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  • Tissues

  • Hierarchy of organizationAtomsMoleculesCellsTissuesOrgansOrgan systemsOrganism

  • Tissues are the fundamental units of organs and organ systems.

  • Tissues are the fundamental units of organs and organ systems.

  • Tissues are the fundamental units of organs and organ systems.

  • Tissues are the fundamental units of organs and organ systems.

  • Histology is the study of tissues.A tissue is a group of cells and intercellular materials that have a similar developmental origin, structure, and function.

    TissuesLoose connective tissue

  • Know the structure and be able to identify it from a slide. Know the function.Know location in the body it is likely to be found.Know any special attributes of that tissue.

    What you should know about a tissue

  • Identify where the lumen (space) is in the image if you can. Identify where the basement membrane is in the image is you can. The basement membrane is where the tissue stops.Look at how many layers of cells there are. (1)Look at the shape of the cells closest to the lumen. (long)Look for other special features of the tissue. Give the tissue a complete name.

    How to start identifying a tissue image.Image from: http://biology.clc.uc.edu/fankhauser/Labs/Bio_Lab113/Tissues/Human_Histology.html

  • To prepare tissue slides, scientists must slice through the tissue. They can slice in different ways.

    An important thing to remember when looking under the microscopeCross sectionLongitudinal section

  • Epithelial Tissue (Epithelium)functions include protection, absorption, filtration, and secretion.Connective Tissuefunctions include protecting, supporting, binding together tissues, separating, storing energy, transporting materials.Muscle Tissuefunctions in the movement of the skeleton, pumping of the heart and the movement of food. Nervous Tissuesend electrical signals through the body, thus forming a communication system through the body. There are four basic tissue types.

  • Cells fit closely together to form continuous sheets and are bound together at many points by cell junctions.Cells have one free surface or edge. This apical surface is exposed to the bodys exterior or to a cavity (the lumen)The lower cell surface rests on a basement membrane, a structureless material secreted by the cells.These tissues are avascular, meaning that they have no blood supply and depend on diffusion from capillaries in the underlying connective tissueIf well nourished, they can regenerate easily.Characteristics of the epithelium

  • Characteristics of the epithelium apical surface of cells near lumenbasement membraneImage from: http://biology.clc.uc.edu/fankhauser/Labs/Bio_Lab113/Tissues/Human_Histology.html

  • Number of Layers:Simple single layerStratified multiple-layeredPseudostratified only appears to be multi-layered Characteristics of the epithelium

  • Characteristics of the epithelium Cell Shape:

  • Simple Squamous EpitheliumStratified Squamous EpitheliumSimple Cuboidal EpitheliumStratified Cuboidal EpitheliumSimple Columnar EpitheliumStratified Columnar EpitheliumPseudostratified Columnar EpitheliumTransitional Epithelium

    Types of Epithelium

  • Simple squamous Epithelium lines alveoli in lungs.Simple cuboidal EpitheliumForms tubes in kidneys.Simple columnar Epithelium lines the intestine.Stratified squamous Epithelium lines the esophagus.Epithelium is found everywhere.

  • Thin and leakyGood for exchange of materials by diffusionBlood vesselsAlveoli

    Simple squamous epithelium

  • Simple squamous epitheliumImages from: http://biology.clc.uc.edu/fankhauser/Labs/Anatomy_&_Physiology/A&P201/Epithelium/Epithelial_Tissues.htmThese are the same tissue. Why do they look so different?

  • Regenerates rapidly by division of cells at its attached surfaceNew cells move toward the free surface; older cells slough offSuited for covering and lining surfaces subject to abrasion2 types nonkeratinized and keratinizedkeratin is a strong, fibrous protein

    Stratified squamous epithelium

  • Stratified squamous epitheliumImages from: http://biology.clc.uc.edu/fankhauser/Labs/Anatomy_&_Physiology/A&P201/Epithelium/Epithelial_Tissues.htm

  • Mouth, throat, esophagus, urethra, skin (keratinized)

  • Simple Cuboidal epithelium Secretion, absorption, protectionDucts of many glands, covering of ovary, form kidney tubulesStratified Cuboidal epitheliumSecretion, absorptionLines ducts of sweat glands.Cuboidal epithelium

  • Cuboidal epithelium Images from: http://biology.clc.uc.edu/fankhauser/Labs/Anatomy_&_Physiology/A&P201/Epithelium/Epithelial_Tissues.htmKidney section

  • Kidney tubules, glands, lining of terminal bronchioles, etc.

