Transport in Animals

Question 1

What substances are transported by the blood?

Answer 1

Water, digested food substances(amino acids, glucose, lipids, vitamins, minerals), hormones (e.g. insulin), heat, respiratory gases (e.g. o2 &co2), metabolic wastes (e.g. urea)

Question 2

Which is the valve between right atrium and right ventricle?

Answer 2

Tricuspid valve

Question 3

Why are pulmonary artery and veins called so?

Answer 3

They are exception to the other types of arteries and veins. Pulmonary arteries carry deoxygenated blood and pulmonary veins carry oxygenated blood.

Question 4

Which valve is present in aorta and prevents the back flow of blood into the heart?

Answer 4

Semilunar valve

Question 5

Which has a thicker wall left or right ventricle? Why?

Answer 5

Left ventricle as it pumps blood to be transported to the extremities and the right ventricle transports blood to the lungs.

Question 6

Which is the biggest artery? List one of its exceptions

Answer 6

Aorta is the biggest artery.

It has a valve to prevent back flow in the heart

Question 7

List all the characteristics of an artery.

Answer 7

Most of them carry oxygenated blood, always carry blood away from the heart. Blood is at high pressure (pumped directly by the heart) so walls are strong, thick and elastic.

Question 8

List all characteristics of a vein.

Answer 8

Most of them carry deoxygenated blood, always carry blood towards the heart. Thinner walls as blood is at low pressure, wider lumen to allow flow of blood. Valves are present to prevent back flow of blood due to gravity. Contraction and relaxation of muscles moves the blood forward.

Question 9

List all the characteristics of a capillary.

Answer 9

They are too small to be seen by naked eyes. They deliver oxygen and food directly to the body tissues and takes waste products away. Their walls are only one cell thick to allow easy diffusion of food and waste substances in and out of them.

Question 10

What are lymphatic vessels? What is their function?

Answer 10

They are thin walled vessels (bigger than the capillaries) and help to drain out the fluid called lymph from tissues throughout the body and help in the exchange of nutrients and wastes between the tissues and the blood.

Question 11

What is the path of transfer of blood from artery to vein?

Answer 11

artery => arteriole => capillary => venule => veins

Question 12

What is caused by the fatty deposits in the artery?

Answer 12

Atheroma

Question 13

Explain the formation of atheroma and a blocked artery step by step.

Answer 13

Fatty deposits can line arteries as we become older.
These deposits are called atheroma.
Fibrin can be deposited on rough areas of atheroma.
A blood clot called a thrombus can block the narrow artery
This can starve a part of the body of oxygenated blood.

Question 14

What are the causes of formation of atheroma? (controllable) And explain why?

Answer 14

Diet - high saturated fats can increase the risk of atheroma
Smoking - can increase the rick of atheroma blocks artery
Stress - release of adrenaline, heart pumps nutrients to response to stress.

Question 15

Name three factors causing the formation of atheroma that are uncontrollable.

Answer 15

Age, gender and family history of atheroma

Question 16

Name two treatments for atheroma and blocked artery

Answer 16

Anglioplasty and bypass

Question 17

What is the composition of blood?

Answer 17

45% cells / cell fragments (RBC, WBCs, platelets)

55% plasma (serum and fibrinogen)

Question 18

Explain in detail everything about RBCs.

Answer 18

• Carry oxygen to all cells in the body
• Have a biconcave shape to give maximum surface area to absorb o2
• Contains haemoglobin which contains a lot of iron
• In the lungs, haemoglobin binds with o2 to form oxyhaemoglobin and the reverse happens to release o2 in cells.
• Have no nucleus to make more room for haemoglobin.

Question 19

Explain in detail everything about WBCs.

Answer 19

• Main role is the defence against diseases.
• There are 2 types of WBCs
• Lymphocytes : have a big nucleus, and produce antibodies against pathogens
• Phagocytes : engulf the pathogens and digest them in their vacuole.
• WBCs also produce antitoxins to neutralise the toxins produced by the pathogens.

Question 20

Explain in detail everything about plasma.

Answer 20

• Pale-straw coloured liquid
• Carries RBCs, WBCs and platelets.
• Digested food products like glucose and amino acids
• CO2, urea, hormones, antibodies and antitoxins from WBCs

Question 21

Explain in detail everything about platelets.

Answer 21

• Small fragments of cells
• Have no nucleus
• Help to blood clot a wound

Question 22

Describe the process of blood clotting.

Answer 22

• When tissue gets damaged and blood vessels cut the platelets clump together and block the smaller wounds.
• The platelets and the damaged cells at the wound also produce a substance that acts through a series of reactions on the plasma protein called fibrinogen
• The soluble fibrinogen is changed into insoluble fibrin which forms a network of fibres across the wound.
• RBCs become trapped in the fibres and form a blood clot.
• The clot not only prevents further loss of blood, but also prevents the entry of harmful microbes into the wound.