Endocrine System: Part 2

Important Glands

• Adrenal Gland: Main Location: Near the kidneys, two parts - Cortex and Medulla
• Thyroid Gland: Largest endocrine gland, located in the neck, two lobes
• Parathyroid Gland: Located behind the thyroid, four small glands
• Pancreas: Functions as both endocrine and exocrine gland
• Pineal Gland: Small-sized endocrine gland
• Thymus: Role in immune system, lobular structure

Adrenal Gland

• Location: Above the kidneys
• Parts: 2 parts - Cortex (outer) and Medulla (inner)
• Cortex: Three layers – Zona Glomerulosa, Zona Fasciculata, Zona Reticularis
• Hormones: Mineralocorticoids, Glucocorticoids, and Sex Hormones
  • Mineralocorticoids: Main hormone - Aldosterone (sodium reabsorption)
  • Glucocorticoids: Main hormone - Cortisol (stress, metabolism, increase in blood sugar)
  • Sex Hormones: Main hormone - Androgen
• Medulla: Hormones - Epinephrine and Norepinephrine (fight and flight response)

Thyroid Gland

• Location: Near the trachea in the neck
• Structural Feature: Butterfly-shaped
• Hormones: T3, T4, and Calcitonin
  • T3 and T4: Body growth, metabolism, energy generation
  • Calcitonin: Lowers the level of calcium in the blood

Parathyroid Gland

• Location: Behind the thyroid, four small glands
• Hormone: Parathyroid Hormone (PTH)
  • Increases calcium level in the blood

Pancreas

• Location: Behind the stomach, three parts - head, body, tail
• Parts: Pancreatic Islets
  • Alpha Cells: Glucagon
  • Beta Cells: Insulin (lowers blood glucose level)
  • Delta Cells: Somatostatin

Pineal Gland

• Location: Third ventricular, diencephalon area
• Hormone: Melatonin (regulation of biological clock)

Thymus Gland

• Location: In front of the trachea, below the thyroid
• Hormone: Thymosin (proliferation and maturation of T cells)

Other Sex Glands

• Ovaries and Testes: Covered in the fifth unit
• Local Hormones: Histamine, Serotonin, Prostaglandins

General Disorders

Thyroid Gland

• Hyperthyroidism: Excess of thyroid hormones
• Hypothyroidism: Deficiency of thyroid hormones
• Goiter: Enlargement of the neck due to lack of iodine

Parathyroid Gland

• Hypoparathyroidism: Deficiency of PTH, hypocalcemia
• Hyperparathyroidism: Excess of PTH, hypercalcemia