Lecture 3 Tissue COVID (4) PDF

Tissue Level of Organization Tissues Collections of cells and cell products that perform specific, limited functions Histology: study of tissues  Classification of Tissues Epitheliu Connectiv Muscle Neural m...

Tissue Level of Organization Tissues Collections of cells and cell products that perform specific, limited functions Histology: study of tissues  Classification of Tissues Epitheliu Connectiv Muscle Neural m e Epitheli Glands Skeleta Smooth a l Cardia Endocri Exocrin Neuron Neurogli ne e Fluid CT c CT proper a Supportive Dense Blood Lymph CT Loose Bone Cartilage IrregularRegular Areolar Adipose Reticular Elastic Hyaline ElasticFibrocartilage  Types of Tissues Epitheliu Connectiv Muscle Neural m e Supports other Specialized for tissues contraction Fills internal spaces Skeletal, cardiac & No contact with the smooth muscles environment Covers exposed Carries electrical surfaces signals from one Lines internal part of the body to passageways another Forms glands Epithelial Tissue Characteristics of Epithelial Tissue 1. Cellularity (cell junctions) 2. Polarity (apical and basal surfaces) 3. Attachment (basement membrane) 4. Avascularity (no blood vessels) 5. Regeneration Functions of Epithelial Tissue Physical protection Control permeability Sensation (neuroepithelium) Secretions (glandular epithelium) Increasing Surface Area Microvilli increase absorption or secretion Cilia (ciliated epithelium) move fluids Integrity of Epithelial Tissue Maintained by: ̶intercellular connections ̶attachment to basement membrane ̶maintenance and repair Intercellular Connections (Cell Junctions) Bonds between adjacent cells Support and communication Tight junction Include: Adhesion belt tight junctions Terminal web gap junctions desmosomes:  belt Gap junctions  button (spot) Spot desmosome Hemidesmosome Basement Membrane (Basal Lamina) 2 layers: lamina lucida: Separates epithelium from   thin layer produced by epithelium CT lamina densa:  thick fibers Clear layer Basement  produced by connective tissue Dense membrane layer Attachment of epithelial cells to basal lamina: hemidesmosomes Maintenance & Repair of Epithelial Cells Epithelia are replaced by division of germinative (stem) cells: ̶near basal lamina Classes of Epithelial Tissues Epithelia: (aka surface epithelium) layers of cells covering external or lining internal surfaces Glands: structures that produce secretions Classes of Surface Epithelium Cell Shape Layers Squamous Simple epithelium: epithelia: – single layer of cells flat shaped Stratified Cuboidal epithelia: epithelium: square shaped – several layers of Columnar cells epithelia: tall shaped Squamous Epithelium Simple squamous epithelium Stratified squamous epithelium Simple Squamous Epithelium Most delicate epithelium: diffusion and absorption Mesothelium – endothelium – lung alveoli Stratified Squamous Epithelium Toughest type of epithelium: physical protection Skin – lining of mouth, esophagus, rectum, vagina, … Cuboidal Epithelium Simple cuboidal epithelium Stratified cuboidal epithelium Transitional epithelium Simple Cuboidal Epithelium Absorption and secretion Renal tubules – thyroid gland Stratified Cuboidal Epithelium a r e Protection, absorption, and secretion R Sweat and mammary gland ducts ! Transitional Epithelium Stretch and recoil Urinary bladder – ureters Columnar Epithelium Simple columnar epithelium Stratified columnar epithelium Pseudostratified columnar epithelium Simple Columnar Epithelium Absorption and secretion Stomach – Intestine – uterine tubes Stratified Columnar Epithelium Protection Salivary gland ducts Pseudostratified Columnar Epithelium Protection, secretion, and cilia movement Trachea – bronchi Glandular Epithelium Endocrine Exocrine glands glands  Endocrine Glands No ducts (ductless glands) Release hormones into interstitial fluid blood e.g., thyroid gland – adrenal gland –... s t e m e S y c r i n n d o h e E i n t s s e d i s c u b e d W i l l Exocrine Glands Have ducts Produce secretions ducts epithelial surfaces E.g., sweat glands Modes of secretion: merocrine secretion apocrine secretion holocrine secretion Merocrine Secretions Released by vesicles (exocytosis) e.g., sweat glands – salivary glands Apocrine Secretions tay Released by shedding cytoplasm l s s e.g., mammary gland l Ce live a