Tissues Chapter 5

Four Major types:  Epithelial: form protective coverings, fxn in secretion and absorption  Connective: supports soft body parts and bind structures together  Muscle: produces body movements  Nervous: conducts impulses that help control and coordinate body activities.

Epithelial Tissues Found throughout the body, covers organs, lines body cavities and lines hollow organs. It always has a free (apical) surface (not covered) Underside is attached to connective tissue by a thin, nonliving layer called the basement membrane. Usually is lacking in blood vessels, receiving nutrients by diffusion from connective tissue

Epithelieal Continued Readily divide, resulting in fast healing injuries Readily divide, resulting in fast healing injuries Tightly packed: making good protective barriers to the outside Tightly packed: making good protective barriers to the outside Some invloved in absorption, excretion, and excretion. Some invloved in absorption, excretion, and excretion. Classified according to shape, number of layers of cells Classified according to shape, number of layers of cells

Classification Of Epithelial Cells Squamous: thin, flattened cells Cuboidal: cube shaped Columnar: tall, elongated Single layers: simple Stratified: two or more layers The free surface epithelial cells are modified in ways that reflect their specialized functions.

Simple Squamous Epitheleal Con. Line air sacs (alveoli) of lungs. Forms walls of capillaries Lines the insides of blood and lymph vessels Covers the membranes that line body cavities Because they are so thin, they are easily damaged.

Simple Cuboidal Epithelial Cells Single Layer Cube shaped Covers ovaries and most of the kidney tubules and the ducts of certain glands Functions in secretion and absorption in glands of the kidneys and secrets glandular products.

Simple Cuboidal Eptherlium

Simple Columnar Epithelium  Elongated: longer than they are wide  Single layer of cells, with elongated nuclei.  May be ciliated  Ciliated cells in the female reproductive tubes cilia aid in movement of the egg  Nonciliated SCE cells line the uterus and most organs of the digestive tract including the stomach and both intestines/

SCE The elongation leads to the formation of thick tissue which provides protection for underlying tissues The elongation leads to the formation of thick tissue which provides protection for underlying tissues Some secrete digestive fluids and absorb nutrients from digested foods Some secrete digestive fluids and absorb nutrients from digested foods Those specialized for absorption often have many tiny extensions from their surfaces called microvilli to increase surface area for greater absorption Those specialized for absorption often have many tiny extensions from their surfaces called microvilli to increase surface area for greater absorption

SCE ► Specialized flask shaped glandular cells (goblet cells) are often scattered among them. They secrete a protective fluid (mucus) onto the free surface of the tissue

Simple Columnar Epithethelium Cells

Pseudostratified Columnar Epithelium Appear to be stratified/layered but are not. Appear to be stratified/layered but are not. This is due to nuclei of the cells are found in two or more layers. All of the cells share the same basement membrane. Some of them may not contact the free surface. This is due to nuclei of the cells are found in two or more layers. All of the cells share the same basement membrane. Some of them may not contact the free surface. Commonly have cilia. Commonly have cilia. Goblet cells in this tissue secrete mucus. Goblet cells in this tissue secrete mucus. Found in passages of respiratory system. Found in passages of respiratory system.

Pseudostratified Columnar

Stratified Squamous Epi Relatively thick Relatively thick Cell division occurs in deeper layers and newer cells push older ones to the surface where they flatten. In naming stratified epi tissues, based on cell shape, the appearance of the top layer is used. Cell division occurs in deeper layers and newer cells push older ones to the surface where they flatten. In naming stratified epi tissues, based on cell shape, the appearance of the top layer is used. Forms the outer layer of the skin. As skin cells age, they accumulate a protein called keratin, then harden and die. Keritinization pr4oduces a covering of dry, tough protective material preventing water and other substances from escaping and blocking various chemicals and microorganisms from entereing. Forms the outer layer of the skin. As skin cells age, they accumulate a protein called keratin, then harden and die. Keritinization pr4oduces a covering of dry, tough protective material preventing water and other substances from escaping and blocking various chemicals and microorganisms from entereing. Stratifired Squ. Epi lines the oral cavity, esophagus, vagina and anal canal. Here it is not keratinized, stays soft and moist and surface cells remain alive. Stratifired Squ. Epi lines the oral cavity, esophagus, vagina and anal canal. Here it is not keratinized, stays soft and moist and surface cells remain alive.

Stratified Squamous epi

Stratified Cuboidal Epi Two or 3 layers of cuboidal cells forming a lining of a lumen. Provides more protection than a single layer of cells. Two or 3 layers of cuboidal cells forming a lining of a lumen. Provides more protection than a single layer of cells. Lines larger ducts of the mammary glands, sweat glands, salivary glands, and pancreas. Also forms the lining of developing ovarian follicles and seminiferous tubules. Lines larger ducts of the mammary glands, sweat glands, salivary glands, and pancreas. Also forms the lining of developing ovarian follicles and seminiferous tubules.

Stratified cuboidal Epi

Stratified Columnar Epi Several layers of cells Several layers of cells Superficial cells are columnar, base layers are cuboidal. So, look for layers of cells and a change to columnar in the outer layer. Superficial cells are columnar, base layers are cuboidal. So, look for layers of cells and a change to columnar in the outer layer. Found in male urethra and ductus deferens and in parts of pharynx Found in male urethra and ductus deferens and in parts of pharynx

Stratified columnar Epi

Transitional Epi Specialized to change in response to increased tension. Forms inner lining of bladder and lines ureters. Specialized to change in response to increased tension. Forms inner lining of bladder and lines ureters. When contracted, there will be several layers of cuboidal cells. Distended, there will be less layers. When contracted, there will be several layers of cuboidal cells. Distended, there will be less layers. Also helps provide a barrier to prevent urinary tract contents from diffusing back in to the internal environment. Also helps provide a barrier to prevent urinary tract contents from diffusing back in to the internal environment.

Transitional Epi