  • Sweat gland ducts, salivary gland ducts, etc.

  • Transportation, absorption, secretion, protectionLarge surface areaLines much of the digestive tract, gall bladder, and large ducts of glandsMay have a brush border of microvilliMay be ciliated uterus, small bronchi, and paranasal sinuses.

    Simple columnar epithelium

  • Simple columnar epithelium Brush borderCiliaImages from: http://biology.clc.uc.edu/fankhauser/Labs/Anatomy_&_Physiology/A&P201/Epithelium/Epithelial_Tissues.htm

  • Goblet Cell secreting mucousCilia

  • Glands, bronchioles, stomach, intestines, bile ducts, etc.

  • Surface cells are columnarSecretion, absorption, protectionSome large excretory ducts, portions of the male urethraNo ciliaNot common

    Stratified columnar epithelium

  • Mammary gland ducts, larynx, urethra (males)

  • Surface cells are columnarSecretion, absorption, lubrication, protection, transportationLines most of trachea, primary bronchi, epididymis and ductus deferens, nasal cavity, male urethra, large excretory ducts.Usually ciliated.May contain goblet cells, which secrete mucous

    Pseudostratified columnar epithelium

  • Pseudostratified columnar epithelium trachea

  • Lines nasal cavity & sinuses, auditory tubes, trachea, bronchi

  • Surface cells are dome-shaped when relaxes but flattened when streched.Protection, distensibleLines urinary tractTransitional epithelium

  • Transitional epithelium Image from: http://erl.pathology.iupui.edu/HISTO/GENER64.HTMDistended bladder

  • Bladder lining, ureters, and superior urethra

  • Glandular Epithelia - Endocrine & exocrine glandsEndocrine Glands - Release hormones into interstitial fluid; no ducts Exocrine Glands - Produce secretions onto epithelial surfaces; through ducts

    Figure 46

  • Modes of SecretionMerocrine secretionFigure 46aApocrine secretion*Are produced in Golgi apparatus *Are released by shedding cytoplasm*e.g., mammary glands

    Are produced in Golgi apparatusAre released by vesicles (exocytosis) e.g., sweat glandsHolocrine secretionAre released by cells bursting, killing gland cellsGland cells replaced by stem cellse.g., sebaceous gland

  • Connective TissueCharacterized by the cells widely separated from each other in a matrix that is produced by the cells.Tissue protects and supports.Cell Matrix composed of two regionsGroundLiquid (sol), Gel, Gum or solidFibersNon-elastic (= white or Collagen)Elastic (= yellow fibers)Types of Connective tissue

  • Types of Connective TissueLoose (Areolar) Connective TissueDense Connective TissueAdiposeCartilageBoneBlood

  • Classification of Connective Tissues (3)Connective tissue proper:connect and protectFluid connective tissues:transportSupportive connective tissues:structural strengthConnective Tissue ProperCategoriesLoose connective tissue:more ground substance, less fibers e.g., fat (adipose tissue)Dense connective tissue:more fibers, less ground substance e.g., tendons

  • 8 Cell Types of Connective Tissue ProperFibroblasts most abundant cell type-in all connective tissue proper & secrete proteins & hyaluronan (cellular cement)Macrophages-large, amoeba-like cells of the immune system:eat pathogens and damaged cells, fixed macrophages stay in tissue, free macrophages migrateAdipocytes-fat cells-each cell stores a single, large fat dropletMesenchymal Cells -stem cells that respond to injury or infection: differentiate into fibroblasts, macrophages, etc.Melanocytes -synthesize and store the brown pigment melaninMast Cells -stimulate inflammation after injury or infection:release histamine and heparin Basophils are mast cells carried by bloodLymphocytes-specialized immune cells in lymphatic system: e.g., plasma cells which produce antibodiesMicrophages -phagocytic blood cells: respond to signals from macrophages and mast cells, e.g., neutrophils and eosinophils

