Chapter 8- Transport in man

Question 1

What are the various components a of blood?

Answer 1

1. Plasma (55%) 2. White blood cells and platelets (45%, 1% of blood) 3. Red blood cells (45%; 99% of blood)

Question 2

What does the plasma transport?

Answer 2

1. Proteins- fibrinogen, prothrombin, antibodies 2. Nutrients- proteins, fats, glucose 3. Minerals- chlorides, sulfates (from calcium and sodium) 4. Waste products- urea, iris acid, creatinine 5. Hormones- HGH, sex hormones

Question 3

Describe the features of a red blood cell.

Answer 3

1. No nucleus (limits lifespan) 2. Contains haemoglobin (transports oxygen) 3. Elastic (squeeze in tiny blood capillaries) 4. Biconcave shape (surface area to volume ratio)

Question 4

What is the structure and function of a lymphocyte?

Answer 4

1. Large and rounded nucleus. 2. Small amount of non-granular cytoplasm. 3. Function- produces antibodies against bacteria.

Question 5

How do antibodies help fight against bacteria?

Answer 5

1. They bind to specific bacteria and cause their surface membranes to rupture. (Different antibodies > different pathogens) 2. Bacteria cells clump together in the presence of antibodies. 3. Antibodies neutralize the toxins produced by the bacteria.

Question 6

What is the function and structure of a phagocyte?

Answer 6

1. Small, lobed nucleus. 2. Contains granular cytoplasm, which contains enzymes. 3. Function- ingest (destroy) and engulf foreign particles.

Question 7

What is the function and structure of a platelet?

Answer 7

1. Fragments of cytoplasm which are membrane bound. 2. Not a true cell; does not contain most organelles. 3. Function- releases thrombokinase and helps in blood clotting.

Question 8

What are the two functions of blood?

Answer 8

1. It’s a transport medium. 2. It helps to protect the body. - Blood clotting - Phagocytosis - Production of antibodies

Question 9

What does blood transport?

Answer 9

1. Digested food substances (glucose, proteins, fats) 2. Waste materials (CO2, urea) 3. Hormones (HGH, sex hormones) 4. Heat 5. Oxygen (RBCS only)

Question 10

What is the transport process of blood around the body?

Answer 10

1. Blood passes through lungs; oxygen diffuses from air sacs in the lungs into the RBCS in the blood. 2. Haemoglobin binds to oxygen to form oxyhaemoglobin. 3. Blood transports oxygen to all parts of the body. 4. At tissue cells, oxyhaemoglobin releases oxygen.

Question 11

What is acclimatization?

Answer 11

It is the increase in red blood cells in blood levels for people living at high altitudes. Higher altitudes have higher pressure, thus the amount of oxygen in the air is significantly lesser. The increased number of RBCS increase the amount of haemoglobin, and thus more oxygen can be transported to all parts of the body per unit time.

Question 12

How does blood clotting occur?

Answer 12

Blood clots help seal wounds and prevent entry of bacteria / prevent further loss of blood. During blood clotting, platelets release an enzyme known as thrombokinase. It converts prothrombin in blood to thrombin (active form) with the addition of calcium ions. Thrombin then converts the soluble fibronogen in blood to insoluble fibrin threads, which entangle blood cells to form a clot.

Question 13

What do the antibodies do during an organ transplant?

Answer 13

1. The recipient may produce antibodies to destroy the organ transplant (as it is a foreign object). 2. Tissue matching or immunosuppressive drugs can help to lower the chances of this happening. 3. Donations from family or siblings also proves to be more effective.

Question 14

Why do multicellular organisms require a transport system, as opposed to unicellular organisms?

Answer 14

1. In unicellular organisms, the exchange of materials occurs easily by diffusion. (Large surface area to volume ratio). 2. Multicellular organisms have a reduced surface area to volume ratio, which means that waste and nutrients cannot enter quickly. 3. Cells are also located deeper inside the body, meaning diffusion only works for cells on the surface.

Question 15

How are blood groups classified?

Answer 15

1. People have natural antibodies in their plasma, which recognizes and binds to specific antigens on the red blood cells. 2. The red blood cells have proteins called antigens on their surfaces. 3. Blood group types are formed in line with the names of the antigen (e.g blood group A has A antigens and b antibodies).

Question 16

What is agglutination?

Answer 16

Agglutination occurs when the recipient’s antibodies binds to the donor’s antigens. It is defined as the clumping of blood cells. It may cause clogging of blood vessels and sometimes death because blood isn’t able to flow.

