Arteries & Veins Flashcards
(20 cards)
Function of arteries?
To transport high pressure blood away from the heart to the tissue
Describe the structure of your arteries
Thick layer of muscle and elastic tissue
What does elastic tissue allow in arteries?
Allows the wall to handle the high blood pressure of the heart
Walls stretch and relax, therefore…
Elasticity helps to maintain blood pressure
What do arteries branch into?
They branch into aortials
What are aortials
Aortials are small, less elastic and don’t significantly change in diameter with each heart beat. Branched off from arteries.
What are the 4 main structures of arteries and veins?
Lumen, Tunica Intima, Tunica Media, Tunica Externa
Lumen (location and composition)
Where blood flows, empty space.
Tunica Intima
Inner layer of your artery/vein, for the artery it’s a smooth epithelial lining that’s 1 cell thick. Also reduces friction. For your veins, it’s a valve.
Tunica Media
The middle layer of your arteries/valves. The arteries thickest layer, and is an alternating band of muscle and elastic fibres. For the veins, it only has thinner bands.
Tunica Externa
The outer layer, has connective and elastic tissues, nerves, lymphatic vessels, and the vaso vasorum. The veins only had less elastic tissue.
Vaso Vasorum
Means “vessels of the vessels”. Its function is to supply blood to the cells of larger arteries and veins.
Function of veins
Returns blood from the body to the heart.
Structure of veins
Larger diameter than arteries, but thinner, less elastic walls. Doesn’t contract and stretch easily.
Venous valves
One way valves that prevent back flow
How do muscles work in veins?
The muscles surrounding the veins squeeze them and pushes the blood up towards the heart.
Standing still for a long time causes fainting, why?
Because blood pools in the lower half of the body, then low pressure and O2 to brain, which causes you to faint.
What happens when contructon occurs?
The valves aren’t stretched equally, therefore can’t function properly and allow the back flow of blood.
Varicose veins
Veins become distended, bulge, break, and become varicosities
What causes varicosities
Caused by obesity, excessive standing, or pressure changes during pregnancies.
