Introduction to Body Tissues PDF

Introduction to body Tissues Doctor explanation. Key information Abbreviation Writer 1: FATIMAH EMAD Writer 2: ABDULLAH AL AMEER Explanation 219-220 notes Mnemonic Book Deleted References Bodytissues There are four basic tissues which include: 1) Epithelium 2) Connective tissue 3) Muscular tiss...

Introduction to body Tissues Doctor explanation. Key information Abbreviation Writer 1: FATIMAH EMAD Writer 2: ABDULLAH AL AMEER Explanation 219-220 notes Mnemonic Book Deleted References Bodytissues There are four basic tissues which include: 1) Epithelium 2) Connective tissue 3) Muscular tissue 4) Nervous tissue All of them are composed of cells and extracellular matrix in different proportions -All organs contain all 4 tissues -Extracellular matrix=biochemical substances –bio molecules Origin of bodytissues In early embryonic life: -Endoderm: epithelial -Mesoderm: connective- epithelial -Ectoderm: nervous system Functions of epithelialtissue Main function:Lining of surface or body cavities; glandular secretion (1)Provide physical protection e.g skin (2) Control permeability e.g intestine (3) Secretory e.g glands (4) Provide sensation 3) All glands are epithelial tissues modified to secret 4)Tongue (Taste buds)-nose (olfactory epithelium) 1 2 3 4 Characteristics of epithelialtissue 1)Closely packed cells with very little extracellular matrix. • 2)The cells are of different shapes (squamous-cuboidalcolumnar). 3)The cells have adhesions and junctions and are arranged as one or more layers. -4) Continuous renewal. Round cell e- long cell flat cell Characteristics of epithelialtissue 5) Non vascular 6)Rest on basal lamina(basement membrane ). 7)Supported by connective tissue (lamina propria). 5) Takes the nutrients from the underlining connective tissue. 6)Made of extracellular materials (macromolecules) Epithelial tissue Basement membrane Connective tissue Connective tissue Connective tissue if these is blood Vessels in epthelial tissue thats mean " canso " Characteristics of epithelialtissue 8)Because different poles(apical-basal) contain different proteins +different organelles. 8)Show polarity. 9)Show apical membrane modifications like cilia and microvilli 8)The region of the cell contacting the ECM and connective tissue is called the basal pole and the opposite end, usually facing a space, is the apical pole, with the two poles differing significantly in both structure and function. 9) Microvilli : gives more surface area for absorption (ex-small intestine) Cilia: longer and larger microvilli cilia Classification (types) of epithelium Covering and lining epithelium Glandular epithelium Cover the surfaces and line body cavities Epithelial cells are specialized to secrete Classification of covering epithelium I According to the number of layers One layer Simple epithelia Stratified epithelium Two or more layers Classification of covering epithelium squamous II According to the cell shape cuboidal columnar Basallamina Definition: Extracellular boundary between epithelium and connective tissue. Functions: - Attachment/support - Filter (sieve) Reticular lamina: collagen fibers under basal lamina Basement membrane: -Basal lamina + Reticular lamina - Seen by LM ( +ve PAS staining) https://youtu.be/IZ3ffJQwFfU Structure: under EM Simpleepithelia ( a) Simple squamous epithelium Description: - Flattened cells with flat central nuclei . -1layer of squamous cells. -thinnest(rapid diffusion) Air sacs of lung tissue Function: - diffusion and filtration Nuclei of squamous epithelial cells Location: - Kidney glomeruli; - air sacs (alveoli) - Endothelium (blood and lymphatic vessels) - Mesothelium. Peritoneum Kidney glomeruli Simpleepithelia -1layer of cuboidal cells. (b) Simple cuboidal epithelium Description: - With large, spherical central nuclei. Simple cuboidal epithelial cells Function: - Secretion and covering. Basement membrane Location: - Kidney tubules -Thyroid gland -ovary surface Connective tissue Kidney tubules Simple epithelia (c) Simple columnar epithelium Description: - with round to oval basal nuclei -May have microvilli, cilia, goblet cells Function: - Absorption; - Secretion. - Protection Location: -lining of stomach, intestine and gall bladder - Lining of uterine tubes stomach mucosa. -1layer of columnar cells. -most common in the digestive tract -in fallopian tubes Simple epithelia iast (d) Pseudostratified columnar epithelium Gives false impression (mostly columnar cells) Description: -Single layer of cells of differing heights - nuclei seen at different levels - may be with goblet cells and cilia. Cilia Function: - Secretion - Protection -Propulsion of mucus by ciliary action. Location: Respiratory epithelium of upper air ways (nasal cavity, trachea and bronchi Trachea Pseudo-stratified epithelial layer Photomicrograph: Pseudostratified ciliated columnar epithelium lining the human trachea (570x). Basement membrane Stratified epithelia (a) Stratified squamous epithelium -thickest-strongest epithelium. Description: - Several cell layers with -Basal layers: cuboidal to columnar - Intermediate layer: polyhedral Non keratinized -Surface layers: flattened (squamous) Location: -Non keratinized:, mouth, esophagus, vagina, anal canal - keratinized: epidermis of the skin Function: - Protection and prevents water loss keratinized Stratified epithelia (b) Transitional epithelium Description: - surface cells are dome shaped (umbrella /large cuboidal)/ may be binucleated Function: - protection - distensibility. Transitional epithelium ‫ﺗﺗﻣدد‬ Location: - ureters, urinary bladder Basement membrane Connective tissue Glandularepithelium Classification of glandular epithelium Exocrine glands Have ducts which carry their Secretion e.g salivary and sweat glands Endocrine glands Lack ducts/secrete hormones which pass directly into the blood capillaries e.g pituitary and thyroid glands Classification of exocrineglands I. According to the number of cells Unicellular e.g Goblet cells multicellular e.g salivary gland Classification of exocrineglands II. According to the mode of secretion Merocrine The most common method Exocytosis e.g salivary gland Apocrine e.g mammary gland -Merocrine: exocytosis. Merocrine -Apocrine: detach of the upper part Apocrine -Holocrine:enlarg and explod . Holocrine Holocrine e.g sebaceous gland Classification of exocrineglands -Serous : protein. -Seromucous: mixed. -Mucous: carbohydrates . serous Watery e.g parotid salivary gland III. According to the nature of secretion Mixed “seromucous” e.g submandibular salivary gland mucous thick mucus e.g sublingual salivary gland Connective tissue One of the basic tissues in the body characterized by abundant extracellular matrix (ECM). ECM: Extracellular matrix It is the opposite from epithelial tissue. -Epithelial tissue consists MAINLY of cells and small amount of extracellular matrix (ECM). -Connective tissue consists MAINLY of ECM and small amount of cells. Characteristics of Connectivetissue 1)One of the basic tissues in the body characterized by abundant extracellular matrix (ECM). 2)Variation in CT types is mainly due to the difference in the composition and structure of ECM. 3) Originate from mesenchyme (mesoderm) epithelium Connective tissue Connective tissue Functions of connectivetissue The main functions are: 1) Supportive -Providing and maintaining the shape and form of organs. -Binding and connecting tissues and cells together. 2) Nutritive Because it contains blood vessels which supply cells with nutrients. -Providing a medium for diffusion of nutrients and waste products to and from the cells. 3) Immunological or defense role - Providing immune cells for immunological reactions. Connective tisuue contain immune cells & it is the site of immunological reactions. Functions of connectivetissue These 2 pictures only explain the functions and they are not very important. Structure of connective tissue ‫اﻟﻔرق ﺑﯾن ﻛﻼ اﻟﻧوﻋﯾن‬ Epithelial & Connective tissues .