TISSUE PDF

TISSUE  Group of similar cells that perform a common function. MATRIX  Nonliving intercellular material.  PRIMARY GERM LAYERS ECTODERM  Epithelium (Epidermis) of the skin  Lining of mouth, anus, nostrils  Sweat and sebaceous glands  Epidermal derivatives (...

TISSUE  Group of similar cells that perform a common function. MATRIX  Nonliving intercellular material.  PRIMARY GERM LAYERS ECTODERM  Epithelium (Epidermis) of the skin  Lining of mouth, anus, nostrils  Sweat and sebaceous glands  Epidermal derivatives (hair, enamel of teeth)  Nervous system (Brain and spinal cord)  Epithelial (Sensory) parts of eyes, nose, ear MESODERM  Muscle  Skeleton (bones and cartilages)  Blood  Epithelial Lining of the blood vessels  Dermis of skin and dentin of teeth  Organs (except lining) of excretory and reproductive systems  Connective tissues ENDODERM  Epithelium (lining) of digestive and respiratory system  Secretory parts of liver and pancreas  Urinary bladder  Epithelial lining of Urethra  Thyroid, parathyroid, thymus  EPITHELIAL TISSUE Epithelial Tissue   Covers and protects the body surface, lines body cavities, specializes in moving substances into and out of the blood (Secretion, excretion, and absorption) and forms many glands.  Subdivision:  Membranous (Covering or Lining) epithelium- covers the body and some of its parts and lines the serous cavities (pleural, pericardial, and peritoneal), the blood and lymphatic vessels, respiratory, digestive, and genitourinary tracts.  Glandular epithelium- is grouped in solid cords or specialized follicles that form the secretory units of endocrine and exocrine glands. FUNCTIONS:  Protection- relatively tough and impermeable epithelial covering of the skin that protects the body from mechanical and chemical injury and also from invading bacteria and other disease- causing microorganism.  Sensory function- specialized sensory function are found in the skin, nose, eye and ear.  Secretion- Secretory products include hormones, mucus, digestive juices, and sweat.  Absorption- epithelium of the gut and respiratory tract allow for the absorption of the nutrients and gases.  Excretion- epithelial lining of kidney tubules makes he excretion and concentration products in the urine. GENERALIZATION ABOUT EPITHELIAL TISSUE  Limited amount of matrix material  Membranous type attached to a basement membrane.  Avascular.  Cells are in close proximity with many desmosomes and tight junctions.  Capable of reproduction. CLASSIFICATION BASED on SHAPE (MEMBRANOUS)  Squamous- cells are flat and platelike came from latin word “Scaly”.  Cuboidal Cells- are cube-shaped and have more cytoplasm than the scalelike squamous cells.  Columnar Epithelial Cells- are higher than they are wide and appear narrow and cylindrical.  Pseudostratified Columnar Epithelial- has only one layer of oddly shaped columnar cells. CLASSIFICATIONS BASED on LAYERS OF CELLS SIMPLE EPITHELIUM  Simple squamous epithelium   One-cell layer of flat cells.  Permeable to many substances.  Found in endothelium lines in blood vessels; mesothelium in pleura.  Simple cuboidal epithelium  One-cell layer of cuboidal –shaped cells.  Found in many glands and duct.  SIMPLE COLUMNAR EPITHELIUM  Single layer of tall, column-shaped cells  Cells often modified for specialized functions such as Goblet cells (Secretion), cilia (Movement), microvilli (Absorption).  Often lines hollow visceral structure.  Pseudostratified Columnar Epithelium  Columnar cells of differing heights.  All cells rest on basement membrane but may not reach the free surface above.  Cell nuclei at odd and irregular levels.  Found lining air passages and segments of male reproductive system.  Motile, cilia, and mucus are important modifications.  STRATIFIED EPITHELIUM  Stratified epithelium (Keratinized)  Multiple layers of flat, squamous cells  Covering the outer skin on body surface  Stratified Epithelium (Nonkeratinized)  Lining of vagina, mouth, and esophagus  Free surface is moist.  Stratified Cuboidal Epithelium  Two or more rows of cells are typical.  Basement membrane is indistinct.  Located in sweat gland ducts and pharynx.  Stratified Columnar Epithelium   Multiple layers of columnar cells.  A rare type and located only in segments of male urethra and near anus.  Stratified Transitional Epithelium  Located lining of hollow viscera subjected to stress.  Often 10 or more layers thick.  GLANDULAR EPITHELIUM  Specialized for secretory activity.  Exocrine Glands- discharge secretions into ducts.  Endocrine Glands- “Ductless” glands secreted discharge on blood directly. STRUCTURAL CLASSIFICATION OF EXOCRINE GLANDS  Multiple exocrine glands are classified by the shape of their ducts and the complexity of their ducts.  Shapes include tubular and alveolar.  Simple exocrine glands- only one duct leads to the surface.  Compound exocrine glands- Have two or more ducts. FUNCTIONAL CLASSIFICATION OF EXOCRINE GLANDS  Apocrine Glands  Secretory products collect near apex of cell and are secreted by pinching off the distended end.  Holocrine Glands  Secretion products, when released, cause rupture and death of the cell.  Merocrine Glands  Secrete directly through cell membrane.  CONNECTIVE TISSUE CONNECTIVE TISSUE  General Function- Connects, support, transports, and protects.  