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4 The Tissue Level of Organization. An Introduction to Tissues. Tissues Structures with discrete structural and functional properties Tissues in combination form organs, such as the heart or liver Organs can be grouped into 11 organ systems. 4-1 Four Types of Tissue. Tissue - PowerPoint PPT Presentation
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© 2012 Pearson Education, Inc.
PowerPoint® Lecture Presentations prepared byJason LaPresLone Star College—North Harris
4The Tissue Level of Organization
© 2012 Pearson Education, Inc.
An Introduction to Tissues
• Tissues
• Structures with discrete structural and functional
properties
• Tissues in combination form organs, such as the
heart or liver
• Organs can be grouped into 11 organ systems
© 2012 Pearson Education, Inc.
4-1 Four Types of Tissue
• Tissue
• Are collections of cells and cell products that
perform specific, limited functions
• Four types of tissue
1. Epithelial tissue
2. Connective tissue
3. Muscle tissue
4. Neural tissue
© 2012 Pearson Education, Inc.
4-1 Four Types of Tissue
• Epithelial Tissue
• Covers exposed surfaces
• Lines internal passageways
• Forms glands
• Connective Tissue
• Fills internal spaces
• Supports other tissues
• Transports materials
• Stores energy
© 2012 Pearson Education, Inc.
4-1 Four Types of Tissue
• Muscle Tissue
• Specialized for contraction
• Skeletal muscle, heart muscle, and walls of hollow organs
• Neural Tissue
• Carries electrical signals from one part of the body to another
© 2012 Pearson Education, Inc.
4-2 Epithelial Tissue
• Epithelia
• Layers of cells covering internal or external surfaces
• Glands
• Structures that produce secretions
© 2012 Pearson Education, Inc.
4-2 Epithelial Tissue
• Characteristics of Epithelia
• Cellularity (cell junctions)
• Polarity (apical and basal surfaces)
• Attachment (basement membrane or basal
lamina)
• Avascularity
• Regeneration
© 2012 Pearson Education, Inc.
Figure 4-1 The Polarity of Epithelial Cells
Cilia
Microvilli
Apicalsurface
Golgiapparatus
Nucleus
Mitochondria
Basement membrane
Basolateralsurfaces
© 2012 Pearson Education, Inc.
4-2 Epithelial Tissue
• Functions of Epithelial Tissue
1. Provide Physical Protection
2. Control Permeability
3. Provide Sensation
4. Produce Specialized Secretions (glandular
epithelium)
© 2012 Pearson Education, Inc.
4-2 Epithelial Tissue
• Specializations of Epithelial Cells
1. Move fluids over the epithelium (protection)
2. Move fluids through the epithelium (permeability)
3. Produce secretions (protection and messengers)
• Polarity
1. Apical surfaces
• Microvilli increase absorption or secretion
• Cilia (ciliated epithelium) move fluid
2. Basolateral surfaces
© 2012 Pearson Education, Inc.
4-2 Epithelial Tissue
• Maintaining the Integrity of Epithelia
1. Intercellular connections
2. Attachment to the basement membrane
3. Epithelial maintenance and repair
© 2012 Pearson Education, Inc.
4-2 Epithelial Tissue
• Intercellular Connections
• Support and communication
• CAMs (cell adhesion molecules)
• Transmembrane proteins
• Intercellular cement
• Proteoglycans
• Hyaluronan (hyaluronic acid)
• Glycosaminoglycans
© 2012 Pearson Education, Inc.
4-2 Epithelial Tissue
• Intercellular Connections
• Cell junctions
• Form bonds with other cells or extracellular material
1. Tight junctions
2. Gap junctions
3. Desmosomes
© 2012 Pearson Education, Inc.
4-2 Epithelial Tissue
• Tight Junctions
• Between two plasma membranes
• Adhesion belt attaches to terminal web
• Prevents passage of water and solutes
• Isolates wastes in the lumen
© 2012 Pearson Education, Inc.
4-2 Epithelial Tissue
• Gap Junctions
• Allow rapid communication
• Are held together by channel proteins (junctional
proteins, connexons)
• Allow ions to pass
• Coordinate contractions in heart muscle
© 2012 Pearson Education, Inc.
4-2 Epithelial Tissue
• Desmosomes
• CAMs, dense areas, and intercellular cement
• Spot desmosomes
• Tie cells together
• Allow bending and twisting
• Hemidesmosomes
• Attach cells to the basal lamina
© 2012 Pearson Education, Inc.
4-2 Epithelial Tissue
• Attachment to the Basement Membrane
• Clear layer (lamina lucida)
• Thin layer
• Secreted by epithelia
• Barrier to proteins
• Dense layer (lamina densa)
• Thick fibers
• Produced by connective tissue
• Strength and filtration
© 2012 Pearson Education, Inc.
Figure 4-2 Cell Junctions
Gapjunctions
Hemidesmosome
Spotdesmosome
ClearlayerDenselayer
Intermediatefilaments
Basementmembrane
Dense area
Embedded proteins(connexons)
Proteoglycans
Cell adhesionmolecules (CAMs)
Terminal web
Adhesion belt
Tight junction
Interlockingjunctional
proteins
Tight junction
Adhesion belt
© 2012 Pearson Education, Inc.
