UNIT 2. THE TISSUE LEVEL. 2.3. CONNECTIVE TISSUE_2023 2024.pdf
Transcript
Unit 2 TISSUE LEVEL 2.3. CONNECTIVE TISSUE Ve más allá OUTLINE ▪ 2.1 Tissue level & types of tissue. ▪ 2.2 Epithelial tissue. ▪ 2.2.1 General characteristics of epithelial tissue. ▪ 2.2.2 Basement membrane ▪ 2.2.3 Types of epithelium • a. Lining epithelium • b. Glandular epithelium ▪ 2.3 Connecti...
Unit 2 TISSUE LEVEL 2.3. CONNECTIVE TISSUE Ve más allá OUTLINE ▪ 2.1 Tissue level & types of tissue. ▪ 2.2 Epithelial tissue. ▪ 2.2.1 General characteristics of epithelial tissue. ▪ 2.2.2 Basement membrane ▪ 2.2.3 Types of epithelium • a. Lining epithelium • b. Glandular epithelium ▪ 2.3 Connective tissue ▪ 2.4 Membranes © Copyright Universidad Europea. Todos los derechos reservados OUTLINE ▪ 2.3 Connective tissue ▪ 2.3.1 General characteristics of connective tissue ▪ 2.3.2 Connective tissue cells ▪2.3.3 Extracellular matrix • Ground substance • Fibres ▪ 2.3.4 Classification of connective tissues • Embryonic • Mature ▪ 2.3.5 Types of connective tissue • Loose connective tissue • Dense connective tissue ▪2.4 Membranes © Copyright Universidad Europea. Todos los derechos reservados GENERAL CHARACTERISTICS: connective tissue Letters ✔ ✔ ✔ ✔ Syllabes Words Sentences Cells rarely touch due to “extracellular matrix.” Matrix (fibers & ground substance) is secreted by cells. Consistency varies: liquid, gel or solid. Good nerve & blood supply except in cartilage & tendons. © Copyright Universidad Europea. Todos los derechos reservados GENERAL CHARACTERISTICS Abundant and widely distributed. Derives from mesoderm. Cells are derived from MESENCHYME (embryonic connective tissue): mesenchymal cells (MSCs) ▪ Immature cells have names that end in –blast (e.g., fibroblast, chondroblast). ▪ Mature cells have names that end in -cyte (e.g., osteocyte). Ectoderm Mesoderm -BLAST Endoderm -CYTE © Copyright Universidad Europea. Todos los derechos reservados GENERAL CHARACTERISTICS FUNCTIONS · Bind, support, repair and strengthen other tissues. · Protect and insulate internal organs. · Compartmentalize structures (muscles). · Transport (blood). · Storage: ▪ Energy reserves (adipose tissue). ▪ Water and electrolytes in extracellular matrix. · Immune response. © Copyright Universidad Europea. Todos los derechos reservados OUTLINE ▪ 2.3 Connective tissue ▪ 2.3.1 General characteristics of connective tissue ▪ 2.3.2 Connective tissue cells ▪2.3.3 Extracellular matrix • Ground substance • Fibres ▪ 2.3.4 Classification of connective tissues • Embryonic • Mature ▪ 2.3.5 Types of connective tissue • Loose connective tissue • Dense connective tissue ▪2.4 Membranes © Copyright Universidad Europea. Todos los derechos reservados COMPONENTS of CONNECTIVE tissue CELLS + RESIDENT TRANSITORY -Immature (-blast) -Mature (-cyte) - Leucocytes - Macrophages - Mastocytes - Plasma cells LMMP © Copyright Universidad Europea. Todos los derechos reservados EXTRACELLULAR MATRIX FIBRES - Collagen - Reticular - Elastic CRE GROUND SUBSTANCE - Water - Salts - Proteoglycans Flexible WSP + F COMPONENTS of CONNECTIVE tissue © Copyright Universidad Europea. Todos los derechos reservados CELLULAR COMPONENTS RESIDENT (non recruited) - Immature (-blast) - Mature (-cyte) © Copyright Universidad Europea. Todos los derechos reservados TRANSITORY -Leucocytes -Macrophages -Mast cells -Plasma cells CELLULAR COMPONENTS RESIDENT CELLS – Mesenchymal cells (MSCs) – ORIGIN OF other tissue cells – Fibroblasts / Fibrocytes – Connective tissue proper – Adipocytes Adipose – __________ tissue – Osteoblasts /Osteocytes Bones – __________ tissue – Chondroblasts / Chondrocytes Cartilage – __________ tissue © Copyright Universidad Europea. Todos los derechos reservados MESENCHYMAL CELLS • • • Multipotent and undifferentiated. Star-like shape, they differentiate into other cellular types. They normally exist during embryonic stages, but some could last through adulthood. RELEVANCE TO TEETH. Mesenchymal cells form the following differentiated