Presentation on theme: "T ISSUES AND M EMBRANES C HAPTER 6 Joe Pistack MS/ED."— Presentation transcript:
T ISSUES AND M EMBRANES C HAPTER 6 Joe Pistack MS/ED
T ISSUES Tissues-groups of cells that are similar to each other in structure and function. Four Major types: epithelial connective nervous muscular Histology- the study of tissues.
E PITHELIAL T ISSUE Also called epithelium. Forms large continuous sheets. Helps form skin and covers entire outer surface of the body. Line most of the inner cavities such as the mouth, respiratory tract, reproductive tract.
E PITHELIAL T ISSUE Primarily concerned with: protection absorption filtration secretion Abundant in organs such as digestive tract. Forms glands that secrete a variety of hormones and enzymes.
E PITHELIAL T ISSUE Characteristics: Forms continuous sheets. Cells fit together snugly like tiles. Has two surfaces, one surface is always unattached, like the skin or lining of the mouth. Under surface attaches to basement membrane (very thin material that anchors epithelium to underlying structures).
E PITHELIAL T ISSUE Avascular-has no blood supply. Nourished from blood supply from underlying connective tissue. (able to repair and regenerate quickly).
Classified-according to shape and number of layers. Three Shapes: squamous cuboidal columnar
CLASSIFICATION Squamous epithelium-cells are thin and flat like fish scales. Cuboidal epithelium-cells are cubelike, look like dice. Columnar epithelium-cells are tall and narrow, look like columns. Epithelial cells-arranged in layers.
CLASSIFICATION Simple epithelium-one layer. Stratified epithelium-two or more layers. Shape and number of layers are used to describe types of epithelium.
S IMPLE E PITHELIA One layer of cells. Layer is thin. Concerned primarily with the movement, or transport of various substances across the membranes from one compartment to another. Simple squamous epithelium-single layer with an underlying basement membrane. Found where substances move by rapid diffusion or filtration.
Found in the walls of capillaries-(the smallest blood vessels). Eg.-the walls of the alveoli-(air sacs of the lungs). The tissue allows the rapid diffusion of oxygen from alveoli into the blood.
S IMPLE CUBOIDAL EPITHELIUM Single layer of cells resting on a basement membrane. Cuboidal in shape. Found in glands and kidney tubules. Functions in the transport and secretion of various substances.
S IMPLE C OLUMNAR E PITHELIUM Single layer of columnar cells resting on its basement membrane. Tall, tightly packed cells. Line the entire length of the digestive tract. Play a major role in absorption of the products of digestion. Goblet cells-modified columnar cells that produce mucous.
P SEUDOSTRATIFIED COLUMNAR EPITHELIUM Single layer of columnar cells. Cells are irregular shaped, appear multilayered. Pseudostratified means falsely stratified. Function is to facilitate absorption and secretion.
S TRATIFIED E PITHELIA Multilayered, stronger than simple epithelia. Function-protective function for tissues exposed to everyday wear and tear. Found in the mouth, esophagus, and skin.
T RANSITIONAL E PITHELIUM Found primarily in organs that need to stretch such as the bladder. Transitional because the cells slide past one another when tissue is stretched.
G LANDULAR E PITHELIA Function-secretion. Two types of glands: 1. exocrine 2. endocrine Exocrine glands-contain ducts or tiny tubes into which the exocrine secretions are released before reaching the body surfaces or body cavities. Ducts carry the exocrine secretions outside the body.
G LANDULAR E PITHELIA Exocrine secretions include; mucous, sweat, saliva, and digestive enzymes. Eg. Sweat flows from the sweat glands through ducts onto the surface of the skin for evaporation.
E NDOCRINE GLAND Secrete hormones, such as insulin. Do not have ducts, called ductless glands. Because endocrine glands are ductless, hormones are secreted directly into the blood. Blood then carries the hormone to the site of action.
