Objectives
Chapter 3
Epithelial tissues
Tissues
• Groups of cells that are similar in structure
and function
• Four primary types
– Epithelium
– Connective
– Nervous
– Muscle
1. Name the four major tissue types and
their subcategories (a. epithelial)
2. Explain the structure and function of
each tissue
3. Give the primary locations of the tissue
types in the body
4. Identify slides or pictures of each tissue
EPITHELIA
TISSUES
•Location includes linings,
coverings & glands
• Functions include protection,
absorption, filtration & secretion
•http://www.stegen.k12.mo.us/tchrpges/sghs/ksulkowski/TissueS
lides.htm
•http://kcfac.kilgore.cc.tx.us/kcap1/practical_1_photos.htm
Characteristics of Epithelia Tissues
APICAL SURFACE
• Form continuous sheets bound by cell junctions
(p. 57)
• Free surface or apical surface is exposed to
body’s exterior or cavity of an organ
• Basement membrane are underlining layers
• Avascular – no blood vessels; rely on diffusion of
gases & nutrients from underlying connective
tissues
• regenerates
BASEMENT
MEMBRANE
1
Classification of Tissue
simple squamous
stratified squamous
Given two names:
• Cell arrangement (layers)
– Simple: one layer
– Stratified: more than one layer
• Cell shape
simple columnar
simple cuboidal cells
– Squamous: flat
– Cuboidal: cube shaped
– Columnar: columns
SIMPLE EPITHELIA
Functions mainly to absorb,
secrete & filtrate substances;
too thin to protect
1. SIMPLE SQUAMOUS
• Single, flat & scale like
• Large central nucleus
• Forms membranes
where rapid diffusion
occurs
• Locations: air sacs of
lungs, lining heart,
blood vessels &kidneys,
serous membranes
2. SIMPLE CUBOIDAL
• Single, cube shaped
• Large central nuclei
• Locations: tubules of
kidneys, ducts of
glands & ovary
2
3. SIMPLE COLUMNAR
• Single layer of tall
cells with oval nuclei
• May contain goblet
cells that secrete
mucus
• Locations: lines
digestive tract & gall
bladder, mucous
membranes
STRATIFIED EPITHELIA
Multiple layers of cells found in
areas of protection
2. Stratified Cuboidal
• 2 layers; cube shaped
• Found in adult sweat
glands, conjunctiva of
eye, male urethra,
pharynx & epiglottis
4. PSEUDOSTRATIFIED
COLUMNAR
• “false layers”
• Some cells look shorter
than others making it look
stratified
• Nuclei at various levels
• Can be ciliated –
respiratory tract
• Nonciliated located in
ducts of glands & male
urethra
1. Stratified Squamous
• Free surface looks
squamous while lower
layers are either
cuboidal or columnar
• Found in areas of
friction – mouth,
esophagus, skin or
birth canal
3. Stratified Columnar
• Multiple layers of
column shaped cells
• Lines tubules of
kidneys
3
4. Transitional
• Modified stratified
squamous but large &
more rounded
• Ability to change
shape allowing
organs to stretch or
distend
• Lines urinary bladder,
ureters & urethra
GLANDULAR EPITHELIA
• Consists of one or more cells that produce
or secrete a product called a hormone
1. Endocrine
• Ductless glands
• Hormones diffuse
directly into blood
vessels that weave
through the gland
• Thyroid, pituitary,
adrenal
2. Exocrine
• Contains a duct
through which
secretions empty
• Sebaceous (oil),
sweat, mammary,
pancreatic, liver
4
5