Blood Vessels Flashcards
How does the structure of arteries relate to its functions?
Arteries have thick walls to handle high pressure without tearing. The walls are muscular and elastic to control blood flow
How does the structure of Veins relate to its function?
Veins have thin walls due to lower pressure, therefore requiring valves to ensure blood doesn’t flow backwards. They also have less muscular and elastic tissue as they do not have to control blood flow
How is the structure of capillaries suited to its function?
The walls are only one cell thick to ensure a short diffusion pathway. They are also very narrow so that it can permeate tissues and red blood cells can lie flat against the wall, effectively delivering oxygen to tissues. They are also numerous and highly branched to provide a large surface area
What is tissue fluid
A watery substance containing glucose, amino acids, oxygen, and other nutrients. It supplies these to the cells, whilst also removing any waste materials.
How is tissue fluid formed?
As blood is pumped through increasingly small vessels, this creates hydrostatic pressure which forces fluid out of the capillaries. It bathes the cells, and then returns to the capillaries when the hydrostatic pressure is low enough
What is the name of the inner lining of blood vessels
The endothelium
What is the advantage of blood vessels being lined with a smooth endothelium?
It reduces friction with moving blood
What are the elastic fibres made of in blood vessels and what is their function?
They are made up of elastin and are used to stretch and recoil to provide flexibility
Why are arteries thick?
To withstand high pressures of blood
Why do arteries have a narrow lumen?
To maintain a high pressure
Why do arteries have a folded inner wall?
To allow the lumen to expand as blood flow increases
What is the role of smooth muscle in arteries
To allow vasodilation and vasoconstriction to take place in response to the need for blood in particular organs
Where does the arteries have the most elastic tissue in order to stretch and recoil against the fluctuations in pressure created by the heart?
Near the heart of
True or false: arteries further from the heart have more muscle tissue in their wall
True
What are arterioles?
Small blood vessels that distribute blood from arteries to capillaries
