Tissues Tissues
Dec 17, 2015
TissuesTissues
Types of Tissues in the BodyTypes of Tissues in the Body
TissuesTissues
Histology is the study of tissuesHistology is the study of tissues Tissues are groups of specialized cells with Tissues are groups of specialized cells with
limited number of functionslimited number of functions There are 4 PRIMARY types of tissues in There are 4 PRIMARY types of tissues in
the human bodythe human body Epithelial tissueEpithelial tissue Connective tissueConnective tissue Muscle tissueMuscle tissue Nervous tissueNervous tissue
Epithelial tissueEpithelial tissue
Epi- means uponEpi- means upon Epithelial tissue covers all exposed Epithelial tissue covers all exposed
surfaces and lines body cavitiessurfaces and lines body cavities Various types of epithelial tissues Various types of epithelial tissues
each with specific functionseach with specific functions
Characteristics of Epithelial Characteristics of Epithelial TissueTissue
Tightly packed cellsTightly packed cells Polarity – epithelial cells have a “top” Polarity – epithelial cells have a “top”
and “bottom” orientation. Surface and “bottom” orientation. Surface that faces the surface of the body or that faces the surface of the body or internal space is the APICAL layerinternal space is the APICAL layer
Attachment – basement membraneAttachment – basement membrane Avascularity – no blood supplyAvascularity – no blood supply RegenerationRegeneration
Functions of Epithelial Functions of Epithelial TissueTissue
Physical protectionPhysical protection Control of permeabilityControl of permeability SensationsSensations SecretionsSecretions
Classification of epitheliaClassification of epithelia
ShapeShape Squamous = flat Squamous = flat
cellscells Cuboidal = squareCuboidal = square Columnar = tall Columnar = tall
and thinand thin
NumberNumber Simple epithelial = Simple epithelial =
one layer of cellsone layer of cells Stratified epithelial Stratified epithelial
= several layers of = several layers of cellscells
Epithelial TissueEpithelial Tissue
Epithelial TissueEpithelial Tissue
Simple Squamous Simple Squamous epitheliumepithelium
Single layer of flat cellsSingle layer of flat cells
Simple Squamous Simple Squamous EpitheliumEpithelium
Endothelial cellsEndothelial cellsSimple squamous epitheliumSimple squamous epithelium
Simple cuboidal epitheliumSimple cuboidal epithelium
Simple cuboidal epitheliaSimple cuboidal epithelia
Single layer of square cellsSingle layer of square cells
Simple columnar epitheliumSimple columnar epithelium
Simple columnar epitheliaSimple columnar epithelia
Single layer of tall thin cellsSingle layer of tall thin cells
Stratified Squamous EpitheliaStratified Squamous EpitheliaNon-keratinizedNon-keratinized
Several layers of flat cellsSeveral layers of flat cells
Stratified squamous epithelium Stratified squamous epithelium non-keratinized non-keratinized
Stratified squamous epitheliumStratified squamous epitheliumnon-keratinizednon-keratinized
Stratified Squamous EpitheliaStratified Squamous EpitheliaKeratinizedKeratinized
Several layers of flat cells with a top Several layers of flat cells with a top layer of dead keratinized cellslayer of dead keratinized cells
Transitional epitheliaTransitional epithelia
SeveralSeveral layers of cells. Apical cells layers of cells. Apical cells rounded in shape. rounded in shape.