Figure 4-2a Cell Junctions
This is a diagrammatic view of an epithelial cell,showing the major types of intercellularconnections.
Gapjunctions
Hemidesmosome
Spotdesmosome
Terminal web
Adhesion belt
Tight junction
© 2012 Pearson Education, Inc.
Figure 4-2b Cell Junctions
Tight junction
Adhesion belt
A tight junction is formed by the fusion of the outer layers of two plasma membranes. Tight junctions prevent the diffusion of fluids and solutes betweenthe cells. A continuous adhesion belt lies deep to the tight junction. This belt is tied to the microfilaments of the terminal web.
Terminal web
Interlockingjunctional
proteins
© 2012 Pearson Education, Inc.
Figure 4-2c Cell Junctions
Embedded proteins(connexons)
Gap junctions permit the free diffusion of ions and small molecules between two cells.
© 2012 Pearson Education, Inc.
Figure 4-2d Cell Junctions
Intermediatefilaments
Dense area
Cell adhesionmolecules (CAMs)
Proteoglycans
A spot desmosome tiesadjacent cells together.
© 2012 Pearson Education, Inc.
Figure 4-2e Cell Junctions
ClearlayerDenselayer
Hemidesmosomes attach a cell to extracellular structures, such as the protein fibers in the basement membrane.
Basementmembrane
© 2012 Pearson Education, Inc.
4-2 Epithelial Tissue
• Epithelial Maintenance and Repair
• Epithelia are replaced by division of germinative
cells (stem cells)
• Near basement membrane
© 2012 Pearson Education, Inc.
4-3 Classification of Epithelia
• Singular = Epithelium; Plural = Epithelia
• Classes of Epithelia
1. Based on shape
• Squamous epithelia — thin and flat
• Cuboidal epithelia — square shaped
• Columnar epithelia — tall, slender rectangles
2. Based on layers
• Simple epithelium — single layer of cells
• Stratified epithelium — several layers of cells
© 2012 Pearson Education, Inc.
Table 4-1 Classifying Epithelia
© 2012 Pearson Education, Inc.
Table 4-1 Classifying Epithelia
© 2012 Pearson Education, Inc.
4-3 Classification of Epithelia
• Squamous Epithelia
• Simple squamous epithelium
• Absorption and diffusion
• Mesothelium
• Lines body cavities
• Endothelium
• Lines heart and blood vessels
© 2012 Pearson Education, Inc.
Figure 4-3a Squamous Epithelia
Simple Squamous Epithelium
Lining of peritoneal cavityConnective tissue
Nucleus
Cytoplasm
LOCATIONS: Mesothelia lining ventral body cavities; endothelia lining heartand blood vessels; portions of kidney tubules (thin sections of nephron loops); inner lining of cornea; alveoli of lungs
FUNCTIONS: Reduces friction; controls vessel permeability; performsabsorption and secretion
LM 238
© 2012 Pearson Education, Inc.
4-3 Classification of Epithelia
• Squamous Epithelia
• Stratified squamous epithelium
• Protects against attacks
• Keratin protein adds strength and water resistance
© 2012 Pearson Education, Inc.
Figure 4-3b Squamous Epithelia
LOCATIONS: Surface of skin; lining of mouth, throat, esophagus, rectum, anus, and vagina
FUNCTIONS: Provides physical protection against abrasion, pathogens, and chemical attack
Surface of tongue
Squamoussuperficial cells
Stem cells
Basementmembrane
Connectivetissue
LM 310
Stratified Squamous Epithelium
© 2012 Pearson Education, Inc.
4-3 Classification of Epithelia
• Cuboidal Epithelia
• Simple cuboidal epithelium
• Secretion and absorption
• Stratified cuboidal epithelia
• Sweat ducts and mammary ducts
© 2012 Pearson Education, Inc.
Figure 4-4a Cuboidal and Transitional Epithelia
Simple Cuboidal Epithelium
LOCATIONS: Glands; ducts;portions of kidney tubules; thyroidgland
FUNCTIONS: Limited protection,secretion, absorption
Kidney tubule
Connectivetissue
Nucleus
Cuboidalcells
Basementmembrane
LM 650
© 2012 Pearson Education, Inc.
Figure 4-4b Cuboidal and Transitional Epithelia
LOCATIONS: Lining of some ducts(rare)
FUNCTIONS: Protection, secretion,absorption
LM 500
Lumenof duct
Sweat gland duct
Stratifiedcuboidal
cellsBasementmembrane
Nuclei
Connectivetissue
Stratified Cuboidal Epithelium
© 2012 Pearson Education, Inc.
4-3 Classification of Epithelia
• Transitional Epithelium
• Tolerates repeated cycles of stretching and recoiling
and returns to its previous shape without damage
• Appearance changes as stretching occurs
• Situated in regions of the urinary system (e.g., urinary
bladder)
© 2012 Pearson Education, Inc.
Figure 4-4c Cuboidal and Transitional Epithelia
Transitional Epithelium
FUNCTIONS: Permitsexpansion and recoilafter stretching
LOCATIONS: Urinarybladder; renal pelvis;ureters
LM 400
Urinary bladder
LM 400
Empty bladder
Epithelium(relaxed)
Connective tissue andsmooth muscle layers
Epithelium(stretched)
Connective tissue andsmooth muscle layers
Basement membrane
Full bladder
Basement membrane
LM 400
© 2012 Pearson Education, Inc.
