Histotechnology: Tissue Preparation & Pathology

• Histotechnology is an art and science performed by histotechnologists to produce high-quality tissue sections for pathologists, aiding in disease diagnosis.

Histopathologic Technique

• Histopathologic technique involves various procedures for preparing materials and tissues for microscopic examination

Pathology

• Pathology, also known as Pathobiology, links basic science and clinical practice, studying structural and functional changes in cells, tissues, and organs due to disease
• It studies the etiology, pathogenesis (disease development mechanism), morphologic changes, and clinical significance of diseases

Microscope Importance

• Microscopes are important for detecting tissue changes, especially in small tissue sections for diagnosis, pathology advancements were made in the 19th century

Pathogenesis

• Pathogenesis is the development of a diseased or morbid condition

Pathologist

• A pathologist interprets and diagnoses the changes caused by disease in the body

Specialist Physicians

• Specialist physicians are experts in disease origin, development, and microscopic tissue analysis, studying disease aspects, causes, abnormal conditions, and resulting structural/functional changes

Medical Technologist

• Medical technologists perform diagnostic analyses on blood, urine, and body fluids like cerebral spinal fluid and stool

Histology

• Histology studies the microscopic anatomy of biological tissues and is the microscopic view of gross anatomy, which views larger structures without a microscope

Epithelium Tissue Types

• Epithelium is a basic animal tissue type that includes Squamous, Cuboidal, and Columnar

Epithelial tissue

• Epithelial tissues line organs, blood vessels, and internal cavities, found as squamous which are flat and scale-like, cuboidal, which a cube-shaped, and columnar which a column-shaped.

Muscle Tissue

• Muscle tissue gives animals the ability to contract
• Opposed to other components like tendons, muscle tissue develops during embryogenesis through myogenesis

Skeletal Muscle

• Skeletal Muscles are striated, under voluntary control, anchored by tendons or aponeuroses to bones for skeletal movement and posture
• The average adult male's body is 42% skeletal muscle. the average adult female's body is 36% skeletal muscle.

Smooth Muscle

• Smooth muscles are non-striated and not under voluntary control, found in organs like the esophagus, stomach, intestines, uterus, bladder, blood vessels, and arrector pili (for body hair erection)

Cardiac Muscle

• Cardiac muscle, found only in the heart, is striated like skeletal muscle but involuntary

Connective tissue

• Connective tissue, developed from the mesoderm, found throughout the body including the nervous system, specifically the meninges (outer membranes enveloping the brain and spinal cord) Connective tissue support and protects the body and contains fibers like collagen, a ground substance, and cells

Types of Connective Tissue

• Connective tissue types include loose, dense, proper, supportive, and fluid, like cartilage(hyaline, elastic fibers, and fibro), bone(compact, and spongy) and blood

Hyaline Cartilage

• Hyaline cartilage provides support, reduces bony friction. It is also located between ribs and sternum, covering bone surfaces at synovial joints, supporting the larynx and trachea, and forming the nasal septum

Elastic Cartilage

• Elastic provides support but tolerates distortion, returning to its original shape, found in the ear auricle, epiglottis, auditory tube, and cuneiform cartilages of the larynx

Fibrous Cartilage

• Fibrous cartilage resists compression, prevents bone contact, and limits movement. It is located in the knee joint, between pelvic bones, and in intervertebral discs

Nervous Tissue

• Nervous tissue, also called Neural Tissue, is the main tissue component of the nervous system and regulates bodily functions
• The nervous system consists of the CNS(brain and spinal cord) and the PNS(branching peripheral nerves)

Neural Tissue Components

• Neural consists of neurons(nerve cells that transmit impulses) and neuroglia (glial cells) that assist nerve impulse propagation and nutrient delivery

Autopsy

• Autopsy, or Necropsy, a "seeing for oneself," systematically examines a cadaver to study/determine cause of death, determine the etiology/pathogenesis of diseases for family counseling

Biopsy

• Biopsy is the examination of cells/tissues from a living organism, excised for diagnosis/confirmation
• Excisions can be performed through incisions to remove total or partial lesions as wedges/cylindrical pieces, or by scraping surface membranes of internal organs

Pathology Divisions

• Pathology divides into general(basic reaction of cells/tissues to underlying diseases)and systemic(specific responses of organs/tissues)