Transitional epitheliumTransitional epithelium
Pseudostratified ciliated Pseudostratified ciliated columnar epithelia (PSCC)columnar epithelia (PSCC)
Not truly stratifiedNot truly stratified All cells touch the basement All cells touch the basement
membrane but not all reach the membrane but not all reach the surfacesurface
GlandsGlands
Epithelial tissues often have Epithelial tissues often have associated cells that produce associated cells that produce secretionssecretions
Two types of secretionTwo types of secretion ExocrineExocrine EndocrineEndocrine
Exocrine secretionExocrine secretion
Secretion onto a surface via a tube or Secretion onto a surface via a tube or DUCTDUCT
Unicellular and multicellular glandsUnicellular and multicellular glands Unicellular exocrine gland is the Unicellular exocrine gland is the
GOBLET CELLGOBLET CELL
Goblet cellGoblet cell(unicellular exocrine gland)(unicellular exocrine gland)
Secrete mucus, often found in the Secrete mucus, often found in the gut and lining the tracheagut and lining the trachea
Goblet cellGoblet cell
Endocrine glandsEndocrine glands
Secrete directly into the bloodSecrete directly into the blood Ductless glandsDuctless glands HormonesHormones
Gland structureGland structure
Modes of secretionModes of secretionMerocrine, apocrine, holocrineMerocrine, apocrine, holocrine
Connective TissueConnective Tissue
Second major tissue type in Second major tissue type in the bodythe body
Connective TissueConnective Tissue
Found throughout the bodyFound throughout the body NEVER exposed to the outsideNEVER exposed to the outside Three basic componentsThree basic components
Specialized cells - fibroblastsSpecialized cells - fibroblasts Extracellular protein fibersExtracellular protein fibers Ground substanceGround substance MATRIX = fibers + ground substance MATRIX = fibers + ground substance
Functions of connective Functions of connective tissuetissue
Structural frameworkStructural framework Transport of fluids and chemicalsTransport of fluids and chemicals ProtectionProtection Energy storageEnergy storage Mineral storageMineral storage ImmunityImmunity
Connective Tissue ProperConnective Tissue Proper
Two typesTwo types Loose CTLoose CT Dense CTDense CT Three types of fibersThree types of fibers
Collagen – long straight fibers, very strongCollagen – long straight fibers, very strong Reticular fibers – thinner fibers, branching Reticular fibers – thinner fibers, branching
interwoven networkinterwoven network Elastic fibers – branching, wavy fibers that Elastic fibers – branching, wavy fibers that
stretchstretch
Connective Tissue ProperConnective Tissue Proper
Loose CT
Areolar CT Adipose CT Reticular CT
Areolar CTAreolar CT
Very common CTVery common CT Open frameworkOpen framework All three types of fibersAll three types of fibers Found under the dermis of the skin, Found under the dermis of the skin,
around muscles and blood vessels.around muscles and blood vessels. Distorts without damageDistorts without damage
Areolar CTAreolar CT
Areolar CTAreolar CT
Adipose CTAdipose CT
Adipocytes are the dominant cell Adipocytes are the dominant cell typetype
Collagen fibers presentCollagen fibers present Found under the skin and around Found under the skin and around
organsorgans Protection and energy storageProtection and energy storage
Adipose CTAdipose CT
Reticular CTReticular CT
Open frame work Open frame work tissue tissue
Composed Composed primarily of primarily of reticular fibersreticular fibers
Structure of liver Structure of liver and spleenand spleen
Dense CTDense CT
Tissue is composed mostly of Tissue is composed mostly of collagen fiberscollagen fibers
Types of dense CTTypes of dense CT Dense regular CTDense regular CT Elastic CTElastic CT Dense irregular CTDense irregular CT
Dense Regular CTDense Regular CT
Tightly packed collagen fibers Tightly packed collagen fibers running parallel to each otherrunning parallel to each other
Very strong tissueVery strong tissue Fibroblasts presentFibroblasts present Tendons and ligamentsTendons and ligaments
Dense Regular CTDense Regular CT
Dense Regular CTDense Regular CT
Dense Irregular CTDense Irregular CT
