Introduction to General Pathology and HistoTechniques- PRELIMS L1

HISTOTECHNOLOGY

Is the art and science performed by the histotechnologist to produce a tissue section of good quality that will enable the pathologist to diagnose the presence or absence of disease.

HISTOPATHOLOGIC TECHNIQUE

Involves different procedures that have been adopted for the preparation of materials and tissue for microscopic examination.

PATHOLOGY

• In ancient Greek pathos= pain and logos= word

• Also called pathobiology.

• Bridging discipline of basic science and clinical practice

• Study of the structural and functional changes in cells, tissues, and organs that underlie disease

ASPECTS OF DISEASES FORMING THE CORE PATHOLOGY

• Etiology/Cause

• Pathogenesis/Mechanism of development

• Morphologic changes/structural alterations

• Clinical significance/functional consequences

MICROSCOPE

An important factor in detecting tissue changes, especially in the examination of small sections of tissue removed for diagnosis; for this reason real progress in pathology was not made until the 19th cent.

PATHOGENESIS

The development of a disease or morbid condition

PATHOLOGIST

• A physician who interprets and diagnoses the changes cause by disease in the body.

• A specialist physician expert in the origin and development of disease and the microscopic analysis of body tissues.

• A physician who studies all aspects of disease with an emphasis on the nature, causes, and development of abnormal conditions, as well as the structural and functional changes that result from disease processes

• The laboratory expert behind the front-line clinical team

MEDICAL TECHNOLOGIST

An Allied Health Professional who performs diagnostic analysis on human blood, urine, and body fluids such as cerebrospinal fluid, peritoneal, pericardial, and synovial, as well as other specimens such as stool and sputum.

HISTOLOGY

• Is the branch of biology which studies the microscopic anatomy of biological tissues.

• Histology is the microscopic counterpart to gross anatomy, which looks at larger structures visible without a microscope.

FOUR BASIC TYPES OF ANIMAL TISSUES

1. Epithelial tissue

2. Muscle tissue

3. Connective tissue

4. Nervous tissue

EPITHELIUM

Epithelial tissues line the outer surfaces of organs and blood vessels throughout the body, as well as the inner surfaces of cavities in many internal organs.

ACCORDING TO CELLULAR ARRANGEMENT

• Simple

• Pseudostratified

• Stratified

SIMPLE

Monolayer or single layer of cells

PSEUDOSTRATIFIED

Pseudo means false, all of the cells are lying in the same basement membrane; irregular arrangement of nucleus makes it look like a stratified tissue

STRATIFIED

Many or more than one layers of cells

ACCORDING TO CELLULAR SHAPE

1. Squamous epithelium

2. Cuboidal epithelium

3. Columnar epithelium

SQUAMOUS EPITHELIUM

• Cells that are wider than their height (flat and scale-like)

• This is found at the lining of the mouth, esophagus, and including blood vessels and in the alveoli of the lungs. (in simple form, for exchange of materials like O2, CO2, nutrients or metabolic products; in stratified form, for protection

CUBOIDAL EPITHELIUM

Cells whose height and width are approximately the same (cube shaped). Involved in secretion.

COLUMNAR EPITHELIUM

Cells taller than they are wide (column-shaped). If ciliated, involved in transport of materials thru ciliary action; mostly seen in intestinal tract

TRANSITIONAL EPITHELIUM

No definite shape, assume different shape, depends on organ, may be balloon-shaped; stretchable

COVERING EPITHELIA

12 covering epithelia in total but not all can be found in the body

SIMPLE SQUAMOUS

For exchange of materials; blood vessels, alveoli of lungs, heart

SIMPLE CUBOIDAL

Secrete; ducts of glands, thyroid follicles

SIMPLE COLUMNAR

Ciliated uterine tube or non-ciliated gallbladder

STRATIFIED SQUAMOUS

For protection; keratinized skin or non-keratinized cervix, vagina and esophagus

STRATIFIED CUBOIDAL

Ducts of sweat glands

STRATIFIED COLUMNAR

Male urethra

TRANSITIONAL

Urinary bladder

PSEUDOSTRATIFIED COLUMNAR

Ciliated trachea

MUSCLE TISSUE

Is a soft tissue that composes muscles in animal bodies, and gives rise to muscles' ability to contract. This is opposed to other components or tissues in muscle such as tendons or perimysium. It is formed during embryonic development through a process known as myogenesis.

SKELETAL MUSCLE

Striated in structure and under voluntary control, is anchored by tendons to bone and is used to effect skeletal movement such as locomotion and to maintain posture. An average adult male is made up of 42% of skeletal muscle and an average adult female is made up of 36% (as a percentage of body mass). It also has striations unlike smooth muscle.

SMOOTH MUSCLE

Neither striated in structure nor under voluntary control, is found within the walls of organs and structures such as the esophagus, stomach, intestines, bronchi, uterus, urethra, bladder, blood vessels, and the arrector pili in the skin (in which it controls erection of body hair).

