HISTOLOGY and PATHOLOGY

Histology

The study of the microanatomy of cells, tissues, and organs as seen through the microscope. This also examines the correlation between structure and their function/s.

1. Epithelial tissue

2. Muscle tissues

3. Connective tissues

4. Nervous tissues

Four Classification of Tissues

• Cell shape

• Number of layers

Epithelial tissues are classified by?

Simple

A type of epithelial tissue that has single arrangement.

Stratified

A type of epithelial tissue that has many layers as arrangement.

Pseudostratified

A type of epithelial tissue that has arrangement at the basement membrane.

• Squamous

• Cuboidal

• Columnar

• Transitional

Determine the type of epithelium by cell shape.

• Flat

• Cube

• Taller than wide

• Changes shape

• Blood vessels

• Capillary vessels

• Lung alveoli

Where is simple squamous epithelium seen?

• Kidney tubules

• Glandular ducts

Where is simple cuboidal epithelium seen?

• Digestive tract lining

• Uterine tubes

Where is simple columnar epithelium seen?

Keratinized: skin epidermis

Non-keratinized: mucuous membranes

Where is stratified squamous epithelium seen?

• Sweat glands

• Salivary glands

• Mammary glands

Where is stratified cuboidal epithelium seen?

Male urethra

Where is stratified columnar epithelium seen?

• Urinary bladder

• Ureters

Where is transitional epithelium seen?

Respiratory tract

Where is pseudostratified columnar epithelium seen?

• Skeletal muscle

• Smooth muscle

• Cardiac muscle

What are the 3 kinds of muscle tissues?

Skeletal muscle

What kind of muscle tissue has striations and is multinucleated?

Smooth muscle

What kind of muscle tissue has no striations, is spindle-shaped, and uninucleated?

Cardiac muscle

What kind of muscle tissue has striations and interacalated discs and is uninucleated?

Missing: Connective and Nervous tissue Historical timeline

• Gross Pathology

• Cellular Pathology

• General Pathology

• Molecular Pathology

• Gross Pathology

• Histopathology

• Anatomic Pathology

What are the Branches of Pathology?

Gross Pathology

It pertains to the macroscopic examination of tissues using the naked eye.

Cellular Pathology

It is the study of disease at cellular level. It uses FNAC and cell blocks.

General Pathology

It pertains to the common reaction of cells to injurious stimuli. Examples are inflammation, necrosis, and neoplasia.

Molecular Pathology

Genetic or Molecular alterations in tissues or cells. An example is the use of biomarkers.

Clinical Pathology

This pertains to the laboratory analysis of bodily fluids.

Histopathology

This pertains to the microscopic analysis of stained tissue sections.

Anatomic Pathology

This is a tissue based-diagnosis, wherein gross pathology and histopathology is used.

Etiology

It pertains to the origin of disease.

Pathogenesis

The sequence of cellular, biochemical, and molecular events that follow the exposure of cells or tissues to an injurious agent.

Morphologic changes

This is the structural alterations in cells of tissues that are either characteristic of a disease or diagnostic of an etiologic process.

Functional derangements and Clinical Manifestations

The end result of genetic, biochemical, and structural changes in cells and tissues, of functional abnormalities with lead to the clinical manifestations of disease, as well as its progress.

Signs: Objective, measurable findings through testing

Symptoms: Subjective, experiences by patients

Differentiate signs and symptoms.

Inflammation

The sum total of changes in the living tissues, in response to an injurious agent.

Rubor

Due to arteriolar and capillary dilation with increased rate of blood flow towards the site of injury and due to the concentration or packing of red cells in the capillaries, causing increased viscosity and consequent slowing of blood flow.

Calor

Due to transfer of internal heat to the surface or site of injury, brought about by increased blood content.

Tumor

Due to increased capillary permeability, allowing extravasation of blood fluid causing localized edema accompanied by escape of blood cells into the injured area.

Functio Laesa

Due to direct damage to the nerve ending; pressure upon the sensory nerve by exudate/tumor.

Dolor

Caused by pain interference with nerve supply and destruction of the functioning units of the tissue or limitation of movement due to swelling. Can be an adaptive mechanism by the body to protect the injured area from further damage.

Retrogressive Change

In this abnormality, the organs appear smaller than normal.

• Aplasia

• Agenesis

• Hypoplasia

• Atresia

What are the examples of developmental defects?

Aplasia

It is the complete failure of an organ to develop during embryogenesis. It did not develop past its earliest stage, hence a rudimentary part may be present.

Agenesis

It is the complete absence of an organ.

Hypoplasia

It is the incomplete development of an organ, wherein it is smaller than normal.

Atresia

It pertains to a body part that is tubular in nature but not possessing an opening or passage, or lacks the ability to allow substances/ materials to pass through.

Atrophy

It is the acquired decrease in size of an organ due to smaller cell size and/or fewer cell number, or both.

Physiologic Atrophy

A type of atrophy that occurs due to normal processes, such as reduced functional demand or hormonal changes.

Pathologic Atrophy

A type of atrophy wherein there is presence of abnormal stressors or a disease state.

Atrophy of disuse

A common cause of atrophy wherein it is due to a decrease in organ activity, causing decreased cell size.

Denervation atrophy

A common cause of atrophy wherein the nerves are damaged, affecting the metabolism and function.

Marasmus (Protein-calorie depletion)

Inadequate nutrition causes atrophy. What disease is an example?

Progressive change

A type of abnormality wherein organs appear larger than normal.

Hypertrophy

Increased tissue or organ size due to increased cell size.

Hyperplasia

Increased tissue or organ due to increased number of cells.

Metaplasia

A reversible degenerative change where one cell type is replaced by another.

Dysplasia

A reversible degenerative change where cells grow with the wrong size or shape.

Anaplasia

A reversible degenerative change where cells grow primitively, showing loose differentiation.

Neoplasia

A reversible degenerative change where cells grow out of control.

Apoptosis

Programmed cell death; focuses on cells that are old, defective, and harmful.

Necrobiosis

A natural and gradual death of old cells.

Necrosis

An uncontrolled cell death; often messy due to cellular protein being broken down and leaking into surrounding tissues.

Pyknosis

Microscopic changes in necrosis wherein there is reduction in size and condensation of nucleus.

Karyorrhexis

Microscopic changes in necrosis wherein there is segmentation and fragmentation of nucleus.

Karyolysis

Microscopic changes in necrosis wherein there is dissolution of the nucleus.