näärmekude

Näärmekude, also known as glandular tissue, is a type of animal tissue that forms glands. Glands are organs that are responsible for synthesizing and secreting substances such as hormones, sweat, saliva, or milk. Glandular tissue is composed of specialized epithelial cells that are organized into structures that facilitate secretion. These cells can be arranged in simple tubes or more complex clusters, depending on the specific gland and its function.

There are two main types of glands: exocrine glands and endocrine glands. Exocrine glands secrete their products into ducts, which then carry the secretions to a body surface or into a body cavity. Examples include sweat glands, salivary glands, and mammary glands. Endocrine glands, on the other hand, secrete their products directly into the bloodstream or surrounding extracellular fluid. These secreted substances, called hormones, travel through the circulation to target cells or organs, where they exert specific effects. Examples of endocrine glands include the thyroid gland, adrenal glands, and pituitary gland.

The cells within glandular tissue are highly specialized for their secretory function. They often contain abundant endoplasmic reticulum and Golgi apparatus, which are involved in protein synthesis and modification, as well as numerous vesicles for storing and releasing secretory products. The specific composition and organization of näärmekude vary widely, reflecting the diverse functions of the glands they comprise. Understanding the structure and function of glandular tissue is crucial for comprehending many physiological processes and the pathogenesis of various diseases.