Exercise 6 Classification of Tissues. What is a tissue? Groups of cells Groups of cells Similar in structure & function Similar in structure & function.

Exercise 6Exercise 6

Classification of TissuesClassification of Tissues

What is a tissue?What is a tissue?

Groups of cells Groups of cells Similar in structure & functionSimilar in structure & function

Tissues are further organized into Tissues are further organized into organs (organs ( organ systems) organ systems)

4 Major Tissue Types4 Major Tissue Types

EpithelialEpithelial Connective Connective MuscleMuscle NervousNervous

Epithelial TissuesEpithelial Tissues

Cover surfacesCover surfaces

Simple or stratified?Simple or stratified? Simple = one layer of cells attached to Simple = one layer of cells attached to

the basement membranethe basement membrane Stratified = two or more layers of cellsStratified = two or more layers of cells

Name this epithelia by whichever “shape” Name this epithelia by whichever “shape” the top layer of cells is (apical layer), not the top layer of cells is (apical layer), not the bottom (basal layer)the bottom (basal layer)

Epithelial TissuesEpithelial Tissues

Shapes of Epithelial CellsShapes of Epithelial Cells SquamousSquamous

Scalelike, flattenedScalelike, flattened CuboidalCuboidal

Cubelike Cubelike ColumnarColumnar

Column-shapedColumn-shaped

Simple squamousSimple squamous

Stratified squamousStratified squamous

Simple cuboidalSimple cuboidal

Stratified cuboidalStratified cuboidal

Simple columnarSimple columnar

Stratified columnarStratified columnar

Epithelial TissuesEpithelial Tissues

Simple squamous epitheliumSimple squamous epithelium

Fig. 4-3

Epithelial TissuesEpithelial Tissues

Simple cuboidal epitheliumSimple cuboidal epithelium

Fig 4-4

Epithelial TissuesEpithelial Tissues

Simple columnar epitheliumSimple columnar epithelium

Fig 4-5

Epithelial TissuesEpithelial Tissues

Pseudostratified columnar epitheliumPseudostratified columnar epithelium Actually simple columnar: nuclei are at Actually simple columnar: nuclei are at

different levels so there appears to be different levels so there appears to be more than one layermore than one layer

Fig 4-5

Epithelial TissuesEpithelial Tissues

Stratified squamous epitheliumStratified squamous epithelium

Fig. 4-3

Epithelial TissuesEpithelial Tissues

Stratified cuboidal epitheliumStratified cuboidal epithelium

Fig 4-4

Epithelial TissuesEpithelial Tissues

Stratified columnar epitheliumStratified columnar epithelium

Fig 4-5

Epithelial TissuesEpithelial Tissues

Fig 4-4

Transitional epitheliumTransitional epithelium Stratified squamous epithelium formed of Stratified squamous epithelium formed of

rounded cells that can slide over one rounded cells that can slide over one another, allowing the organ to stretch: another, allowing the organ to stretch:

urinary system onlyurinary system only

CONNECTIVE TISSUESCONNECTIVE TISSUES

Embryonic connective tissueEmbryonic connective tissue mesenchymemesenchyme

Loose connective tissueLoose connective tissue Areolar, adipose, reticularAreolar, adipose, reticular

Dense connective tissueDense connective tissue Dense irregular, dense regularDense irregular, dense regular

Supportive connective tissueSupportive connective tissue Hyaline, elastic, fibrocartilages; boneHyaline, elastic, fibrocartilages; bone

Fluid connective tissueFluid connective tissue Blood, Blood, lymphlymph

CONNECTIVE TISSUESCONNECTIVE TISSUES

Differing proportions of cells and fibers to Differing proportions of cells and fibers to “matrix”“matrix” Matrix is noncellular, nonliving material Matrix is noncellular, nonliving material

between the connective tissue cellsbetween the connective tissue cells Different proportions have to deal with Different proportions have to deal with

strength of the tissuestrength of the tissue

Classification of Connective Classification of Connective TissuesTissues

Fig. 4-8

Many cell types

Syrupy ground substance

Distinct cell types

Watery matrix

Less diverse cell types

More fibrous matrix

Embryonic Connective Embryonic Connective TissueTissue

MesenchymeMesenchyme Many star-shaped stem cells Gives rise to all other connective tissues Not present in adults

