Tissue Types I. General information A. Every tissue has a ECM that is outside the cell II. Epithelial tissue A. Definition - tissue composed of layers of closely spaced cells that cover organ surfaces, form glands, and serve for protection, secretion, and absorption. B. Representative locations - epidermis, inner lining of the digestive tract, liver and other glands. III. Connective tissue A. Definition - tissue with more matrix that cell volume, often specialized to support, bind together and protect organs.
B. Representative locations - tendons and ligaments, cartilage and bone, and blood. C. Epithelium is anywhere where you need to covering and underneath that is a connective tissue. IV. Nervous tissue A. Definition - Tissue containing excitable cells specialized for rapid transmission of coded information to other cells. B. Representative locations - Brain, spinal cord, nerves. C. nervous tissue send signals to the muscular tissue. V. Muscular Tissue A. Definition - tissue composed of elongated, excitable cells specialized for contraction
B. Representative locations - skeletal muscles, heart (cardiac muscles), walls of viscera (smooth muscle) 4-2 Epithelial Tissue I. General information A. Includes epithelia (layers of cells that cover internal or external surfaces) & glands (produce fluid secretions) II. Characteristics A. Cellularity - mostly cellular tissue and little ecm B. Polarity - cells are polar meaning they are imbalanced in charged. you have abundance of one charge in one place and abundance in another.
Ex. the top part of a cell can have cilia and the bottom another cell C. Attachment - epithelial cells have specific attachment D. Avascularity - they don’t contain blood supply. E. Regeneration - they are replaced easily. this is present in other tissue types but epithelial has the highest rate. When you have good blood supply that brings O2 and nutrients to help cell division. Being able to divide (mitosis) is an important function. Blood vessels bring growth factors to help cells divide. III. Functions - read about these in textbook A. Protection - B. Control Permeability C. Sensation D. Produce Secretions 1. Glandular Epithelial Tissue
IV. Specialization of Epithelial Cells A. Apical surface 1. Microvilli- They are membrane extensions containing microfilaments. They help create modifications to increase surface area, which is helpful in absorption of nutrients. This is why it's found in digestive system. 2. Cilia - a micro organelle in the nose. they help to push things out that don’t need to be there (this is why you sneeze). They are adaptations of the plasma membrane a) The cilium moves by ciliary movement (power stroke and return stroke). B. Lateral surface
1. Occluding/Tight junction - stop transport of material from one cell to another. they lock any transport of molecules. 2. Gap Junction - they contain proteins. The proteins on two
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