‫ھو اﻟﺧﻠطﺔ‬ -Epithelial tissue has more abundant cells. -Connective tissue has more abundant ECM. Extracellular matrix Protein fibers collagen, elastic , reticular Ground substance and interstitial fluid Cells Blood vessels Structure of connective tissue C F cells fibers G Cells of connective tissue Fixed - Fibroblasts - Adipocytes -Mesenchymal cells Free - Macrophage – Mast cells - Plasma cells -White blood cells ‘leucocytes’ Derived from the bone marrow. Cellsof connectivetissue Any protein-producing cell, its cytoplasm is basophilic (Blue) Fibroblasts The most common cell type Description: -Golgi apparatus -branched cells with basophilic Because: the cell cytoplasm “RER” and central oval, exports protein vesicular nucleus -Ribosomes(attached) Function: -Synthesis of all extracellular matrix components (ground substances/ fibers) Types: -Active (fibroblasts) - Inactive (fibrocytes) fibrocyte Branched fibroblast The organelles of inactive fibrocytes are small & not found in big numbers. fibroblast fibrocyte Cellsof connectivetissue White adipocytes (fat cells) Description: -polyhedral cells, contain one huge lipid droplet and nucleus is flattened and eccentric -With H & E stain: signet ring appearance Function: - Storage of neutral fats. - Production of heat. -Endocrine function: Production of “hormone leptin” ‫ﺧﺎﺗم أﺑو ﻓص‬ White fat cells Cellsof connectivetissue Macrophages…….???? Macrophage M Cellsof connectivetissue Macrophages (histiocytes): Mother cell of Macrophage Description: -Irregular surface, many lysosomes and well developed Golgi -Develop from monocytes (type of white blood cells) Function: -Phagocytosis of any foreign particles or foreign organisms. - Immunological role -Comprise a system of phagocytes called mononuclear phagocyte system macrophage Cellsof connectivetissue Mast cells: Description: -Cytoplasm is filled with basophilic secretory granules Function: - Immunological role: Examples of allergic reaction: -Urticaria -Astham Responsible for allergic reaction (release of histamine and heparin) These cells consist of blue granules (vesicles), so it basohilic. They contain histamine and heparin Plasma cells: Description: -basophilic cytoplasm (RER), clockface nucleus Origin: - Blymphocytes Function: -Immunological role: Production of antibodies Cells of Connective tissue: Leucocytes (Lecuco= white , cytes=cells) Cellsof connectivetissue Connective tissuefibers 3 types: Collagen fibers: Elastic fibers: Reticular fibers: Description: Description: - Elongated - Thinner thancollagen fibers - Branching -Not formbundles but form networks - Faintly acidophilic Description: - Short - Thin - Branching - Form networks - Not seen with H &E - Argyrophilic ( i.epositive stain with silversalts) -elongated, tortuous and cylindrical - Non branching -May form bundles and bundles may branch - Acidophilic It is stained black after impregnation with silver salts and are thus termed argyrophilic (Gr. argyros, silver) Connective tissue fibers 3 types Collagen fibers: Elastic fibers: Reticular fibers: Ground Substance of Extracellular matrix in Connective Tissue • Transparent mixture of large molecules (Mixture of carbohydrates and proteins) • Glycose-aminoglycans • Proteoglycans • glycoproteins • Mixed with water (hydrated) • Function: • • • • Fills the spaces between cells. Glue cells with fibers and each other (adhesive) Lubricant barrier Protection “adult CTtypes” ‘Areolar’ Elastic and reticular tissues Most common type of connective tissues (Blood andlymph) Connective tissuetypes MainlyCT fibers Mainlyground substances Connective tissue proper“TYPES” Variety Loose: Low Loose areolar collagen amount connective tissue Ground substance Collagen fibers Dense: High collagen amount Dense irregular Connective tissue Ground substance Collagen fibers Dense regular Connective tissue Characteristic Much ground substance, many types of cells , fibers randomly distributed Less ground substance, less cells, collagen fibers irregularly arranged Regularly arranged collagen fibers, fibroblast few arranged in lines Function Support blood vessels, fills spaces, immunity Protect and support organs Provide strong connections in musculoskeletal system Examples Lamina propria beneath epithelial lining 1 Loose Dermis of skin, organ capsules Tendons, ligaments of joints 2 Dense Connective tissue proper LOOSE CONNECTIVE TISSUE Epithelium of skin DENSE IRRREGULAR CONNECTIVE TISSUE– DERMIS OF SKIN DENSE REGULAR CONNECTIVE TISSUE– TENDON Embryonic connectivetissue (Mesenchyme)