Amerman Anatomy & Physiology Chapter 4 Histology

Amerman Anatomy & Physiology Chapter 4 Histology types of tissues are defined by - ANS 1) the kind of cells 2) the number of cells 3) the amount of cells 4) the composition of the extracellular matrix 5) the specific functions tissue - ANS a group of structurally and functionally related cells and their external environment that together perform common functions. definition of histology - ANS study of normal structures of tissues All tissues share two basic components - ANS 1) discrete population of cells that are related in structure and function 2) the surrounding material called extracellular matrix (ECM). extracellular fluid (ECF) is part of ECM. what is the extracellular matrix and what are its two main components - ANS ECM is made up of substances in a liquid, thick gel, or solid that surrounds the cells of a tissue. It's composed of 1) ground substance 2) protein fibers functions of extra cellular matrix - ANS - resist tensile (stretching) and compressive forces - directs cells to their proper places in a tissue and holds them there - regulates development, mitotic activity, and survival of cells in a tissue Ground substance - ANS Makes up most of the ECM. It consists of extra cellular or interstitial fluid, which is made of water, iosn, nutrions, and other solutes, as well as three families of macromolecules. three types of macromolecules in ground substance - ANS 1) glycosaminoglycans (GAGs) 2) proteoglycans 3) cell-adhesion molecules (CAMs) glycosaminoglycans (GAGs) - ANS macromolecule in ground substance that helps trap water in ECM and resist compression. Negative charges in GAG attract positively charged ions in ECF. This creates a concentration gradiet within ECF that draws water out of cells and blood vessels. Examples of GAGs are chondroitin sulfate and hyaluronic acid proteoglycans - ANS macromolecule in ground substsance that help make the ECM more solid and resistant to compression. Made of glycosaminoglycans (GAGs) bound to a protein core to make a very long proteoglycan aggregate that looks like a bottle brush. proteoglycans form a barrier to the diffusion of substances and keep microorganisms out cell-adhesion molecules (CAMs) - ANS macromolecule in ground substance that holds everything in place in ECM. made up of glycoproteins, these bind to stuff and maintain normal tissue architecture structure of protein fibers and three types - ANS embedded in ground substance in ECM, these multiple fibrous subunits with a ropelike structure that provide enormous tensile strength 1) collagen fibers 2) elastic fibers 3) reticular fibers