CARDIAC MUSCLE (MYOCARDIUM)

Found only in the heart, is a striated muscle similar in structure to skeletal muscle but not subject to voluntary control.

CONNECTIVE TISSUE

• It develops from the mesoderm.

• Connective tissue is found in between other tissues everywhere in the body, including the nervous system. In the central nervous system, the three outer membranes (the meninges) that envelop the brain and spinal cord are composed of connective tissue.

• They support and protect the body.

ALL CONNECTIVE TISSUE THREE MAIN COMPONENTS

1. Fibers (elastic and collagenous fibers)

2. Ground substance

3. Cells

LOOSE/ AREOLAR CONNECTIVE TISSUE

Have more soft structure than the dense CT; Wharton’s jelly, bone marrow, lymphoid, embryo, hypodermis

DENSE CONNECTIVE TISSUE

Tough structure; dermis, capsule of organs, tendons, stroma of the eyes

ELASTIC/ RETICULAR CONNECTIVE TISSUE

Ability to be stretched, forms a soft skeleton that holds the lymphoid tissues, under microscope is like a net

ADIPOSE TISSUE

Thermal regulation and store nutrients in form of neutral lipids; cells are called as adipocytes

SPECIAL CONNECTIVE TISSUE

1. Cartilage

2. Bone

3. Blood

4. Lymph

5. Hematopoietic Tissues

CARTILAGE

Hyaline (trachea), fibrous (intervertebral disc in bet. vertebral column), elastic (external ear, nose bridge)

BONE

• Cancellous or spongy bone (soft, in the head epiphyseal part of the bone)

• Compact bone (body of the long bone or shaft or diaphysis of the bone, hard structure)

DECALCIFICATION

Removes calcium from the specimen to soften

NERVOUS TISSUE

• Also called neural tissue, is the main tissue component of the nervous system. The nervous system regulates and controls bodily functions and activity and consists of two parts

  1. The central nervous system (CNS) comprising the brain and spinal cord

  2. The peripheral nervous system (PNS) comprising the branching peripheral nerves.

• It is composed of neurons, also known as nerve cells, which receive and transmit impulses, and neuroglia, also known as glial cells or glia, which assist the propagation of the nerve impulse as well as provide nutrients to the neurons.

AUTOPSY

• In Greek, a seeing for oneself.

• Also called necropsy, postmortem examination.

• Systematic examination of a cadaver for study or for determining the cause of death.

• Uses many methodical procedures to determine the etiology and pathogenesis of diseases, for epidemiologic purposes, for establishment of genetic causes, for family counsel

BIOPSY

• Examination of cells or tissues from a living organism.

• Excised material may be studied in order to diagnose disease or to confirm findings of normality.

• Incisions may be made and total or partial lesions removed in the form of wedges or cylindrical pieces, or scrapings of the surface membranes of internal organs may be collected.

DIVISIONS OF PATHOLOGY

1. General Pathology

2. Systemic Pathology

3. Gross & Microscopic Pathology

4. Anatomic Pathology

5. Clinical Pathology

GENERAL PATHOLOGY

Basic reaction of cells and tissues to abnormal stimuli that underlie all diseases

SYSTEMIC PATHOLOGY

Specific responses of specialized organs and tissues

GROSS PATHOLOGY

The recognition of disease based on macroscopic examination of surgical specimens generated at the time of surgery or at autopsy.

MICROSCOPIC PATHOLOGY

The recognition of disease based on microscopic examination of surgical specimens generated at the time of surgery or at autopsy.

ANATOMIC PATHOLOHY SUB SECTIONS

1. Surgical Pathology

2. Autopsy Pathology

3. Exfoliative Cytology

ANATOMIC PATHOLOGY

The study of changes in the function, structure, or appearance of organs or tissues, including postmortem examinations and the study of biopsy specimens.

SURGICAL PATHOLOGY

• The pathology of disease processes that are surgically accessible for diagnosis or treatment.

• The study of gross appearance and histology of tissues removed during surgery

AUTOPSY PATHOLOGY

• It involves the external and internal examination of a human body after death.

• The study of gross appearance and histology of tissues removed following death

EXFOLIATIVE CYTOLOGY

A branch of General Cytology which deals with the microscopic study of cells that have been desquamated from the epithelial surfaces

CLINICAL PATHOLOGY SUB SECTIONS

• Clinical Chemistry (incl. Toxicology)

• Hematology

• Blood Banking (incl. Transfusion Medicine)

• Microbiology

• Clinical Immunology & Serology

CLINICAL PATHOLOGY

The branch of general pathology directed to the diagnosis and monitoring of diseases through the examination of blood, body fluids, secretions, and tissue biopsy specimens for chemical, morphological, microbiological, and immunological abnormalities.

• Identifies and interprets changes that characterize different diseases or disease states in cells, tissues, and fluids of the body

• monitor the metabolic status of patients under medical therapy

• Decipher specific markers that characterize individual patients for purposes such as transfusion or transplantation

CLINICAL CHEMISTRY (INC. TOXICOLOGY)

Division of clinical pathology involving biochemical analysis performed on human samples (blood, fluids, tissues) outside the body (in vitro).