4-3 Classification of Epithelia
• Columnar Epithelia
• Simple columnar epithelium
• Absorption and secretion
• Pseudostratified columnar epithelium
• Cilia movement
• Stratified columnar epithelium
• Protection
© 2012 Pearson Education, Inc.
Figure 4-5a Columnar Epithelia
LOCATIONS: Lining ofstomach, intestine, gallbladder,uterine tubes, and collectingducts of kidneys
FUNCTIONS: Protection,secretion, absorption
Simple Columnar Epithelium
Microvilli
Cytoplasm
Intestinal lining
Basementmembrane
Looseconnective tissue LM 350
Nucleus
© 2012 Pearson Education, Inc.
Figure 4-5b Columnar Epithelia
LOCATIONS: Lining ofnasal cavity, trachea, andbronchi; portions of malereproductive tract
FUNCTIONS: Protection,secretion, move mucuswith cilia
Pseudostratified Ciliated Columnar Epithelium
Cilia
Trachea
Cytoplasm
Nuclei
Basementmembrane
Looseconnective tissue
LM 350
© 2012 Pearson Education, Inc.
Figure 4-5c Columnar Epithelia
LOCATIONS: Small areas ofthe pharynx, epiglottis, anus,mammary glands, salivarygland ducts, and urethra
FUNCTION: Protection
Stratified Columnar Epithelium
Salivary gland duct
Deeper basalcells
Looseconnective tissue
Superficialcolumnar cells
Cytoplasm
Nuclei
Basementmembrane
LumenLumen
LM 175
© 2012 Pearson Education, Inc.
4-3 Classification of Epithelia
• Glandular Epithelia
• Endocrine glands
• Release hormones
• Into interstitial fluid
• No ducts
• Exocrine glands
• Produce secretions
• Onto epithelial surfaces
• Through ducts
© 2012 Pearson Education, Inc.
4-3 Classification of Epithelia
• Glandular Epithelia
• Modes of Secretion
1. Merocrine secretion
2. Apocrine secretion
3. Holocrine secretion
© 2012 Pearson Education, Inc.
4-3 Classification of Epithelia
• Merocrine Secretion
• Produced in Golgi apparatus
• Released by vesicles (exocytosis)
• For example, sweat glands
• Apocrine Secretion
• Produced in Golgi apparatus
• Released by shedding cytoplasm
• For example, mammary glands
© 2012 Pearson Education, Inc.
4-3 Classification of Epithelia
• Holocrine Secretion
• Released by cells bursting, killing gland cells
• Gland cells replaced by stem cells
• For example, sebaceous glands
© 2012 Pearson Education, Inc.
Figure 4-6 Modes of Glandular Secretion
Salivary gland
Mammary gland
Hair
Sebaceousgland
Hair follicle
Stem cell
Cell division replaceslost cells
Cells produce secretion,increasing in size
Cells burst, releasingcytoplasmic contents
Secretion Regrowth
Golgi apparatus
Breaksdown
Secretoryvesicle
Golgiapparatus
Nucleus
TEM 3039
© 2012 Pearson Education, Inc.
Figure 4-6a Modes of Glandular Secretion
Salivary gland
Mammary gland
Hair
Sebaceousgland
Hair follicle
Merocrine. In merocrine secretion, secretory vesicles are discharged at the apical surface of the gland cell by exocytosis.
Secretoryvesicle
Golgiapparatus
Nucleus
TEM 3039
© 2012 Pearson Education, Inc.
Figure 4-6b Modes of Glandular Secretion
Salivary gland
Mammary gland
Hair
Sebaceousgland
Hair follicle
Apocrine. Apocrine secretion involves the loss of apical cytoplasm. Inclusions, secretory vesicles, and other cytoplasmiccomponents are shed in the process. The gland cell then undergoes growth and repair before it releases additional secretions.
Secretion Regrowth
Golgi apparatus
Breaksdown
© 2012 Pearson Education, Inc.
Figure 4-6c Modes of Glandular Secretion
Salivary gland
Mammary gland
Hair
Sebaceousgland
Hair follicle
Stem cell
Holocrine. Holocrine secretion occurs as superficial gland cells burst. Continued secretion involves the replacement of these cells through the mitotic division of underlying stem cells.
Cell division replaceslost cells
Cells produce secretion,increasing in size
Cells burst, releasingcytoplasmic contents
© 2012 Pearson Education, Inc.
4-3 Classification of Epithelia
• Glandular Epithelia
• Types of Secretions
• Serous glands
• Watery secretions
• Mucous glands
• Secrete mucins
• Mixed exocrine glands
• Both serous and mucous
© 2012 Pearson Education, Inc.
4-3 Classification of Epithelia
• Glandular Epithelia
• Gland Structure
• Unicellular glands
• Mucous (goblet) cells are the only unicellular exocrine
glands
• Scattered among epithelia
• For example, in intestinal lining
© 2012 Pearson Education, Inc.
4-3 Classification of Epithelia
• Gland Structure
• Multicellular glands
1. Structure of the duct
• Simple (undivided)
• Compound (divided)
2. Shape of secretory portion of the gland
• Tubular (tube shaped)
• Alveolar or acinar (blind pockets)
3. Relationship between ducts and glandular areas
• Branched (several secretory areas sharing one duct)
© 2012 Pearson Education, Inc.
