Lecture Notes on the Endocrine System

Introduction

• Today's topic: Endocrine System
• Areas of discussion:
  • Hypothalamus
  • Pituitary Gland
  • Adrenal Gland
  • Thyroid, Parathyroid, Pineal, and Thymus Glands

Father of Endocrine System

• Thomas Addison is known as the father of the endocrine system.

Study of the Endocrine System

• Endocrinology: The study of the endocrine system.
• First gland to develop: Thyroid Gland
  • Development time: approximately 12 weeks.
  • Thyroxine: Responsible for bone growth.

Types of Glands

Classification of Glands

• Based on Secretion:
  1. Exocrine Glands:
     • Secretion through ducts.
     • Example: Salivary gland.
  2. Endocrine Glands:
     • Secretes without ducts.
     • Example: Thyroid gland.
  3. Heterocrine Glands (Mixed):
     • Secretes via both methods.
     • Example: Pancreas.

Classification Based on Number of Cells

• Unicellular Glands: Only one cell.
  • Example: Goblet cell.
• Multicellular Glands: Multiple cells work together.
  • Example: Pancreas, Pituitary.

Hypothalamus

• Hypothalamus: An organ but functions as a gland.
  • Called the Master of the Master Gland.
• Functions:
  1. Temperature control center
  2. Control of hunger and thirst
  3. Anger control
  4. Control of the pituitary gland

Pituitary Gland

• Pituitary Gland:
  • Size: Pea-shaped.
  • Location: Sella Turcica (in the sphenoid bone).
  • Weight: Approximately 0.5 milligrams.
• Lobes:
  1. Anterior Pituitary (Adenohypophysis)
  2. Posterior Pituitary (Neurohypophysis)

Hormones

• Releasing Hormones and Inhibitory Hormones
  • Growth hormone, prolactin, thyroid stimulating hormone, etc.
• Negative Feedback Mechanism: A process for hormone balance.

Conclusion

• In today's lecture, we studied the endocrine system, its various organs, and hormones.
• In the next class, we will discuss the hormones of the pituitary gland.

Thank You

• Thank you all and see you in the next class!