Transport In Animals.

Question 1

What is the circulatory system?

Answer 1

The circulatory system is a system of blood vessels with a pump and valves to ensure one-way flow of blood.

Question 2

Fish have a single circulatory system. What does this mean?

Answer 2

This means that their heart only has two chambers (consisting of an upper atrium and a lower ventricle), and
blood passes through the heart only once on its circuit around the body.

Question 3

Why do fish not have lungs?

Answer 3

Oxygen is absorbed as blood
passes the gills, thus fish do not have lungs.

Question 4

Describe the pathway of blood with the single circulatory system in fish.

Answer 4

Heart → gills → body → heart.

Question 5

Mammals have a double circulatory system. What does this mean?

Answer 5

This means that for every one circuit of the body, the blood passes through the heart twice. This means that the mammalian heart must have four chambers to keep oxygenated and
deoxygenated blood separate.

Question 6

What is the purpose of the right side of a mammalian heart?

Answer 6

The right side of the heart receives deoxygenated blood from the body and pumps it to the lungs (the pulmonary circulation).

Question 7

What is the purpose of the left side of a mammalian heart?

Answer 7

The left side of the heart receives oxygenated blood from the lungs and pumps it to the body (the systemic circulation).

Question 8

What is the advantage of a double circulatory system?

Answer 8

Double circulatory systems can maintain a higher blood pressure which increases the speed at which the blood flows so nutrients can be delivered and waste can be removed more quickly.

Question 9

In what direction from the heart is blood pumped in arteries and veins?

Answer 9

Blood is pumped from the heart in arteries and returns to the heart in viens.

Question 10

How can heart activity be monitored?

Answer 10

Heart activity can be monitored by using an ECG, measuring pulse rate, or listening to the sounds of valves closing using a stethoscope.

Question 11

How are heart rate/ pulse rate and breathing rate measured?

Answer 11

Heart rate (and pulse rate) is measured in beats per minute.
Breathing rate can be measured by counting the number of breaths per minute.

Question 12

State the effect of physical exercise on heart rate.

Answer 12

Physical exercise increase heart rate.

Question 13

Explain the effect of physical exercise on heart rate.

Answer 13

When physical activity is carried out, muscles respire to release energy for movement. Aerobic respiration requires oxygen, thus the heart rate
speeds up so that blood is pumped around the body more quickly, allowing more oxygen to be delivered to respiring tissues and removing the carbon dioxide quickly.

Question 14

What is coronary heart disease?

Answer 14

Coronary heart disease is caused by a buildup of cholesterol in the coronary artery which narrows the artery thus limiting blood flow to the heart.

Question 15

What are the five common risk factors for coronary heart disease?

Answer 15

• Poor diet ( too much-saturated fat and cholesterol).
• Poor lifestyle (lack of exercise, smoking, obesity, stress).
• Age - as you get older the risk of getting coronary heart disease increases.
• Gender - males are more likely.
• Genetic disposition.

Question 16

Reducing the risks of developing coronary heart disease:

Answer 16

• Diet - reduce animal fats, salty foods and stop drinking and smoking and eat more fruits and vegetables.
• Exercise regularly - exercise can reduce the risk of CHD, as it increases the blood supply to the heart and reduces cholesterol levels.

Question 17

Explain the relative thickness of the muscle walls of the left and right ventricles.

Answer 17

The wall of the left ventricle is much thicker than the right side, as it must be able to pump blood at high pressure around the entire body, rather than just to the lungs.

Question 18

Explain the relative thickness of the muscle walls of the atria compared to those of the ventricles.

Answer 18

The ventricles need to pump blood at a higher pressure to pump it out and round the body and to the lungs whereas the atria only need to pump the blood to the ventricles (a shorter distance) so do not need to generate as high of a pressure.

Question 19

Explain the importance of the septum in separating oxygenated and deoxygenated blood.

Answer 19

The left and right sides of the heart are separated by the septum, which makes sure that oxygenated and deoxygenated blood remains separate.

Question 20

What is the function of the heart (step-by-step)?

Answer 20

• Deoxygenated blood coming from the body flows into the right atrium via the vena cava
• The right atrium contracts and blood moves through a one-way valve (tricuspid valve) to the right ventricle.
• The ventricle contracts and blood exits the heart through a one-way valve (semilunar valve) to the lungs via the pulmonary artery.
• Blood becomes oxygenated in the lungs and then returns to the heart via the pulmonary vein, entering the left atrium.
• The left atrium contracts and blood moves through a one-way valve (bicuspid valve) into the left ventricle.
• The left ventricle contracts and oxygenated blood exits the heart past the semilunar valve through the aorta (artery) and travels around the body, becoming deoxygenated.

Question 21

Give the summarized functioning of the heart.

Answer 21

Vena cava → Right atrium → Right ventricle → Pulmonary artery → Lungs → Pulmonary vein → Left atrium → Left ventricle → Aorta → The body.

Question 22

State the name of the main type of tissue that forms the wall of the heart.

Answer 22

Cardiac muscle.