Fig. 4-10

Loose Connective TissueLoose Connective Tissue

Areolar connective Areolar connective tissuetissue Can contain all cells

and fibers of any connective tissue

Loosely organized ground substance

Cushions & protects body’s organs

Lots of matrix

Fig. 4-9

Loose Connective TissueLoose Connective Tissue

Adipose connective tissueAdipose connective tissue (fat) Insulation for the body’s tissues Food storage Little matrix

Fig. 4-11

Loose Connective TissueLoose Connective Tissue

Reticular connective tissueReticular connective tissue Reticular fibers form a soft internal

skeleton for support

Fig. 4-11

Dense Connective TissueDense Connective Tissue

Dense irregular connective tissueDense irregular connective tissue Fibers in many directions Dermis

Fig. 4-12

Dense Connective TissueDense Connective Tissue

Dense regular connective tissueDense regular connective tissue Fibers in one direction Tendons, ligaments of body’s joints

Fig. 4-12

Fig. 4-15

Supportive Connective Supportive Connective TissueTissue

Hyaline CartilageHyaline Cartilage Support, reinforcement Somewhat flexible Most common cartilage

Supportive Connective Supportive Connective TissueTissue

Elastic CartilageElastic Cartilage Maintains shape, but flexible Many elastic fibers

Fig. 4-15

Supportive Connective Supportive Connective TissueTissue

FibrocartilageFibrocartilage Strength, shock absorption Dense network of collagen fibers

Fig. 4-15

Supportive Connective Supportive Connective TissueTissue

Osseous Connective Tissue (Bone)Osseous Connective Tissue (Bone) Support, protection

Fig. 4-16

Fluid Connective TissueFluid Connective Tissue

BloodBlood Red blood cells, white blood cells, platelets Transport gases and other nutrients and

waste Watery matrix (plasma or serum)

Fig. 4-13

Fluid Connective TissueFluid Connective Tissue

LymphLymph Fluid of the lymphatic system Like plasma without the big proteins Immune defense

MUSCLE TISSUESMUSCLE TISSUES

SkeletalSkeletal CardiacCardiac SmoothSmooth

Fig. 4-19

Skeletal Muscle TissueSkeletal Muscle Tissue

Attached to the skeletonAttached to the skeleton Under conscious controlUnder conscious control Striated tissueStriated tissue Long, cylindrical, multinucleate cellsLong, cylindrical, multinucleate cells

Cardiac Muscle TissueCardiac Muscle Tissue Only in the heartOnly in the heart Striated tissueStriated tissue Under involuntary controlUnder involuntary control Branching, uninucleate cells with Branching, uninucleate cells with

intercalated discsintercalated discs

Fig. 4-19

Smooth Muscle TissueSmooth Muscle Tissue Found in the walls of hollow organs Found in the walls of hollow organs

(digestive, urinary tracts; blood vessels)(digestive, urinary tracts; blood vessels) 2 layers at right angles for

contraction/dilation of the organ cavity Not striated tissue Uninucleate, spindle-shaped cells

Fig. 4-19

Muscle type Cells striations Voluntary?

Cardiac branchedUninucleateIntercalated discs

yes no

Skeletal Long fibersmultinucleate

yes yes

Smooth Spindle shaped1 nucleus

no no

NERVOUS TISSUENERVOUS TISSUE Brain, spinal cord, nervesBrain, spinal cord, nerves 2 basic cell types:2 basic cell types:

Neuroglia cells Protect, support, and insulate the neurons

Neurons Receive stimuli and conduct nerve impulses all

over the body

Fig. 4-20