Endocrine System Overview - Anatomy & Physiology

Introduction

Comprised of a group of duct-less glands with limited or no anatomical contact with each other, the endocrine system integrates and controls metabolic activity through the secretion of hormones into the vascular system. These hormones may have their effects on tissues and organs far from where they were produced.

The endocrine system integrates with, and is under the control of the nervous system with close association between the hypothalamus and the pituitary gland, which acts to co-ordinate many of the body's other endocrine glands. The system relies largely on negative feedback loops to maintain homeostasis, with some examples of positive feedback to elicit suitable responses.

Many of the endocrine glands have a similar basic structure, composed of clusters of secretory cells of epithelial origin. Hormones are secreted into the interstitial space whereby they are rapidly absorbed into the vascular system. In contrast the exocrine system utilises ducts enabling it to secrete its contents directly to its target area.

The Endocrine Glands

• Hypothalamus
• Pituitary Gland
• Thyroid Gland
• Parathyroid Glands
• Adrenal Glands
• Pineal Gland

Tissues and organs with endocrine functions

• Pancreas
• Gut
• Kidney
• Heart
• Adipose Tissue
• Liver
• Skin
• Thymus
• Testes
• Ovaries
• Placenta

Homeostatic mechanisms under hormonal control

• Calcium Homeostasis
• Phosphorus Homeostasis
• Magnesium

Test Yourself on Endocrinology - Anatomy and Physiology

• Endocrinology Flashcards

Acknowledgements and Reference Material

• Dyce, K.M., Sack, W.O. and Wensing, C.J.G. (2002) Textbook of Veterinary Anatomy. 3rd ed. Philadelphia: Saunders.
• Sjaastad, O.V., Hove, K. and Sand, O. (2004) Physiology of Domestic Animals. Oslo: Scandinavian Veterinary Press.
• Histology images provided by RVC