Histology Flashcards

Vocabulary flashcards for histology and tissue types.

Histology

Microscopic study of tissues

Biopsy

Removal of tissues for diagnostic purposes

Autopsy

Examination of organs of a dead body to determine cause of death

Endoderm

Inner embryonic germ layer which forms lining of digestive tract and derivatives

Mesoderm

Middle embryonic germ layer which forms tissues such as muscle, bone, blood vessels

Ectoderm

Outer embryonic germ layer which forms skin and neuroectoderm (which forms nervous system; neural crest cells give rise to peripheral nerves, skin pigment cells, medulla of the adrenal gland, and face tissues.)

Basement membrane

Connects the basal layer of epithelial tissue to underlying tissue

Simple Epithelium

Tissue with one layer of cells; each extends from basement membrane to the free surface

Stratified Epithelium

Tissue with more than one layer where the shape of cells of the apical layer used to name the tissue

Pseudostratified columnar epithelium

Tissue that appears to be stratified, but all cells contact basement membrane, so it is in fact simple

Transitional Epithelium

Special type of stratified epithelium where the cell shape changes from cuboidal/columnar to squamous-like when stretched.

Squamous

Flat, scalelike cells

Cuboidal

Cells about equal in height and width.

Columnar

Cells taller than wide

Desmosomes

Disk-shaped regions of cell membrane; often found in areas that are subjected to stress

Hemidesmosomes

Half of a desmosome; attach epithelial cells to basement membrane preventing movement of the tissue

Tight Junctions

Hold cells together, form permeability barrier

Adhesion Belts

Found just below tight junctions that help anchor epithelial cells to each other to prevent passage of materials between cells; provides additional strength to the tight junctions.

Gap Junctions

Protein channels aid intercellular communication; allows ions and small molecules to pass through

Endocrine Glands

No open contact with exterior; no ducts; have an extensive network of blood vessels; produce hormones.

Exocrine Glands

Open contact maintained with exterior by way ducts that open onto the free surface of the epithelium.

Unicellular Glands

Single cell, For example, goblet cells that secrete mucus

Simple Glands

Multicellular glands with a single, nonbranched duct. Secretory portion can be tubular or acinar (sac-like)

Compound Glands

Multicellular glands with ducts with many branches. Secretory portion may be tubular, acinar or both

Merocrine

Exocytosis (most common type) in exocrine gland secretion

Apocrine

Pinched off fragments of gland cells in exocrine gland secretion; mammary glands and ceruminous glands

Holocrine

Shedding of entire cells in exocrine gland secretion; sebaceous glands

Blasts

Create the matrix in connective tissue

Cytes

Maintain the matrix in connective tissue

Clasts

Break the matrix down for remodeling in connective tissue

Collagen

Most common protein in body; strong, flexible, inelastic

Reticular

Fill spaces between tissues and organs. Fine collagenous, form branching networks

Elastic

Returns to its original shape after distension or compression. Contains molecules of protein elastin that resemble coiled springs; molecules are cross-linked

Hyaluronic Acid

Good lubricant; polysaccharide found in vitreous humor of eye

Proteoglycans

Protein and long polysaccharides called glycosaminoglycans; protein part attaches to hyaluronic acid; trap large amounts of water

Carcinomas

Cancers of epithelial tissue; include nearly all lung, breast, colon, prostate, and skin cancers

Adenocarcinomas

Derived from glandular epithelium

Sarcomas

Relatively rare cancers of mesodermal tissue (connective and muscular)