3Match Tissue Type to Function EpithelialConnectiveNervousMuscleSupports, protects, binds other tissues togetherInternal communicationContracts to cause movementForms boundaries between different environments, protects, secretes, absorbs, filters
4Epithelial Tissue (Epithelium) Two main types (by location):Covering and lining epitheliumGlandular epitheliumForms boundaries b/w different environments
5Functions of Epithelial Tissue ProtectionAbsorptionFiltrationExcretionSecretionSensory reception
6Characteristics of Epithelial Tissue Cells have polarityAre composed of closely packed cellsSupported by a connective tissue reticular lamina (under the basal lamina)Avascular but innervatedHigh rate of regeneration
7Classification of Epithelia Ask two questions:How many layers?1 = simple epithelium>1 = stratified epithelium
8Classification of Epithelia What type of cell?SquamousCuboidalColumnarNote: if stratified, name according to apical layer of cells!
9Overview of Epithelial Tissues For each of the following types of epithelia, note:DescriptionFunctionLocation
19Transitional Epithelium DescriptionFunctionLocationPhotomicrograph: Transitional epithelium lining the urinarybladder, relaxed state (360X); note the bulbous, or rounded,appearance of the cells at the surface; these cells flatten andbecome elongated when the bladder is filled with urine.
20Glandular EpitheliaGland: one or more cells that secretes and aqueous fluidClassified by:Site of product releaseEndocrineExocrineRelative number of cells forming the glandUnicellularMulticellular
21Glands Endocrine Exocrine Ductless glands More numerous!GlandsEndocrineExocrineDuctless glandsSecrete hormones that travel through lymph or blood to target organsExamples: Thyroid Gland, Pituitary GlandCovered in Ch. 16Secrete products into ductsSecretions released onto body surfaces (skin) or into body cavitiesExamples: mucous, sweat, oil, and salivary glands
22Unicellular Exocrine Glands Goblet cell and Mucous cellMucin -> mucous
23Multicellular Exocrine Glands Composed of a duct and a secretory unitClassified according to:Duct typeSimpleCompoundStructure of secretory unitstubularalveolartubuloalveolar
24Compound duct structure Simple duct structure(duct does not branch)Compound duct structure(duct branches)TubularsecretorystructureSimple tubularSimple branchedtubularCompound tubularExampleIntestinal glandsExampleStomach (gastric)glandsExampleDuodenal glands of small intestineAlveolarsecretorystructureSimplealveolarSimple branchedalveolarCompound alveolarCompoundtubuloalveolarExampleNo importantexample in humansExampleSebaceous (oil)glandsExampleMammary glandsExampleSalivary glandsSurface epitheliumDuctSecretory epitheliumFigure 4.5
25Modes of Secretion Merocrine Holocrine Products are secreted by exocytosispancreas, sweat and salivary glandsProducts are secreted by rupture of gland cellssebaceous (oil) glands
26Connective Tissue Most abundant and widely distributed tissue type Four main classesConnective Tissue ProperCartilageBone TissueBloodSee Table 4.1
27Major Functions of Connective Tissue Binding and SupportProtectionInsulationStores reserve fuelTransports
28Characteristics of Connective Tissue Connective tissues have:Mesenchyme as their common tissue of originVarying degrees of vascularityCells separated by nonliving extracellular matrix (ground substance and fibers)3 Structural ElementsGround substanceFibersCells
29Structural Elements of Connective Tissue Ground substanceMedium through which solutes diffuse between blood capillaries and cellsComponents:Interstitial fluidAdhesion proteins (“glue”)ProteoglycansProtein core + large polysaccharidesTrap water -> viscosity
30Structural Elements of Connective Tissue Connective Tissue FibersCollagen (white fibers)Strongest and most abundant typeProvides high tensile strengthElastic (yellow fibers)Networks of long, thin, elastin fibers that allow for stretch/recoilReticularShort, fine, highly branched collagenous fibers
31Structural Elements of Connective Tissue Cells (see table 4.1)Mitotically active and secretory cells = “blasts”Fibroblasts, chondroblasts, osteoblasts, hematopoietic stem cellsMature cells = “cytes”Chondrocytes, osteocytesOther cell typesFat cells, white blood cells, mast cells, and macrophages
35Loose Connective: Areolar CONNECTIVE TISSUE PROPERLoose Connective: AreolarDescriptionFunctionLocationPhotomicrograph: Areolar connective tissue, asoft packaging tissue of the body (300x).
36Loose Connective: Adipose CONNECTIVE TISSUE PROPERLoose Connective: AdiposeDescriptionFunctionLocationPhotomicrograph: Adipose tissue from thesubcutaneous layer under the skin (350x).