Figure 4-7 A Structural Classification of Exocrine Glands
SIMPLE GLANDS
Glandcells
SIMPLETUBULAR
SIMPLE COILEDTUBULAR
Examples:
Examples:
Examples:• Intestinal glands • Merocrine sweat
stage in developmentof simple branchedglands
SIMPLE BRANCHEDTUBULAR
Examples:• Gastric glands• Mucous glands
• Not found in adult; a
SIMPLE ALVEOLAR(ACINAR)
SIMPLE BRANCHEDALVEOLAR
Examples:• Sebaceous (oil)
glandsof esophagus,tongue, duodenum
glands
Duct
© 2012 Pearson Education, Inc.
Figure 4-7 A Structural Classification of Exocrine Glands
COMPOUND GLANDS
COMPOUNDTUBULAR
COMPOUND ALVEOLAR(ACINAR)
COMPOUND TUBULOALVEOLAR
Examples:• Mucous glands (in mouth)
Examples:
• Bulbo-urethral glands (inmale reproductive system)
tubules)
• Mammary glandsExamples:
• Salivary glands• Glands of respiratory
passages• Testes (seminiferous• Pancreas
© 2012 Pearson Education, Inc.
4-4 Connective Tissue
• Characteristics of Connective Tissue
1. Specialized cells
2. Solid extracellular protein fibers
3. Fluid extracellular ground substance
• The Extracellular Components of Connective Tissue (Fibers and Ground Substance)
• Make up the matrix
• Majority of tissue volume
• Determines specialized function
© 2012 Pearson Education, Inc.
4-4 Connective Tissue
• Functions of Connective Tissue
• Establishing a structural framework for the body
• Transporting fluids and dissolved materials
• Protecting delicate organs
• Supporting, surrounding, and interconnecting other
types of tissue
• Storing energy reserves, especially in the form of
triglycerides
• Defending the body from invading microorganisms
© 2012 Pearson Education, Inc.
4-4 Connective Tissue
• Classification of Connective Tissues
1. Connective tissue proper
• Connect and protect
2. Fluid connective tissues
• Transport
3. Supporting connective tissues
• Structural strength
© 2012 Pearson Education, Inc.
4-4 Connective Tissue
• Categories of Connective Tissue Proper
• Loose connective tissue
• More ground substance, fewer fibers
• For example, fat (adipose tissue)
• Dense connective tissue
• More fibers, less ground substance
• For example, tendons
© 2012 Pearson Education, Inc.
4-4 Connective Tissue
• Fibroblasts
• Fibrocytes
• Adipocytes
• Mesenchymal cells
• Macrophages
• Mast cells
• Lymphocytes
• Microphages
• Melanocytes
Connective Tissue Proper Cell Populations
© 2012 Pearson Education, Inc.
4-4 Connective Tissue
• Fibroblasts
• The most abundant cell type
• Found in all connective tissue proper
• Secrete proteins and hyaluronan (cellular cement)
• Fibrocytes
• The second most abundant cell type
• Found in all connective tissue proper
• Maintain the fibers of connective tissue proper
© 2012 Pearson Education, Inc.
4-4 Connective Tissue
• Adipocytes
• Fat cells
• Each cell stores a single, large fat droplet
• Mesenchymal Cells
• Stem cells that respond to injury or infection
• Differentiate into fibroblasts, macrophages, etc.
© 2012 Pearson Education, Inc.
4-4 Connective Tissue
• Macrophages
• Large, amoeba-like cells of the immune system
• Eat pathogens and damaged cells
• Fixed macrophages stay in tissue
• Free macrophages migrate
© 2012 Pearson Education, Inc.
4-4 Connective Tissue
• Mast Cells
• Stimulate inflammation after injury or infection
• Release histamine and heparin
• Basophils are leukocytes (white blood cells) that also
contain histamine and heparin
© 2012 Pearson Education, Inc.
4-4 Connective Tissue
• Lymphocytes
• Specialized immune cells in lymphatic (lymphoid)
system
• For example, lymphocytes may develop into plasma
cells (plasmocytes) that produce antibodies
© 2012 Pearson Education, Inc.
4-4 Connective Tissue
• Microphages
• Phagocytic blood cells
• Respond to signals from macrophages and mast cells
• For example, neutrophils and eosinophils
• Melanocytes
• Synthesize and store the brown pigment melanin
© 2012 Pearson Education, Inc.
4-4 Connective Tissue
• Connective Tissue Fibers
1. Collagen fibers
2. Reticular fibers
3. Elastic fibers
© 2012 Pearson Education, Inc.
4-4 Connective Tissue
• Collagen Fibers
• Most common fibers in connective tissue proper
• Long, straight, and unbranched
• Strong and flexible
• Resist force in one direction
• For example, tendons and ligaments
© 2012 Pearson Education, Inc.
4-4 Connective Tissue
• Reticular Fibers
• Network of interwoven fibers (stroma)
• Strong and flexible
• Resist force in many directions
• Stabilize functional cells (parenchyma) and
structures
• For example, sheaths around organs
© 2012 Pearson Education, Inc.
