Body Tissues PDF

BODY TISSUES, BODY MEMBRANE, AND TISSUE REGENERATION DR LSK. 1 Objectives At the end of the lecture, the student should be able to Discuss the location of principal body tissues Discuss their structure and function Tissue Homeostasis...

BODY TISSUES, BODY MEMBRANE, AND TISSUE REGENERATION DR LSK. 1 Objectives At the end of the lecture, the student should be able to Discuss the location of principal body tissues Discuss their structure and function Tissue Homeostasis 2 Introduction Similar cells with a common function are called tissues. The study of tissues is called histology. There are four (4) primary or major tissue types: 1. Epithelial Tissue 2. Connective Tissue 3. Muscle Tissue 4. Nervous Tissue 3  Intercellular Junctions Tight junctions Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Close space between cells Located among cells that form Cell membrane linings. E.g: Epithelial lining of the bladder Tight junction Desmosomes Form “spot welds” between cells Cell membrane Located among outer skin cells. Cell to cell adhesion E.g cardiac tissues Gap junctions Desmosome Tubular channels between cells Cell membrane Transfer of subst. from one cytoplasm To another. Gap junction Located in cardiac muscle cells 4  Epithelial Tissue General characteristics: Cover organs and the body Line body cavities Line hollow organs Have a free surface Have a basement membrane Are avascular Cells readily divide Cells tightly packed Cells often have desmosomes Function in protection, secretion, absorption, and excretion Classified according to cell shape and number of cell layers 5 Epithelial Tissue Simple squamous: Single layer of flat cells Substances pass easily through Line air sacs Line blood vessels Line lymphatic vessels 6 Epithelial Tissue Simple cuboidal: Single layer of cube-shaped cells Line kidney tubules Cover ovaries Line ducts of some glands e.g Thyroid gland 7 Epithelial Tissue Simple columnar: Single layer of elongated cells Nuclei usually near the basement Membrane at same level Sometimes possess cilia Sometimes possess microvilli Often have goblet cells Line uterus, stomach, intestines 8 Epithelial Tissue Pseudostratified columnar: Single layer of elongated cells Nuclei at two or more levels Appear striated Often have cilia Often have goblet cells Line respiratory passageways 9 Epithelial Tissue Stratified squamous: Many cell layers Top cells are flat Can accumulate keratin Outer layer of skin Line oral cavity, vagina, and anal canal 10 Epithelial Tissue Stratified cuboidal: 2-3 layers Cube-shaped cells Line ducts of mammary glands, sweat glands, salivary glands, and the pancreas 11 Epithelial Tissue Stratified columnar: Top layer of elongated cells Cube-shaped cells in deeper layers Line part of male urethra and part of pharynx 12 Epithelial Tissue Transitional: Many cell layers Cube-shaped and elongated cells Line urinary bladder, ureters, and part of urethra 13  Glandular Epithelium Composed of cells that are specialized to produce and secrete substances There are two (2) types: Endocrine glands are ductless (key word: hormone) Exocrine glands have ducts Unicellular exocrine gland: Composed of one cell Goblet cell Multicellular exocrine gland: Composed of many cells Sweat glands, salivary glands, etc. Simple and compound 14  Summary of Epithelial Tissue Epithelial Tissue- Simple ( Uni-layered) or Stratified ( Multi-layered) Simple epithelium further divided into 1. Squamous 2. Columnar 3. Cuboidal  Squamous- Alveoli lining, endothelium (blood vessel) & endocardium  Columnar ( simple columnar and Ciliated columnar)  Simple columnar e.g Mucus membrane of the stomach and large Intestine  Ciliated Columnar e.g Small Intestine, respiratory tract, and uterus and uterine tube  Cuboidal e.g duct of the glands, thyroid gland  Multi-layered or stratified  Stratified squamous (non-keratinized) e.g Oral cavity, Pharynx and oesophagus  Stratified squamous ( Keratinized ) ee.g..g Skin  Pseudostratified columnar and stratified columnar e.g Male Urethra, Auditory tube, trachea  Stratified cuboidal e.g Mammary gland, sweat gland, salivary  Transitional Epithelial e.g Urinary tracts, renal pelvis, ureter, urethral  Glandular Epithelial – Endocrine and Exocrine gland  Exocrine-Unicellular and Multicellular  Types of glandular secretions e.g Merocrine, Apocrine and Holocrine 15 Structural Types of Exocrine Glands Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Tissue surface Duct Secretory portion Simple tubular Simple branched Simple coiled Simple branched tubular tubular alveolar Compound tubular Compound alveolar 16  Types of Glandular Secretions Merocrine Glands Apocrine Glands Holocrine Glands Fluid product Cellular product Secretory products Salivary glands Portions of cells Whole cells Pancreas gland (?) Mammary glands Sebaceous glands Sweat glands Ceruminous glands Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Pinched off Disintegrating cell portion of cell and its contents