37Loose Connective: Reticular CONNECTIVE TISSUE PROPERLoose Connective: ReticularDescriptionFunctionLocationPhotomicrograph: Dark-staining network of reticularconnective tissue fibers forming the internal skeletonof the spleen (350x).
38Dense Connective: Dense Regular CONNECTIVE TISSUE PROPERDense Connective: Dense RegularDescriptionFunctionLocationPhotomicrograph: Dense regular connectivetissue from a tendon (500x).
39Dense Connective: Dense Irregular CONNECTIVE TISSUE PROPERDense Connective: Dense IrregularDescriptionFunctionLocationPhotomicrograph: Dense irregularconnective tissue from the dermis of theskin (400x).
40Dense Connective: Elastic CONNECTIVE TISSUE PROPERDense Connective: ElasticDescriptionFunctionLocationPhotomicrograph: Elastic connective tissue inthe wall of the aorta (250x).
41Connective Tissue: Cartilage Stands up to both compression and tensionNo nerve fibers, avascular80% waterChondroblasts – produce new matrixChondrocytes – mature cartilage cellsFound in small groups in lacunae
42Hyaline Cartilage Description Function Location CARTILAGE Photomicrograph: Hyaline cartilage from the trachea (750x).
43Elastic Cartilage Description Function Location CARTILAGE Photomicrograph: Elastic cartilage from the human ear pinna; forms the flexible skeleton of the ear (800x).
44Fibrocartilage Description Function Location CARTILAGE Photomicrograph: Fibrocartilage of anintervertebral disc (125x). Special stainingproduced the blue color seen.
45Connective Tissue: Bone DescriptionFunctionLocationPhotomicrograph: Cross-sectional view of bone (125x).
46Connective Tissue: Blood DescriptionFunctionLocation.Photomicrograph: Smear of human blood (1860x); two white blood cells (neutrophil in upper left and lymphocyte in lower right) are seen surrounded by red blood cells.
47Nervous Tissue Description Function Location Photomicrograph: Neurons (350x)
48Muscle Tissue Highly cellular, well vascularized Movement Types SkeletalCardiacSmooth
49Skeletal Muscle Description Function Location MUSCLE TISSUE Photomicrograph: Skeletal muscle (approx. 460x).Notice the obvious banding pattern and thefact that these large cells are multinucleate.
50Cardiac Muscle Description Function Location MUSCLE TISSUE Photomicrograph: Cardiac muscle (500X); notice the striations, branching of cells, and the intercalated discs.
51Smooth Muscle Description Function Location MUSCLE TISSUE Photomicrograph: Sheet of smooth muscle (200x).
52Epithelial Membranes Cutaneous membrane (skin) Mucous membranes MucosaeLine body cavities open to the exterior (e.g., digestive and respiratory tracts)Serous MembranesSerosae—membranes (mesothelium + areolar tissue) in a closed ventral body cavityParietal serosae line internal body wallsVisceral serosae cover internal organs
53(b) Mucous membranes line body cavities open to the exterior. Mucosa ofnasal cavityMucosa ofmouthEsophagusliningMucosa oflung bronchi(b) Mucous membranes line body cavities open to the exterior.Figure 4.11b
54(c) Serous membranes line body cavities closed to the exterior. ParietalperitoneumParietalpleuraVisceralpleuraVisceralperitoneumParietalpericardiumVisceralpericardium(c) Serous membranes line body cavities closed to the exterior.Figure 4.11c
55Steps in Tissue Repair Inflammation Organization and Restored Blood SupplyRegeneration and Fibrosis
56Blood clot in incised wound Vein ScabEpidermisBlood clot in incised woundVeinMigrating white blood cellInflammatory chemicalsArtery1Inflammation sets the stage:• Severed blood vessels bleed and inflammatory chemicals are released.• Local blood vessels become more permeable, allowing white blood cells, fluid, clotting proteins and other plasma proteins to seep into the injured area.• Clotting occurs; surface dries and forms a scab.Figure 4.12, step 1
57Regenerating epithelium Area of granulation tissue ingrowthFibroblastMacrophage2Organization restores the blood supply:• The clot is replaced by granulation tissue, which restores the vascular supply.• Fibroblasts produce collagen fibers that bridge the gap.• Macrophages phagocytize cell debris.• Surface epithelial cells multiply and migrate over the granulation tissue.Figure 4.12, step 2
58Regenerated epithelium Fibrosed area3Regeneration and fibrosis effect permanent repair:• The fibrosed area matures and contracts; the epithelium thickens.• A fully regenerated epithelium with an underlying area of scar tissue results.Figure 4.12, step 3
59Developmental Aspects Primary germ layers: ectoderm, mesoderm, and endodermFormed early in embryonic developmentSpecialize to form the four primary tissuesNerve tissue arises from ectodermMuscle and connective tissues arise from mesodermEpithelial tissues arise from all three germ layers