cells: dentin forming odontoblasts, pulp, periodontal ligament. Endometrial mesenchymal cells © Copyright Universidad Europea. Todos los derechos reservados MESENCHYMAL CELLS Some cells into which they differentiate Chondroblaste/cyte Adipocyte Oestblast/Osteocytes Mesenchymal cell Fibroblast Endothelial cell Mesothelial Cell Chondrobla Adipocyt e st Fibroblas t Chondrocyt es © Copyright Universidad Europea. Todos los derechos reservados Mesotheli al Cell Endothelia Osteoblas l t Cell Osteocyt e FIBROBLASTS ▪ Large flat cells with star-like shape. ▪ Principal active cells of connective tissue. They are in various connective tissues. ▪ They produce FIBRES (collagen and elastic fibres) and the GROUND SUBSTANCE Mouse fibroblasts (amorphous gel-like matrix that fills spaces between cells and fibres). Fibrocytes are mature cells that are trapped within the extracellular matrix and maintain the connective tissue. © Copyright Universidad Europea. Todos los derechos reservados Fibroblast MYOFIBROBLASTS ▪ Modified fibroblasts. ▪ Properties between fibroblasts and smooth muscle cells: they secrete collagen and can also contract. ▪ Abundant in healing areas and in the periodontal ligament. ▪ Actively participate in the formation of the root of the teeth. © Copyright Universidad Europea. Todos los derechos reservados ADIPOCYTES ▪ Form adipose tissue and do not divide by mitosis. ▪ Each adipocyte is surrounded by a net of reticular fibres. ▪ They store triglycerides. ▪ We can find them beneath the skin and around internal organs such as heart and kidneys. Reins ▪ Function: protection, energy store, thermoregulation. ▪ Also known as fat cells or lipocytes. © Copyright Universidad Europea. Todos los derechos reservados ADIPOCYTES © Copyright Universidad Europea. Todos los derechos reservados MORE RESIDENT CELLS • Osteoblasts/ osteocytes • Chondroblasts /chondrocytes © Copyright Universidad Europea. Todos los derechos reservados CELLULAR COMPONENTS TRANSITORY CELLS ORIGIN: pluripotent cells in bone marrow – Macrophages – Plasma cells – Mast cells – Neutrophils – Eosinophils © Copyright Universidad Europea. Todos los derechos reservados Question Which of the following cells synthesize the organic components of the extracellular matrix in connective tissues? a) Macrophages. b) Eosinophils. c) Fibroblasts. d) Mast cells. © Copyright Universidad Europea. Todos los derechos reservados 20 OUTLINE ▪ 2.3 Connective tissue ▪ 2.3.1 General characteristics of connective tissue ▪ 2.3.2 Connective tissue cells ▪2.3.3 Extracellular matrix • Ground substance • Fibres ▪ 2.3.4 Classification of connective tissues • Embryonic • Mature ▪ 2.3.5 Types of connective tissue • Loose connective tissue • Dense connective tissue ▪2.4 Membranes © Copyright Universidad Europea. Todos los derechos reservados CONNECTIVE TISSUE EXTRACELLULAR MATRIX FIBERS GROUND SUBSTANCE Texte - Water - Salts - Proteoglycans © Copyright Universidad Europea. Todos los derechos reservados GROUND SUBSTANCE GOOD AT RESISTING COMPRESSIVE FORCES • Texture: fluid, semifluid, gelatinous or calcified. • Composition: water + salts + proteins + proteoglycans (polysaccharide 95% + protein) – Main polysaccharide: glycosaminoglycans (GAG’s) • Chondroitin sulfate (gelatinous) + • Dermatan sulfate proteins • Keratan sulfate • Hyaluronic acid: dense, viscous, slippery (antiseptic, hydrating) – Adhesion proteins (fibronectins): join collagen fibers with ground substance. © Copyright Universidad Europea. Todos los derechos reservados GROUND SUBSTANCE: GAGs ▪ Capture water, turn the ground surface more jelly-like. • Hyaluronic acid: simplest GAG. viscous substance that brings cells together, maintaining their shape and lubricating them. WBC, sperm and some bacteria make hyaluronidase. Highly negatively charged, inflexible strongly hydrophilic • • • © Copyright Universidad Europea. Todos los derechos reservados Chondroitin sulphate: provides support and adhesiveness to cartilage, bone, skin and blood