This document discusses the three main types of epithelial tissue: simple epithelium consisting of a single layer of cells, stratified epithelium consisting of multiple layers of cells with only the basal layer attached to the basement membrane, and pseudostratified columnar epithelium which appears stratified but is actually a single layer of cells. It also describes the three basic shapes of epithelial cells - squamous, cuboidal, and columnar - and provides examples of each type of epithelium and its functions.
This document discusses the three main types of epithelial tissue: simple epithelium consisting of a single layer of cells, stratified epithelium consisting of multiple layers of cells with only the basal layer attached to the basement membrane, and pseudostratified columnar epithelium which appears stratified but is actually a single layer of cells. It also describes the three basic shapes of epithelial cells - squamous, cuboidal, and columnar - and provides examples of each type of epithelium and its functions.
This document discusses the three main types of epithelial tissue: simple epithelium consisting of a single layer of cells, stratified epithelium consisting of multiple layers of cells with only the basal layer attached to the basement membrane, and pseudostratified columnar epithelium which appears stratified but is actually a single layer of cells. It also describes the three basic shapes of epithelial cells - squamous, cuboidal, and columnar - and provides examples of each type of epithelium and its functions.
This document discusses the three main types of epithelial tissue: simple epithelium consisting of a single layer of cells, stratified epithelium consisting of multiple layers of cells with only the basal layer attached to the basement membrane, and pseudostratified columnar epithelium which appears stratified but is actually a single layer of cells. It also describes the three basic shapes of epithelial cells - squamous, cuboidal, and columnar - and provides examples of each type of epithelium and its functions.
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TISSUE 3 TYPES OF EPITHELIUM/SHAPES
1. Squamous (skwā′mŭs) cells are flat or scalelike.
INTRODUCTION 2. Cuboidal (cubelike) cells are cube-shaped—about as 1. Cells are organized in layers or groups to form tissues. wide as they are tall. 2. Specialized intercellular junctions (tight junctions, 3. Columnar (tall and thin, similar to a column) cells desmosomes, and gap junctions) connect cells. tend to be taller than they are wide. 3. The study of tissues is called histology. 4. The four major types of human tissue are epithelial, EPITHELIAL TISSUES connective, muscle, and nervous. 1. General characteristics - Epithelial tissue covers all free body surfaces, forms 4 BASIC TYPES OF TISSUE the inner lining of body cavities, lines hollow organs, Epithelial tissue: Forms boundaries between different and is the major tissue of gland environments, protects, secretes, absorbs, filters - Epithelial tissue or an epithelium is a sheet of cells that • Lining of digestive tract organs and other hollow covers a body surface or lines a body cavity (epithe = organs laid on, covering). • Skin surface (epidermis b. A basement membrane anchors epithelium to Connective tissue: Supports, protects, binds other connective tissue. Epithelial tissue lacks blood vessels, tissues together has cells that are tightly packed, and is continuously • Bones replaced. • Tendons c. It functions in protection, secretion, absorption, • Fat and other soft padding tissue excretion, filtration and sensory reception. Muscle tissue: Contracts to cause movement 2. Simple squamous epithelium • Muscles attached to bones (skeletal) a. This tissue consists of a single layer of thin, flattened • Muscles of heart (cardiac) cells through which substances pass easily. • Muscles of walls of hollow organs (smooth) b. It functions in the exchange of gases in the lungs and Nervous tissue: Internal communication lines blood vessels, lymph vessels, and membranes • Brain within the thorax and abdomen. • Spinal cord 3. Simple cuboidal epithelium • Nerves a. This tissue consists of a single layer of cube-shaped cells 3 MAJOR TYPES OF EPITHELIAL TISSUE b. It carries on secretion and absorption in the kidneys 1. Simple epithelium consists of a single layer of cells, and various glands. with each cell extending from the basement membrane 4. Simple columnar epithelium to the free surface. a. This tissue is composed of elongated cells whose 2. Stratified epithelium consists of more than one layer nuclei are near the basement membrane. of cells, but only the basal layer attaches the deepest b. It lines the uterus and digestive tract, where it layer to the basement membrane. functions in protection, secretion, and absorption. 3. Pseudostratified columnar epithelium is a special c. Absorbing cells often possess microvilli. d. This tissue type of simple epithelium. The prefix pseudo- means usually contains goblet cells that secrete mucus. false, so this type of epithelium appears to be stratified 5. Pseudostratified columnar epithelium but is not. It consists of one layer of cells, with all the a. This tissue appears stratified because the nuclei are at cells attached to the basement membrane. There two or more levels. appear to be two or more layers of cells because some b. Its cells may have cilia that move mucus over the of the cells are tall and extend to the free surface, surface of the tissue. whereas others are shorter and do not extend to the c. Its lines tubes of the respiratory system. free surface. 6. Stratified squamous epithelium a. This tissue is composed of many layers of cells; the top layers are flattened. b. It protects underlying cells from harmful (3) Holocrine glands release cells filled with environmental effects. secretions. c. It is the outer layer of the skin and lines the oral cavity, esophagus, vagina, and anal canal. 7. Stratified cuboidal epithelium 5.3 CONNECTIVE TISSUES a. This tissue is composed of two or three layers of 1. General characteristics cube-shaped cells. a. Connective tissue connects, supports, protects, b. It lines the larger ducts of the mammary glands, provides frameworks, fills spaces, stores fat, produces sweat glands, salivary glands, and pancreas. blood cells, protects against infection, and helps repair c. It functions in protection. damaged tissues. 