Kjertelcelle

Kjertelcelle refers to a glandular cell, a type of cell found in multicellular organisms that is specialized for secretion. These cells form the secretory units of glands, which are organs responsible for producing and releasing substances such as hormones, enzymes, mucus, sweat, or milk. Kjertelceller are characterized by their abundant endoplasmic reticulum and Golgi apparatus, organelles crucial for protein synthesis, modification, and packaging.

The appearance and function of kjertelceller can vary significantly depending on the type of gland and the substance they secrete. For example, parietal cells in the stomach secrete hydrochloric acid and intrinsic factor, while goblet cells in the respiratory and intestinal tracts secrete mucus. Endocrine glands, such as the thyroid or adrenal glands, are composed of kjertelceller that secrete hormones directly into the bloodstream. Exocrine glands, conversely, release their secretions through ducts onto epithelial surfaces.

The classification of kjertelceller can be based on their secretory product (e.g., serous cells secreting watery fluid, mucous cells secreting viscous mucus) or their mode of secretion. Secretion can occur through exocytosis (merocrine), where vesicles fuse with the cell membrane to release their contents; by shedding the apical portion of the cell containing the secretion (apocrine); or by the entire cell disintegrating to release its contents (holocrine). Understanding the structure and function of kjertelceller is fundamental to comprehending the physiology of various organ systems and the development of related diseases.