Endocrine System

• Endocrine System:

  • Helps cope with changes in the environment
  • Works with the Nervous System, Respiratory System, and other organs like the kidney, gut, and pancreas
  • Maintains and controls body energy levels, reproduction, growth and development, responses to stimuli and stress, and internal balance
• Gland:

  • An organ that produces a secretion for use elsewhere in the body or in a body cavity
  • Body cavities include the mouth and diaphragm
• Endocrine Gland:

  • Ductless glands that secrete their product directly into the bloodstream
• Hormones:

  • Chemical messengers that transport signals from one cell to another
  • React only in specific cell types known as "target cells"
• Exocrine Gland:

  • Secretions pass through a duct to the site where they take effect
  • Examples include salivary, sweat, and mammary glands
• Pituitary Gland:

  • Master of the ductless glands
  • Also known as hypophysis
  • Located at the base of the brain
  • Hormones produced:
  • Oxytocin: responsible for uterine muscle contractions during the final stage of pregnancy
  • Vasopressin: increases blood pressure and decreases urine flow (antidiuretic hormone)
  • Growth Hormone: essential for normal growth
  • Adrenocorticotropic Hormone (ACTH): controls adrenal glands during emergency or stressful situations
  • Prolactin: initiates milk production
• • Luteinizing Hormone (LH): stimulates ovarian hormone formation and egg release
  • Follicle Stimulating Hormone (FSH): responsible for follicle formation in females and sperm development in males
• Thyroid Gland:

  • H-shaped organ located beneath the larynx
  • Hormones produced:
  • Thyroxine (T4): controls body metabolism
  • Calcitonin (T3): regulates Ca and P balance in blood and bones
• Parathyroid Gland:

  • Four small glandular bodies attached to the back of the thyroid gland
  • Hormone produced: Parathyroid hormone (Parathormone) that controls Ca levels in the body and bone growth
• Thymus Gland:

  • Two lobes located in the upper chest, below the neck
  • Hormones produced:
  • Thymosin: manufactures WBC and antibodies for immunity
  • Promine: promotes growth
  • Retine: retards growth
• Adrenal Glands:

  • Small glands above each kidney
  • Adrenal Cortex: outer portion that secretes corticoids to regulate metabolism and body functions
  • Adrenal Medulla: inner portion that secretes adrenaline and noradrenaline for stress response
• Pancreas:

  • Located between the kidneys
  • Hormone-secreting cells found in the islet of Langerhans
  • Hormones produced:
  • Glucagon: converts stored sugar to glucose
  • Insulin: controls sugar storage and breakdown
  • Associated with diabetes mellitus and diabetes insipidus
• Male and Female Gonads:

  • Testes (male) and Ovaries (female) in the lower abdomen
  • Hormones produced:
  • Testes: androgen and testosterone for male characteristics
  • Prostate Gland: produces fluid for semen
  • Cowper’s Gland: adds fluids and protection to semen
  • Ovaries: secrete estrogen and progesterone for female traits and reproductive support