vessels. Keratan sulphate: bone, cartilage and cornea. Dermatan sulphate: skin, blood vessels, cardiac valves and tendons. GROUND SUBSTANCE: PROTEOGLYCANS Proteoglycan aggregate – glycosamino glycans (GAGs) – hyaluronic acid is thick, viscous and slippery. – adhesion proteins (fibronectin) bind collagen fibers to ground substance. © Copyright Universidad Europea. Todos los derechos reservados Proteoglycan molecule: core Question The glycosaminoglycans (GAGs)… a) … present a high molecular weight. b) … are negatively charged. c) … can be sulfated. d) All the previous statments are correct. © Copyright Universidad Europea. Todos los derechos reservados 26 FIBRES ▪ GOOD AT RESISTING TENSILE FORCES EXTRACELLULAR MATRIX FIBRES - Collagen Collagen - Reticular - Elastic © Copyright Universidad Europea. Todos los derechos reservados Elastin & fibrillin –Collagen that forms fibres – type I (skin, bones, tendons, ligaments). –Collagen associated to fibrils (types I,II,III, V & IX). –Collagen that forms networks in basal lamina (type IV). –Collagen for anchorage VI (basement membrane: basal lamina binding to epidermis). FIBRES • COLLAGEN – Composition: collagen I proteins. – Function: provide strength and resistance to tension. – Allow tissue flexibility. – Location: bone, cartilage, tendons and ligaments. Movement • RETICULAR – Composition: fine collagen fibrils (collagen III and glycoproteins). – Function: support and strength in blood and lymphatic vessel walls. Plenty of them in reticular connective tissue. – Provide a network around cells such as adipocytes, nervous fibers, smooth and skeletal muscle fibers. Found in basement membrane. • ELASTIC (extensile, ability to recoil) – Composition: elastin + fibrillin. – Function: strength and elasticity. – Location: skin, blood vessel walls, lungs. © Copyright Universidad Europea. Todos los derechos reservados FIBRES • COLLAGEN • RETICULAR • ELASTIC © Copyright Universidad Europea. Todos los derechos reservados Question What type of fibers form filtering structures in organs such as spleen and lymph nodes? a) Collagen fibers type I. b) Elastic fibers. c) Reticular fibers. d) All of them. © Copyright Universidad Europea. Todos los derechos reservados 30 Clinical connection Ehlers-Danlos Syndrome (EDS) . In some patients, EDS is due to mutations in collagen genes. . Symptoms include: HYPERMOBILITE ARTICULAIRE Joint hypermobility, which may cause frequent discolationss (i.e.: temporomadicular joint luxation). • Strechly skin. • Fragile skin. • https://www.compleowaco.com/ehlers-danlos-syndrome/ © Copyright Universidad Europea. Todos los derechos reservados 31 CLINICAL APPLICATION Mutation in fibres MARFAN SYNDROME • Inherited disorder of fibrillin gene • Abnormal development of elastic fibers. – Tendency to be tall with very long legs, arms, fingers and toes. – Life-threatening weakening of aorta may lead to rupture. High arched palate OSTEOGENESIS IMPERFECTA • Mutations in Collagen I. • Weak bones that fracture easily. Dentinogenesis imperfecta. EHLERS-DANLOS SYNDROME • Type III collagen • Fragile skin, blood vessels and hypermobile joints (luxations in TMJ). Internal use OUTLINE ▪ 2.3 Connective tissue ▪ 2.3.1 General characteristics of connective tissue ▪ 2.3.2 Connective tissue cells ▪2.3.3 Extracellular matrix • Ground substance • Fibres ▪ 2.3.4 Classification of connective tissues • Embryonic • Mature ▪ 2.3.5 Types of connective tissue • Loose connective tissue • Dense connective tissue ▪2.4 Membranes © Copyright Universidad Europea. Todos los derechos reservados CLASSIFICATION OF CONNECTIVE TISSUE Matur e Mesenchyme Mucous connective tissue Areolar connective tissue Loose connective Adipose tissue Reticular connective tissue tissue Dense regular connective tissue Dense connective Dense irregular connective tissue tissue Elastic connective tissue Hyaline cartilage Cartilage Elastic cartilage Fibrocartilage Bone tissue Liquid connective tissue © Copyright Universidad Europea. Todos