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Exercise 6
Classification of Tissues
What is a tissue?
 Groups of cells
 Similar in structure & function
 Tissues are further organized into
organs ( organ systems)
4 Major Tissue Types
 Epithelial
 Connective
 Muscle
 Nervous
Epithelial Tissues
 Cover surfaces
 Simple or stratified?
Simple = one layer of cells attached to
the basement membrane
 Stratified = two or more layers of cells


Name this epithelia by whichever “shape”
the top layer of cells is (apical layer), not
the bottom (basal layer)
Epithelial Tissues
 Shapes of Epithelial Cells
 Squamous
Simple squamous


Cuboidal


Scalelike, flattened
Cubelike
Columnar

Column-shaped
Stratified squamous
Simple cuboidal
Stratified cuboidal
Simple columnar
Stratified columnar
Epithelial Tissues
 Simple squamous epithelium
Epithelial Tissues
 Simple cuboidal epithelium
Fig 4-4
Epithelial Tissues
 Simple columnar epithelium
Epithelial Tissues
 Pseudostratified columnar epithelium

Actually simple columnar: nuclei are at
different levels so there appears to be
more than one layer
Fig 4-5
Epithelial Tissues
 Stratified squamous epithelium
Epithelial Tissues
 Stratified cuboidal epithelium
Epithelial Tissues
 Stratified columnar epithelium
Fig 4-5
Epithelial Tissues
 Transitional epithelium

Stratified squamous epithelium formed of
rounded cells that can slide over one
another, allowing the organ to stretch:
urinary system only
Fig 4-4
CONNECTIVE TISSUES
 Embryonic connective tissue
 mesenchyme
 Loose connective tissue
 Areolar, adipose, reticular
 Dense connective tissue
 Dense irregular, dense regular
 Supportive connective tissue
 Hyaline, elastic, fibrocartilages; bone
 Fluid connective tissue

Blood, lymph
CONNECTIVE TISSUES
 Differing proportions of cells and fibers to
“matrix”
 Matrix is noncellular, nonliving material
between the connective tissue cells
 Different proportions have to deal with
strength of the tissue
Classification of Connective
Tissues
Fig. 4-8
Many cell types
Distinct cell types
Less diverse cell types
Syrupy ground substance
Watery matrix
More fibrous matrix
Embryonic Connective Tissue
 Mesenchyme



Many star-shaped stem cells
Gives rise to all other connective tissues
Not present in adults
Fig. 4-10
Loose Connective Tissue: Areolar
Loose Connective Tissue
 Adipose connective tissue




(fat)
Insulation for the body’s tissues
Food storage
Little matrix
Fig. 4-11
Loose Connective Tissue
 Reticular connective tissue

Reticular fibers form a soft internal
skeleton for support
Dense Irregular
Collagenous Connective
Tissue
Dense Irregular Elastic
Dense Connective Tissue
 Dense regular connective tissue


Fibers in one direction
Tendons, ligaments of body’s joints
Fig. 4-12
Dense Regular Elastic
Supportive Connective Tissue
Supportive Connective Tissue
 Elastic Cartilage


Maintains shape, but flexible
Many elastic fibers
Supportive Connective Tissue
 Fibrocartilage


Strength, shock absorption
Dense network of collagen fibers
Supportive Connective Tissue
 Osseous Connective Tissue (Bone)

Support, protection
Fluid Connective Tissue
Fluid Connective Tissue
 Lymph



Fluid of the lymphatic system
Like plasma without the big proteins
Immune defense
MUSCLE TISSUES
 Skeletal
 Cardiac
 Smooth
Skeletal Muscle Tissue
Cardiac Muscle Tissue
 Only in the heart
 Striated tissue
 Under involuntary control
 Branching, uninucleate cells with
intercalated discs
Smooth Muscle Tissue
 Found in the walls of hollow organs
(digestive, urinary tracts; blood vessels)
 2 layers at right angles for
contraction/dilation of the organ cavity
 Not striated tissue
 Uninucleate, spindle-shaped cells
Muscle type
Cells
striations
Voluntary?
Cardiac
branched
Uninucleate
Intercalated discs
yes
no
Skeletal
Long fibers
multinucleate
yes
yes
Smooth
Spindle shaped
1 nucleus
no
no
NERVOUS TISSUE
 Brain, spinal cord, nerves
 2 basic cell types:

Neuroglia cells


Protect, support, and insulate the neurons
Neurons

Receive stimuli and conduct nerve impulses all
over the body