Ch 4: Tissue
• Groups of cells that are similar in structure
and perform a common or related functions
are called TISSUE
• The study of tissue, or histology,
complements the study of gross anatomy.
Together they provide the structural basis
for understanding organ physiology.
Tissues
• The tissues of the human body include four
major types: general function
• Epithelial: covering
• Connective: support
• Muscle: movement
• Nervous: control
Types of Tissue!!
EPITHELIAL TISSUES
EPITHELIAL TISSUES
• Epithelial Tissue: is a
sheet of cells that
covers a body surface
or lines a body cavity
• Nearly all substances
received or given off
by the body must pass
through an epithelium
layer.
EPITHELIAL TISSUES
• Epithelial Tissue
lacks of blood vessels,
contains little
intercellular material
and are continually
being replaced
• They function in
protection, secretion,
absorption, filtration,
excretion, and sensory
reception.
EPITHELIAL TISSUES
• Epithelium Tissue has
many characteristics
that separate it from
other tissue types
• ET has Polaritywhich means it has an
apical surface (near
the top) and a basal
surface (near the
bottom)
• Specialized Contacts
• Supported by
connective tissue.
EPITHELIAL TISSUES
.
• Each Epithelium Tissue is •given
two names.
• The first name indicates the number of cell
layers present.
– Simple- one layer
– Stratified- more than one layer
• The second describes the shape of its cells
– Squamous, cuboidal, and columnar.
EPITHELIAL TISSUES
• .
Simple Squamous Epithelium
• This tissue consists of a single layer of thin,
flattened cells through which substances can pass
easily. So delicate they can easily be damaged.
• Common site of diffusion and osmosis. Its
functions in the exchange of gases in the lungs
• Lines the air sacs of the lungs (gas exchange),
forms the walls of the capillaries, lines the insides
of blood vessels and lymph vessels.
• Covers the membrane that line body cavities.
• EX: Cheek Cells
Simple Squamous Epithelium
Simple Squamous Epithelium
Simple Cuboidal Epithelium
• This tissue consists of a single layer of
cube-shaped cells. Usually have a centrally
located spherical nuclei
• It carries on secretion and absorption.
Secretes glandular products.
• Covers the ovaries, lines the kidneys,
tubules and ducts of certain glands like
pancreas and the liver.
Simple Cuboidal Epithelium
Simple Cuboidal Epithelium
Simple Columnar Epithelium
• The tissue is composed of a single layer of
elongated cells whose nuclei are usually at about
the same level, near the basement membrane.
• Some have cilia some do not
• Secretes and absorbs…this tissue is thick!!
• This tissue lines uterus and portions of the
digestive tract like small/large intestines and
stomach.
Simple Columnar Epithelium
Simple Columnar Epithelium
Simple Columnar Epithelium
Pseudostratified Columnar
Epithelium
• They appear stratified but are NOT, They appear
to have two or more nuclei but they each reach the
basement level.
• Goblet cells scattered throughout the tissue that
secret mucus, which the cilia sweep away.
• It lines tubes of the respiratory system. The
mucus and cilia created by this tissue trap the dust
and microorganisms that enter the airway.
Pseudostratified Columnar
Epithelium
• “C” the nuclei appear
at various levels
giving it the stratified
appearance
• “B” the cilia can easily
be seen
Pseudostratified Columnar
Epithelium
Pseudostratified Columnar
Epithelium
Stratified Squamous Epithelium
• Named for the shape of the cells,…consists of
many layers, relatively thick. Cells nearer the
surface are flat where as the deeper are cuboidal
and columnar.
• Tissue can contain Keratin, which is a protein that
accumulates and protect the underlying tissue.
• Epidermis-outer most layer of the skin
• Also lines the skin and lines the oral cavity, throat,
vagina, and anal canal.
Stratified Squamous Epithelium
• Observe that the
surface cells (at B) are
flattened (are
squamous).
Stratified Squamous Epithelium
Stratified Cuboidal Epithelium
• This tissue is composed of two or thee
layers of cube-shaped cells.
• It lines the larger ducts of the mammary
glands sweat glands, salivary glands, and
pancreas. Forms the lining of ovarian
follicles and seminiferous tubules
• It functions in protection.
Transitional Epithelium
• This tissue is specialized to change in
response to tension..
• Transition epithelium is unstretched and
consists of many layers when the organs
wall contract the tissue stretches and
appears thinner when the organ is distended.
• Forms the lining of the urinary bladder and
lines the ureters and part of the urethra.
Transitional Epithelium
Transitional Epithelium