MTM AP04 - connective tissue Flashcards
What are the 3 connective tissue types?
Loose connective tissue
Dense irregular tissue
Dense regular tissue
Where is loose connective tissue?
underneath the epidermis, around organs, blood vessels, and nerves
What is within loose connective tissue?
fibroblasts
elastic fibres
mast cells
macrophage
What do fibroblasts do?
secrete proteoglycans and collagen
What are mast cells?
Cells filled with basophilic secretory granules
What do mast cells secrete?
heparin (anticoagulant)
Histamine (promotes smooth muscle contraction)
How do macrophage react to India ink?
They absorb it, as it is a foreign substance
What is the dominant cell type in dense irregular tissue?
Fibroblasts
Where is dense irregular tissue found?
In the reticular dermis
What advantage does the irregular nature of DIT offer?
It is very strong, so can resist forces in multiple directions
What does DIT contain more of than dense regular tissue?
Ground substance, as there is more friction between collagen fibres
What types of fibre are found in DRT?
White collagen fibres or yellow elastin fibres
They can then be either in chord or sheath arrangement
What helps with strength in DRT
Uniparallel fibres type I collagen
Fibroblasts
What are elastic fibres made of?
Elastin and microfibrils like fibrin
Why do adipocytes show up as white?
Under Masson’s trichrome, the fat dissolved, and the nucleus is compressed to one side anyway
What is brown fat?
Multilocular fat
elliptical and smaller cells, with many lipid droplets, more mitochondria, and an oval nucleus
Iron in mitochondria makes them brown
What is white fat?
Spherical and have a single lipid droplet, with a flattened peripheral nucleus
What is EDS?
Ehler’s Danlos syndrome
caused by an abnormality of collagen arrangement
hypermobile is far less serious than vascular EDS
What two main substances do all connective tissue contain?
fibres Ground substance (contains glycoaminoglycans, strongly hydrophilic)
What are fibrocytes?
quiescent fibroblasts
What is non-specialised loose connective tissue?
Areolar
What is mucosa comprised of?
epithelia
basement membrane
lamina propria