4-4 Connective Tissue
• Elastic Fibers
• Contain elastin
• Branched and wavy
• Return to original length after stretching
• For example, elastic ligaments of vertebrae
© 2012 Pearson Education, Inc.
4-4 Connective Tissue
• Ground Substance
• Is clear, colorless, and viscous
• Fills spaces between cells and slows pathogen
movement
© 2012 Pearson Education, Inc.
Figure 4-8 The Cells and Fibers of Connective Tissue Proper
Reticularfibers
Melanocyte
Fixedmacrophage
Plasma cell
Bloodin vessel
Adipocytes(fat cells)
Groundsubstance
Mast cell
Elasticfibers
Freemacrophage
Collagenfibers
Fibroblast
Mesenchymalcell
Lymphocyte
© 2012 Pearson Education, Inc.
Figure 4-8 The Cells and Fibers of Connective Tissue Proper
Elasticfibers
Collagenfibers
Fibroblast
Freemacrophage
Connective tissue proper LM 502
© 2012 Pearson Education, Inc.
4-4 Connective Tissue
• Embryonic Connective Tissues
• Are not found in adults
• Mesenchyme (embryonic stem cells)
• The first connective tissue in embryos
• Mucous connective tissue
• Loose embryonic connective tissue
© 2012 Pearson Education, Inc.
Figure 4-9a Connective Tissues in Embryos
Mesenchymalcells
Mesenchyme
This is the first connectivetissue to appear in an embryo.
LM 136
© 2012 Pearson Education, Inc.
Figure 4-9b Connective Tissues in Embryos
Mesenchymalcells
Blood vessel
Mucous connective tissue(Wharton’s jelly)
LM 136
This sample was taken fromthe umbilical cord of a fetus.
© 2012 Pearson Education, Inc.
4-4 Connective Tissue
• Loose Connective Tissues
• The “packing materials” of the body
• Three types in adults
1. Areolar
2. Adipose
3. Reticular
© 2012 Pearson Education, Inc.
4-4 Connective Tissue
• Areolar Tissue
• Least specialized
• Open framework
• Viscous ground substance
• Elastic fibers
• Holds blood vessels and capillary beds
• For example, under skin (subcutaneous layer)
© 2012 Pearson Education, Inc.
4-4 Connective Tissue
• Adipose Tissue
• Contains many adipocytes (fat cells)
• 2 types of adipose tissue
1. White fat
2. Brown fat
© 2012 Pearson Education, Inc.
4-4 Connective Tissue
• White fat• Most common
• Stores fat
• Absorbs shocks
• Slows heat loss (insulation)
• Brown fat• More vascularized
• Adipocytes have many mitochondria
• When stimulated by nervous system, fat breakdown accelerates, releasing energy
• Absorbs energy from surrounding tissues
© 2012 Pearson Education, Inc.
4-4 Connective Tissue
• Adipose Tissue
• Adipose cells
• Adipocytes in adults do not divide
• Expand to store fat
• Shrink as fats are released
• Mesenchymal cells divide and differentiate
• To produce more fat cells
• When more storage is needed
© 2012 Pearson Education, Inc.
4-4 Connective Tissue
• Reticular Tissue
• Provides support
• Complex, three-dimensional network
• Supportive fibers (stroma)
• Support functional cells (parenchyma)
• Reticular organs
• Spleen, liver, lymph nodes, and bone marrow
© 2012 Pearson Education, Inc.
Figure 4-10a Adipose and Reticular Tissues
Adipose Tissue
LOCATIONS: Deep to the skin,especially at sides, buttocks,breasts; padding around eyesand kidneys
FUNCTIONS: Providespadding and cushionsshocks; insulates(reduces heat loss);stores energy
Adipose tissue
Adipocytes(white adipose
cells)
LM 300
© 2012 Pearson Education, Inc.
Figure 4-10b Adipose and Reticular Tissues
Reticular Tissue
FUNCTIONS: Provides supportingframework
LOCATIONS: Liver, kidney, spleen,lymph nodes, and bone marrow
Reticular tissuefrom liver
Reticular Tissue
Reticular fibers
LM 375
© 2012 Pearson Education, Inc.
4-4 Connective Tissue
• Dense Connective Tissues
• Connective tissues proper, tightly packed with high
numbers of collagen or elastic fibers
• Dense regular connective tissue
• Dense irregular connective tissue
• Elastic tissue
© 2012 Pearson Education, Inc.
4-4 Connective Tissue
• Dense Regular Connective Tissue
• Tightly packed, parallel collagen fibers
• Tendons attach muscles to bones
• Ligaments connect bone to bone and stabilize organs
• Aponeuroses attach in sheets to large, flat muscles
© 2012 Pearson Education, Inc.
Figure 4-11a Dense Connective Tissues
Dense Regular Connective Tissue
Collagenfibers
Fibroblastnuclei
Tendon LM 440
LOCATIONS: Between skeletalmuscles and skeleton (tendonsand aponeuroses); betweenbones or stabilizing positionsof internal organs (ligaments);covering skeletal muscles;deep fasciae
FUNCTIONS: Providesfirm attachment; conductspull of muscles; reducesfriction between muscles;stabilizes relative positionsof bones
© 2012 Pearson Education, Inc.
