Special Histology and Embryology: Practical Course - V. K. Napkhanyuk 2001

Endocrine System

The Endocrine System (systema endocrinum), along with The Nervous system, regulates and coordinates body Functions.

The endocrine system comprises highly specialized secretory Organs (Endocrine glands)—ductless glands richly supplied by microcirculatory vessels into which they secrete their products—as well as individual endocrine Cells scattered throughout various organs and Tissues of the body. The Classification of endocrine organs is presented in Fig. 13.

All Components of the endocrine system are capable of synthesizing and releasing Hormones into the Blood AND Lymph. These highly specific BIOLOGICALLY ACTIVE SUBSTANCES, acting in concert with the nervous system, regulate metabolic processes.

Most hormones are Proteins (Peptides, oligopeptides, glycopeptides) or Amino Acid Derivatives, while the rest are Steroids (Sex Hormones and Adrenal Cortex Hormones).

Endocrine glands are characterized by the following features:

— the presence of specialized secretory cells with a well-developed synthetic secretory apparatus (micrographs 9-13);

— numerous Blood and Lymphatic vessels (some of which are sinusoidal blood capillaries);

— the absence of an excretory duct.



Last update: 10/08/2026

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