Topic 3B - More exchange + transport systems

Question 1

Blood Vessels in circulatory system

Answer 1

1. Arteries
2. Arterioles
3. Veins
4. Venules
5. Capillaries

Question 2

Arteries

Answer 2

1. Carry oxygenated blood, pumped away from heart at high pressure to rest of body (except for pulmonary artety)
2. Thick walls which have thick layer of muscle tissue + lots of elastic tissue allowing them to stretch and recoil to manage this high pressure
3. Folded endothelium. Allows arteries to stretch, therefore manage high blood pressure

Question 3

Arterioles

Answer 3

1. Smaller vessels. Carry oxygenated blood
2. Arteries branch into arterioles and arterioles branch into capillaries
3. Arterioles “feed” blood into capillaries / control bloodflow into capillairies
4. They have muscle tissue which contracts and relaxes, so this is what allows them to control the blood flow into capillaries

Question 4

Veins

Answer 4

1. Carry deoxygenated blood, back to heart at low pressure (except pulmonary vein)
2. Less muscle tissue. Less elastic tissue. This is because blood is at lower pressure
3. Wider lumen - blood is at lower pressure, helps maintain blood flow
4. Valves - prevent backflow of blood. Due to low BP

Question 5

Capillaries

Answer 5

1. Smallest blood vessel. Arterioles branch into capillaries
2. Involved with exchange of substances between body cells (gas exhange, exchange of glucose)
3. Endothelium 1 cell thick. Short diffusion pathway. More efficient exchange
4. Large no. of capillaries. Increases SA for exhange
5. Capillaries usually found close to body tissue where exchange is taking place (cells in alveoli). Short diffusion pathway.
6. Network of capillaries in tissue - capillary bed

Question 6

Tissue Fluid

Answer 6

1. Fluid made up of small molecules from blood plasma (oxygen, water, nutrients). This is because the larger molecules including red blood cells and proteins are too large to be pushed out of capillary walls
2. Surrounds the body cells
3. Exchanges substances with them. For example, cells take in oxygen from tissue fluid and release metaolic waste (CO2) into tissue fluid
4. Formed by pressure filtration

Question 7

Hydrostatic Pressure

Answer 7

Pressure created due to ventricles of heart contracting to pump blood.

Question 8

Formation of tissue fluid

Answer 8

Pressure Filtration

1. Hydrotstatic pressure at the arteriole end of the capillary is higher than hydrostatic pressure in the tissue fluid outside. This forces fluid inside capillary to move outside and form tissue fluid
2. As you move along the capillary bed, hydrostatic pressure decreases as more fluid is forced out
3. At the venule end of capillary bed, water potential is lower than it is in the tissure fluid outside. This is because lots of fluid has been forced out and therefore, the conc of proteins in blood plasma in capilarries at venule end is now really high.
4. So, water moves from tissue fluid into venule end of capillary bed via osmosis
5. Also, at venule end of capillary, because lots of fluid has been forced out, the hydrostatic pressure is higher in the tissue fluid outside than inside the venule end of capillaries. This high hydrostatic pressure forces the fluid back into the cappilaries.

Question 9

What happens to excess tissue fluid?

Answer 9

Excess tissue fluid is drained by lymphatic system which then ventually transports it back to circulatory system

Question 10

4 Main Blood Vessels in the heart

Answer 10

Aorta - Connected to left ventricle. Pumps oxygenated blood to all parts of body except lungs
Vena Cava - Recieves deoxygenated blood from all parts of the body, except lungs. Connected to right atrium
Pulmonary artery - connected to right ventricle. Pumps deoxygenated blood from left ventricle to lungs to get oxygenated (CO2 removed)
Pulmonary Vein - Connected to left atrium. Recieves oxygenated blood from lungs

Question 11

Double Closed Circulatory System

Answer 11

Double - The heart has 2 pumps. One pumps deoxygenated blood to lungs to get oxygenated. One pumps oxygenated blood to rest of body. This is to maintain BP around body. The blood slows down + loses pressure as it returns from lungs

