Chapter 5 Notes

Chapter 5: Tissues I.

Introduction A. Cells are arranged in tissues that provide specific functions for the body B. Cells of different tissues are structured differently, which leads to their differences in function C. Tissues of the human body include four major types: 1. Epithelial Tissues a. widespread throughout the body…covers organs and lines body surfaces b. anchored to a basement membrane c. are made up of tightly packed cells containing little intercellular material d. generally lack blood vessels e. are replaced frequently f. functions in protection, secretion, absorption, excretion, and sensory reception g. there are 9 types of epithelial tissues: 1. Simple Squamous Epithelium -made up of a single layer of thin, flattened cells -functions in the exchange of gases in the lungs -lines blood and lymph vessels as well as body cavities 2. Simple Cuboidal Epithelium -consists of a single layer of cube-shaped cells with centrally located nuclei -functions in secretion and absorption in the kidneys and in secretion in glands 3. Simple Columnar Epithelium -made up of a row of elongated cells whose nuclei are all located near the basement membrane -lines the uterus, stomach, and intestines where it protects underlying tissues, secretes digestive fluids and absorbs nutrients -in the intestines, these cells passes microvilli that increases the surface area available 4. Pseudostratified Columnar Epithelial

-appeared layered due to the varying positions of their nuclei within the rows of cells, but are not truly layered -Cilia may be present -Cilia on these cells aid in moving eggs through the oviducts to the uterus in the female reproductive system 5. Stratified Squamous Epithelium -made up of layers of flattened cells that are designed to protect underlying layers -makes up the outer layer of skin -lines the mouth, throat, vagina, and anal canal 6. Stratified Cuboidal Epithelium -consists of two-three layers of cuboidal cells lining a lumen (opening) of the mammary glands, sweat glands, and pancreas -several layers of cells provide greater protection than a single layer 7. Stratified Columnar Epithelium -consists of several layers of cells -found in part of the male urethra and parts of the pharynx 8. Transitional Epithelium -designed to distend and return to its normal size -found in the urinary bladder -design provides dispensability (stretching) and keeps urine from diffusing back into the internal cavity 9. Glandular Epithelium -made up of cells designed to produce and secrete substances into ducts or into body fluids -exocrine glands- glands that secrete products into ducts -endocrine glands- glands that secrete products into body fluids and blood 2. Connective Tissues

a. Bind, support, protect, serve as frameworks, fill spaces, store fat, produce blood cells, protect against infection and repair tissue damage b. Unlike epithelial tissue, have abundant intercellular material and have good blood supplies (except in cartilage) c. There are 6 types of connective tissues: 1. Loose Connective Tissue -forms delicate, thin membranes, throughout the body that bind body parts together -binds the skin to underlying organs and fills space within muscles 2. Adipose Tissue -designed to store fat -pound beneath the skin around joints, padding the kidneys and other internal organs and in certain abdominal membranes 3. Dense Connective Tissues -consists of densely packed fibers and is very strong but lacks a good blood supply -is found a part of tendons and ligaments 4. Cartilage -provides a supportive framework for various structures -Hyaline Cartilage- is white with abundant white collagen fibers -is found at the end of bones and supports respiratory passages -Elastic Cartilage -provides a framework for the external ears and parts of the larynx -Fibrocartilage -tough tissue that provides a shock absorbing function in intervertebral disks in the knees and pelvic girder 5. Bone -the most rigid connective tissue -bone cells are called Osteocytes

-has a good blood supply enabling rapid recovery after an injury 6. Blood -composed of red and white cells suspended in plasma -formed in the red bone marrow -functions to transport substances throughout the body 3. Muscle Tissue a. Muscle cells or fibers can contract b. Consists of 3 major types: 1. Skeletal Muscle Tissue -attached to bone -can be controlled by conscious effort (voluntary) -cells (muscle fibers) are long and cylindrical, striated (striped) and have many nuclei -contracts from nervous impulses then relaxes 2. Smooth Muscle Tissues -lacks striations, only has one nucleus and consists of spindle shaped cells -is involuntary muscle -found in the walls of internal organs and in the digestive tract, blood vessels and urinary bladder 3. Cardiac Muscle Tissue -found only in the heart -consists of branching fibers that are connected to each other -involuntary muscle -has a single nucleus in each cell, but appears striated 4. Nervous Tissue a. found in the brain, spinal cord, and nerves b. neutrons, or nerve cells, conduct nervous impulses c. neuroglia, or helper cells, support, and nourish the neutrons