HISTO LEC: Module 1 - PART I

DO NOT EXPLOIT.

Histology

The science that deals with the study of normal tissues; prelude to pathology.

Pathology

The study of abnormal tissues; focused on the study and diagnosis of disease.

Tissues

Groups of cells that have similar structures and intercellular materials that are interrelated to perform a specific function.

Abnormal tissues

Tissues with altered structures and functions.

Mitosis

The division of a cell (somatic cell) into two daughter cells that are genetically identical to the parent cell.

Meiosis

The division of germ/sex cells; results in four daughter cells which are not identical to the parent cell (only one copy of each paternal and maternal chromosome can be found in each of the daughter cells).

Anton Von Leeuwenhoek

• Dutch microbiologist who was the first to observe and describe living cells using a handheld microscope

• Developed and ground compound microscope lenses

• Discovered protozoa and bacteria as well as the structure of muscles and nerves

Robert Hooke

• English microscopist and physicist who, upon observing a slice of cork under a microscope, had discovered many small “compartments” that resemble honeycomb structures which he described as cells (from the Latin term cellula, meaning “small room”).

Marcelo Malpighi

Italian anatomist who was the first to describe the units forming animal tissues using simple microscope lenses; known as the True Father of Histology.

Robert Brown

• Scottish botanist who discovered the cell nucleus as he observed small dense centers in the epidermal cells of orchids

• Introduced the nucleus in the 17th century.

Marie Francois Bichat

French pathologist who termed tissues as “textures” and described them as different groups of cells.

Matthias Jakob Schleiden

• German botanist who proposed the cell theory for plants .

• Co-founder of the cell theory along with Theodor Schwann and Rudolf Virchow

Theodor Schwann

• German physician and physiologist who stated that animals are made of cells

• Discovered cells that form a sheath (called the myelin sheath) surrounding the nerve (called Schwann cells)

Friedrich Gustav Jakob Henle

German physician and pathologist who published his work on human histology titled “A Treatise on General Pathology”

Max Schultze

German microscopic anatomist who was the first to describe the cell as a nucleated mass of protoplasm.

Rudolf Virchow

• German pathologist that described the human body as “cell state”

• Stated that all diseases involved changes in normal cells.

19th Century

Involves microtome; fixing, embedding, and staining techniques.

TRUE

TRUE OR FALSE: The elements that compose the human body are: cells, intercellular substances, and body fluid.

Cell

Structural, functional, hereditary, and developmental unit of all living organisms.

TRUE

TRUE OR FALSE: Cell structure is composed of three major structures: cell membranes, nucleus and cytoplasm.

Cell membrane

• Also known as plasmalemma, plasma membrane, or the “guardian of the cell.”

• It divided via intercellular and extracellular fluid.

• It is not seen under light microscope.

Physical barrier

• It establishes the flexible boundary that protects cell contents and supports structure.

• Has selective permeability that regulates the entrance and exit of nutritive and excretory substances.

Electrochemical gradients

It keeps constant ion content of the cytoplasm and communication, which is how the cell interacts with other cells.

Protoplasm

It refers to all structure inside the cell membrane (e.g. organelles, inclusion bodies, and nucleus)

Cytoplasm

It refers to all contents outside the nucleus (e.g. organelles and inclusion bodies).

Irritability

The passive to respond to stimulus and the expression of life that disappears upon cell death.

Contractility

The property of changing shapes, shortening the direction of its long axis, under developed in muscle fibers.

Conductivity

This is the ability to transmit electrical impulse which are highly developed in nerve cells.

Respiration

Food substances and oxygen interact chemically to produce water and carbon dioxide.

Absorption

Inhibition of dissolved substances; also known as endocytosis.

Pinocytosis

Cell drinking

Phagocytosis

Cell eating

Exocytosis

• Exclusion of waste products by the cell

• Secretion - hormones/digestive enzymes (insulin)

• Excretion - exclusion of waste products of metabolism (urine)

Growth and Reproduction

Increasing cell number and involves cell division.

Organelles

Internal cell component that performs specific function for the cell.

Mitochondria

• Double-membraned powerhouse of the cell; produces adenosine triphosphate (ATP) as a source of energy that is used by the cell for metabolic activities.

• Contains soluble enzymes: Kreb’s cycle

Lysosome

Known as the suicide bag of the cell, which contains hydrolytic enzymes for protein and carbohydrate breakdown.

Centrosome

Center of activity associated with cell division; maintains chromosome number during mitosis.

Centrioles

A component of centrosome that forms the mitotic spindle during cell division.

Ribosomes

It has dense aggregates of RNA; the site of protein synthesis