Question 17

What is the structure and function of the arteries?

Answer 17

Function: 1. Transport oxygenated blood from the heart to other organs. Structure: 1. Thick, muscular walls that pushes blood in spurts. 2. Support for blood coming in with high pressure. 3. Contraction and dilation of arteries at times- push blood.

Question 18

What is the function and structure of the veins?

Answer 18

Structure: 1. Transports deoxygenate blood back to the heart. Function: 1. Thinner walls, lesser elastic tissue- slow pressure. 2. Semi lunar valves, which prevent the backflow of blood due to gravity.

Question 19

What is the function and structure of the capillaries?

Answer 19

Structure: 1. Microscopic blood vessels found between cells of all tissues. Function: 1. Has only the endothelium- single layer of flattened cells- this allows easier diffusion of substances. 2. Capillary network- increase total surface area to volume ratio.

Question 20

Why do mammals need double circulation?

Answer 20

1. Full oxygenation - Blood enters pulmonary circulation at low pressures, ensuring sufficient time for the blood to be fully oxygenated. 2. Quick distribution - Blood pumped at high pressures into the systematic circulation system- oxygenated blood is quickly distributed to all tissues.

Question 21

Describe the movement of blood through the heart.

Answer 21

1. Deoxygenated blood returns to the heart via vena cava. 2. Right atrium contracts, then right ventricle contracts. 3. Blood leaves via pulmonary arch and enters lungs. 4. Oxygenated blood flows from lungs to atrium via pulmonary vein. 5. Left atrium contracts, left ventricle contracts, blood moves to the aortic arch and is distributed throughout the body.

Question 22

Describe the ventricular systole.

Answer 22

1. Blood from vena cava and pulmonary vein fill the atriums. 2. Both atria contract, blood moves to ventricles. 3. Closure of bicuspid and tricuspid valves- prevent backflow of blood into the atrium. 4. A lub sound is produced by the closure.

Question 23

Describe the ventricular diastole.

Answer 23

1. When pressure in the ventricles are higher than in the aorta, the semi-lunar valves in the aortic and pulmonary arches open. 2. When blood leaves, the ventricles and atria relax. 3. After ventricles relax, semi-lunar valves close to prevent backflow of blood into the ventricles. Dub sound is produced. 4. Dec. in pressure allows bi and tricuspid valves to open.

Question 24

Name all the blood vessels in the diagram.

Answer 24

1-6: Pulmonary vein, aorta, dorsal artery, hepatic artery, artery to gut, renal artery.

7-12: Pulmonary artery, anterior vena cava, posterior vena cava, hepatic vein, hepatic portal vein, renal vein.

Question 25

Describe what happens at the five points on the graph.

Answer 25

1. Atria contract and forces blood into the ventricles.
2. Ventricles contract: bicuspid and tricuspid valves close.
3. Ventricles contract until semi-lunar valves open.
4. Ventricles start to relax.
5. Ventricles relax: bicuspid and tricuspid valves open

Question 26

What is blood pressure? How can it be measured?

Answer 26

Blood pressure refers to the force exerted by the blood on the walls of the blood vessels. It can be measured using a sphygmomanometer. (mm Hg) The arteriole pressure is the highest during ventricular systole and decreases during ventricular diastole.

Question 27

What is a pulse?

Answer 27

A pulse refers to the rhythmic bulging of the artery walls with each heartbeat.

Question 28

Describe the formation of the coronary heart disease.

Answer 28

1. Build up of fatty substances on the inner surfaces of coronary arteries. (Atherosclerosis) 2. Lumen is narrowed, causing blood clots. (Thrombosis) 3. Blood clot reduces flow of blood to the heart. 4. Heart muscles receive reduced supply of oxygen. 5. May cause a heart attack.

Question 29

What are the causes of coronary heart disease?

Answer 29

1. High fat diet rich in saturated fats. 2. Lack of exercise. (Sedentary lifestyle) 3. Smoking. 4. Emotional stress.

Question 30

How can we prevent coronary heart disease?

Answer 30

1. Eat foods high in polyunsaturated plant fat and avoid a high fat diet rich in saturated animal fat. 2. Exercise regularly. 3. Manage stress well. 4. Quit smoking.

Question 31

What are some treatment methods for coronary heart disease?

Answer 31

1. Balloon angioplasty 2. Coronary bypass