  • Fibers in Connective Tissue ProperCollagen fibers: most common fibers in CTP, strong and flexibleresists force in 1 direction, e.g., tendons and ligamentsReticular fibers: network of interwoven fibers (stroma), strong and flexibleresists force in many directions, e.g., sheaths around organsElastic fibers: contain elastin, return to original length after stretchinge.g., elastic ligaments of vertebrae

  • Ground Substance in Connective Tissue ProperIn connective tissue proper and ground substance: is clear, colorless, and viscousfills spaces between cells and slows pathogens

  • Loose Connective Tissues The packing materials of the body 3 types in adults: areolar, adipose, reticular

    Areolar Tissue - Least specialized, Elastic fibers, Holds blood vessels and capillary beds (e.g., under skin (subcutaneous layer))

    Adipose Tissue-White fat:most common, stores fat, slows heat loss (insulation) Brown fat: more vascularized, breaks down fat, produces heat

    -- Reticular Tissue-Supportive fibers (stroma) that support functional cells,reticular organs: spleen, liver, lymph nodes, and bone marrow.

  • Loose Connective Tissue (Areolar)Gel like ground with both elastic and non-elastic fibers running though the ground in many directions.Wraps and cushions organsUnder the skin

  • Adipose (Fat)Function as storage cells for adipose (lipids)Adipose cells contain a large vacuole which in the live cell contains lipids.Cell nucleus and cytoplasm are pushed out to edge of cell membrane.

  • Dense Connective TissuesConnective tissues proper, tightly packed with high numbers of collagen or elastic fibers: dense regular connective tissue Attachment and stabilizationtendons, ligamentsdense irregular connective tissueInterwoven networks of collagen fibers layered in skin, around cartilage, around bones, form capsules around some organs (e.g., liver, kidneys)elastic tissue made of elastic fiberselastic ligaments of spinal vertebrae

  • Dense Regular Connective TissueNuclei and fibers arranged in parallel rows.Tendons and ligamentsFibers mostly non-elastic

  • Fluid Connective TissuesFluid connective tissues: blood and lymphwatery matrix of dissolved proteinscarry specific cell types (formed elements)

  • Vascular Tissue (Blood)Liquid matrix = plasma 90% water10%Plasma proteins, electrolytes, hormones, oxygen, glucose etc.Formed elementsErythrocytes -48billion(female) to 54 billion (male) cell / ml of blood in humans. Mammals are enucleated while rest of the vertebrates they have nucleiLeukocytes -about 7.5 million / ml of bloodPlatelets -blood clotting

  • Blood

  • Supportive Connective TissuesSupport soft tissues and body weight:cartilage: gel-type ground substancefor shock absorption and protectionbone: calcified (made rigid by calcium salts, minerals)for weight support

  • Cartilage Matrix Proteoglycans, ground substance proteins, cells (chondrocytes) surrounded by lacunae (chambers)Cartilage Structure No blood vessels:chondrocytes produce antiangiogenesis factorPerichondrium:outer, fibrous layer (for strength), inner, cellular layer (for growth and maintenance)

  • CartilageGround of matrix is gum like.Cells are found in Lacunae within the matrix.Fibers may be elastic or non-elastic, or a form of non-elastic called reticular(where the non-elastic fibers of very thin)Hyaline Cartilage-example on the ends of bonesElastic Cartilage- example ear cartilageNon-elastic Cartilage- example nose cartilage.

  • Types of Cartilage (3)Hyaline cartilage, Elastic cartilage, FibrocartilageHyaline cartilage:stiff, flexible supportreduces friction between bonesfound in synovial joints, rib tips, sternum, and trachea

  • Hyaline cartilage

  • Elastic cartilage:supportive but bends easilyfound in external ear and epiglottisFibrocartilageLimits movementPrevents bone-to-bone contactPads knee jointsFound between pubic bones and intervertebral discs

  • Elastic Cartilage

  • BoneGround of matrix is Solid (Calcium carbonate).Has blood supply and nerves running through the Haversian canal systems.