C ONNECTIVE TISSUE Connects or binds parts of the body together. Most abundant of the four types of tissue. Widely distributed throughout the body. Found in blood, under the skin, in bone and around many organs. Other functions, support, protection, fat storage, and transport of substances.
C ONNECTIVE TISSUE Although different types of connective tissue do not resemble each other closely they do share two characteristics: 1. Most connective tissue have a good blood supply except ligaments, tendons, and cartilage. 2. All connective tissues have an abundance of intercellular matrix. Intracellular matrix-material that makes the types of tissues so different Within connective tissue are fibers made of protein. They are: Different types-collagen, elastin, and reticular fibers. 1. Collagen- strong and flexible not easily stretched 2. Elastin- very strong but stretchy 3. Reticular- like collagen but finer and smaller
T YPES OF CONNECTIVE TISSUE Different Types: Loose connective tissue Dense fibrous connective tissue Cartilage Bone Liquid connective tissue (blood & lymph)
T YPES OF CONNECTIVE TISSUE Loose connective tissue: contains fibers that are loosely arranged around cells. Three types of connective tissue: areolar adipose reticular
T YPES OF LOOSE CONNECTIVE TISSUE Areolar Tissue: Made up of collagen and elastin fibers in a gel- like intercellular matrix. Surrounds, protects, and cushions many of the organs. Acts like “tissue glue” holds the organs in position.
T YPES OF CONNECTIVE TISSUE Adipose Tissue: Type of loose connective tissue. Stores fat Forms the tissue layer underlying the skin (subcutaneous). Insulates the body from extremes of outside temperature.
T YPES OF CONNECTIVE TISSUE Reticular connective tissue: Network of delicately interwoven cells and reticular fibers. Forms the internal framework for lymphoid tissue such as the spleen, lymph nodes, and bone marrow.
T YPES OF CONNECTIVE TISSUE Dense fibrous connective tissue: Composed of an intercellular matrix that contains many collagen and elastic fibers. Fibers form strong, supporting structures such as tendons, ligaments, capsules and fascia.
D ENSE FIBROUS CONNECTIVE TISSUE Supporting structures: Tendons-cordlike structures composed of dense fibrous connective tissue that attach muscle to bone. Ligaments-dense fibrous connective tissue that cross joints and attach bones to each other. Capsules-dense fiber forms tough capsules around such organs as the kidney and liver. Fascia-dense fibrous connective tissue that forms bands or sheets to cover muscle, blood vessels and nerves.
T YPES OF CONNECTIVE TISSUE Cartilage: Formed by chondrocytes or cartilage cells. Cartilage secrete a protein-containing intercellular matrix that is firm, smooth and flexible Perichondrium-layer of connective tissue that covers cartilage, carries blood vessel supply to the cartilage.
T YPES OF CARTILAGE Three types of cartilage: Hyaline cartilage Elastic cartilage Fibrocartilage Hyaline cartilage is found in in the: larynx or voicebox, ends of long bones and joints, the nose and the area between the breastbone and the ribs. Elastic cartilage is found in the external ear and larynx Fibrocartilage is found in the intervertebral discs, pads in the knee joint, and in the pubic bone
T YPES OF CONNECTIVE TISSUE Bone Tissue (osseous tissue): Bone cells are called osteocytes. Bone cells secrete an intercellular matrix that includes, collagen, calcium salts, and other minerals. Bone acts as a storage site for mineral salts, especially calcium Collagen provides flexibility and strength, and the mineral containing matrix as a whole makes the bone tissue hard. The hardness enables protection of organs such as the brain.
O STEOPOROSIS Occurs when mineralization of bone tissue is diminished. Bone is weakened and tends to break easily. Adequate intake of dietary calcium is essential for strong bones. Calcium is needed throughout the life cycle. Estrogen encourages the deposition of calcium in bone tissue.
T YPES OF CONNECTIVE TISSUE Blood and Lymph: Two types of connective tissue that have a watery intercellular matrix. Form a liquid connective tissue. Blood consists of blood cells surrounded by a fluid matrix called plasma.