Four main types:  Fibrous  Loose, ordinary (Areolar)   Adipose  Reticular  Dense  Bone  Cartilage  Hyaline  Fibrocartilage  Elastic  Blood FIBROUS CONNECTIVE TISSUE  Loose connective Tissue  One of the most widely distributed of all tissues.  Intercellular substance is prominent and consists of collagenous and elastic fibers interwoven and embedded in soft viscous ground substance.  Functions-Connection  Several kinds of cells present such as fibroblasts and macrophages, also mast cells, plasma cells, fat cells, and some white blood cells.  ADIPOSE TISSUE  Similar to loose connective tissue but contains mainly fat cells.  Functions-protection, insulation, support, and food reserve.  RETICULAR TISSUE  Forms framework of spleen, lymph nodes, and bone marrow.  Consists of network of branching reticular fibers with reticular cells overlying them.  Functions- defense against microorganisms and other injurious substances, reticular meshwork filters out injurious particles and reticular cells phagocytose them. DENSE FIBROUS TISSUE  Matrix consist of mainly fibers packed densely and relatively few fibroblast cells.  Regular- bundles of fibers are arranged in regular parallel rows.  Irregular- Fibers intertwine to form a thick mat  Locations- composes structures that need great tensile strength, such as tendons and ligaments.   Function- furnishes flexible but strong connection. BONE TISSUE  Highly specialized connective tissue type.  Osteocytes embedded in a calcified.  Inorganic component of matrix accounts for 65 % of total bone tissue.  Functions- Support, protection, point of attachment to muscles and reservoir of minerals.  OSTEON  Structural unit of bone  Spaces for osteocytes called LACUNAE  Matrix present in concentric rings called LAMELLAE  CANALICULI are canals that join lacunae with the central Haversian Canal. CELL TYPES  Osteocyte- Mature, inactive bone cell.  Osteoblast- Active bone-forming cell.  Osteoclast- Bone destroying cell. FORMATION (Ossification)  In membranes example is flat bones of the skull.  From cartilage (Endochondral)- long bones, such as humerus. Cartilage  Chrondrocyte in only cell type present.  Lacunae house cells as in bone.  Avascular- therefore nutrition of cells depends on diffusion of nutrients through matrix.  Heals slowly after injury.  Perichondrium is membrane that surrounds the cartilage. TYPES  Hyaline  Appearance is shiny and translucent.  Most prevalent type of cartilage.  Located at the end s of articulating bones.   Fibrocartilage  Strongest and most durable type of cartilage.  Matrix is semigrid and filled with strong white fibers.  Found in intervertebral disks and pubic symphysis.  Serves as shock-absorbing material between bones at the knee.  Elastic  Contains many fine elastic fibers.  Provides strength and flexibility.  Located in external ear and larynx BLOOD  A liquid tissue that contains neither ground substance nor fibers.  Composition of whole blood.  A liquid fraction (Plasma) is the matrix- 55% of total volume.  Formed elements contribute 45 % of total blood volume.  Erythrocytes, Leukocytes, and Thrombocytes.  Functions- transportation, regulation of body temperature, regulation of body pH, and WBC destroy bacteria.  Circulating blood tissue is formed in the red bone marrow by a process called HEMATOPOIESIS in the Hematopoietic tissue. MUSCLE TISSUE  Types:  Skeletal, or striated voluntary.  Smooth or nonstriated involuntary, or visceral.  Cardiac or striated involuntary.  Microscopic characteristics  Skeletal muscles- Threadlike cells with many cross striations and many nuclei per cell.  Smooth muscle- elongated narrow cells, no cross striations, one nucleus per cell.  Cardiac muscle- branching cells with intercalated disks. NERVOUS TISSUE   Functions- rapid regulation and integration of body activities.  Specialized characteristics  Excitability  Conductivity  Organs  Brains  Spinal Cord  Nerves  CELL TYPES  Neuron- conducting unit system.  Cell body, or soma  Processes  Axon (Single process)- transmit nerve impulse away from the cell body.  Dendrites (One or more)- Transmit nerve impulse toward the cell body.  Neuroglia- special connecting and supporting cell. TISSUE REPAIR  Regeneration  Scar  Epithelial and connective tissue have the greatest ability to regenerate.  Muscle and nervous tissues have a limited capacity to regenerate. BODY MEMBRANES  Thin tissue layers that cover surfaces, line cavities, and divide spaces or organs. EPITHELIAL MEMBRANES ARE MOST COMMON TYPE  Cutaneous membrane (Skin)  Primary organ of integumentary system.  One of the most important organs.  Compose of approximately 16% of body weight.  Serous membrane  Parietal   Visceral  Pleura  Peritoneum  Mucous membrane  Lines and protects organ that open to the exterior of the body.  Found lining ducts and passageways of respiratory and digestive tract.  Connective Tissue Membrane  Do not contain epithelial components.  Synovial membranes- line the spaces between bone in joints.  Have smooth and slick membranes that secret synovial fluid.  Help reduce friction between opposing surfaces in a moveable joint.  Synovial membranes also line BURSAE. Prepared by: CHRISTIAN JAY S. ORTE, RN, RM, MAN, MSN, PhDN, FOPd, FMIOSD Anatomy Professor