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| The in-depth study of human cells |
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Cell Adhesion junctions ocluding / tight junctions created through integral protiens: occludin + occludin claudin + claudin create barrier to prevent entrance of anything between cells = paracellular diffusion barrier "cap" cadherin related (zonula) adherens (aka belt desmosomes) "seem" (spot) desmosomes (aka Macula adherens) "reinforcement" gap junction 6 connexins create a connexon 2 connexon of adjacent cells adhere to form gap purpose: action potential and Ca pass through can be open or closed hemidesmosomes Basement membrane connects epithelial tissue to connective tissue 2 sections basal lamina made of laminim type 4 collagen protoglycans reticular lamina made of collagen integrin hooks epithileal tissue to basement membrane laminim in basal lamina additional connective tissue basil to reticular to main connective tissue Definition attachment of cells to each other to create tissues Principals cell adhesion molecules (CAM) in membrane cadherins ligand: cadherins Ca++ dependent connects epithelial and muscle cells at cell jucntions (zonula) adherens (aka belt desmosomes) cadherins are arranged in strips on sides catenins link (are combining component) of cadherins to actin of cytoskeletin enables vibrations in one cell to be felt in other plaque (a peripheral protein) cements cadherins to cell wall from with in (spot) desmosomes (aka Macula adherens) plaque anchors each cadherins to cell wall from with in plaque has keratin filaments to further anchor in cell directly spot reinforcement of zonula adherens E-cadherin to E-cadherin E- (for epithileal), N- (for nerves), P- (platelets and epithilelal) always two together = dimer connected by calcium bond to each other at binding site on dimer connects to other dimer via calcium bond at binding sites homophilic interaction (cadherin + cadherin) purpose: create permanent sheets of epithelium selectins ligand: polysaccharide designed to glycoproteins of another cell Ca++ dependent CRD - Carbohydate Recognition Domain = Binding site of selectins turned on by calcium types L-Selectin (Leukocytes) to E-Selecting E-Selecting (Epithelium) to L-Selectin  P-Selectin (Platelets) to Mucins (PSGL-1) purpose: to connect temporary WBC with Epithelial cells of blood vessel wall also with integrin to Ig-CAM at same time integrins ligand: fibromnectin, laminin, fibrinogen, ig-cam not dependant on Ca++ actions binds cell to matrix in connective tissue connects to cytoskeletin know integrins on pg 515 LFA-1 connected to ig-CAMs (between white blood cells and endothelial cells) MAC-1 connected to ig-CAMs (between white blood cells and endothelial cells) Laminin cell matrix connection Fibronectin cell matrix connection (GPIIb/GPIIIa) Fibrinogen platelet aggregations has alpha and beta sub unit linked by various proteins to actin of cytoskeletin immunoglobulins ligand: other CAM not dependant on Ca++ know ICAM-1 intercellular ICAM-2 VCAM-1 vascular NCAM-1 neuro CD4 in T4 cells - helpers CD8 T-attack / suppressor cells prupose: white blood cell interaction with endothelium (simple squamus style) cells all our integral membrane proteins CAM associated to a ligand cell controls adhesion through surface density of CAMs state of agregation to move next to other cell state of activiation to turn on CAMs Rate of ligand binding and association CAMs interact with cytoskeletin of cell for movement CAM + Ligan can activate cellular intracellular signal transduction pathways | |
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