Blood Vessel Ultra Tissue Flashcards
The average volume of blood in a man
6 litres
Three major types of vessels
Arteries, Veins, Capillaries
Three sections of vessel walls
Tunica intima (inner), tunica media (middle) tunica adventitia (outer)
Arteries found near the heart
Large elastic conducting arteries
Examples of large elastic conducting artieries
Aorta, pulmonary artery
Tunica Intima of large elastic arteries
Endothelial cells - has a sub endothelium of connective tissue and discontinuous elastic laminae
Tunica Media of elastic artery
40-70 fenestrated (porous) elastic membranes with smooth muscle cells and collagen in between layers
Tunica adventitia of elastic artery
Thin layer of connective tissue which contains lymphatics, nerves and vasa vasorum
Vasa Vasorum
Small vessels which supply blood to larger arteries and veins
Medium muscular arteries supply…
Blood to the sub regions of the body
Tunica intima of medium muscular arteries
Endothelium, a sub endothelial layer and a thick elastic lamina
Tunica media of medium muscular arteries
40 layers of smooth muscle joined by gap junctions to allow for co-ordinated contraction
Tunica adventitia of medium muscular arteries
Thin layer of connective tissue containing minor vasa vasorum, lymphatics and nerve fibres
Arterioles carry…
Blood from the medium muscular arteries to the metarterioles (micro circulation)
Structure of arterioles
Less than 0.1mm diameter, three layers of smooth muscle cells, no internal elastic lamina, external elastic lamina in larger arterioles
Metarterioles supply…
Blood to capillary beds
Metarterioles structure
Intermediate rings of smooth muscle (precapillary sphincters) - control blood flow
Precapillary sphincters are important in…
Tissue perfusion
Tissue perfusion is…
The relaxation of precapillary sphincters in metarterioles to allow blood more easily in certain areas of the body
Capillaries consist of…
One endothelial layer and it’s concordat basement membrane
Types of capillaries
Continuous, fenestrated and sinusoidal
What can leave continuous capillaries?
Water and ions
What can leave sinusoidal capillaries?
Large molecules such as cells and proteins
Post capillary venules carry blood from the…
Capillaries to the venules
Tissue fluid tends to drain into…
Post capillary venules as their pressure is lower than the capillaries or tissues
Structure of post capillary venules
An endothelial lining with associated pedicytes and a diameter of 10-30 micrometers. Permeable walls to allow for leukocyte migration
During inflammation (venules)…
Pressure of venules is higher than surrounding interstitium, allows fluid to leak out along with white blood cells and cytokines
Interstitium meaning
Surrounding connective tissue which lies between the cells of an organ
Venules carry…
Blood from post capillary venules to veins
Venule structure
Endothelial lining associated with pericytes or smooth muscle cells (the beginning of a tunica media). Diameter of up to 1mm and also contain valves
Many venules unite to form
Veins
Small and medium veins have…
A well developed tunica adventitia and thinner tunica media and tunica intima
Large veins structure
Diameters greater than 10mm, thick tunica intima, longitudinal muscle in the tunica adventitia, smooth circular muscle in the tunica media.
Veins contain (v)…
Valves to prevent back flow of blood and propel it forward to the heart
Venae Comitantes…
Are veins wrapped in a sheath with arteries. The pulsations of the artery stimulate the vein to push blood forward
