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Podocytes
Podocytes are cells in Bowman's capsule in the kidneys that wrap around capillaries of the glomerulus. Podocytes make up the epithelial lining of Bowman's capsule, the third layer through which filtration of blood takes place. Bowman's capsule filters the blood, retaining large molecules such as proteins while smaller molecules such as water, salts, and sugars are filtered as the first step in the formation of urine. Although various viscera have epithelial layers, the name visceral epithelial cells usually refers specifically to podocytes, which are specialized epithelial cells that reside in the visceral layer of the capsule. The podocytes have long primary processes called ''trabeculae'' that form secondary processes known as ''pedicels'' or foot processes (for which the cells are named '' podo-'' + '' -cyte''). The pedicels wrap around the capillaries and leave slits between them. Blood is filtered through these slits, each known as a filtration slit, slit diaphragm, or s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Foot Process
Cellular extensions also known as cytoplasmic protrusions and cytoplasmic processes are those structures that project from different Cell (biology), cells, in the body, or in other organisms. Many of the extensions are cytoplasmic protrusions such as the axon and dendrite of a neuron, known also as cytoplasmic processes. Different glial cells project cytoplasmic processes. In the brain, the processes of astrocytes form terminal endfeet, foot processes that help to form protective barriers in the brain. In the kidneys specialised cells called podocytes extend processes that terminate in podocyte foot processes that cover glomerulus, capillaries in the nephron. End-processes may also be known as ''vascular footplates'', and in general may exhibit a pyramidal or finger-like morphology. Mural cells such as pericytes extend processes to wrap around capillaries. Foot-like processes are also present in Müller glia (modified astrocytes of the retina), pancreatic stellate cells, Dendri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nephrin
Nephrin is a protein necessary for the proper functioning of the renal filtration barrier. The renal filtration barrier consists of fenestrated endothelial cells, the glomerular basement membrane, and the podocytes of epithelial cells. Nephrin is a transmembrane protein that is a structural component of the slit diaphragm. It is present on the tips of the podocytes as an intricate mesh connecting adjacent foot processes. Nephrin contributes to the strong size selectivity of the slit diaphragm, however, the relative contribution of the slit diaphragm to exclusion of protein by the glomerulus is debated. The extracellular interactions, both homophilic and heterophilic—between nephrin and NEPH1—are not completely understood. In addition to eight immunoglobulin G–like motifs and a fibronectin type 3 repeat, nephrin has a single transmembrane domain and a short intracellular tail. Tyrosine phosphorylation at different sites on the intracellular tail contribute to the regul ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glomerular Capillaries
The glomerulus (: glomeruli) is a network of small blood vessels (capillaries) known as a ''tuft'', located at the beginning of a nephron in the kidney. Each of the two kidneys contains about one million nephrons. The tuft is structurally supported by the mesangium (the space between the blood vessels), composed of intraglomerular mesangial cells. The blood is filtered across the capillary walls of this tuft through the glomerular filtration barrier, which yields its filtrate of water and soluble substances to a cup-like sac known as Bowman's capsule. The filtrate then enters the renal tubule of the nephron. The glomerulus receives its blood supply from an afferent arteriole of the renal arterial circulation. Unlike most capillary beds, the glomerular capillaries exit into efferent arterioles rather than venules. The resistance of the efferent arterioles causes sufficient hydrostatic pressure within the glomerulus to provide the force for ultrafiltration. The glomerulus and its ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CD2AP
CD2-associated protein is a protein that in humans is encoded by the ''CD2AP'' gene. Function This gene encodes a scaffolding molecule that regulates the actin cytoskeleton. The protein directly interacts with filamentous actin and a variety of cell membrane proteins through multiple actin binding sites, SH3 domains, and a proline-rich region containing binding sites for SH3 domains. The cytoplasmic protein localizes to membrane ruffles, lipid rafts, and the leading edges of cells. It is implicated in dynamic actin remodeling and membrane trafficking that occurs during receptor endocytosis and cytokinesis. Haploinsufficiency of this gene is implicated in susceptibility to glomerular disease. Interactions CD2AP has been shown to interact with: * Cbl gene, * NPHS2, * Nephrin, and * RAB4A Ras-related protein Rab-4A is a protein that in humans is encoded by the ''RAB4A'' gene. Interactions RAB4A has been shown to interact with: * CD2AP, * KIF3B, * RAB11FIP1, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Renal Corpuscle
