Anatomical terms of microanatomy
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Anatomical terminology is used to describe microanatomical (or histological) structures. This helps describe precisely the structure, layout and position of an object, and minimises ambiguity. An internationally accepted lexicon is Terminologia Histologica.
Layout
Epithelia and endothelia
Epithelial cells line body surfaces, and are described according to their shape, with three principal shapes: squamous, columnar, and cuboidal.
- Squamous epithelium has cells that are wider than their height (flat and scale-like).
- Cuboidal epithelium has cells whose height and width are approximately the same (cube shaped).
- Columnar epithelium has cells taller than they are wide (column-shaped).
Epithelium can be arranged in a single layer of cells described as "simple", or more than one layer, described as "stratified". By layer, epithelium is classed as either simple epithelium, only one cell thick (unilayered) or stratified epithelium as stratified squamous epithelium, stratified cuboidal epithelium, and stratified columnar epithelium that are two or more cells thick (multi-layered),[2][3] and both types of layering can be made up of any of the cell shapes.[4] However, when taller simple columnar epithelial cells are viewed in cross section showing several nuclei appearing at different heights, they can be confused with stratified epithelia. This kind of epithelium is therefore described as pseudostratified columnar epithelium.[5]
Transitional epithelium has cells that can change from squamous to cuboidal, depending on the amount of tension on the epithelium.[6]
Mucosa
A mucous membrane or mucosa is a
Submucosal and muscular layers
The
The
The layers are not truly longitudinal or circular, rather the layers of muscle are helical with different pitches. The inner circular is helical with a steep pitch and the outer longitudinal is helical with a much shallower pitch.
Serosa and adventitia
- retroperitoneal) -- these last two tissue types differ slightly in form and function according to the part of the gastrointestinal tract they belong to.
Position on the cell membrane
The hollow inner part of a body organ (such as the gastrointestinal tract) or tube (such as an artery) is called the lumen. The side of a cell facing the lumen is called the apical surface; the opposite side, facing away from the lumen is the basolateral surface, which faces instead towards the interstitium, and away from the lumen.
References
- ^ "Endothelium" at Dorland's Medical Dictionary
- ^ van Lommel, 2002: p. 97
- ^ van Lommel, 2002: p. 94
- ISBN 0-8053-4281-8.
- ISBN 978-0-683-30644-6.
- ^ Pratt, Rebecca. "Epithelial Cells". AnatomyOne. Amirsys, Inc. Archived from the original on 2012-12-19. Retrieved 2012-09-28.
- ^ ISBN 978-0-4430-6-8508.
- ^ "Oral: Four layers of the G.I. tract". The Histology Guide. University of Leeds. Retrieved 4 January 2014.