HISTOLOGY
Four Basic Types of Tissue
1. Epithelial
2. Connective
3. Muscle
4. Nerve
EPITHELIAL TISSUE
 Cells are bound tightly together
 Little extracellular material
 Arranged in sheets
Cover internal and external surfaces
Often control passage of material
Classified by shape of cells and number of layers
EPITHELIAL TISSUE
CELL SHAPE
Squamous shape
Thin, flat cells
Look like fried eggs
 Cubodial shape
square shape- cross section
6sided polygon- surface
 Columnar
Rectangular- cross section
Polygonal- surface view
CELL NUMBER
Simple
Single layer
 Stratified
2+ layers
 Pseudostratified
Appear stratified- but not
Transitional
Change shape
EPITHELIAL TISSUE
SIMPLE SQUAMOUS
Single layer
Squamous shape
Lining of body cavity, lungs,
blood vessels
EPITHELIAL TISSUE
SIMPLE CUBOIDAL
Single layer
Cuboidal shaped
Kidney tubules, glands
EPITHELIAL TISSUE
SIMPLE COLUMNAR
Single layer
Columnar shape
Lining of digestive tract
Modified by presence of cilia
EPITHELIAL TISSUE
STRATIFIED SQUAMOUS
Multi layer
Outer most layer- squamous cells
Inner- cuboidal or columnar
Lining of mouth, esophagus, skin
EPITHELIAL TISSUE
PSEUDOSTRATIFIED
COLUMNAR
One layer
Appears stratified
Respiratory tract
Types
CONNECTIVE TISSUE
Fibrous
Loose – Areolar, Adipose, Reticular
Dense – Regular, Irregular
Cartilage – Hyaline, Elastic, Fibrocartilage
Bone
Blood
Abundant extracellular material
Matix (dominant part)
 Fiber, cells in liquid, gel, or solid matrix
 Function
Bind and/or support other tissue
Fibrous - CONNECTIVE TISSUE
LOOSE Connective
Areolar
Few fibers
Delicate arrangement
Reticular
Loose network of reticular
fibers and cells
Forms supportive stroma
(framework) for lymphatic
organs
Found in lymph nodes,
spleen, thymus and bone
CONNECTIVE TISSUE
LOOSE Connective
Adipose Tissue
Store large droplets of fat
Connective Tissue
• Dense Connective
– Regular
– Densely, packed,
parallel collagen
fibers
• Ex: Tendons and
ligaments
Connective Tissue
• Dense Connective
– Irregular
• Densely packed,
randomly arranged,
collagen fibers and
few visible cells
• Ex: Deep layer of
skin & capsules
around organs
ConnectiveTissue
• Cartilage
– Supportive connective tissue with rubbery
matrix
– Chondroblasts produce matrix
– No blood vessels
• heals slowly
• Types of cartilage vary with fiber types
– hyaline, fibrocartilage and elastic cartilage
Hyaline Cartilage
• Rubbery matrix; dispersed collagen fibers;
clustered chondrocytes in lacunae
• Ends of bones at movable joints; sternal ends of
ribs; and fetal skeleton
Elastic Cartilage
• Hyaline cartilage with elastic fibers
• Provides flexible, elastic support
– external ear and epiglottis
Fibrocartilage
• Hyaline cartilage with extensive collagen fibers (never has
perichondrium)
• Resists compression and absorbs shock
– pubic symphysis, meniscus and intervertebral discs
Connective Tissue
• BLOOD
– Lymph
– Liquid matrix
– RBC- Red Blood Cells
– WBC- White Blood Cells
CONNECTIVE TISSUE
BONE
Osteocytes
Small cavities- lacunae
Hardest CT
Impregnated w/ calcium salts
Spongy
Loose rods of bones
Ends of arms and legs
Compact
Shafts of long bones
Tightly organized
MUSCLE TISSUE
 Cells have ability to contract
Function
Locomotion
Other body movement
SKELETAL
MUSCLE TISSUE
Voluntary movement
Long and cylindrical
Transverse striation
Each fiber is multi-nuclear
MUSCLE TISSUE
SMOOTH
Involuntary movement
Predominant
Long, spindle shape
Single nucleus
Internal organs
MUSCLE TISSUE
CARDIAC
Striations
Involuntary
One nucleus
Deep center
Heart muscle
NERVE TISSUE
 Cells very high ability to
Respond to stimuli
Transmit impulses
NERVE TISSUE
NEURON
Cell Body(3)
Dendrites (5)
Axon(1)