A renal corpuscle (or Malpighian body) is the blood-filtering component of the nephron of the kidney. It consists of a glomerulus - a tuft of capillaries composed of endothelial cells - and a glomerular capsule known as Bowman's capsule. Structure The renal corpuscle is composed of two structures, the glomerulus and the Bowman's capsule. The glomerulus is a small tuft of capillaries containing two cell types. Endothelial cells, which have large fenestrae, are not covered by diaphragms. Mesangial cells are modified smooth muscle cells that lie between the capillaries. They regulate blood flow by their contractile activity and secrete extracellular matrix, prostaglandins, and cytokines. Mesangial cells also have phagocytic activity, removing proteins and other molecules trapped in the glomerular basement membrane or filtration barrier. The Bowman's capsule has an outer parietal layer composed of simple squamous epithelium. The visceral layer, composed of modified sim ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bowman's Capsule
Bowman's capsule (or the Bowman capsule, capsula glomeruli, or glomerular capsule) is a cup-like sac at the beginning of the Renal tubule, tubular component of a nephron in the mammalian kidney that performs the first step in the filtration of blood to form urine. A glomerulus (kidney), glomerulus is enclosed in the sac. Fluids from blood in the glomerulus are collected in the Bowman's capsule. Structure Outside the capsule, there are two poles: * The vascular pole is the side with the afferent arteriole and efferent arteriole. * The tubular pole, is the side with the proximal convoluted tubule. Inside the capsule, the layers are as follows, from outside to inside: *''Parietal layer''—A single layer of simple squamous epithelium. Does not function in filtration. *''Bowman's space (or "urinary space", or "capsular space")''—Between the visceral and parietal layers, into which the filtrate enters after passing through the filtration slits. *''Visceral layer''—Lies just above ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nephron
The nephron is the minute or microscopic structural and functional unit of the kidney. It is composed of a renal corpuscle and a renal tubule. The renal corpuscle consists of a tuft of capillaries called a glomerulus and a cup-shaped structure called Bowman's capsule. The renal tubule extends from the capsule. The capsule and tubule are connected and are composed of epithelial cells with a lumen. A healthy adult has 1 to 1.5 million nephrons in each kidney. Blood is filtered as it passes through three layers: the endothelial cells of the capillary wall, its basement membrane, and between the podocyte foot processes of the lining of the capsule. The tubule has adjacent peritubular capillaries that run between the descending and ascending portions of the tubule. As the fluid from the capsule flows down into the tubule, it is processed by the epithelial cells lining the tubule: water is reabsorbed and substances are exchanged (some are added, others are removed); first wit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Intermediate Filament
Intermediate filaments (IFs) are cytoskeleton, cytoskeletal structural components found in the cells of vertebrates, and many invertebrates. Homologues of the IF protein have been noted in an invertebrate, the cephalochordate ''Branchiostoma''. Intermediate filaments are composed of a family of related proteins sharing common structural and sequence features. Initially designated 'intermediate' because their average diameter (10 Nanometre, nm) is between those of narrower microfilaments (actin) and wider myosin filaments found in muscle cells, the diameter of intermediate filaments is now commonly compared to actin microfilaments (7 nm) and microtubules (25 nm). Animal intermediate filaments are subcategorized into six types based on similarities in amino acid sequence and protein structure. Most types are cytoplasmic, but one type, Type V is a nuclear lamin. Unlike microtubules, IF distribution in cells shows no good correlation with the distribution of either ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microtubule
Microtubules are polymers of tubulin that form part of the cytoskeleton and provide structure and shape to eukaryotic cells. Microtubules can be as long as 50 micrometres, as wide as 23 to 27 nanometer, nm and have an inner diameter between 11 and 15 nm. They are formed by the polymerization of a Protein dimer, dimer of two globular proteins, Tubulin#Eukaryotic, alpha and beta tubulin into #Structure, protofilaments that can then associate laterally to form a hollow tube, the microtubule. The most common form of a microtubule consists of 13 protofilaments in the tubular arrangement. Microtubules play an important role in a number of cellular processes. They are involved in maintaining the structure of the cell and, together with microfilaments and intermediate filaments, they form the cytoskeleton. They also make up the internal structure of cilia and flagella. They provide platforms for intracellular transport and are involved in a variety of cellular processes, in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
