house needs to be built on strong basement upon which the structure could be assembled and the house could be built. if no basement house could collapse. in case of epithelial tissue- the epithelial cell layer has to be on top of the basement- basement is basal lamina. composed of several fibrous materials - has specific structures connecting cell to basal lamina 1. intergrins - protein components the cell has on basolateral side - mostly basal side - on basal side the intergrin is composed of 2 subunits alpha intergin and beta integrin subunits - when they form a dimer they are active. the integrin has 2 states - inactive where they are interacting with adaptors like sharprin and active state interacting with adaptors like talin. what is the functional roles of integrin in terms of providing structural support or functionality of the integrin. integrin can interact with several adaptor molecules - this can be talin and vinculin. all these adaptor molecules help to connect integrin cytoplasmic domain to the cells actin cytoskeleton network. and the other side the head domain of integrin is connected to ECM components. mainly integrin connects with collagen fibres. 2. Lamnin- coil coil protein structure and has 3 big domains - alpha beta gamma domains - they belong to glycoprotein family and present in nearly all organisms - they come from: many cells secrete lamnin to be part of ECM. also vital for maintenance and survival of several tissues. defective lamnin can cause muscular dystrophy and problem in fibroblast. alpha domain helps to interact with integrin. beta and gamma domain are helping in self assembly process. the end of coil-coil domain can interact with integrin. perlecan and dystroglycans. all this interaction will ensure lamnin network formed. 4. type 4 collagen - they are initially monomer but they can form trimers amongst themselves. and these trimers form the meshwork which can be further connected with lamnin lattice. (we talked on collagen network and lamnin lattice. question is how are these 2 connected?) several cementing molecules which work like cement - perlecan and nidogen connect the collagen 4 to lamnin. remember in lamnin we have several perlcan and nidogen interaction domains. in terms of collagen there are several domains that interact with these connective molecules. all of these interactions make the ECM extremely complex structure due to these repetitive meshwork and strong lattic like structures on top of which epithelial cell layers can build. not only have structural roles. it turns out that ep cells receive several important signals to ECM. function of ECM??
Tissue fluid and extracellular fluid are closely related terms that refer to fluid found outside of cells in the body. 1. Tissue fluid: Tissue fluid, also known as interstitial fluid, is the fluid that fills the spaces between cells in tissues. It is derived from blood plasma, as it filters out of capillaries and into the interstitial spaces. Tissue fluid contains water, dissolved nutrients, gases, hormones, and waste products. It plays a vital role in supplying cells with oxygen and nutrients while removing metabolic waste. 2. Extracellular fluid: Extracellular fluid (ECF) is a broader term that encompasses all the fluid outside of cells in the body, including tissue fluid. ECF includes not only interstitial fluid but also other compartments such as plasma (the fluid component of blood) and lymph (the fluid found in lymphatic vessels). Extracellular fluid is essential for maintaining cell function, distributing nutrients and hormones, regulating body temperature, and facilitating waste removal. In summary, tissue fluid specifically refers to the fluid found in the spaces between cells in tissues, while extracellular fluid is a broader term encompassing all fluid outside of cells, including tissue fluid, plasma, and lymph.
