ch. 4: tissue: the living fabric microscopy epithelial tissue connective tissue nervous tissue...
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Ch. 4: Tissue: The Living Fabric Microscopy Epithelial Tissue Connective Tissue Nervous Tissue Muscle Tissue Covering and Lining Membranes Wound repair; development. Microscopy Microscopic Anatomy Fix (Preserve) Section (Slice) Stain (Add Contrast) Light Microscopy Add color - PowerPoint PPT PresentationTRANSCRIPT
Ch. 4: Tissue: The Living Fabric
MicroscopyEpithelial TissueConnective TissueNervous TissueMuscle TissueCovering and Lining MembranesWound repair; development
Microscopy
Microscopic AnatomyFix (Preserve)Section (Slice)Stain (Add Contrast)
Light Microscopy Add colorDifferent stains for different tissues
H&E the defaultDifferent aspects of different tissues
Electron MicroscopyAdd heavy metal to deflect electron beam
Artifacts of fixation, sectioning, staining
Skeletal muscle, H&E stainwww.anatomy.uiowa.edu/genhisto/GHWIN/unit1/image/i-08.jpg
Light microscopy: organ of Corti, earKeele University, UK, www.keele.ac.uk/depts/bi/emunit/galleries/gallery1/index.htm
Scanning electron microscopy: organ of Corti, earKeele University, UK, www.keele.ac.uk/depts/co/em96/em96.htm
Outer hair cells, earScanning and transmission electron micrographs
Keele University, UK, www.keele.ac.uk/depts/co/em96/em96.htm
Epithelial Tissue
Special CharacteristicsPolarity, sidedness: apical (microvilli), basalSpecialized contacts on the sides: tight junctions,
desmosomesSupported by connective tissue: basal lamina
(noncellular) and reticular connective tissue belowAvascular, innervatedHigh regeneration rate
ClassificationGlandular
Epithelial Tissue
Special CharacteristicsClassification
Two-part namesPart 1: cell layers
Simple (1), stratified (>1)Part 2: shape (of apical layer in stratified)
Squamous, cuboidal, columnarGlandular
Figure 4.1
Figure 4.2a
Figure 4.2b
Figure 4.2c
Figure 4.2d
Figure 4.2e
Figure 4.2f
Epithelial Tissue
Special CharacteristicsClassificationGlandular
Endocrine glandsMake & release hormones into blood; ductless;
most are small organs; ch. 16Exocrine glands
Make & secrete product to “outside”Unicellualr: goblet cell make mucin, forms mucus;
resp & GI tractsMulticellular: duct & secretory unit (acinus); sweat,
various in GI tract, mammary, salivary
Figure 4.3
Goblet cellUnicellular exocrine gland
Figure 4.4
Types of multicellular exocrine glandsClassified by structure
Connective Tissue
Common CharacteristicsOrigin: embryonic mesenchymeLarge amount of extracellular matrix
Structural ElementsGround substance – between the cellsFibers
CollagenElasticReticular
CellsSee Fig 4.6. -blasts vs. -cytes
Types
Figure 4.6
Connective TissueTypes
Connective Tissue ProperLoose
Areolar: support, hold fluid, defense v. infectionAdipose: cushion, store energy, insulate; often subQReticular: like areolar but only retic fibers; many
lymphocytes; lymph nodes, spleen, bone marrowDense (Fibrous: fibers are main component)
Regular: unidirectional collagen fibers; ligaments, tendons
Irregular: multidirectional collagen fibers; makes sheets; dermis, joint capsules, etc.
Elastic: elastic (large) arteriesCartilageBoneBlood
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Areolar connective tissue as general connective tissue example
Macrophage
Fibroblast
Lymphocyte
Fat cell
Mast cell
Neutrophil
Capillary
Cell typesExtracellular matrix
• Collagen fiber• Elastic fiber• Reticular fiber
Ground substance
Figure 4.7
Figure 4.8a
Figure 4.8b
Figure 4.8c
Figure 4.8d
Figure 4.8e
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(f) Connective tissue proper: dense connective tissue, elastic
Description: Dense regularconnective tissue containing a highproportion of elastic fibers.
