Endothelial Tissue

Question 1

What does the pulmonary artery do?

Answer 1

Takes blood away from the heart

Question 2

What does the pulmonary vein do?

Answer 2

Takes blood towards the heart

Question 3

What happens at point P in the ELECTROCARDIOGRAM system?

Answer 3

Impulse spreads through atria walls = contraction

Question 4

What happens at QRS?

Answer 4

Impulse spreads through ventricle walls = contraction - blood out of the heart

Question 5

What happens at T?

Answer 5

Walls relax and the heart is at rest

Question 6

what are the features of the artery?

Answer 6

• Walls are very thick and contain 4 layers
• Leads away from the heart
• Walls contain thick muscle layer to cope with high pressures
• Carries blood at high pressures
• Contains no valves but has smooth muscle
• Lumen diameter fairly large. Many RBC’s flow, but closely packed together
• Plaques can form under endothelial walls

Question 7

What are the features of the vein?

Answer 7

• Contains valves to stop backflow
• Lumen diameter very large, so many RBC can flow at once
• Leads towards the heart
• Wall thin because pressure is low
• Carries blood at very low pressures
• Walls are thin and contain 3 layers of tissue
• Plaques can form under endothelial wall

Question 8

What are the features of the capillaries?

Answer 8

• Walls are made from one layer of endothelial cells
• Mostly deep beneath the skin
• Lumen diameter small
• Carries blood at low pressure
• Found throughout all tissue
• Not connected to the heart
• Contains no valves
• Only blood vessels with gaps between cells for exchange

Question 9

What is atherosclerosis?

Answer 9

Condition where the bodies arteries become narrowed and hardened by fatty substances

Question 10

What are the stages of atherosclerosis?

Answer 10

• Endothelium is damaged
• Cholesterol accumulated under endothelium and causes inflammatory response
• White blood cells enter the artery wall, transform into macrophages and digest cholesterol becoming large foam cells
• Calcium salts and fibrous tissue join to form large hard plaques under the endothelium
• Plaque narrows the lumen of the artery making it difficult for blood to flow through
• If this happens in the coronary the heart muscle is starved of 02 and dies, which causes a heart attack