Tissues• Definition?• Histology- study of tissues within the body

systems• Classified based on:– Embryonic development– Intercellular space

• Four Tissue Types

EPITHELIAL TISSUE

Very Little intercellular space material

Derived from all three embryonic layers

Regeneration??

Arranged in sheets with a basement membrane

Exposed surface (internal or external)

Function

Protection

Cover internal and external surfaces

Secretion and absorbtion (Glands)

Classified by shape of cells and number of layers

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

Glands

• One cell or a group of specialized epithelial cells to secrete substances into ducts, the surfaces or blood

– Exocrine• Example- sweat or salivary glands

– Endocrine• Example- hormones

CONNECTIVE TISSUE

Abundant extracellular material

Derived from the mesoderm

Matrix (dominant part)

Fiber, cells in liquid, gel, or solid matrix

Highly vascular

Function

Bind and/or support other tissue

Store nutrients

CONNECTIVE TISSUE

Tendons

Dense fiberous

Abundant, well organized fiber

CONNECTIVE TISSUE

ADIPOSE TISSUE

Loose connective

Semisolid matrix

Store large droplets of fat

BLOOD

Lymph

Liquid, fluid matrix

Sometimes in different category

RBC- Red Blood Cells

WBC- White Blood Cells

CONNECTIVE TISSUE

CARTILAGE

Chondrocytes

Small cavities- lacunae

Dense, solid elastic matrix

Ear, nose

CONNECTIVE TISSUEBONE

Osteocytes

Solid, rigid matrix

Hardest CT

Impregnated w/ calcium salts

MUSCLE TISSUE

Derived from mesoderm

Little intercellular matrix, fibers close together

Cells have ability to contract

Function

Locomotion

Other body movement

Pg 156-157,162; slides 161

MUSCLE TISSUESKELETAL

Voluntary movement

Typically attach to bone

Long and cylindrical

Transverse striation

Each fiber is multi-nuclear

MUSCLE TISSUE

SMOOTH

Involuntary movement

Nonstriated

Predominant

Long, spindle shape

Single nucleus

Internal organs

MUSCLE TISSUE

CARDIAC

Striations

Involuntary

One nucleus

Deep center

Heart muscle

NERVE TISSUE

Derived from ectoderm

Little intercellular matrix

Cells very high ability to

Respond to stimuli

Transmit impulses

Two types:

Neurons and Neuroglia

NERVE TISSUE

NEURON

Cell Body(3)

Dendrites (5)

Axon(1)

List of intercellular matrix

• Least to most– Epithelial– Muscular– Nervous– connective