Collagen fibers in less organized fabricCollagen fibers in less organized fabric Meshwork, no consistent patternMeshwork, no consistent pattern More elasticMore elastic Strength to areas of the body that are Strength to areas of the body that are
stressed from many directionsstressed from many directions Found in the dermis of the skin and Found in the dermis of the skin and
around many organsaround many organs
Dense Irregular CTDense Irregular CT
Elastic CTElastic CT
Type of dense regular CTType of dense regular CT Composed mostly of elastic fibersComposed mostly of elastic fibers Allows for stretchAllows for stretch Found between the vertebrae and Found between the vertebrae and
walls of large blood vesselswalls of large blood vessels
Elastic CTElastic CT
Supportive CTSupportive CT
CartilageCartilage Strong frame work for supportStrong frame work for support Matrix contains numerous fibersMatrix contains numerous fibers Three typesThree types
HyalineHyaline ElasticElastic Fibrocartilage (Fibrous cartilage)Fibrocartilage (Fibrous cartilage)
Hyaline cartilageHyaline cartilage
Most commonMost common Matrix of collagen fibersMatrix of collagen fibers Chondrocytes = Chondrocytes =
cartilage cellscartilage cells Lacuna = chamber Lacuna = chamber
around the cartilage around the cartilage cellcell
Perichondrium presentPerichondrium present LocationsLocations
End of long bonesEnd of long bones Tracheal ringsTracheal rings Costal cartilageCostal cartilage
Perichondrium of hyaline Perichondrium of hyaline cartilagecartilage
Elastic cartilageElastic cartilage
Contains elastic Contains elastic fibers in the matrix fibers in the matrix for stretchfor stretch
Found in the pinna Found in the pinna of the ear, and of the ear, and epiglottisepiglottis
Perichondrium Perichondrium presentpresent
Fibrocartilage (Fibrous Fibrocartilage (Fibrous cartilage)cartilage)
Matrix of collagen Matrix of collagen fibersfibers
Densely woven fibersDensely woven fibers Very tough and Very tough and
durabledurable No perichondriumNo perichondrium Found:Found:
Intervertebral discsIntervertebral discs Meniscus of the kneeMeniscus of the knee Pubic symphysisPubic symphysis
FibrocartilageFibrocartilage
BoneBone
Type of supportive CTType of supportive CT Bone cells are osteocytesBone cells are osteocytes Bone forming cells are osteoblastsBone forming cells are osteoblasts Matrix is mineralized collagen fibersMatrix is mineralized collagen fibers
BoneBone
Fluid CTFluid CT
BloodBlood LymphLymph
MembranesMembranes
Combination of epithelial tissues and CTCombination of epithelial tissues and CT Consists of epithelial sheet and underlying Consists of epithelial sheet and underlying
CTCT Membranes cover and protect Membranes cover and protect Four typesFour types
Mucous membranesMucous membranes Serous membranesSerous membranes Cutaneous membraneCutaneous membrane Synovial membraneSynovial membrane
Mucous membranesMucous membranes
Line passageways that communicate Line passageways that communicate with the outsidewith the outside Digestive, respiratory, reproductive, Digestive, respiratory, reproductive,
urinary tractsurinary tracts Important barriers to prevent entry Important barriers to prevent entry
of pathogensof pathogens Usually a simple epithelial lining but Usually a simple epithelial lining but
NOT alwaysNOT always
Serous membranesSerous membranes
These membranes line the subdivisions of These membranes line the subdivisions of the ventral body cavitythe ventral body cavity
Simple squamous epithelial (mesothelium) Simple squamous epithelial (mesothelium) and areolar CTand areolar CT
Very thin and attached to the body wall Very thin and attached to the body wall and organs coveredand organs covered PleuraPleura PeritoneumPeritoneum Pericardial Pericardial
Cutaneous membraneCutaneous membrane
SkinSkin Covers the surface of the bodyCovers the surface of the body Keratinized stratified squamous Keratinized stratified squamous
epithelial and underlying CT epithelial and underlying CT
MembranesMembranes
Other Tissue TypesOther Tissue Types
Muscles tissueMuscles tissue Skeletal muscleSkeletal muscle Cardiac muscleCardiac muscle Smooth muscleSmooth muscle
Nervous TissueNervous Tissue
Skeletal muscleSkeletal muscle
Cardiac muscleCardiac muscle
Smooth muscleSmooth muscle
Nervous tissueNervous tissue
Nervous TissueNervous Tissue