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PATHOPHYSIOLOGY
PATHOPHYSIOLOGY
 DEFINED
• Involves the study of function
that results from disease
processes.
PATHOPHYSIOLOGY
 What
is pathology?
PATHOPHYSIOLOGY
 Pathology
is the branch of medical
sciences that treats the essential
nature of disease, especially the
changes of structure and function
in tissues and organs of the body
that cause or are caused by disease.
PATHOPHYSIOLOGY
 Why
is pathophysiology studied?
PATHOPHYSIOLOGY
 In
the clinical setting, pathologists,
histotechnologists, and
cytotechnologist study tissues and
cells to establish the cause of a
disease.
 Physicians use that information to
form a treatment plan.
PATHOPHYSIOLOGY
 What
is a pathologist?
PATHOPHYSIOLOGY
A
pathologist is a physician who is
specifically trained and
experienced in anatomical and
physiological pathology.
PATHOPHYSIOLOGY

What is a histologic technician or
histotechnologist?
PATHOPHYSIOLOGY

Histologic technicians and Histotechnologists
prepare slides of body tissue for microscopic
examination.
 Career opportunities for both are excellent in
hospitals, research institutions, industrial labs, and
government agencies
 A technician requires a 12-month, hospital-based
on-the-job training program or an AAS degree.
 A histotechnologist requires a BS degree and one
year of additional laboratory experience.
PATHOPHYSIOLOGY
 What
type of studies are performed
in the clinical pathology
laboratory?
PATHOPHYSIOLOGY

Tissue of all types are sent to the histology
department for studies into the disease
process. Any exam done by a microscope is
called a microscopic exam.
PATHOPHYSIOLOGY

The pathologist studies the tissue by doing a
gross examination. Any exam done with
the naked eye is a called a gross
examination.
PATHOPHYSIOLOGY

Tissues are looked at closely and all observations
are recorded.
PATHOPHYSIOLOGY

The tissue is then prepared for microscopic
studies by placing it in a tissue cassette.
PATHOPHYSIOLOGY

The histotechnologist prepares the tissue for
microscopic examination. This is done by
using the embedding center. The tissue is
placed in paraffin wax in order to cut thin
slices of the tissue.
PATHOPHYSIOLOGY
 The
embedding center instrument
PATHOPHYSIOLOGY

The histotechnologist pours paraffin wax
over a tissue specimen.
PATHOPHYSIOLOGY

Once the tissue is embedded in paraffin, the block of wax
is cooled. The histotechnologist then cuts ribbon-like
sections for placement on slides. The instrument used is
called a microtome.
PATHOPHYSIOLOGY

A water bath is used for spreading the
paraffin ribbons and sections are placed on
microscope slides to be stained.
PATHOPHYSIOLOGY

Tissues are stained at the staining center.
The basic stain for all tissues is the
Hemotoxylin and Eosin (counterstain) stain.
Pink
Blue
PATHOPHYSIOLOGY

Special stains are used for particular details.
They include:
•
•
•
•
AFB-Acid Fast Bacilli Stain
PAS-Periodic Acid Schiff Stain
Trichrome Stain
Iron Stain
Acid Fast Bacilli Stain (AFB)

Type of bacteria that resists decolorizing by
acids during staining
• Ex: -Mycobacteria, tuberculosis, leprae, some
parasites
Periodic Acid Schiff Stain (PAS)

Used to identify glycogen in tissue;
oxidizes the glucose residues and creates
aldehydes that react with schiff reagant and
creates a purple color
• For glucose storage diseases: Pagets disease
Paget's disease is a chronic condition of bone characterized by
disorder of the normal bone remodeling process.
Trichrome Stain

3 color staining process used to distinguish
cells from connective tissues
•
•
•
•
Red= keratin and muscle fibers
Blue/green= collagen and bone
Light red or pink= cytoplasm
Dark brown to black= cell nuclei
Trichrome stained liver
showing fibrous tissue.
The fibrous tissue is
stained blue while the
cytoplasm of hepatocytes
are stained red.
The nuclei can be seen as
dark red to black
structures within cells;
Collagen is the fibrous
tissue are stained Blue
(with aniline blue) or very
light green (by aniline
light green).
Trichrome stain showing
cirrhotic liver. As it is
evident, the normal
architecture of the liver is
destroyed in this disease
and the liver shows
nodules surrounded by
fibrous bands.
PATHOPHYSIOLOGY

The pathologist then studies the slide to determine
pathological states within the tissues. A written report is
then given to physician to aid him/her in the diagnosis and
treatment of the patient.
PATHOPHYSIOLOGY

Pathologists also perform frozen sections
for patient’s in surgery on the Cryostat.
PATHOPHYSIOLOGY
 Exciting
opportunities await
students who want to explore the
physiology of the tissues and cells
under the microscope!