Introduction to Histology and Microscopic Anatomy

Vocabulary flashcards defining key histology terms, tissue classifications, cell measurement units, and microscopic preparation techniques based on the lecture material.

Histology (Microanatomy)

A visual science that explores the body’s tissues and how they are arranged to produce functional organs.

Extracellular Matrix (ECM)

A component of tissues involving macromolecules that supports cells and contains fluid for transporting nutrients and carrying away wastes.

Epithelium

Tissue that forms continuous sheets of cells lining internal surfaces and covering the external surface of the body, often giving rise to glands.

Connective Tissue

Tissue that supports, binds together, and protects organs, composed of cells in an abundant extracellular matrix; includes cartilage, bone, and blood.

Muscle Tissue

Tissue specialized for contraction to produce movement using contractile proteins actin and myosin.

Nerve Tissue

Tissue specialized for the rapid communication of information through the body, with the neuron as its structural and functional unit.

Prokaryotes

Single-celled organisms, including bacteria and archaea, whose genetic material is stored in a nucleoid floating in the cytoplasm.

Plasmids

Small, circular strings of DNA in bacteria that replicate independently and often carry genes for advantages like antibiotic resistance.

Fimbriae

Short, hair-like projections on the surface of bacterial cells that attach the bacterium to a substrate or other cells.

Pili

Bacterial surface structures that can assist in movement or the transfer of DNA to another bacterium.

Cell Theory

A theory developed by Theodor Schwann, Matthias Jakob Schleiden, and Rudolf Virchow stating all organisms are composed of at least one cell and all cells originate from preexisting ones.

SA / Vol Ratio

The relationship between surface area and volume; as a cell grows, volume increases faster than surface area, leading growing cells to divide to maintain a high ratio suitable for survival.

Micrometer ($\boldsymbol{\mu m}$)

A unit of linear measurement where $1.0\,mm = 1,000\,\mu m$ (mcm) or microns ($\mu$).

Angstrom ($\boldsymbol{\AA}$)

A unit of linear measurement where $1\,nm = 10\,\AA$ and $1\,\AA = 0.1\,nm$.

Magnification

The power of a microscope to increase the apparent size of an object.

Resolution

The power of a microscope to show detail clearly, specifically the ability to produce separate images of closely positioned objects.

Fixation

The use of chemical solutions to terminate cell metabolism, prevent enzymatic degradation by autolysis, and harden tissue through protein cross-linking or denaturing.

Formalin

A common fixative consisting of a $37\%$ aqueous solution of formaldehyde.

Clearing

The process in tissue preparation where alcohol is removed by organic solvents that are miscible with both alcohol and paraffin.

Microtome

A device used to section trimmed paraffin blocks into slices typically ranging between $5\,\mu m$ and $15\,\mu m$ for light microscopy.

Cryofixation

A fixation method involving rapid freezing of a sample in liquid nitrogen or liquid helium, transforming water content into vitreous ice.

Ultramicrotome

A device equipped with glass or diamond knives used to cut semi-transparent sections between $30\,nm$ and $60\,nm$ for electron microscopy.

Basophilic

Tissue components with a net negative charge, such as nucleic acids, that bind to and stain with basic dyes.

Acidophilic

Tissue components with a net positive charge, such as ionized amino groups in proteins, that bind to and stain with acidic dyes.

Hematoxylin

A positively charged blue dye complex that stains basophilic structures like the nucleus.

Eosin

An acidic dye commonly used with hematoxylin to stain cytoplasmic and extracellular features.

Artifacts

Minor structural abnormalities not present in living tissue, such as shrinkage, cracks, wrinkles, or precipitates from stain.

Sputter Coating

The process of coating a specimen with a conductive material, most commonly gold, to prevent charge buildup during Scanning Electron Microscopy (SEM).

Goblet Cells

Unicellular glands that secrete mucus and are characterized by basal nuclei, large Golgi complexes, and apical cytoplasm filled with secretory granules.

Virtual Microscopy

The use of specialized software to display digital representations of glass slides that have been scanned by high-resolution automated slide scanners.