where are tight junctions found in the human body
vertebrates
title: Cell junction text: extracellular fluid. Gap junctions play vital roles in the human body, including their role in the uniform contractile of the heart muscle. They are also relevant in signal transfers in the brain, and their absence shows a decreased cell density in the brain. Retinal and skin cells are also dependent on gap junctions in cell differentiation and proliferation. Found in vertebrate epithelia, tight junctions act as barriers that regulate the movement of water and solutes between epithelial layers. Tight junctions are classified as a paracellular barrier which is defined as not having directional discrimination; however, movement of the solute is title: Tight junction text: the case. Epithelia are classed as "tight" or "leaky", depending on the ability of the tight junctions to prevent water and solute movement: Tight junction Tight junctions, also known as occluding junctions or zonulae occludentes (singular, zonula occludens) are multiprotein junctional complexes whose general function is to prevent leakage of transported solutes and water and seals the paracellular pathway. Tight junctions may also serve as leaky pathways by forming selective channels for small cations, anions, or water. Tight junctions are present only in vertebrates. The corresponding junctions that occur in invertebrates are septate junctions. Tight junctions are composed of a title: Tight junction text: Tight junction Tight junctions, also known as occluding junctions or zonulae occludentes (singular, zonula occludens) are multiprotein junctional complexes whose general function is to prevent leakage of transported solutes and water and seals the paracellular pathway. Tight junctions may also serve as leaky pathways by forming selective channels for small cations, anions, or water. Tight junctions are present only in vertebrates. The corresponding junctions that occur in invertebrates are septate junctions. Tight junctions are composed of a branching network of sealing strands, each strand acting independently from the others. Therefore, the efficiency of the junction in preventing ion passage increases title: Gap junction text: cells throughout the body of most animals. Electrical coupling can be relatively fast acting. Tissues in this section have well known functions observed to be coordinated by gap junctions with inter-cellular signaling happening in time frames of micro-seconds or less. Gap junctions are particularly important in cardiac muscle: the signal to contract is passed efficiently through gap junctions, allowing the heart muscle cells to contract in unison. Gap junctions are expressed in virtually all tissues of the body, with the exception of adult fully developed skeletal muscle and mobile cell types such as sperm or erythrocytes. Several human genetic disorders title: Cell junction text: Cell junction A cell junction (or intercellular bridge) is a type of structure that exists within the tissue of some multicellular organisms, such as animals. Cell junctions consist of multiprotein complexes that provide contact between neighboring cells or between a cell and the extracellular matrix. They also build up the paracellular barrier of epithelia and control the paracellular transport. Cell junctions are especially abundant in epithelial tissues. Cell junctions are especially important in enabling communication between neighboring cells via specialized proteins called communicating junctions. Cell junctions are also important in reducing stress placed upon cells. Combined with cell adhesion molecules