Histology of The Vasculature

Question 1

What are the three layers of the blood vessels and their features. Try draw a blood vessel

Answer 1

Tunica Intima, Tunica media, Tunica adventitia

Question 2

Describe the features of the tunica intima

Answer 2

It is simple squamous epithelium called endothelium and in larger vessels a subendothelial layer of loose connective tissue supports the endothelium.

Question 3

Describe the features of tunica media

Answer 3

Circular arranged smooth muscle cells and sheets of elastin. The activity of smooth muscle regulated by sympathetic vasomotor fibres.

Question 4

Describe features of adventitia

Answer 4

Loosely woven collagen fibres that protect and reinforce the vessel. In large vessels the adventitia contains blood vessels called vaso vasorum

Question 5

Describe features of elastic/conducting vessels

Answer 5

Largest diameter vessel, containing lots of elastin especially in the media layer. This means they can withstand large pressure fluctuations by expanding when the heart pumps out blood at high forces. They conduct blood from heart to medium arteries, hense the name.

Question 6

Describe features of muscular/distributing arteries

Answer 6

These vessels deliver blood directly to organs. They have the thickest tunica media of the arteries which contains more smooth muscle than elastic arteries, this means they are more active in vasoconstriction

Question 7

Describe features of arterioles

Answer 7

Smallest of the arteries. Larger arterioles have all the tunics, while smaller arterioles are a layer of smooth muscle spiralled around an endothelial layer. They determine how much blood flows into capillaries because as the muscle constricts then blood supply is dramatically decreased, if its relaxed then blood flow dramatically increases

Question 8

Describe features of venules

Answer 8

They form when capillaries merge together. Post capillary venules consist of endothelium and are still very porous. Larger venules have 1 or 2 layers of smooth muscle with a thin advintitia.

Question 9

Describe features of veins

Answer 9

Usually have 2 distinct tunics but their walls tend to be thinner and their lumen larger than corresponding arteries. Little smooth muscle and elastin in tunica media, tends to be a thin layer even in big veins. The tunica adventita is the thickest layer full of collagen and elastic networks. As pressure in veins is low pressure the walls can be thinner however they need valves therefore, to prevent backflow of blood

Question 10

Draw difference between muscular and elastic artery

Answer 10