Arteries And Veins Flashcards
What are the layers of blood vessels?
Tunica intima
Tunica media
Tunica adventitia
What do the layers of blood vessels consist of?
Tunica intima - simple squamous epithelium, basement membrane and connective tissue
Tunica media - smooth muscle (elastic tissue)
Tunica adventitia - connective tissue
Describe the difference in the structure of veins and arteries with regards to the layers.
Arteries are smaller in diameter than veins because it has a thicker wall
Arteries have a thicker tunica media
Veins have a larger tunica adventitia compared to arteries as it requires more support to attach it to its surroundings because it is floppy
Give 3 examples of elastic arteries.
Aorta
Common carotid
Pulmonary
Give examples of muscular arteries.
Coronary arteries
Radical artery
Femoral artery
Arteriosus are terminal branches which supply why?
The blood to the capillary beds
What is the difference between conducting and distributing arteries?
Conducting arteries are large elastic arteries such as the aorta.
Distributing arteries are muscular such as the coronary arteries
How does the elastic arteries such as the aorta act as a pressure reservoir?
Controls the pressure so during systole the pressure doesnt go too high and diastole to ensure pressure doesn’t drop too low.
The vessel i.e. aorta stretches during systole as the heart contracts and fills with blood and recoils during diastole as the heart relaxes.
What is the recoil and stretchability in elastic arteries due to the presence of?
Elastic fibres in the tunica media in the form of layers called laminae.
The fibres are secreted by smooth muscle.
In muscular arteries, there isn’t a lot of elastic fibres like the elastic arteries. Instead the elastic fibres are concentrated where?
In 2 sheets called the internal elastic laminate (IEL) just under the epithelium
and the thin external/outer elastic lamina (OEL) between the tunica media and tunica adventitia.
Histologically, what is the difference between arteries and arterioles?
There is no internal elastic lamina in the tunica intima
There is only 1-2 layers of smooth muscle
They only have 2 layers, they don’t have a tunica adventitia.
What is the nerve innervation of capillaries?
Sympathetic
What are pericytes and where are they found?
Pericytes are found in capillaries
They are an incomplete layer of cells which surround the basement membrane
They have contraction properties which help control flow of blood in the capillaries.
Why is the blood pressure in the capillaries low?
Because the sum of all the capillaries in the body is less than that of the aorta
What are the 3 types of capillaries?
Continuous
Fenestrated
Discontinuous