Function: Allows recoil of tissuefollowing stretching; maintainspulsatile flow of blood througharteries; aids passive recoil of lungsfollowing inspiration.
Location: Walls of large arteries;within certain ligaments associatedwith the vertebral column; within thewalls of the bronchial tubes.
Elastic fibers
Aorta
HeartElastic connective tissue in the wall of the aorta (250x)
Figure 4.8f
Connective Tissue
Common CharacteristicsStructural ElementsTypes
Connective Tissue ProperCartilage
Hyaline c.Elastic c.Fibrocartilage
BoneBlood
Collagen• Most abundant protein in the body• Type I (most common): In bone, scar tissue, tendons,
ligaments.
• Type II: Hyaline cartilage.
• Type III: Found in extracellular matrix of early granulation (wound healing) tissue; replaced by type I collagen in mature scar tissue.
• Type IV: Lens of eye; basal lamina beneath epithelium (esp. in skin, beneath epidermis); capillaries, including glomeruli.
• Type V: Interstitial tissue (loose connective tissue); placenta.
• List goes up to XXVIII=28…
Collagen StructureHas 3 subunits (strands) which wrap around each other with a right-handed (RH) twist – i.e. a triple helix.
Each subunit (strand) is a LH helix (not an -helix which is RH).
Combination of RH and LH helices makes collagen hard to stretch.
How to tell the handedness of a helix: fingers show sense of rotation when travelling in direction that thumb points.
http://en.wikipedia.org/wiki/Image:Collagentriplehelix.png
Julian Voss-Andreae"Unraveling Collagen:
a metaphor for aging and growth”
Figure 4.8g
Figure 4.8h
Figure 4.8i
Connective Tissue
Common CharacteristicsStructural ElementsTypes
Connective Tissue ProperCartilageBoneBlood
Figure 4.8j
Connective Tissue
Common CharacteristicsStructural ElementsTypes
Connective Tissue ProperCartilageBoneBlood
Develops from mesenchymeHas a noncellular matrix - plasma
Figure 4.8k
Nervous Tissue
NeuronsExcitable (electro-chemically)Brain, spinal cord, nerves, some organsCell body = somaDendrites receive inputAxon carries output
Neuroglia = glial cellsSupport, insulate (electrically), protectNot excitable
Figure 4.9
Muscle TissueTypes of MuscleBy Looks: striated vs smooth
StriatedSkeletalCardiac
SmoothBy control: voluntary vs involuntary
Voluntary: skeletalInvoluntary: cardiac, smooth
Figure 4.10a
Figure 4.10b
Figure 4.10c
Covering and Lining Membranes
Cutaneous membrane (Skin)“largest organ”; epidermis over dermis; dry; ch. 5
Mucous membranes (mucosae)Line body cavities that connect to outside; wetSimple columnar or stratified squamous epithelium over
lamina propria (loose areolar conn. tiss.)Often adapted for absorption & secretionSome but not all secrete mucus
Serous membranes (serosae)In ventral body cavities: thorax, abdominopelvicHave inner (visceral) & outer (parietal) layers
Figure 4.11
Figure 4.11
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Minor skin wound repair: regeneration and fibrosis
1 Inflammation 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.
2 Organization restores the bloodsupply:• 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.
Scab Blood clot in incised wound
Epidermis
Vein
Inflammatory chemicals
Migrating whiteblood cell
Artery
Regenerating epithelium
Area ofgranulationtissue ingrowth
Fibroblast
Macrophage
3 Regeneration and fibrosiseffect permanent repair:• The fibrosed area matures and contracts; the epithelium thickens.• A fully regenerated epithelium with an underlying area of scar tissue results.
Regenerated epithelium
Fibrosed area Fig. 4.12
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Where it comes from: embryonic germ layersectoderm, mesoderm, endoderm
(outer, middle, inner)
MesodermEndoderm
16-day-old embryo(dorsal surface view, cephalic end up, length 1 mm)
EpitheliumNervous tissue(from ectoderm)
Muscle and connectivetissue (mostly frommesoderm)Ectoderm
Figure 4.13See also Medical Embryology, 4th ed, Langman, 1981.