8. Stratified columnar epithelium b. Connective tissue cells usually have considerable a. The top layer of cells in this tissue contains elongated extracellular matrix between them. columns. Cube-shaped cells make up the bottom layers. c. This extracellular matrix consists of fibers, a ground b. It is in part of the male urethra and ductus deferens, substance, and fluid. and parts of the pharynx. 2. Major cell types c. This tissue functions in protection and secretion. a. Fibroblasts produce collagenous and elastic fibers. 9. Transitional epithelium b. Macrophages are phagocytes. a. This tissue is specialized to become distended. c. Mast cells release heparin and histamine. b. It lines the urinary bladder, ureters, and superior 3. Connective tissue fibers urethra. a. Collagenous fibers are composed of collagen and c. It helps prevent the contents of the urinary have great tensile strength. passageways from diffusing out. b. Elastic fibers are composed of elastin and are elastic. 10. Glandular epithelium c. Reticular fibers are fi ne collagenous fibers. a. Glandular epithelium is composed of cells specialized 4. Categories of connective tissues to secrete substances. a. Connective tissue proper includes loose connective b. A gland consists of one or more cells. tissue (areolar, adipose, reticular) and dense connective (1) Exocrine glands secrete into ducts. tissue (dense regular, dense irregular, elastic). (2) Endocrine glands secrete into tissue fluid or b. Specialized connective tissues include cartilage, bone, blood. and blood. c. Exocrine glands are classified according to the 5. Areolar tissue organization of their cells. a. Areolar tissue forms thin membranes between organs (1) Simple glands have ducts that do not branch and binds them. before reaching the secretory portion. b. It is beneath the skin and between muscles. (2) Compound glands have ducts that branch 6. Adipose tissue repeatedly before the secretory portion. a. Adipose tissue is a specialized form of connective (3) Tubular glands consist of simple epithelium- tissue that stores fat, cushions, and insulates. lined tubes. b. It is found beneath the skin; in certain abdominal (4) Alveolar glands consist of saclike dilations membranes; and around the kidneys, heart, and various connected to the surface by narrowed ducts joints. d. Exocrine glands are classified according to the 7. Reticular tissue composition of their secretions. a. Reticular connective tissue largely consists of thin, (1) Merocrine glands secrete watery fluids branched collagenous fibers. without loss of cytoplasm. Most secretory cells b. It supports the walls of the liver, spleen, and are merocrine. lymphatic organs. (a) Serous cells secrete watery fluid 8. Dense regular connective tissue with a high enzyme content. Dense regular connective tissue is largely composed of (b) Mucous cells secrete mucus. strong, collagenous fibers that bind structures as parts (2) Apocrine glands lose portions of their cells of tendons and ligaments. during secretion. 9. Dense irregular connective tissue Dense irregular connective tissue has thicker, randomly 2. Synovial membranes are composed of connective distributed collagenous fibers and is found in the tissue only, and line joints. dermis. 10. Elastic connective tissue Elastic connective tissue is mainly composed of elastic 5.5 MUSCLE TISSUES fibers and imparts an elastic quality to the walls of 1. General characteristics certain hollow internal organs such as the lungs and a. Muscle tissue contracts, moving structures attached blood vessels. to it. 11. Cartilage b. Three types are skeletal, smooth, and cardiac muscle a. Cartilage provides a supportive framework for various tissues. structures. 2. Skeletal muscle tissue b. Its extracellular matrix is composed of fi bers and a a. Muscles containing this tissue usually attach to bones gel-like ground substance. and are controlled by conscious effort. c. It lacks a direct blood supply and is slow to heal. b. Muscle cells are long and threadlike, containing d. Most cartilaginous structures are enclosed in a several nuclei, with alternating light and dark cross- perichondrium, which contains blood vessels. markings (striations). e. Major types are hyaline cartilage, elastic cartilage, c. Muscle cells contract when stimulated by nerve and fibrocartilage. impulses, then immediately relax when they are no f. Cartilage is at the ends of various bones; in the ear; in longer stimulated. the larynx; and in the pads between the bones of the 3. Smooth muscle tissue spinal column, pelvic girdle, and knees. a. This tissue of spindle-shaped cells, each with one 12. Bone nucleus, is in the walls of hollow internal organs. a. The extracellular matrix of bone contains mineral b. Usually it is involuntarily controlled. salts and collagen. 4. Cardiac muscle tissue b. Its cells usually form concentric circles around central a. This tissue is found only in the heart. canals. Canaliculi connect the cells. b. Striated cells, each with a single nucleus, are joined c. It is an active tissue that heals rapidly. by intercalated discs and form branched networks. 13. Blood c. Cardiac muscle tissue is involuntarily controlled a. Blood is composed of cells suspended in fluid. b. Blood cells are formed by special tissue in the hollow 5.6 NERVOUS TISSUES parts of certain bones. 1. Nervous tissue is in the brain, spinal cord, and peripheral nerves. 5.4 TYPES OF MEMBRANES 2. Neurons 1. Epithelial membranes a. Neurons sense changes and respond by transmitting a. Serous membranes nerve impulses to other neurons or to muscles or (1) Serous membranes line body cavities that do glands. not open to the outside. b. They coordinate, regulate, and integrate body (2) They are composed of epithelium and loose activities. connective tissue. 3. Neuroglia (3) Cells of serous membranes secrete watery a. Some of these cells bind and support nervous tissue. serous fluid that lubricates membrane surfaces. b. Others carry on phagocytosis. b. Mucous membranes c. Still others connect neurons to blood vessels. (1) Mucous membranes line cavities and tubes d. Some are involved in cell-to-cell communication opening to the outside of the body. (2) They are composed of epithelium and loose connective tissue. (3) Cells of mucous membranes secrete mucus. c. The cutaneous membrane is the external body covering commonly called skin.