Blood Vessels Flashcards
What is Tunica Externa?
The tunica externa is the outer layer of the blood vessel wall. It consists of connective tissue and is mainly collagenous fibres.
What is Tunica Media?
The tunia media consists of layers of smooth muscles supported by connective tissue that are mainly made of elastic fibres.
What is Tunica Intima?
A layer of endothealial cells lining the lumen of the vessel as wall as subendothelial layer made of loose connective tissue.
Capillaries are only a layer of tunica intima.
What is Vasa Vasorum?
The vasa vasorum are blood vessels that form capillary networks in large blood vessels. They are mini blood vessels in tunica externa for supplying nutrients and oxygen to the vessel itself.
What is Nervi Vasorum?
Nervi vasorum are small nerve fibres found in tunica media that trigger/initiating smooth muscle contraction.
What are two important characteristics of veins?
1) Veins carry deoxygenated blood towards your heart
2) Veins don’t have a muscular layer like arteries so they rely on one-way valves to keep blood moving in one direction towards the heart
What are three characteristics of arteries?
1) Arteries carry oxygenated blood from the heart to all the organs
2) Arteries have a thick layer of muscle tissue inside
3) They handle a large amount of force and pressure from your blood flow but don’t carry a large volume of blood.
What are three characteristics of capillaries?
1) Capillaries have very thin walls and are located inside all tissues
2) They carry oxygenated and deoxygenated blood between veins and arteries
3) They don’t have muscle tissue or valves
What are arterioles?
Arterioles are blood vessels that branch from your arteries and carry blood away from your heart to your tissues and organs. Arterioles are small arteries that link capillaries.
What are venules?
Venules are very small blood vessels that connect your capillaries. Venules moves deoxygenated blood that contains waste from your capillaries to your veins.
What are capillary splinchters?
Precapillary sphincters are segments of smooth muscle that help direct bloodflow into capillaries. They control and regulate the flow of blood through capillaries to where blood is needed.
What is the relationship between blood velocity and total cross-sectional area?
Cross-sectional area is essentially the diameter of the lumen. As total cross-sectional area of the vessel increases, the velocity of the blood flow decreases. Blood flow is slowest in the capillaries (large cross-sectional area), which allows time for exchange of gases and nutrients
What is the order of blood flow from the heart through blood vessels?
1) Artery
2) Arteriole
3) Capillary
4) Venule
5) Veins
What happens to blood pressure and blood velocity when distance from the heart decreases?
In general blood pressure and blood velocity decreases further away from the heart.
What causes blood pressure?
Blood pressure is determined by two things: the amount of blood the heart pumps and how hard it is for the blood to move through the arteries. The more blood the heart pumps and the narrower the arteries, the higher the blood pressure.