Holocrine Secretions ll s Ce Released by cells bursting Gland cells are replaced by stem cells e.g., sebaceous gland d i e Types of Exocrine Glands Serous glands: ̶watery secretions ̶e.g., parotid salivary gland Mucous glands: ̶secrete mucins ̶e.g., sublingual salivary gland Mixed exocrine glands: ̶both serous and mucous ̶e.g., submandibular salivary gland Structure of Exocrine Glands Unicellular glands Multicellular glands Unicellular Exocrine Glands Goblet cells: the only unicellular exocrine gland scattered among epithelia:  e.g., in intestinal lining secrete mucin Multicellular Exocrine Glands Structure of the duct: simple (undivided) compound (divided) Shape of secretory portion: tubular (tube shaped) alveolar/acinar (blind pocket/chamber) tubuloalveolar/tubuloacinar Relationship between ducts and glands: branched (several secretory areas sharing 1 duct) Simple Multicellular Exocrine Glands Compound Multicellular Exocrine Glands Match the following organs to the correct epithelial lining 1. Urinary bladder A. Simple squamous 2. Skin B. Simple cuboidal 3. Renal tubule C. Transitional 4. Trachea D. Stratified columnar 5. Artery E. Stratified squamous F. Pseudostratified col Match the following organs to the correct epithelial lining 1. Urinary bladder A. Simple squamous 2. Skin B. Simple cuboidal 3. Renal tubule C. Transitional 4. Trachea D. Stratified columnar 5. Artery E. Stratified squamous F. Pseudostratified col Salivary gland ducts Connective Tissue Function of Connective Tissues Connect epithelium to the rest of the body Provide structure Store energy Transport materials Components of Connective Tissues Specialized cells Extracellular matrix (most of tissue volume): solid: protein fibers fluid: ground substance Classification of Connective Tissues Connective tissue proper: connect and protect (fat & tendons) Fluid connective tissues: transport (blood & lymph) Supportive connective tissues: structural strength (cartilage & bone) Classification of Connective Tissues Connective tissue proper: connect and protect (fat & tendons) Fluid connective tissues: transport (blood & lymph) Supportive connective tissues: structural strength (cartilage & bone) Connective Tissue Proper Cells Matrix Fibers Ground substance Cells of Connective Tissue Proper Permanent Migratory Residents Lymphocyt Fibroblasts es Adipocytes Macrophag Mesenchymal es cells Microphage Melanocytes s Mast cells Cells of Connective Tissue Proper Permanent Migratory Residents Lymphocyt Fibroblasts es Adipocytes Macrophag Mesenchymal es cells Microphage Melanocytes s Mast cells Fibroblasts Most abundant cell type Found in all connective tissue proper Secrete: proteins hyaluronan (cellular cement) Adipocytes Fat cells Each cell stores a single, large fat droplet Mesenchymal Cells Stem cells Divide to compensate for injury: differentiate into fibroblasts, macrophages, etc. Melanocytes Synthesize and store the brown pigment Cells of Connective Tissue Proper Permanent Migratory Residents Lymphocyt Fibroblasts es Adipocytes Macrophag Mesenchymal es cells Microphage Melanocytes s Mast cells Lymphocytes Specialized immune cells in blood & lymphatic system 2 main types: T & B lymphocytes B lymphocytes may develop into plasma cells which produce antibodies Macrophages y tos i s goc Large, amoeba-like cells P ha Part of the immune system: engulf pathogens and damaged cells 2 conditions: free macrophages migrate:  e.g., monocytes in blood fixed macrophages stay in tissue:  e.g., kupffer cells in the liver Microphages y tos i s goc P ha Small, phagocytic blood cells Respond to signals from macrophages and mast cells e.g., neutrophils and eosinophils Mast Cells Stimulate inflammation after injury or infection Granules release histamine and heparin Basophils are mast cells carried by blood Antibodies secreting cells are: A. Mast cells B. T Lymphocytes C. Eosinophils D. Plasma cells E. Basophils Antibodies secreting cells are: A. Mast cells B. T Lymphocytes C. Eosinophils D. Plasma cells E. Basophils Fibers of Connective Tissue Proper Collagen fibers Reticular fibers Elastic fibers All formed by fibroblasts Collagen fibers Most common fibers in CTP Long, straight, and unbranched Strong and flexible Bundle of fibrous protein strands Resist force in 1 direction (along longitudinal axis) e.g., tendons and ligaments