1. UNIT 11: Body Tissues, Excretion, and Digestion Chapters 21 and 22

2. Structural hierarchy in a human: Anatomy - study of the structure of an organism and its parts Physiology - study of the function of these structures 5 Levels of Organization: Cell - basic unit of all living organisms. (Ex: muscle cell) Tissue - a collection of many structurally similar cells that act to perform a specific function (Ex: cardiac muscle tissue) Organ - 2 or more tissues packaged into 1 working unit that performs a specific function (Ex: Heart) Organ System - teams of organs that work together to perform vital body functions (Ex: Circulatory System) Organism (Ex: coordination of all systems working together)

3. Tissues - 4 Types of : 1. Epithelial, 2.Connective, 3.Muscle and 4.Nervous 1. Epithelial -covers surface of body, lines organs and cavities. Sheets of tightly packed cells riveted together. Ex: outer layer of skin, linings of heart, blood vessels digestive tract, respiratory tract, genitourinary tract. Sweat glands and mammary glands - secrete chemical substances Surface-lining epithelium is continually shedding old cells and growing new ones. Entirely renewed every 2 weeks. Rapid cell division = cancer risk Ex: skin, lung, breast carcinomas

4. Types of Epithelial Tissue:

5. 2. Connective Tissue - 6 major types of: Sparse cells scattered (not tightly packed) through an extracellular matrix. The matrix is a web of protein fibers embedded in liquid blood, jelly-like adipose tissue, or solid bone. Binds and supports other tissues. Ex: Dermis lies under the epidermis. Dermis contains blood and fluids that nourish the epidermis. See 6 types to left, and on next pages.

6. a. Loose connective - most widespread, binds epithelia to underlying tissues, holds organs in place. Loose weave of protein fibers (ex: collagen), very strong, has elastic fibers. (Ex: under the skin) b. Adipose connective - stores fat in closely packed cells in sparse matrix of fibers. Fats stores energy, insulates body. Contains large globule of fat;cell swells when fat is stored, shrinks when fat is used for energy. con’t.