Mass transport- heart

Question 1

What does right side do vs left side?

Answer 1

-Right side pumps deoxygenated blood to the lungs and left side pumps oxygenated blood to the whole body.

Question 2

Describe left ventricle-

Answer 2

-Has thicker, more muscular walls than the right ventricle, because it needs to contract powerfully to pump blood all the way around the body. The right side only needs to get blood to the lungs which are nearby

Question 3

Ventricles vs atria-

Answer 3

-Ventricles have thicker walls than atria because they have to push blood out of the heart whereas atria need to push blood into the ventricles

Question 4

Atrioventricular (AV) valves-

Answer 4

-Link the atria to the ventricles and stop blood flowing back into the atria when the ventricles contract

Question 5

Semi-lunar (SV) valves-

Answer 5

-Link the ventricles to the pulmonary artery and aorta and stop blood flowing back into the heart after the ventricles contract

Question 6

What do cords do-

Answer 6

-Attach the atrioventricular valves to the ventricles to stop them being forced up into the atria when the ventricles contract

Question 7

What are the three stages of cardiac cycle?

Answer 7

1)Atria contracts, ventricles relax
2)Atria relax, ventricles contract
3)Both atria and ventricles relax

Question 8

Describe the first stage of cardiac cycle-

Answer 8

-Ventricles relax, atria contract decreasing the volume of the chambers and increasing the pressure inside the chambers
-This pushes the blood into ventricles
-Slight increase in ventricular pressure and chamber volume as the ventricles receive the ejected blood from the contracting atria

Question 9

Describe the second stage of cardiac cycle-

Answer 9

-Atria relax, ventricles contract decreasing their volume, increasing their pressure.
-Pressure becomes higher in the ventricles than the atria, forces the atrioventricular valves to shut to prevent the back-flow.
-Pressure in ventricles higher than in the aorta and pulmonary artery, which forces open semi-lunar valves and blood is forced out into these arteries

Question 10

Describe the last stage of cardiac cycle-

Answer 10

-Ventricles and atria relax
-Higher pressure in the pulmonary artery and aorta closes the semi-lunar valves to prevent back-flow into the ventricles.
-Blood returns to heart and the atria fill again due to the higher pressure in the vena cava and pulmonary vein.
-This starts to increase the pressure of the atria
-As the ventricles continue to relax, their pressure falls below the pressure of the atria and so the atrioventricular valves open. This allows blood to flow passively into the ventricles from atria
-Atria contract and the whole process begins again

Question 11

How does atheroma forms and what does it do?

Answer 11

-If damage occurs to the endothelium layer within the arteries, white blood cells and lipids from the blood, clump together under the lining to form fatty streaks.
-Over time, more white blood cells, lipids and connective tissues build up and harden to form a fibrous plaque called an atheroma
-Plaque partially blocks the lumen of the artery and restricts blood flow, which causes blood pressure to increase
-Coronary heart disease (CHD) is a type of cardiovascular disease, occurs when the coronary arteries have lots of atheromas in them which restricts the blood flow to the heart muscle, can lead to myocardial infarction.

Question 12

How does aneurysm disease form?

Answer 12

-Atheroma plaques damage and weaken arteries, also narrow arteries, increasing the blood pressure
-when blood travels through a weakened artery at high pressure, it may push the inner layers of the artery through the outer elastic layer to form a balloon-like swelling- an aneurysm
-Aneurysm may burst, causing haemorrhage (bleeding)

Question 13

How does thrombosis disease form?

Answer 13

-Atheroma plaque can rupture the endothelium of an artery
-This damages the artery wall and leaves a rough surface
-Platelets and fibrin (a protein) accumulate at the site of damage and form a blood clot (a thrombosis)
-Blood clot can cause a complete blockage of the artery or it can become dislodged and block a blood vessel elsewhere in the body
-Debris from the rupture can cause another blood clot to form further down the artery.

Question 14

What causes myocardial infarction?

Answer 14

-Interrupted blood flow

Question 15

Importance of myocardial arteries

Answer 15

-Heart muscle is supplied with blood by the coronary arteries
-This blood contains the oxygen needed by heart muscle cells to carry out respiration
-If coronary artery becomes blocked an area of the heart muscle will be totally cut off from its blood supply, receiving no oxygen
-This causes myocardial infarction

Question 16

Symptoms of myocardial infarction

Answer 16

-Pain in the chest and upper body, shortness of breath and sweating
-If large areas of the heart are affected complete heart failure can occur which is often fatal

Question 17

What factors increase the risk of cardiovascular disease?

Answer 17

-High blood cholesterol and poor diet
-Cigarette smoking
-High blood pressure
-genetic predisposition (some forms of diabetes)

Question 18

Explain how high blood cholesterol and poor diet increases the risk of cardiovascular disease?

Answer 18

-Because cholesterol is one of the main constituents of the fatty deposits that form atheromas
-Atheromas can lead to increased blood pressure and blood clots
-This would block the flow of blood to coronary arteries, causing a myocardial infarction
-A diet high in saturated fat is associated with high blood cholesterol levels
-A diet high in salt also increases the risk of cardiovascular disease because it increases the risk of high blood pressure

Question 19

Explain how high blood pressure increases the risk of cardiovascular disease?

Answer 19

-Increases the risk of damage to the artery walls
-Damaged walls have an increased risk of atheroma formation, causing a further increase in blood pressure
-Atheromas can cause blood clots to form which could block the blood flow to the heart muscle, resulting in myocardial infarction
-Anything that increases blood pressure also increases the risk of cardiovascular disease (being overweight, not exercising and excessive alcohol consumption)

Question 19

Explain how cigarette smoking increases the risk of cardiovascular disease?

Answer 19

-Nicotine and carbon monoxide found in cigarette smoke
-Nicotine increases the risk of high blood pressure
-Carbon monoxide combines with haemoglobin and reduces the amount of oxygen transported in the blood so reduces the amount of oxygen available to tissues. If heart muscle doesnt receive enough oxygen it can lea to a heart attack
-Smoking decreases the amount of antioxidants in the blood (important for protecting cells from damage) fewer antioxidants means cell damage in the coronary artery walls is more likely and can lead to atheroma formation