hormones, and Their Functions

Anterior Pituitary

• Thyroid-stimulating hormone (TSH):
  • Tropic hormone.
  • Stimulates secretion of thyroid hormones.
• Adrenocorticotropic hormone (ACTH):
  • Tropic hormone.
  • Stimulates adrenal cortex secretion of hormones.
• Follicle-stimulating hormone (FSH):
  • Tropic hormone.
  • Typical Female: Stimulates development of ovarian follicles and secretion of estrogens.
  • Typical Male: Stimulates seminiferous tubules of testes to grow and produce sperm.
• Luteinizing hormone (LH):
  • Tropic hormone.
  • Typical Female: Stimulates maturation of ovarian follicle and ovum; stimulates secretion of estrogen; triggers ovulation; stimulates development of corpus luteum (luteinization).
  • Typical Male: Stimulates interstitial cells of the testes to secrete testosterone.
• Growth hormone (GH):
  • Stimulates growth in all organs.
  • Mobilizes nutrient molecules, causing an increase in blood glucose concentration.
• Prolactin (PRL) (lactogenic hormone):
  • Stimulates breast development during pregnancy.
  • Stimulates milk production and secretion by glandular cells after childbirth.

Posterior Pituitary

• Antidiuretic hormone (ADH):
  • Stimulates retention of water by the kidneys.
• Oxytocin (OT):
  • Stimulates uterine contractions at the end of pregnancy.
  • Stimulates the movement of milk into the breast ducts or milk let-down.
  • Enhances parent-infant social bonds.

Hypothalamus

• Releasing hormones (RHs):
  • Stimulates anterior pituitary secretion of hormones.
• Inhibiting hormones (IHs):
  • Inhibits anterior pituitary's secretion of hormones.

Thyroid

• Thyroxine (T4) and triiodothyronine (T3):
  • Stimulates the energy metabolism of all cells.
• Calcitonin (CT):
  • Inhibits the breakdown of bone.
  • Causes a decrease in blood calcium concentration.

Parathyroid

• Parathyroid hormone (PTH):
  • Stimulates the breakdown of bone.
  • Causes an increase in blood calcium concentration.

Adrenal Cortex

• Mineralocorticoids (MCs): Aldosterone
  • Regulates electrolyte and fluid homeostasis.
• Glucocorticoids (GCs): Cortisol (hydrocortisone)
  • Stimulates gluconeogenesis, causing an increase in blood glucose concentration.
  • Has anti-inflammatory, anti-immunity, and anti-allergy effects.
• Androgens
  • Stimulates sexual drive in the typical female but has negligible effects in the typical male.

Adrenal Medulla

• Epinephrine (Epi) (adrenaline) and Norepinephrine (NE) (noradrenaline):
  • Prolongs and intensifies the sympathetic nervous response during stress.

Pancreas (Islets)

• Glucagon:
  • Stimulates liver glycogenolysis, causing an increase in blood glucose concentration.
• Insulin:
  • Promotes glucose entry into all cells, causing a decrease in blood glucose concentration.

Ovary

• Estrogens:
  • Promotes development and maintenance of typical female sexual characteristics (see Chapter 21).
• Progesterone:
  • Promotes conditions required for pregnancy (see Chapter 21).

Testis

• Testosterone:
  • Promotes development and maintenance of typical male sexual characteristics (see Chapter 21).

Thymus

• Thymosins:
  • Promotes development of immune system cells.

Placenta

• Chorionic gonadotropin, estrogens, progesterone:
  • Promotes conditions required during early pregnancy.

Pineal Gland

• Melatonin:
  • Inhibits tropic hormones that affect the ovaries.
  • Helps regulate the body's internal clock and sleep cycles.

Heart (Atria)

• Atrial natriuretic hormone (ANH):
  • Regulates fluid and electrolyte homeostasis.

Gastrointestinal Tract (GI Tract)

• Ghrelin:
  • Affects energy balance (metabolism).

Fat-Storing Cells

• Leptin:
  • Controls how hungry or full we feel.