Closed - Blood confined into vessels. Maintains BP

Question 12

Cords

Answer 12

Attach AV valves to ventricles

Ensure AV valves do not open when ventricles contract

Question 13

Formation of atheroma

Answer 13

• Damage to artery endothelium
• WBC + lipids clump together
• Forms fatty deposit
• More WBC + Lipids + connective tissue, hardens forms fibrous plaque
• Partially blocks artery lumen
• Restricts blood flow
• This can lead to aneurysm and/or thrombosis
• Thrombosis can lead to CHD

Question 14

Aneurysm

Answer 14

Aneurysm - Baloon like swelling. Formed when:

1. Due to formation of lots of atheromis in artery.
2. Atheroma blocks artery lumen
3. Restricts blood flow
4. This leads to higher BP which damages and weakens artery
5. Blood flows at high pressurethrough damaged + weakened artery
6. Pushes inner layer outwards through the elastic + muscle layer forming a baloon like swelling - aneurysm
7. Aneurysm bursts - bleeding / haemorage

Question 15

Thrombosis

Answer 15

1. Atheroma bursts through endothelium
2. Platelets clump together + plug damaged area
3. This leads to formation of blood clot / thrombus
4. Complete blockage of artery
5. Blood flow completely restricted
6. Mycardial infraction

Question 16

CHD - Coronary Heart Disease

Answer 16

1. Formation of atheromas in coronary arteries
2. This leads to thrombosis - formation of blood clots in coronary arteries
3. Complete blockage of coronary arteries
4. Blood flow completely restricted
5. Blood containing O2 cannot be delivered to muscle of heart for respiration
6. Heart muscle cells cannot respire
7. Mycardial infraction - heart attack
8. This can lead to death / damage of heart muscle tissue
9. If too much heart muscle tissue is damaged, complete heart failure = death

Question 17

Risk factors of CHD

Answer 17

• High blood cholestrol (resulting from a poor diet|)
• Smoking cigarettes
• High blood pressure

Question 18

Risk factors of CHD

Answer 18

• High blood cholestrol (resulting from a poor diet / diet high in saturated fat)
• Smoking cigarettes
• High blood pressure

Question 19

High Blood Cholestrol

Answer 19

• Results from diet high in saturated fat
• Cholestrol type of lipid
• Lipid involved in formation of fatty deposits leading to formation of atheroms in arteries
• Formation of

Question 20

High Blood Cholestrol

Answer 20

• Results from diet high in saturated fat
• Cholestrol type of lipid
• Lipid involved in formation of fatty deposits leading to formation of atheroms in arteries
• Formation of atheroma can lead to aneurysm (leads to beeding / hamorage) and thrombosis (leads to myocardial infraction / CHD)

Question 21

Smoking cigarettes

Answer 21

• Cigarettes contain nicotine and CO
• Nicotine leads to high BP
• CO combines with haemoglobin, reducing the amount of O2 carried by blood
• Less oxygen reaches muscle of heart
• Mycordial infraction
• Smoking leads to less anti oxidants
• Antioxidants protect cells from damage
• Less antioxidants could result in damage to endothelium of coronary arteries. Leads to formation of atheromas which can lead to aneurysm (which can lead to bleeding / haemorage) and thrombosis (mycardial infraction / CHD)

Question 22

High Blood Pressure

Answer 22

1. Damage to artery endothelium
2. Formation of atheromas
3. Atheromas lead to aneurysm (leads to bleeding / haemorage) and thrombosis ( CHD / mycardian infraction)
4. What leads to high BP?

Factors we can control:

• Cigarette smoking
• Excessive alcohol
• Sedentry lifestyle / less exercise
• Overweight

Factors we cannot control:

• Age
• Gender
• High BP as a result of another condition e.g. diabetes
• Genetic predisposition to high BP