N ERVOUS TISSUE Nervous Tissue: Makes up the brain, spinal cord, and nerves. Consists of two types of cells: neurons and neuroglia. Neurons-nerve cells that transmit electrical signals to and from the brain and spinal cord. Neuroglia-cells that support and take care of neurons.
M USCLE TISSUE Muscle tissue: Composed of cells that shorten, or contract. Cause movement of body part by shortening and contracting. Three types of muscle tissue are: Skeletal (striated) Smooth (non-striated) Cardiac
S KELETAL M USCLE Skeletal Muscle: Generally attached to bones. Appears to be striped or striated. Moves the muscle, maintains posture, and stabilizes the joints.
S MOOTH M USCLE Smooth Muscle: Generally found in the walls of the viscera or organs such as the stomach, intestines and urinary bladder. Also found in tubes, such as breathing passages and blood vessels. Function is related to the organ in which it is found. As an example, stomach muscle help to churn food, bladder muscles help to expel urine.
C ARDIAC M USCLE Cardiac Muscle: Found only in the heart. Functions to pump blood into a vast network of blood vessels. Cardiac muscle fibers are long branching cell that fit together tightly at junctions. Arrangement promotes rapid conduction of electrical signals throughout the heart.
T ISSUE R EPAIR Two types of tissue repair: 1. regeneration-replacement of tissue by cells that are identical to the original cells. 2. fibrosis-replacement of injured tissue by the formation of fibrous connective tissue or scar tissue.
T ISSUE REPAIR Pressure ulcer-(bedsore) formerly known as a decubitus ulcer Ulcer that is caused by an interruption of the blood supply to the tissue. Decubitus comes from the Latin word meaning to lie down. Caused by the weight of the body on the skin overlying a boney area. E.g.. Elbow, heel, hip, sacrum. Weight of the body compresses the blood vessels, cutting off the supply, tissues are deprived, tissue dies, forming an ulcer. Keloid Scar - excessive fibrosis at an injury site
MEMBRANES Membranes: Thin sheets of tissue that cover surfaces, line body cavities and surround organs. Classified as epithelial or connective tissue.
M EMBRANES Epithelial membranes: Includes the cutaneous membrane (skin), mucous membranes, and the serous membranes. Cutaneous membranes: The outer layer of the skin (epidermis) is stratified squamous epithelium. The underlying layer (dermis) is composed of fibrous connective tissue.
M UCOUS MEMBRANES Mucous membranes: Line all body cavities open to the exterior. Include: digestive, urinary, reproductive, and respiratory tracts. Mucous membranes secrete mucous. Mucous keeps the membranes moist and lubricated.
S EROUS MEMBRANES Serous membranes: Line the ventral body cavities, which do not open to the exterior. Parietal layer-part of the membrane that lines the walls of the cavity. Visceral layer-part of the membrane that covers the outside of an organ.
S EROUS MEMBRANES Three serous membranes: Pleurae-found in the thoracic cavity. Parietal pleura-line the walls of the thoracic cavity. Visceral pleura-cover each lung. Pleural cavity-space between the pleural layers.
S EROUS MEMBRANES Pleurisy-inflammation of the pleura and a decrease in serous fluid. Inflamed and dry pleura membranes slide past one another during breathing movements. Patient experiences pain.
S EROUS MEMBRANES Pericardium membranes: Found in the thoracic cavity and partially surrounds the heart. Parietal and visceral pericardium offers a slinglike support to the heart. Pericardial cavity-space between the pericardial membranes.
S EROUS MEMBRANES Peritoneum Membrane: Found within the abdominal cavity. Parietal peritoneum lines its walls and the visceral peritoneum covers the abdominal organs. Peritonitis-infection in the abdominal cavity, can be life threatening.
A S YOU AGE Tissues consist of cells, cellular aging alters the tissues formed by the cells. Collagen and elastin decrease in connective tissue, tissues become stiffer, less efficient in functioning. Tissue atrophy causes a decrease in the mass of most organs.