4-4 Connective Tissue
• Dense Irregular Connective Tissue
• Interwoven networks of collagen fibers
• Layered in skin
• Around cartilages (perichondrium)
• Around bones (periosteum)
• Form capsules around some organs (e.g., liver,
kidneys)
© 2012 Pearson Education, Inc.
Figure 4-11b Dense Connective Tissues
Collagenfiber
bundles
Deep dermis LM 111
Dense Irregular Connective Tissue
LOCATIONS: Capsules ofvisceral organs; periosteaand perichondria; nerveand muscle sheaths; dermis
FUNCTIONS: Providesstrength to resist forcesapplied from manydirections; helpsprevent overexpansionof organs such asthe urinary bladder
© 2012 Pearson Education, Inc.
4-4 Connective Tissue
• Elastic Tissue
• Made of elastic fibers
• For example, elastic ligaments of spinal vertebrae
© 2012 Pearson Education, Inc.
Figure 4-11c Dense Connective Tissues
Elasticfibers
Fibroblastnuclei
Elastic ligament
Elastic Tissue
LOCATIONS: Between vertebraeof the spinal column (ligamentumflavum and ligamentum nuchae);ligaments supporting penis;ligaments supporting transitionalepithelia; in blood vessel walls
FUNCTIONS: Stabilizespositions of vertebrae andpenis; cushions shocks;permits expansion andcontraction of organs
LM 887
© 2012 Pearson Education, Inc.
4-4 Connective Tissue
• Fluid Connective Tissues
• Blood and lymph
• Watery matrix of dissolved proteins
• Carry specific cell types (formed elements)
• Formed elements of blood
• Red blood cells (erythrocytes)
• White blood cells (leukocytes)
• Platelets
© 2012 Pearson Education, Inc.
4-4 Connective Tissue
• Fluid Elements of Connective Tissues
• Extracellular
• Plasma
• Interstitial fluid
• Lymph
© 2012 Pearson Education, Inc.
Figure 4-12 Formed Elements of the Blood
Red blood cells
Red blood cells account for roughlyhalf the volume ofwhole blood andgive blood its color.
Red blood cells, orerythrocytes(e-RITH-ro-sıts), areresponsible for the transport of oxygen (and, to a lesser degree, of carbon dioxide) in the blood.
¯ ¯
© 2012 Pearson Education, Inc.
Figure 4-12 Formed Elements of the Blood
White blood cells
Eosinophil
Neutrophil
Basophil
White blood cells, or leukocytes(LOO-ko-sıts; leuko-, white), help defend the body from infection and disease.
¯ ¯
Eosinophils and neutro-phils are phagocytes. Ba-sophils promote inflamma-tion much like mast cells in other connective tissues.
Lymphocytes are un-common in the bloodbut they are the domi-nant cell type in lymph,the second type of fluid connective tissue.
Monocytesare phagocytessimilar to thefree macro-phages inother tissues.
© 2012 Pearson Education, Inc.
Figure 4-12 Formed Elements of the Blood
Platelets
Platelets aremembrane-enclosedpackets of cytoplasmthat function in bloodclotting.
These cell fragmentsare involved in theclotting responsethat seals leaks indamaged or brokenblood vessels.
© 2012 Pearson Education, Inc.
4-4 Connective Tissue
• Lymph
• Extracellular fluid
• Collected from interstitial space
• Monitored by immune system
• Transported by lymphatic (lymphoid) system
• Returned to venous system
© 2012 Pearson Education, Inc.
4-4 Connective Tissue
• Fluid Tissue Transport Systems
• Cardiovascular system (blood)
• Arteries
• Capillaries
• Veins
• Lymphatic (lymphoid) system (lymph)
• Lymphatic vessels
© 2012 Pearson Education, Inc.
4-5 Supporting Connective Tissues
• Support Soft Tissues and Body Weight
• Cartilage
• Gel-type ground substance
• For shock absorption and protection
• Bone
• Calcified (made rigid by calcium salts, minerals)
• For weight support
© 2012 Pearson Education, Inc.
4-5 Supporting Connective Tissues
• Cartilage Matrix
• Proteoglycans derived from chondroitin sulfates
• Ground substance proteins
• Chondrocytes (cartilage cells) surrounded by
lacunae (chambers)
© 2012 Pearson Education, Inc.
4-5 Supporting Connective Tissues
• Cartilage Structure
• No blood vessels
• Chondrocytes produce antiangiogenesis factor
• Perichondrium
• Outer, fibrous layer (for strength)
• Inner, cellular layer (for growth and maintenance)
© 2012 Pearson Education, Inc.
Figure 4-13a The Growth of Cartilage
Interstitial growth
Chondrocyte undergoes divisionwithin a lacuna surrounded bycartilage matrix.
As daughter cells secrete additional matrix, theymove apart, expanding the cartilage from within.
LacunaChondrocyte
MatrixNew matrix
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Figure 4-13b The Growth of Cartilage
Appositional growth
As the matrix enlarges, morechondroblasts are incorporated;they are replaced by divisions ofstem cells in the perichondrium.
These immaturechondroblasts secretenew matrix.
New matrix
ImmaturechondrocyteOlder matrix
Maturechondrocyte
FibroblastDividing stem cell
Perichondrium
Cells in the cellular layerof the perichondriumdifferentiate intochondroblasts.
