vascular tree

Question 1

draw and label the structure of an artery

Answer 1

r

Question 2

Draw and label the structure of a vein

Answer 2

d

Question 3

Describe the tunica intima

Answer 3

Single layer of flat epithelia cells. Supporting layer of collagen, smooth, friction reducing lining.

Question 4

Describe the tunica media

Answer 4

Smooth muscle and elastic fibres. For stretch and recoil. Activated by sympathetic NS causing vasodilation and vasocontriction

Question 5

Decribe the tunica externa

Answer 5

Made of fibrous connective tissue and vaso vesorum. Protective and supporting layers

Question 6

Define the term vasuclar tree

Answer 6

Highly ramified structures containing all the vascular vessels of the body

Question 7

Define anastome

Answer 7

Arteries communicating with one another ie. the circle of willis in the brain

Question 8

define collateral circulation

Answer 8

Enlargement of an anastome

Question 9

Why is collateral circulation important

Answer 9

It is important in lower limb ischemia - it allows blood to flow in non-anatomical pathways

Question 10

Define the term anuersym

Answer 10

Localised dilation of an affected artery. Dilated over 50% of normal diameter.

Question 11

What do aneuryms cause

Answer 11

damage and loss of tunica intima, reduction of collagen and elstin in tunica media

Question 12

Define embolism

Answer 12

Blockage of vessel by solid, liquid, gas at a site distant from its origin

Question 13

How can strokes be caused

Answer 13

Internal corotid artery supplies the brain. The common carotid bifurction os the site of atherosclerosis causing lumen narrowing and potential embolism. Subsequently, cerebral ischaemia can occur and cause an ischaemic attack or a stroke

Question 14

Define arteriosclerosis

Answer 14

hardening of arteriess

Question 15

Define atheroscleroisis

Answer 15

Hardening of arteries characterised by calcification and plaque formation

Question 16

name some risk factors for atherosclerosis

Answer 16

age, sex, smoking, diabetes and obesity

Question 17

What changes occur to blood vessels during atherosclerosis

Answer 17

Plaque forms narrowing lumen
walls become weaker
thrombosis occurs

Question 18

Describe the pathology of atherosclerosis

Answer 18

Endothelial cells are activated, recruiting monocytes and forming fatty streaks. Plaque forms and builds up, before rupturing and resulting in thrombosis

Question 19

describe the formation of collagen

Answer 19

Step1 - The individual collage polypeptide chains are synthesised on membrane-bound ribosomes and then injected into the lumen of the ER as large precursors called pro-α chains. These chains also have propeptides on their amino- and carboxyl-terminal ends. •
Step 2 & 3 - In the lumen of the ER, selected proline and lysin residues are hydroxylated to form hydroxyproline and hydroxylysine (some of which are glycosylated). •
Step 4 & 5 - Each pro-α chain then combines with two others to form a hydrogen-bonded, triple-stranded helical molecule known as procollagen.
• Step 6 - The procollagen is then moved out of the cell via exocytosis and enters the extracellular space
• Step 7 - The propeptides on the 2 ends are removed (cleaved) and then becomes a collagen molecule. #
• Step 8 - It then self-assembles into much larger collagen fibrils.
• Step 9 - Aggregation of collagen fibrils to form a collagen fibre.