  • BoneAlso called osseous tissue:strong (calcified: calcium salt deposits)resists shattering (flexible collagen fibers)Bone Cells - Osteocytes:arranged around central canals within matrixsmall channels through matrix (canaliculi) access blood supplyPeriosteum: covers bone surfacesfibrous layercellular layer

  • 4 Types of Membranes

    How do epithelial and connective tissues combine to form 4 types of membranes?Membranes - are physical barriers that line or cover portions of the body consisting of an epithelium and supported by connective tissuesMucousSerousCutaneousSynovial

  • Mucous membranes (mucosae):line passageways that have external connections also in digestive, respiratory, urinary, and reproductive tractsMucous Tissues Epithelial surfaces must be moist to reduce friction, to facilitate absorption and excretion Lamina propria is areolar tissue

  • Serous MembranesLine cavities not open to the outsideAre thin but strongHave fluid transudate to reduce frictionSerous membranes: double, have a parietal portion covering the cavity and a visceral portion (serosa) covering the organsPleural membrane lines pleural cavities covers lungsPeritoneum lines peritoneal cavity covers abdominal organsPericardium lines pericardial cavity covers heart

  • Cutaneous membrane:is skin, surface of the bodythick, waterproof, and dry

  • How do connective tissues form the framework of the body?Connective tissues:provide strength and stabilitymaintain positions of internal organsprovides routes for blood vessels, lymphatic vessels, and nervesfascia:the bodys framework of connective tissue layers and wrappings that support or surround organs

  • 3 Types of FasciaeSuperficial fascia

    Figure 417Deep fasciaSubserous fascia

  • What are the structures and functions of the three types of muscle tissue?Skeletal muscle:large body muscles responsible for movementCardiac muscle:found only in the heart3 Types of Muscle TissueSmooth muscle:found in walls of hollow, contracting organs (blood vessels; urinary bladder; respiratory, digestive and reproductive tracts)

  • Classification of Muscle CellsStriated (muscle cells with a banded appearance): or nonstriated (not banded)Muscle cells can have a single nucleus: or be multinucleateMuscle cells can be controlled voluntarily (consciously):or involuntarily (automatically)

  • Muscle TissueTissue with cells having fibers specialized for contraction.Skeletal Muscle (Striated, voluntary) Parallel elongated cells (fibers) multinucleated and each cell is the length of the muscle.Light meat, Dark meatSlow twitch, fast twitch muscle Smooth Muscle (Visceral, involuntary)Cells are long and tapered. Organized into sheets of muscle.Cardiac MuscleIntercalated discMyogenicbranched

  • Figure 418aSkeletal muscle cells:Striated, voluntary, and ultinucleatedare long and thinare usually called muscle fibersdo not dividenew fibers are produced by stem cells (satellite cells)

  • Skeletal Muscle

  • Cardiac muscle cells:are called cardiocytesform branching networks connected at intercalated disksare regulated by pacemaker cellsstriated, involuntary, and single nucleus

  • Cardiac Muscle

  • Smooth muscle cells:are small and taperedcan divide and regenerate nonstriated, involuntary, and single nucleus

  • Smooth Muscle

  • What is the basic structure and role of neural tissue?Neural tissue is concentrated in the central nervous system:brainspinal cord2 Kinds of Neural CellsNeurons:nerve cells perform electrical communicationNeuroglia:support cellsrepair and supply nutrients to neurons

  • Nervous TissueCells specialized to polarize and depolarize.Cell is a neuron

  • Cell Parts of a NeuronCell body:contains the nucleus and nucleolusDendrites:short branches extending from the cell bodyreceive incoming signalsAxon (nerve fiber):long, thin extension of the cell bodycarries outgoing electrical signals to their destination

  • NeurogliaFigure 419

  • End of Tissue presentation