![]() ![]() Their functions are to establish membrane polarity, connect adjacent cells and anchor the epithelial tissue to the connective tissue underneath it. Intercellular junctions are protein complexes on the basolateral cell membranes of epithelial cells. Their respective functions are removing foreign particles from the epithelial surface, transportation of signals from the ECM to the intracellular space, and fetal development. There are three types of cilia motile, non-motile (primary) and nodal. Cilia - fingerlike structures present on almost every epithelial cell.Their functions are absorption ( epididymis and ductus deferens) and mechano-sensory reception ( inner ear) Stereocilia - a type of microvilli, but these are immotile and longer than microvilli.The enterocytes of the small intestine has such specializations to facilitate absorption of food in the gut. Large quantities of microvilli are said to form a 'brush border', due to their appearance in histological preparation. Microvilli - are microscopic protrusions of the cell membrane which mainly function to increase the apical surface area for absorption.There are three types of specializations They differ in their length, motility and function. As both lateral and basal surfaces are adjusted to interact with surrounding structures, they’re often mentioned together as a basolateral surface.Īpical specializations are different types of fingerlike cytoplasmic extensions of the apical surface. Basal surfaces are in contact with the underlying basement membrane. Lateral surfaces are the sites where adjacent cells interconnect, forming tightly packed contiguous cells. This pole may also show apical membrane specializations which alter the shape of this surface. These can include receptors and channels for transportation of substances that the epithelial cell needs to internalize or expel, or membrane specializations.Īpical poles project towards the external surface or the lumen of an organ which epithelia cover, which is why they’re also called free surfaces or free domains. Secretion, absorption, transportation, protection, receptor function (sensation)Įach membrane pole exhibits various features. Secreting: tubular, acinar and tubuloacinar glands Supported by connective tissue (lamina propria)Īpical: microvilli, cilia, stereocilia, modified stereocilia (sensory receptors) Polarity (apical, lateral and basal cell surfaces) Simple, stratified, pseudostratified, transitional Think epithelial tissue is not so interesting? What until you read about all its specializations! This page will introduce you to the histology, characteristics and functions of epithelial tissue. Functions of epithelial tissue are secretion, protection, absorption, transportation and special sensory receptive. Forming sheets that cover the internal and external body surfaces (surface epithelium) and secreting organs (glandular epithelium). ![]() The cells in this tissue are tightly packed within a thin ECM. Like all types, it is formed by cells within an extracellular matrix (ECM). Epithelium is one of only 4 types of human body tissues.
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