Question

Give a shout answers:

6) Write short notes on the structure and function of the intima, media and adventitia of arteries.

7) Describe the pressure and volume changes that occur in the left ventricle during the course of a single normal cardiac cycle. In your answer provide brief notes on the function of the relevant cardiac valves.

8) Compare and contrast the blood pressures and bulk flow rates within the systemic and pulmonary circulations, including in your response clearly labelled diagrams and short notes on the contribution of windkessels and resistance arteries to the observed pressures.

9) Write short notes on the structures and functions of the intima, media and adventitia of arteries.

10) Describe the pressure and volume changes that occur in the left ventricle during the course of a single normal cardiac cycle. In your answer provide brief notes on the function of the relevant cardiac valves.

Answer 1

6) Histologically artery walls have three consecutive layers. tunica intima, tunica media and tunica adventitia are the three layers of artery walls .

i) Tunica intima: structure= This is the innermost layer of the artery. This layer is consisted of endothelial lining, basal lamina and internal elastic lamina . Endothelial layer is a single larger endothelium cell lining which is situated in contact with blood in the lumen of the artery. After endothelial layer there is a elastic lamina layer is situated, which is consisted of elastic fibre.

Function: The elastic layer in the tunica intima helps artery to bend properly and to flow the blood through its lumen.

ii) Tunica media: structure= This is the middle layer in the anatomy of the artery structure. It is situated after the intima layer. It is consisted of smooth muscle and elastic tissue.

Function: This tunica media layer mainly comprises of smooth muscle, so it can regulate the blood flow through rhe artery by the contraction and relaxation of the smooth muscle in this layer.

iii) Tumica adventitia: structure= This is the outermost layer of the artery. It is situated after the tunica media layer. Structurally this layer is consisted of collagen fibres and other connective tissues.

Function: Collagen fibres in this tunica adventitia layer helps to protect the blood vessels (artery) from overstretching and distension. For example in scurvy disease vitamin C synthesis is hampered, vitamin C is responsible for collagen synthesis in our body. So in scurvy, the arterial tunica adventitia layer lack collagen fibres. This will lead to rupture of artery walls due to overstretching. Blood flow through the artery will be disrupted.