Epithelial Tissue Flashcards
Where are the nuclei usually positioned in cuboidal epithelium?
centrally positioned
Which epithelium lines the duodenum?
Simple columnar
Where are the nuclei usually positioned in columnar epithelium?
Basally positioned
What type of epithelium lines the sweat gland duct?
Stratified cuboidal
Is the stratified squamous epithelium in the oesophagus keratinised?
No
It is non-keratinised stratified squamous
Which 2 layers does interdigitation occur between?
connective tissue dermal ridges and epithelial ridges
Which epithelium usually lines blood vessel lumens?
simple squamous
Define epithelia
Sheets of contiguous cells, of varied embryonic origin, that cover the external surface of the body and line the internal surfaces.
On which parts of the body is the epithelium derived from the ectoderm?
Epidermis of Skin and Cornea of Eye
For which parts of the body are the epithelia derived from mesoderm?
Urogenital tract, Blood and Lymphatic vessels, Pericardial and Pleural Sac lining and Peritoneal lining
For which parts of the body is the epithelial derived from endoderm?
Respiratory tract, GI tract, Liver and Many glands eg. thyroid and salivary
What is a basement membrane?
It is a non-cellular layer that lies between the epithelial cells and the connective tissue. It is a thin and flexible, cellular and molecular filter.
Define endothelium
The simple squamous epithelial lining of all vascular elements.
Define mesothelium
The simple squamous epithelial lining of the pleural sac, pericardial sac and the peritoneum.
What are the functions of simple squamous epithelium?
Lubrication, Gas exchange, Barrier and Active transport by pinocytosis
What are the functions of simple cuboidal epithelium?
Absorption and conduit (channel for the passage of fluids)
Absorption and secretion
Barrier
Hormone synthesis, storage and mobilisation
What is occludin?
A protein that tightly binds adjacent plasma membranes in apical portions of some epithelia.
What are the functions of simple columnar epithelium?
Absorption, Secretion, Lubrication and Transport
What are principal cells?
Cells of the epididymis that absorb fluid, secrete substances to promote sperm maturation and phagocytose residual bodies or degenerate sperm.
What are the functions of pseudostratified epithelia?
Secretion and conduit
Absorption
Mucus secretion
Particle trapping and removing
What are the functions of non-keratinised stratified squamous epithelia?
protection against abrasion and reduces water loss
What are the functions of keratinised stratified squamous epithelia?
protection against abrasion and trauma
prevents water loss
prevents ingress of microbes
shields against UV light damage
Define a gland
An epithelial cell or collection of cells specialised for secretion.
What does CFTR stand for?
cystic fibrosis transmembrane regulator
Give 2 examples of a simple, branched, tubular gland
mucous glands of oesophagus and duodenum
What type of gland are the sebaceous glands?
Simple, branched, alveolar
Where would you find compound tubular glands?
mouth and testes
What type of gland are the mammary glands?
Compound, alveolar (acinar)
Which glands stain better: mucous or serous?
Serous stains better pink in H and E
What type of molecule are mucins?
Glycosylated polypeptides
What are the 3 major salivary glands called?
submandibular, parotid and sublingual
Which type of salivary gland only secretes serous secretions?
Parotid
Where are the salivary glands located?
submandibular: under the tongue
parotid: just in front of the ear
sublingual: inside of cheek
Which enzyme catalyses the formation of T3 and T4?
Thyroid peroxidase
Name the 3 sections of the adrenal cortex and state what they secrete
Zona glomerulosa: mineralocorticoids eg. aldosterone
Zona fasciculata: glucocorticoids eg. cortisol
Zona reticularis: sex hormones/androgens
What are the 3 layers of a mucous membrane?
epithelial lining
layer of connective tissue: lamina propria
muscularis mucosa (only in the alimentary tract)
What 2 layers does a serous membrane consist of?
mesothelium
thin layer of connective tissue
What is the difference between the visceral and parietal serosa?
Visceral - inner lining: closer to the organs
Parietal - outer lining: closer to the skin
Name the 4 layers of the gut wall
mucosa
submucosa
muscularis externae
serosa
What are Peyer’s patches?
Aggregations of lymphocytes which are often present in the lamina propria. (Usually towards the colon where bacterial attack is likely to occur)
What are the 3 layers of a mucosa?
epithelium
lamina propria
muscularis mucosae
What is a submucosa?
A layer of connective tissue bearing glands, arteries, veins and nerves.
In the muscularis externa, which layer is longitudinal and which is circular?
longitudinal = outer layer circular = inner layer
What are rugae?
Folds of gastric mucosa forming longitudinal ridges in an empty stomach.
Where does most of the absorption of nutrients occur?
Jejunum
What are the type I and type II cells of the alveoli and how much does each contribute to the total number of cells?
Type I = simple squamous epithelium (90%)
Type II = simple cuboidal epithelium (10%)
