Overview of Tissues
Learning Objectives
Identify the four primary tissues
Compare and contrast primary tissue structure and function
Identify examples of epithelial and connective tissue and where they are
located
Compare and contrast the structure and function of epithelial and connective
tissue types
Identify the three types of epithelial membranes
Histology
The science that deals with the
study of tissues.
Hist – tissue
ology – study of
Types of Tissue
 Epithelial
 Connective
 Muscle
 Nervous
Overview of Epithelial
Tissue
Covering and Lining Epithelium
 Covers body surfaces
 Lines body cavities, hollow organs and
ducts
Glandular
 Forms glands
Epi – on top
thelium - covering
General Features of
Epithelium
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Consists of packed cells with little
extracellular material between them
Cells are arranged in continuous sheets, in
either single or multiple layers
Have a free surface and a basal surface
– Lumen – the hollow space in an organ or tube
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Are avascular : a- without vascular- blood
vessels
Have nerve supply
High capacity for renewal by cell division
Functions of Epithelium
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Protection
Secretion
Absorption
Excretion
Sensory reception
Generation of gametes
Types of Epithelial Tissue
Covering and Lining
Epithelium
Classification by shape
 Squamous - flat
 Cuboidal – cubes or hexagons
 Columnar – tall, rectangular and
cylindrical
 Transitional – range in shape from flat
to columnar and often change shape
Classification by Arrangement of Layers
 Simple – single layer in areas of diffusion,
osmosis, filtration, secretion and absorption
 Stratified – two or more layers used for
protecting underlying tissues
 Pseudostratified columnar – contains one layer,
appears to have several layers but not all cells
reach the surface, ciliated or secrete mucous
Simple Squamous
Epithelium
Single layer, flat cells, central nucleus
Lines the heart, blood vessels, lymphatic
vessels, alveoli, glomerular capsules, and
forms the epithelial layer of serous membranes
Function: filtration, diffusion, osmosis,
secretion in serous membranes
Simple Cuboidal Epithelium
Single layer, cube shaped, central nucleus
Lines the tubes and smaller ducts of the
kidneys
Function: secretion and absorption
Noncilialted Simple Columnar
Epithelium
Single layer, nonciliated, rectangular,
cylindrical cells, nucleus at base, contain
goblet cells, some have microvilli
Goblet cells make and secrete mucus
Lines GI, respiratory, reproductive and urinary
tracts
Function: secretion and absorption
Ciliated Simple Columnar Epithelium
Single layer, ciliated, rectangular, cylindrical cells,
nucleus at base, some goblet cells
Lines portions of trachea and upper respiratory tract,
Fallopian tubes, uterus, some paranasal sinuses
and central canal of the spinal cord
Function: moves mucus and other substances
Stratified Squamous Epithelium
Several layers, cuboidal or columnar deep,
squamous superficial, basal cells replace
surface cells
Keratinized epidermis, nonkeratinized lines
the mouth, esophagus, vagina and tongue
Function: protection
Stratified Cuboidal Epithelium
Two or more layers, superficial cells cubeshaped
Ducts of adult sweat glands and part of male
urethra
Function: protection and limited secretion and
absorption
Stratified Columnar Epithelium
Several layers, irregularly shaped cells,
columnar cells superficial
Lines part of urethra and large excretory ducts
Function: protection and secretion
Transitional Epithelium
Variable cell shapes, superficial cells
squamous when stretched, cuboidal when
relaxed
Lines urinary bladder and portions of ureters
and urethra
Function: permits organs to stretch without
rupturing
Pseudostratified Columnar
Epithelium
Not true stratified tissue, cells at different
layers, all cells attached to basement
membrane, only some reach surface
Ciliated lines airways of most of the upper
respiratory tract (trachea)
Function: secretion and movement of mucus
Glandular Epithelium
 Endocrine – ductless glands
Pituitary, thyroid, and adrenal glands
 Exocrine – glands with ducts
Sweat and salivary glands
Connective Tissue
General Features
 Two basic elements: cells and a matrix
 Does not occur on body surfaces
 Has a nerve supply, except cartilage
 Usually highly vascular except cartilage (avascular)
and tendons
 Various tissue types confer a variety of functions
Two Major Types
 Embryonic – found in the embryo and fetus
 Mature – present in newborns to adults
Connective Tissue Cells
 Fibroblasts
 Macrophages
 Plasma
Cells
 Mast Cells
 Adipocytes
 Leukocytes
Connective Tissue Matrix
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Ground substance
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Fibers
Connective Tissue Fibers
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Collagen
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Elastic
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Reticular
Embryonic Connective
Tissue
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Mesenchyme – tissue from which
mature connective tissue will arise
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Mucous Connective Tissue – found
primarily in the umbilical cord of the
fetus
Mature Connective Tissue
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Loose Connective Tissue
Dense Connective Tissue
Cartilage
Bone
Blood
Lymph
Loose Connective Tissue
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Areolar Connective Tissue
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Adipose Tissue
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Reticular Connective Tissue
Areolar Connective Tissue
Fibers and several kinds of cells embedded in
a semifluid ground substance
Subcutaneous layer deep to skin, superficial
part of dermis, mucous membranes, around
blood vessels, nerves and body organs
Function: strength, elasticity, and support