los derechos reservados Blood Lymp h Connective tissue proper Embryoni c OUTLINE ▪ 2.3 Connective tissue ▪ 2.3.1 General characteristics of connective tissue ▪ 2.3.2 Connective tissue cells ▪2.3.3 Extracellular matrix • Ground substance • Fibres ▪ 2.3.4 Classification of connective tissues • Embryonic • Mature ▪ 2.3.5 Types of connective tissue • Loose connective tissue • Dense connective tissue ▪2.4 Membranes © Copyright Universidad Europea. Todos los derechos reservados CLASSIFICATION OF CONNECTIVE TISSUE ▪ EMBRYONIC Mesoderme is the origin of « The response reverses a change in a controlled condition. » and « The response reverses a change in a controlled condition. » Connective tissue that is present primarily in the embryo or fetus. – Mesenchyme: tissue from which all other connective tissue arise. Found almost exclusively in the embryo. – Mucous connective tissue: (Wharton’s jelly) is found in the umbilical cord of the fetus. What is the unique jellatinous tissue ? © Copyright Universidad Europea. Todos los derechos reservados CLASSIFICATION OF CONNECTIVE TISSUE ▪ EMBRYONIC: mesenchymal • Mesenchymal cells are irregular. • Semifluid ground substance contains reticular fibres. • Location: embryo (first 2 months of pregnancy). Foetus: from 3rd month until birth. © Copyright Universidad Europea. Todos los derechos reservados CLASSIFICATION OF CONNECTIVE TISSUE ▪ EMBRYONIC: Warton’s jelly • Fibroblasts in jelly-like ground substance that contains collagen fibers. • Found in umbilical cord to give support to the vein and arteries. © Copyright Universidad Europea. Todos los derechos reservados OUTLINE ▪ 2.3 Connective tissue ▪ 2.3.1 General characteristics of connective tissue ▪ 2.3.2 Connective tissue cells ▪2.3.3 Extracellular matrix • Ground substance • Fibres ▪ 2.3.4 Classification of connective tissues • Embryonic • Mature ▪ 2.3.5 Types of connective tissue • Loose connective tissue • Dense connective tissue ▪2.4 Membranes © Copyright Universidad Europea. Todos los derechos reservados CLASSIFICATION OF CONNECTIVE TISSUE ▪ MATURE Loose connective tissue (skin) Ligament s Adipos e tissue Cartilag e Bloo d © Copyright Universidad Europea. Todos los derechos reservados Bon e MATURE CONNECTIVE TISSUE ▪ Connective tissue proper Matur e Loose connective tissue Dense connective tissue © Copyright Universidad Europea. Todos los derechos reservados Areolar connective tissue Adipose tissue Reticular connective tissue Dense regular connective tissue Dense irregular connective tissue Elastic connective tissue MATURE CONNECTIVE TISSUE ▪ LOOSE CONNECTIVE TISSUE • Cell types: fibroblasts, plasma cells, macrophages, mast cells and a few white blood cells. • All types of fibers present: collagen, reticular, elastic. • Ground substance: gelatinous (semifluid). • Location: beneath epithelial membranes and glandular epithelium, papillary dermis, mucosal lamina propria, blood vessels and nerves. © Copyright Universidad Europea. Todos los derechos reservados LOOSE CONNECTIVE TISSUE ▪ AREOLAR: beneath epithelia, external wrapping of vessels, nerves and muscles. • • • • Black lines= elastic fibres. Brown/pink= collagen. Most common cell type fibroblasts (nuclei are mostly from them). FUNCTION: allows for diffusion of oxygen and nutrients between microvasculature and adjacent tissue. © Copyright Universidad Europea. Todos los derechos reservados LOOSE CONNECTIVE TISSUE WH ▪ ADIPOSE: found wherever areolar tissue is located, primarily beneath the skin. Adipose tissue consists of adipocytes which are specialized for storing triglycerides (calories, fat). – Functions: • Reduces heat loss through the skin. • Energy reserve. • Support and protection. • Generation of heat. Brown fat in newborns allows maintenance of body temperature. – Highly vascularized. – Subtypes: white and brown (many mitochondria). © Copyright Universidad Europea. Todos los derechos reservados WHITE FAT TISSUE LOOSE CONNECTIVE TISSUE ▪ WHITE ADIPOSE TISSUE • Peripheral nuclei