Transport In Animals

Question 1

Why do multicellular animals need transport systems?

Answer 1

They have a small surface area to volume ratio and high metabolic demands.

Question 2

What are the features of a good transport system?

Answer 2

Fluid medium, pump, exchange surfaces, tubes/vessels, two circuits (for mammals).

Question 3

What is the difference between an open and a closed circulatory system?

Answer 3

Open: blood flows freely through cavities; Closed: blood is enclosed in vessels.

Question 4

What is a single circulatory system?

Answer 4

Blood passes through the heart once per circulation (e.g., fish).

Question 5

What is a double circulatory system?

Answer 5

Blood passes through the heart twice per circulation (e.g., mammals).

Question 6

What are the advantages of a double circulatory system?

Answer 6

Higher blood pressure and faster oxygen delivery to tissues.

Question 7

What are the three main types of blood vessels?

Answer 7

Arteries, veins, and capillaries.

Question 8

What is the structure and function of arteries?

Answer 8

Thick muscular walls and elastic tissue; carry blood away from heart under high pressure.

Question 9

What is the structure and function of veins?

Answer 9

Thin walls, valves present; carry blood to heart under low pressure.

Question 10

What is the function of capillaries?

Answer 10

Enable exchange of substances between blood and tissues.

Question 11

What is tissue fluid?

Answer 11

The fluid that surrounds cells in tissues, formed by plasma leaking out of capillaries.

Question 12

How is tissue fluid formed?

Answer 12

High hydrostatic pressure forces fluid out of the capillaries into surrounding tissues.

Question 13

How is tissue fluid returned to the blood?

Answer 13

Low hydrostatic pressure and high osmotic pressure draw fluid back in at the venous end.

Question 14

What is the role of the lymphatic system?

Answer 14

Returns excess tissue fluid to the bloodstream and helps with immune response.

Question 15

What is the structure of the mammalian heart?

Answer 15

Four chambers: two atria and two ventricles, separated by valves.

Question 16

What is the cardiac cycle?

Answer 16

The sequence of events in one heartbeat: atrial systole, ventricular systole, diastole.

Question 17

What are the roles of atrioventricular and semilunar valves?

Answer 17

AV: prevent backflow into atria; SL: prevent backflow into ventricles.

Question 18

How is the heartbeat controlled?

Answer 18

By electrical impulses from the SAN, AVN, Bundle of His, and Purkyne fibres.

Question 19

What is an ECG?

Answer 19

Electrocardiogram – a trace of the electrical activity of the heart.

Question 20

What do the P wave, QRS complex, and T wave represent on an ECG?

Answer 20

P: atrial depolarisation, QRS: ventricular depolarisation, T: ventricular repolarisation.

Question 21

What is the function of haemoglobin?

Answer 21

Transports oxygen in red blood cells.

Question 22

What is cooperative binding?

Answer 22

Binding of one O₂ molecule makes it easier for the next to bind.

Question 23

What is the Bohr effect?

Answer 23

Increased CO₂ decreases haemoglobin’s affinity for oxygen.

Question 24

How is CO₂ transported in the blood?

Answer 24

As hydrogen carbonate ions, dissolved CO₂, and bound to haemoglobin.

Question 25

How does fetal haemoglobin differ from adult haemoglobin?

Answer 25

Fetal Hb has a higher affinity for oxygen to absorb O₂ from the mother's blood.

Question 26

What are the main components of blood?

Answer 26

Plasma, red blood cells, white blood cells, and platelets.

Question 27

What is the function of red blood cells (erythrocytes)?

Answer 27

Transport oxygen using haemoglobin.

Question 28

What is the function of white blood cells (leukocytes)?

Answer 28

Defend the body against infection and foreign substances.

Question 29

What is the function of platelets?

Answer 29

Help in blood clotting to prevent bleeding.

Question 30

What is plasma?

Answer 30

The liquid part of blood that transports nutrients, hormones, and waste.

Question 31

What are the four chambers of the heart?

Answer 31

Left and right atria, left and right ventricles.

Question 32

What is the function of the left ventricle?

Answer 32

Pumps oxygenated blood to the body at high pressure.

Question 33

What is the function of the right ventricle?

Answer 33

Pumps deoxygenated blood to the lungs at lower pressure.

Question 34

What separates the left and right sides of the heart?

Answer 34

The septum.

Question 35

What are the coronary arteries?

Answer 35

Blood vessels that supply oxygenated blood to the heart muscle itself.

Question 36

Where is the sinoatrial node (SAN) located?

Answer 36

In the wall of the right atrium.

Question 37

What does the SAN do?

Answer 37

Acts as the pacemaker of the heart by initiating electrical impulses.

Question 38

Where is the atrioventricular node (AVN) located?

Answer 38

Between the atria and ventricles.

Question 39

What is the function of the AVN?

Answer 39

Delays the impulse to allow the atria to fully contract before ventricles contract.

Question 40

What is the role of the Bundle of His and Purkyne fibres?

Answer 40

Transmit impulses through the septum and cause ventricular contraction.

Question 41

What is an oxygen dissociation curve?

Answer 41

A graph showing the relationship between oxygen saturation of haemoglobin and partial pressure of oxygen.

Question 42

Why is the oxygen dissociation curve 'S-shaped'?

Answer 42

Due to cooperative binding: binding of one O₂ molecule makes it easier for the next to bind.

Question 43

How does the Bohr effect shift the oxygen dissociation curve?

Answer 43

Shifts the curve to the right, showing decreased affinity for O₂ in high CO₂ conditions.

Question 44

What does a left-shifted oxygen dissociation curve mean?

Answer 44

Higher affinity for oxygen (e.g., fetal haemoglobin).

Question 45

Why is the Bohr effect useful?

Answer 45

It helps release more oxygen to respiring tissues where CO₂ is high.