ToB 2 Epithelia Flashcards
Define epithelia:
Sheets of contiguous cells, of varied embryonic origin, which cover the external surface of the body, and line internal surfaces.
Which 3 interior spaces in the body have epithelial linings, and are open to the exterior?
1) Gastrointestinal tract 2) Respiratory tract 3) Genitourinary tract
Which 5 interior spaces do not open to the exterior but have epithelial linings?
1) Peritoneum 2) Pleural sac 3) Pericardial sac 4) Blood vessels 5) Lymph vessels
What is the peritoneum?
The epithelial membrane lining the cavity of the abdomen and covering the abdominal organs.
What are pleural sacs?
The epithelial double membrane which covers a lung.
What is a pericardial sac?
The epithelial double membrane which encases the heart
What are the 3 embryonic germ layers which form the trilaminar embyonic disk?
1) Ectoderm 2) Mesoderm 3) Endoderm
Which embryonic germ layer creates skin?
Ectoderm
From which embryonic germ layer does the GI tract epithelium derive?
Endoderm
Which main 6 epithelia are derivatives of the embryonic mesoderm layer?
1) Blood vessels lining 2) Lymph vessels lining 3) Pericardial sac lining 4) Pleural sacs lining 5) Peritoneum lining 6) Epithelium of urogenital tract
From which embryonic germ layer does the respiratory tract derive?
Endoderm
What word describes an epithelium which is one cell thick?
Simple
What does ‘compound epithelium’ mean?
Epithelium consists of more than one layer of cells.
Define pseudostratified epithelium:
An epithelium which is one cell thick, but gives the appearance of a stratified epithelium due to the position of the cell nuclei.
What is meant if a cell is described as ‘squamous’?
Very thin and flat, such that the cells nucleus creates a bump in the membrane
What type of cells make up the basement membrane?
The basement membrane is a non-cellular layer
Define basement membrane:
A thin, delicate non-cellular membrane which separates an epithelium from underlying tissue.
How is the basement membrane sometimes thicker than usual?
Reticular cells may produce type III collagen, which thickens the basement membrane
What is the name of the membrane to which epithelial cells adhere?
Basement membrane
Which part of an epithelial membrane acts as a cellular and molecular filter?
Basement membrane
What is the (often used) Latin name for the basement membrane?
Basal lamina
What name is given to the simple squamous epithelium lining of all vascular elements?
Endothelium
What is a mesothelium?
The simple squamous epithelia which line the pericardial sac, pleural sacs and the peritoneum.
Describe the upper respiratory tract epithelia:
Ciliated pseudostratified epithelia
Describe the epithelium lining the loop of Henle:
Simple squamous epithelia
Give 2 examples of simple squamous epithelia in the kidney:
1) Lining of the loop of Henle 2) Bowman’s capsule
What are the 4 main functions of a simple squamous epithelium?
1) Barrier 2) Gas exchange 3) Active transport (pinocytosis) 4) Lubrication
How would you describe an epithelium which is one cell thick, where each cell is (roughly) as tall as it is wide?
Simple cuboidal epithelium
What type of cells line the thyroid gland follicles?
Simple cuboidal epithelia
What type of cells line the collecting ducts of the kidney?
Simple cuboidal epithelia
Which hormone do the epithelial cells lining the collecting duct of the kidney respond to?
Anti-diuretic hormone (ADH)
What type of epithelia line the surface of an ovary?
Simple cuboidal epithelia
Small ducts of many exocrine glands are lined by what type of epithelia?
Simple cuboidal epithelia