Cardiovascular system: Blood vessels Flashcards
What are the different types of arteries?
Elastic arteries, muscular arteries and arteriole
Where are elastic arteries found?
Just off the heart (where the pressure is highest FYI)
What is a unique property of elastic arteries compared to other types of arteries?
They are elastic and expand when the pressure increases
What makes the elastic arteries elastic?
They are made of sheets of elastin in the middle tunic (i.e. the middle layer)
When do the elastic arteries stretch?
During the contraction of the left ventricle
Why do the elastic arteries stretch when the heart beats?
The ventricle pumps blood faster than blood can flow therefore the arteries convert some energy into elastic energy
What is the benefit of the elastic arteries absorbing some of the energy from the heart beat?
During relaxation the elastic artery release the elastic energy and pumps more blood therefore smoothing out the pulses of pressure so there is a more continuous flow of blood
What is the function of muscular arteries?
distribution blood around the body at a high pressure and in the lungs at a medium pressure
What is the structure of muscular arteries?
Collagen layer of outer tunic (for binding to surrounding tissue), layers of smooth muscle in the middle tunic and a layer of endothelial cells on the inner tunic
How do the muscular arteries control blood pressure?
The smooth muscle can vasoconstrict or dilate to increase or decrease blood pressure
How is flow rate proportional to radius?
By the fourth power (i.e. flow ~ r^4)
When doing exercise, how will the muscular arteries respond?
They will vasodilate for the muscles to allow for increased blood flow and vasoconstrict for the digestive system as it isn’t necessary
What is the function of the arteriole?
It controls blood flow into the capillary beds
How doe she muscular wall of the arteriole compare relatively to the other arteries?
It is the thickest muscular wall of any artery
Why is the muscular wall of the arteriole much thicker relatively?
They have to protect the capillaries by reducing the pressure to the arteries the most therefore experience the greatest resistance.