-There are three different modesof secretion from Exocrine glands: Merocine, Apocrine, and Holocrine.1.Merocinesecretionsare very analogous to exocytosis. Cell makes a secretory product and releases the product via exocytosis into the apical surface of the cell. Just the product itself is being released into the duct. (Ex:Sweat glands)2.Apocrinesecretionsmake a secretory product were part of the plasma membrane (apical surface of the cell) pinches off and becomes part of the secretory product. This is kind of a lipid secretion as well, but not as much as a holocrine secretion because only the apical surface of the cell is becoming part of the product. This is neither endocytosis nor exocytosis, it is an apocrine secretion. (Ex:We find apocrine secretions in Mammary glands, or breast tissue).3.Holocrinesecretionsmake a secretory product where the entire cell dies off and becomes part of that product. Holocrine secretions are always lipid filled and very oily. (Ex:the oil released into hair shafts by the sebaceous glands). It is very oily because the whole cell that is dying off and becoming part of the product is composed of the lipid bilayer membrane. Lipid is very oily.-There are three different typesof secretions: 1.Seroussecretionsare a protein-enzyme rich secretion where water is mixed with enzymes. 2.Mucoussecretionsare a carbohydrate rich secretion mixed with water. 3.Mixedsecretionsare a combination of both serous and mucous secretions.-Epithelium invaginates down and forms the gland that has modified cells that make up the secretory portion of the gland. The cells are modified to make serous, mucous, and mixed secretions. The secretions are then secreted in the duct and are then dumped into the surface of the epithelium.-Exocrine glands secrete product into a duct or the bloodstream. -Most glands are multicellular exocrine glands. But the Goblet Cellis a very unique gland because it is a unicellularexocrine gland. It secretes mucous into many environments of the body to facilitate movement of stuff and help lubricate the epithelium to protect it from physical abrasion.
(Ex:Oral cavity, small/large intestine is loaded with goblet cells. They are NOTfound in the stomach). Interdispersed with the pseudostratified epithelium are goblet cells.
Connective Tissue– does not have many cells and is classified by its extracellular matrix.-Extracellular matrixis composed of two things:1.Ground Substance which is a sugary like medium.2.Fibers(proteins)Functions of Connective Tissue-Structural support- bone supports the body, cartilage supports the ears, nose, and lines the articulate surfaces of bones.-Background tissue - holds everything together. (Ex: Ligaments connect bone to bone. Tendons connect muscle to bones).