due to large fat storage in one droplet. • Located in the deeper layer of skin and surrounding abdominal organs. • Function: important for organ padding and energy storage. © Copyright Universidad Europea. Todos los derechos reservados LOOSE CONNECTIVE TISSUE C ▪ BROWN ADIPOSE TISSUE Called « ANGEL » • Several fat droplets are located in the cytoplasm; they are numerous and may present several sizes. • Brown fat has more blood vessels and mitochondria and is responsible for heat generation (keeping the baby or an hibernating animal warm). © Copyright Universidad Europea. Todos los derechos reservados © Copyright Universidad Europea. Todos los derechos reservados 47 LOOSE CONNECTIVE TISSUE ▪ RETICULAR It consists of fine interlacing reticular fibres and reticular cells. • Functions: – Forms the stroma (scaffold) of certain organs (liver, spleen, lymphatic ganglia). – Brings the cells of smooth muscle together. – Filtration (spleen, blood, lymph) to remove dead cells and microbes. © Copyright Universidad Europea. Todos los derechos reservados DENSE CONNECTIVE TISSUE ▪ DENSE REGULAR • Numerous, thicker and denser fibres. Fewer cells. • Collagen fibres in parallel bundles with fibroblasts in between. • White, tough and pliable (forms tendons and ligaments). • Also known as white fibrous connective tissue. • Function: binding of structures. © Copyright Universidad Europea. Todos los derechos reservados DENSE CONNECTIVE TISSUE ▪ DENSE IRREGULAR • Collagen fibers are irregularly arranged (interwoven in all directions). • Function: tissue can resist tension from any direction. • Location: white of eyeball, dermis of skin, capsular membranes, cardiac valves, fascia. © Copyright Universidad Europea. Todos los derechos reservados DENSE CONNECTIVE TISSUE ▪ ELASTIC • • • • Branching elastic fibers and fibroblasts. Can stretch & still return to original shape. Function: allows organ stretching. Location: lung tissue, true vocal cords, some ligaments between vertebrae, walls of large arteries (aorta) © Copyright Universidad Europea. Todos los derechos reservados CONNECTIVE TISSUE within the ORAL CAVITY ▪ Loose and dense connective tissue : LAMINA PROPRIA. Sublingual mixed connective tissue. © Copyright Universidad Europea. Todos los derechos reservados Gingival recession: connective tissue implant from palate.. © Copyright Universidad Europea. Todos los derechos reservados What type of connective tissue is shown in the picture? Indicate name, cells, fibres, characteristics of ground substance, function and location. https://www.earthslab.com/wp-content/uploads/2018/08/irregular.jpg © Copyright Universidad Europea. Todos los derechos reservados 54 What type of connective tissue is shown in the picture? icate name, cells, fibres, characteristics of ground substance, function and location. https://i.pinimg.com/originals/bf/c7/4c/bfc74c44e0cbc4a9f66cbb67c1ad0c04.jpg © Copyright Universidad Europea. Todos los derechos reservados 55 VIDEOS ▪ https://www.youtube.com/watch?v=i5tR3csCWYo ▪ (HISTOLOGY / 4 types of BODY TISSUES) ▪ https://www.youtube.com/watch?v=D-SzmURNBH0 ▪ (connective tissue and curious facts about it) RESEARCH PAPERS Oral anatomy and tissue types. Semin Dermatol. 1994 Jun;13(2):68-73. © Copyright Universidad Europea. Todos los derechos reservados Bibliography ▪ Silverthorn DU. "Human Physiology: An Integrated Approach”. 7th Edition. Pearson eds, 2016. ▪ Tortora GJ & Derrickson B. "Principles of Anatomy and Physiology”. 14th Edition. Wiley eds, 2014. ▪ Netter, FH. “Atlas of Human Anatomy: with Student Consult Access”. 6th Edition. Saunders Elsevier eds, 2014. ▪ Sobotta "Sobotta - Atlas of Human Anatomy”. 15th Edition. Elsevier eds, 2011. ▪ Stevens A, & Lowe J.S. “Human Histology: With STUDENT CONSULT Online Access”. 4th Edition. Elsevier eds, 2015. © Copyright Universidad Europea. Todos los derechos reservados Natural Sciences Museum, Madrid THANK YOU Ve más allá © Copyright Universidad Europea. Todos los derechos reservados
