The blood vessels Flashcards
What are elastic fibres?
Elastic fibres are made from elastin which allows them to stretch and recoil. This allows the walls of the vessels to be flexible
What is smooth muscle?
The smooth muscle allows the vessel to contract or relax in order to change the size of the lumen
What is collagen?
The collagen provides structural support to maintain the shape and volume of the vessel
Draw and label a diagram of an artery
What is the function of the arteries?
They carry the oxygenated blood away from the heart and around the body.
During pregnancy what is the function of the umbilical artery?
The umbilical artery carries deoxygenated blood from the fetus to the placenta.
Is the blood in the arteries under low or high pressure?
High
What are arteries constructed out of?
Lumen Endothelium Elastic fibres Smooth muscle Collagen
What is the purpose of the elastic fibres inside of the arteries?
The elastic fibres can stretch which enables the arteries to withstand the high pressure and large volume of the blood coming from the heart. In between the contractions of the heart the elastic fibres recoil and return to there original length.
What is the purpose of the elastic fibres inside of the arteries?
The elastic fibres can stretch which enables the arteries to withstand the high pressure and large volume of the blood coming from the heart. In between the contractions of the heart the elastic fibres recoil and return to there original length. This feature helps to even out the surges of blood pumped from the heart so that there is a continuous flow.
What is in the arteries which limits how far the elastic fibres can stretch?
The callogen limits how far the elastic fibres can stretch
Why does the endothelium (lining if the artery) need to be smooth?
So that the blood can flow easily through it
Write out the different arteries in order of size
Aorta Medium sized artery Arteriole
Describe the structure of the arteriole compared to an artery
Arterioles have more smooth muscle and less elastin in there walls compared to arteries.
Why do the arterioles have a small elastic layer?
As they are further away from the heart they have little pulse surge and so do not need to expand and recoil as much as an artery.
How can arterioles control the volume of blood that is accessed by individual organs?
The smooth muscle of an arteriole contracts which constricts the vessel and prevents blood flow.
When the blood flow in the arteriole is constricted what is the result and what is the name given?
The blood is prevented from flowing into a capillary bed. This is called vasoconstriction
What happens with the smooth muscle in the wall of an arteriole relaxes and what is the name given?
Blood is able to flow into the capillary bed. This is called vasodilation