Chondroblasts
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4-5 Supporting Connective Tissues
• Types of Cartilage
1. Hyaline cartilage
2. Elastic cartilage
3. Fibrocartilage (fibrous cartilage)
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4-5 Supporting Connective Tissues
• Hyaline Cartilage
• Stiff, flexible support
• Reduces friction between bones
• Found in synovial joints, rib tips, sternum, and
trachea
• Elastic Cartilage
• Supportive but bends easily
• Found in external ear and epiglottis
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4-5 Supporting Connective Tissues
• Fibrocartilage (Fibrous Cartilage)
• Limits movement
• Prevents bone-to-bone contact
• Pads knee joints
• Found between pubic bones and
intervertebral discs
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Figure 4-14a Types of Cartilage
Hyaline Cartilage
LOCATIONS: Between tips of ribs and bones of sternum; covering bone surfaces at synovial joints; supporting larynx (voice box), trachea, and bronchi; forming part of nasal septum
FUNCTIONS: Provides stiff butsomewhat flexible support;reduces frictionbetween bonysurfaces
Hyaline cartilage
LM 500
Matrix
Chondrocytesin lacunae
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Figure 4-14b Types of Cartilage
Elastic Cartilage
LOCATIONS: Auricle of externalear; epiglottis; auditory canal;cuneiform cartilages of larynx
FUNCTIONS: Provides support,but tolerates distortion withoutdamage andreturns tooriginal shape
Elastic cartilage
Elastic fibersin matrix
Chondrocytein lacuna
LM 358
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Figure 4-14c Types of Cartilage
Fibrocartilage
LOCATIONS: Pads within kneejoint; between pubic bones ofpelvis; intervertebral discs
FUNCTIONS: Resistscompression;prevents bone-to-bonecontact; limitsmovement
Fibrocartilage
Fibrousmatrix
Chondrocytesin lacunae
LM 400
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4-5 Supporting Connective Tissues
• Bone or Osseous Tissue• Strong (calcified calcium salt deposits)
• Resists shattering (flexible collagen fibers)
• Bone Cells or Osteocytes• Arranged around central canals within matrix
• Small channels through matrix (canaliculi) access blood supply
• Periosteum • Covers bone surfaces
• Fibrous layer
• Cellular layer
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Figure 4-15 Bone
Canaliculi
Osteocytesin lacunae
Matrix
Central canal
Blood vessels
LM 375
Osteon
Osteon
Fibrouslayer
Cellularlayer
Periosteum
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Table 4-2 A Comparison of Cartilage and Bone
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4-6 Membranes
• Membranes
• Physical barriers
• Line or cover portions of the body
• Consist of:
• An epithelium
• Supported by connective tissue
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4-6 Membranes
• Four Types of Membranes
1. Mucous membranes
2. Serous membranes
3. Cutaneous membrane
4. Synovial membranes
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4-6 Membranes
• Mucous Membranes (Mucosae)
• Line passageways that have external connections
• In digestive, respiratory, urinary, and reproductive tracts
• Epithelial surfaces must be moist
• To reduce friction
• To facilitate absorption and excretion
• Lamina propria
• Is areolar tissue
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Figure 4-16a Membranes
Mucous secretion
Mucous membranes are coated with thesecretions of mucous glands. These membranes line the digestive, respiratory, urinary, and reproductive tracts.
Epithelium
Lamina propria(areolar tissue)
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4-6 Membranes
• Serous Membranes
• Line cavities not open to the outside
• Are thin but strong
• Have fluid transudate to reduce friction
• Have a parietal portion covering the cavity
• Have a visceral portion (serosa) covering the organs
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4-6 Membranes
• Three Serous Membranes
1. Pleura
• Lines pleural cavities
• Covers lungs
2. Peritoneum
• Lines peritoneal cavity
• Covers abdominal organs
3. Pericardium
• Lines pericardial cavity
• Covers heart
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Figure 4-16b Membranes
Serous membranes line the ventral body cavities (the peritoneal, pleural, and pericardial cavities).
Transudate
Mesothelium
Areolar tissue
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4-6 Membranes
• Cutaneous Membrane
• Is skin, surface of the body
• Thick, waterproof, and dry
• Synovial Membranes
• Line moving, articulating joint cavities
• Produce synovial fluid (lubricant)
• Protect the ends of bones
• Lack a true epithelium
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Figure 4-16c Membranes
The cutaneous membrane, or skin, covers the outer surface of the body.
Epithelium
Areolar tissue
Dense irregularconnective tissue
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Figure 4-16d Membranes
Synovial membranes line joint cavities and produce the fluid within the joint.
