Human Tubes Flashcards
Explain the difference between endothelium and epithelium?
Endothelium generally lines fully internal pathways (e.g. blood vessels) while epithelium generally lines pathways that are open to the external environment (e.g. respiratory)
What is the first layer of blood vessels called?
Tunica Intima
What is the second layer of blood vessels called?
Tunica Media
What is the layer of blood vessels outside the Tunica Media?
Tunica Adventitia
How thick are each of the layers in arteries?
Tunica Intima- Strong and well adapted
Tunica Media- Very Thick
Tunica Adventitia- Very Thick
How thick are each of the layers in veins?
Tunica Intima- Valves attach
Tunica Media- Reasonable size for vasoconstriction and vasodilation
Tunica Adventitia- Thickest
What is the vaso vasorum?
A small blood vessel that provides oxygen and nutrients to the walls of larger blood vessels. (blood vessels of the blood vessels)
What is the role of the Tunica Media in arteries and what is it made up of?
Lots of elastic and smooth muscle fibres. This layer allows distension and recoil of the vessel to accommodate fluctuations in blood pressure while the heart beats.
What is the subendonthelium?
loose connective tissue that supports the endothelium and provides cushioning to it.
What component of the aorta allows it to withstand high blood pressure?
Elastic fibres
Why does our body develop anastomoses in various places?
Exist to ensure adequate blood supply to certain areas of the body. By having multiple pathways to a particular tissue, it means that if one pathway becomes damaged, blood can still reach that particular tissue.
What is each type of capillary suited to?
Continuous= located where very close regulation of exchange between blood and the surrounding tissues is required
Fenestrated= where larger molecules are exchanged with the surroundings but still need some regulation
Sinusoidal= largest amount of exchange with the surroundings. Entire cells can fit through the gaps. Least regulation.
What is leukocyte extravasation?
This is the migration of white blood cells towards the site of damage or infection. This usually happens in the venules. Leukocytes can pass from the bloodstream into interstitial fluid because the venules are slow flowing and thin.
What are the 3 types of capillaries?
Continuous capillaries, Fenestrated capillaries and sinusoidal capillary
What is the lymphatic system?
A drainage system that removes surplus fluid and molecules from the tissue