Intact (secretion) (secretion) cell Secretion New cell forming by mitosis and cytokinesis (a) Merocrine gland (b) Apocrine gland (c) Holocrine gland 17 Connective Tissues General characteristics: Most abundant tissue type Many functions: Bind structures Provide support and protection Serve as frameworks Fill spaces Store fat Produce blood cells Protect against infections Help repair tissue damage Have a matrix Have varying degrees of vascularity Have cells that usually divide 18 Connective Tissue Major Cell Types Present Fibroblasts Macrophages Fixed cell Wandering cell Most common cell Phagocytic Large, star-shaped Important in injury or Produce fibers infection Mast cells Fixed cell Release heparin Release histamine Wound healing and immune tolerance 19 Connective Tissue Fiber Types Present Collagenous fibers Elastic fibers Thick Bundles of microfibrils Composed of collagen embedded in elastin Great tensile strength Fibers branch Abundant in dense CT Elastic Hold structures together Vocal cords, air passages Tendons, ligaments Reticular fibers Very thin collagenous fibers Highly branched Form supportive networks 20  Connective Tissues Connective Tissue Proper: Specialized Connective Tissue: Loose connective tissue Cartilage Adipose tissue Bone Reticular connective tissue Blood Dense connective tissue Elastic connective tissue 21 Connective Tissue Types Loose Connective Tissue Mainly fibroblasts Fluid to gel-like matrix Collagenous fibers Elastic fibers Bind skin to structures Beneath most epithelia Blood vessels nourish nearby epithelial cells Between muscles 22 Connective Tissue Types Adipose Tissue Adipocytes Cushions Insulates Store fats Beneath skin Behind eyeballs Around kidneys and heart 23 Connective Tissue Types Reticular Connective Tissue Composed of reticular fibers Supports internal organ walls Walls of liver, spleen, lymphatic organs 24 Connective Tissue Types Dense Connective Tissue Packed collagenous fibers Elastic fibers Few fibroblasts Bind body parts together Tendons, ligaments, dermis Poor blood supply 25 Connective Tissue Types Elastic Connective Tissue Abundant in elastic fibers Some collagenous fibers Fibroblasts Attachments between bones Walls of large arteries, airways, heart 26 Connective Tissue Types Bone (Osseous Tissue) Solid matrix Supports Protects Forms blood cells Attachment for muscles Skeleton Osteocytes in lacunae 27  Connective Tissue Types Hyaline cartilage Most abundant Ends of bones Cartilage Nose, respiratory passages Rigid matrix Embryonic skeleton Chondrocytes in lacunae Elastic cartilage Poor blood supply Flexible Three (3) types: External ear, larynx Hyaline Cartilage Elastic Cartilage Fibrocartilage Fibrocartilage Very tough Shock absorber Intervertebral discs Pads of knee and pelvic girdle 28 Connective Tissue Types- hyaline cartilage 29 Connective Tissue Types- elastic cartilage 30 Connective Tissue Types- fibrocartilage 31  Connective Tissue Types Blood Fluid matrix called plasma Red blood cells Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. White blood White blood cells cell Red blood Platelets cells Plasma Transports (extracellular matrix of blood) Defends Platelets Involved in clotting (a) (b) b: © The McGraw-Hill Companies, Inc./Al Telser, photographer Throughout body in blood vessels Heart 32 Types of Membranes There are four (4) types of epithelial membranes: 1. Serous Membranes 2. Mucous Membranes Line body cavities that Line tubes and organs that do not open to the open to outside world outside Lining of mouth, nose, Reduce friction throat, etc. Inner lining of thorax Secrete mucus and abdomen 3. Cutaneous Membranes Cover organs of thorax Covers body and abdomen Skin Secrete serous fluid 4. Synovial Membranes Composed entirely of connective tissue Lines joints 33 Muscle Tissues Skeletal muscle Attached to bones Striated General characteristics: Voluntary Muscle cells also called muscle fibers Smooth muscle Contractile Walls of organs Three (3) types: Skin Skeletal muscle Walls of blood vessels Smooth muscle Involuntary Cardiac muscle Non-striated Cardiac muscle Heart wall Involuntary Striated Intercalated discs 34  Muscle Tissue Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Striations Cytoplasm Nuclei Nucleus Portion of a muscle fiber (a) (b) (a) (b) b: © The McGraw-Hill Companies, Inc./Dennis Strete, photographer b: © The McGraw-Hill Companies, Inc./Al Telser, photographer Skeletal Muscle Smooth Muscle Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Striations Nucleus Intercalated disc (a) (b) b: © The McGraw-Hill Companies, Inc./Al Telser, photographer Cardiac Muscle 35  Nervous Tissue Found in brain, spinal cord, and peripheral nerves Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Functional cells are neurons Cellular process Cytoplasm Neuroglial cells support and Nucleus bind nervous tissue components Cell membrane Neuroglial cells Sensory reception (a) (b) b: © Ed Reschke. Conduction of nerve impulses 36 Any questions? 37