• Substances which could be assayed include sugars, lipids, proteins, antibodies, enzymes, hormones, vitamins, metals, electrolytes.

• Methods employed are spectrophotometry, fluorometry, enzyme kinetics, enzyme immunoassay (EIA), electrophoresis, flame photometry, ion selective electrodes, HPLC, gas chromatography, mass spectrometry, and atomic absorption spectrometry.

• Most instruments are however almost completely automated.

• In the toxicology subsection, the blood, urine, and other body fluids are analyzed for the presence of drugs and substances of abuse.

• An equally important application of toxicology testing is to measure the blood levels of therapeutic drugs to assure that concentrations are adequate to treat the disease but not so high as to cause toxic side effects.

HEMATOLOGY

• Involves assessment of the cellular elements (red blood cells, white blood cells, and platelets) in blood samples.

• The blood cells may be enumerated, either by manual cell-counting techniques or by automated particle sensing and sizing instruments.

• Microscopic observation of stained peripheral blood smear is limited to assessing the morphology of atypical cells as they may appear in cases of dysplastic syndromes and overt leukemias.

• Pathologists specialized in this field (hematopathologists) also examine bone marrow and lymph node biopsies. They are expert in the field of anemia, leukemia and lymphomas.

• In complicated cases where the diagnosis of a hematological disorder cannot be made by study of the peripheral blood smear, a bone marrow examination may be necessary.

BLOOD BANKING (INC. TRANSFUSION MEDICINE)

• Also called Immunohematology

• A division of clinical pathology that deals with collection, storage, compatibility and safety of blood and its various components for the purpose of human transfusion.

SPECIFIC TASKS OF BLOOD BANKING (INC. TRANSFUSION MEDICINE)

1. Blood collection after donor screening

2. Chemical and serologic tests to exclude transmission of infective diseases

3. Component preparation and proper storage

4. Blood typing, screening for antibodies against red cells and compatibility testing

5. Immunophenotyping of blood cells

6. Investigation into transfusion reactions

7. Apheresis & plasmapheresis

MICROBIOLOGY (INC. IMMUNOLOGY)

• A division of clinical pathology involved in isolation, culture, and identification, of micro-organisms (parasites, fungi, bacteria & viruses) in biological samples.

• In addition to conventional microscopic and biochemical methods for identification, DNA/RNA based assays (including PCR) and immunoassays are increasingly being used.

• Subdivisions include bacteriology, parasitology, mycology (fungi) and virology.

• Presumptive identification of microbes can be made by microscopically examining direct mounts of an appropriate portion of the specimen or thin smears that have been stained with one of a variety of dyes.

• Rapid presumptive diagnoses can also be made by directly testing specimens with a variety of immunological reagents.

• Specimens are applied to the surface of a variety of agar culture media for the purpose of recovering in pure culture any bacterial species that may be clinically significant.

• Gram stains may determine the cellular morphology and staining characteristics of the bacteria, and a variety of rapid, direct tests can be performed to provide an early identification.

CLINICAL IMMUNOLOGY AND SEROLOGY

• The discipline in which infectious diseases are diagnosed by detecting antibodies in serum and other body fluids.

• In practice, immunologic and serologic techniques are used to diagnose an infectious disease when the agent may be too difficult to recover in culture.

MEDICAL TECHNOLOGIST’S ROLE IN THE HEALTH CARE PROCESS

• A Medical Technologist's role in the healthcare process is to provide accurate results in a timely manner.

• These results will ultimately be used to help make a diagnosis or monitor treatment.

• Observe details of cells, ova and cysts of parasitic infections

• Test whether the blood of the donor is compatible with the blood of patient-recipient

• Utilize special stains to identify microorganisms.

• Measure substances in blood and other body substance

• Reagent preparation

• Collect specimen for study

• Preparation of specimen

• Quality control

DISEASE

• Abnormal condition of an organism

• That impairs bodily functions

DISEASE IS CAUSED BY

A. External Factors

B. Internal Factors

EXTERNAL FACTORS

Invading organism

INTERNAL FACTORS

Autoimmune disease, congenital, hereditary disorders.

MANIFESTATION OF DISEASE

A. Signs

B. Symptoms

SIGNS

Evidence of disease: an idication of the presence of the disease, especially one observed by a doctor but may/ may not apparent to the patient.

SYMPTOMS

Indication of illness felt by the patient

PREDISPOSING FACTORS OF AN INDIVIDUAL TO DISEASE

1.Behavioral

• Obesity- HD, DM, CA
• Smoking- Lung cancer, emphysema, HD, LBWI, Arteriosclerosis

• Alcohol use- mouth cancers, complications of pregnancy, LBWI

2. Mental/ emotional

3. Environmental

a. Air pollution-emphysema, bronchitis,lung cancer

b. living near the toxic waste dumps- spontaneous abortion

c. Pesticide- birth defect

4. Genetics

5. Drugs

6. Lifestyle