Articular (hyaline) tissue
Synovial fluid
Capsule
Capillary
Adipocytes
Areolartissue
EpitheliumSynovialmembrane
Bone
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4-7 Internal Framework of the Body
• Connective Tissues
1. Provide strength and stability
2. Maintain positions of internal organs
3. Provide routes for blood vessels, lymphatic vessels, and
nerves
• Fasciae
• Singular form = fascia
• The body’s framework of connective tissue
• Layers and wrappings that support or surround organs
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4-7 Internal Framework of the Body
• Three Types of Fasciae
1. Superficial fascia
2. Deep fascia
3. Subserous fascia
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Figure 4-17 The Fasciae
Body wall
Body cavity
Skin
Connective Tissue Framework of Body
Superficial Fascia
Deep Fascia
Subserous Fascia
Rib
Serous membrane
Cutaneous membrane
• Forms a strong, fibrous
• Dense connective tissue• Bound to capsules,
• Between serous
• Areolar tissue
internal framework
tendons, and ligaments
membranes anddeep fascia
• Between skin and
adipose tissue• Also known as
underlying organs• Areolar tissue and
subcutaneous layeror hypodermis
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4-8 Muscle Tissue
• Muscle Tissue
• Specialized for contraction
• Produces all body movement
• Three types of muscle tissue
1. Skeletal muscle tissue
• Large body muscles responsible for movement
2. Cardiac muscle tissue
• Found only in the heart
3. Smooth muscle tissue
• Found in walls of hollow, contracting organs (blood vessels; urinary bladder; respiratory, digestive, and reproductive tracts)
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4-8 Muscle Tissue
• Classification of Muscle Cells
• Striated (muscle cells with a banded appearance)
• Nonstriated (not banded; smooth)
• Muscle cells can have a single nucleus
• Muscle cells can be multinucleate
• Muscle cells can be controlled voluntarily (consciously)
• Muscle cells can be controlled involuntarily
(automatically)
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4-8 Muscle Tissue
• Skeletal Muscle Cells
• Long and thin
• Usually called muscle fibers
• Do not divide
• New fibers are produced by stem cells (myosatellite
cells)
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Figure 4-18a Muscle Tissue
Skeletal Muscle Tissue
Skeletal muscle
Cells are long, cylindrical, striated, and multinucleate.
LOCATIONS: Combinedwith connective tissuesand neural tissue inskeletal muscles
FUNCTIONS: Moves orstabilizes the position ofthe skeleton; guardsentrances and exits tothe digestive,respiratory, and urinarytracts; generates heat;protects internal organs
Nuclei
Musclefiber
Striations
LM 180
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4-8 Muscle Tissue
• Cardiac Muscle Cells
• Called cardiocytes
• Form branching networks connected at intercalated
discs
• Regulated by pacemaker cells
• Smooth Muscle Cells
• Small and tapered
• Can divide and regenerate
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Figure 4-18b Muscle Tissue
Cardiac Muscle Tissue
Cardiac muscle
Cells are short, branched,and striated, usually with asingle nucleus; cells areinterconnected byintercalated discs.
FUNCTIONS:Circulates blood;maintains blood(hydrostatic) pressure
LOCATION: Heart
LM 450
Nucleus
Cardiacmuscle
cells
Intercalateddiscs
Striations
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Figure 4-18c Muscle Tissue
Smooth muscle
Cells are short, spindle-shaped, andnonstriated, with a single, centralnucleus.
LOCATIONS: Found inthe walls of blood vesselsand in digestive, respiratory,urinary, and reproductive organs
FUNCTIONS: Moves food,urine, and reproductive tractsecretions; controlsdiameter of respiratorypassageways; regulatesdiameter of blood vessels
LM 235
Nucleus
Smoothmuscle
cell
Smooth Muscle Tissue
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4-9 Neural Tissue
• Neural Tissue
• Also called nervous or nerve tissue
• Specialized for conducting electrical impulses
• Rapidly senses internal or external environment
• Processes information and controls responses
• Neural tissue is concentrated in the central nervous
system
• Brain
• Spinal cord
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4-9 Neural Tissue
• Two Types of Neural Cells
1. Neurons
• Nerve cells
• Perform electrical communication
2. Neuroglia
• Supporting cells
• Repair and supply nutrients to neurons
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4-9 Neural Tissue
• Cell Parts of a Neuron
• Cell body
• Contains the nucleus and nucleolus
• Dendrites
• Short branches extending from the cell body
• Receive incoming signals
• Axon (nerve fiber)
• Long, thin extension of the cell body
• Carries outgoing electrical signals to their destination
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Figure 4-19 Neural Tissue
NEURONS NEUROGLIA (supporting cells)
• Maintain physical structure
• Repair tissue framework
• Perform phagocytosis
• Regulate the composition of theinterstitial fluid surrounding neurons
of tissues
after injury
• Provide nutrients to neurons
Axon
NucleolusNucleusof neuron
Dendrites(contacted byother neurons)
Axon (conductsinformation toother cells)
Cell body
Dendrites
MitochondrionNucleus
Microfibrils andmicrotubules
Nucleolus
Cell body (contains nucleusand major organelles) A representative neuron
(sizes and shapes vary widely)
Contact with other cells
Nuclei of neuroglia
LM 600
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Figure 4-19 Neural Tissue
NEUROGLIA (supporting cells)
• Maintain physical structure
• Repair tissue framework
• Perform phagocytosis
• Regulate the composition of theinterstitial fluid surrounding neurons
of tissues
after injury
• Provide nutrients to neurons
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Figure 4-19 Neural Tissue
Dendrites(contacted byother neurons)
Axon (conductsinformation toother cells)
MitochondrionNucleus
Microfibrils andmicrotubules
Nucleolus
Cell body (contains nucleusand major organelles) A representative neuron
(sizes and shapes vary widely)
Contact with other cells