Gross Pathology

• Gross pathology recognizes disease via macroscopic examination of surgical specimens or autopsy

Microscopic pathology

recognition of disease based on microscopic surgical or autopsy specimens

Anatomical Pathology

• Anatomical pathology studies changes in function, structure, or organ/tissue appearance, including postmortem and biopsy specimens

Surgical Pathology

• Surgical pathology studies diseases accessible by surgery, including gross appearance and histology of removed tissues

Autopsy Pathology

• Autopsy pathology involves external and internal body examination after death, studying tissue appearance/histology

Exfoliative cytology

• Exfoliative cytology involves microscopic study of cells shed from epithelial surfaces

Clinical pathology

• Clinical pathology monitors diseases by analyzing blood, body fluids, secretions, and tissue biopsies for abnormalities. It identifies and interprets changes characterizing different disease states in cells, tissues, and body fluids.

Clinical Chemistry (Toxicology)

• Clinical chemistry analyzes human samples (blood, fluids, tissues) biochemically outside the body
• It tests for sugars, lipids, proteins, antibodies, enzymes, hormones, vitamins, metals, and electrolytes using various automated instruments and methods like Spectrophotometry, Fluorometry, Enzyme Kinetics, Enzyme Immunoassay (EIA), Electrophoresis, Flame Photometry, lon Selective Electrodes, HPLC, Gas Chromatography, Mass Spectrometry, and Atomic Absorption Spectrometry.
• Toxicology analyzes for drugs and substances of abuse and equally monitors therapeutic drug levels to ensure adequate concentrations without causing toxic side effects

Hematology

• Hematology assesses cellular elements e.g. red/white blood cells, platelets via cell-counting or microscopic peripheral blood smear observation for atypical cell morphology

Medical Microbiology

• Medical microbiology isolates, cultures, and identifies microorganisms - bacteria, parasites, fungi, and viruses within the biological samples
• Beside the conventional methods, DNA/RNA-based assays like PCR and immunoassays are increasingly used. It uses Bacteriology, Parasitology, Mycology, and Virology to examine infectious agents by direct mounts of stains.

Rapid Diagnostics

• Rapid presumptive diagnostics are conducted to examine infectious agents with a variety of immunological reagents. Specimen are cultured on the agar to identify any bacterial species . Gram stains are used to determine bacterial morphology plus staining characteristics

Mycology and Virology.

• The identification of fungi and the diagnosis of fungal infections are similar to that described for the bacteria
• Viruses are detected in specimens that are inoculated on special fungal media and incubated for 4 weeks to identify any mold and yeast morphologically and biochemically. Nucleic Acid Probes are available to quickly confirm any suspected fungi but viruses live only in viable cells.

Clinical Immunology and Serology

• Clinical Immunology and Serology detects diagnoses for infectious diseases by antibody detection in the serum and other body fluids
• Serologic techniques are used to diagnose infectious diseases that difficult to recover

Medical technology

• Medical technology provides accurate results timely, to help diagnosis or monitoring treatment
• In the process, medical technologists can provide tests for blood type, detect microorganisms, reagent and specimen preparation and quality control amongst other methods
• In addition to external factors and and internal factor, abnormal conditions may be result

Diseases

• Diseases are defined as the abnormal condition of an organism that impairs bodily functions
• Diseases can be caused by:
  • External Factors: Invading Organism
  • Internal Factors: Autoimmune Disease, Congenital, Hereditary Disorders

Manifestation of Diseases

• Manifestation of Diseases include signs (evidence that observed by a doctor, like infection) and symptoms (felt by the patient)

Contributors to Disease

• The factors predisposing an individual to disease include behavioral, mental/emotional, environmental, genetics, drugs
• Behavioral: Obesity. Leads to heart disease, Diabetes Mellitus (DM), Cancer (CA) Smoking: Lung Cancer, Emphysema, Heart Disease (HD), Low Birth Weight Infant (LBWI), Arteriosclerosis and Alcohol Use: Mouth Cancers, Complications of Pregnancy
• Environmental Air Pollution: Emphysema, Bronchitis, Lung Cancer and Living Near the Toxic Waste Dumps: Spontaneous Abortion. Lifestyle:
• Air Pollution: Emphysema, Bronchitis, Lung Cancer
• Living Near the Toxic Waste Dumps: Spontaneous Abortion
• Pesticide: Birth Defect