[Maximum number: 5]

Each of statements A to E describe a structure associated with the mammalian heart.
For each statement, identify the structure that is being described.

The chamber that pumps blood into the pulmonary artery.

A blood vessel that transports deoxygenated blood into the right atrium.

The specialised tissue responsible for delaying the conduction of impulses from the atria to the ventricles.

The blood vessels that supply cardiac muscle with oxygenated blood. E The valve that prevents the backflow of blood from the ventricle that contains oxygenated blood.

(a)

Examination of the transplanted hearts showed that the hearts in group A had significant damage to their coronary arteries, whereas in group D these blood vessels appeared normal.

Explain the importance of the coronary arteries of the heart.

[ 3 ]

[Maximum number: 4]

Fig. 2.1 is a diagram of a vertical section through a healthy mammalian heart.

Fig. 2.1

(a)

(i)

Label the two chambers of the heart by writing in the boxes provided on Fig. 2.1.

[ 1 ]

(b)

Match the one correct area from A to G on Fig. 2.2 with each of the congenital heart diseases.

The first one has been completed for you.
patent ductus arteriosus A
pulmonary stenosis
coarctation of the aorta
ventricular septal defect

[ 3 ]

[Maximum number: 13]

Fig. 3.1 is a vertical section of the heart. The regions concerned with initiating and conducting impulses are shown.

Fig. 3.1

(a) Name chamber P and blood vessel Q.

P

Q
(b) Describe how the sinoatrial node (SAN) and Purkyne tissue, shown on Fig. 3.1, are involved in the initiation and co-ordination of the contraction of the heart.

SAN

Purkyne tissue
(c) The heart forms part of a closed double circulation in mammals.

Explain what is meant by a closed double circulation.
(d) The blood in the pulmonary vein has travelled through the capillary network in the lungs, where gas exchange has taken place.
(i) Describe the process of oxygen transfer between the alveolus and the blood in the surrounding capillary.
(ii) When a person starts to smoke cigarettes, one immediate effect is a decrease in the oxygen that is taken up in the lungs.

Explain why this is so.

(a)

The circulatory system of mammals is a double circulation.

[ 3 ]

(i)

Fig. 3.1 is a photograph showing one valve in the mammalian heart.

Fig. 3.1

Identify the structures labelled A in Fig. 3.1 and describe their role during the cardiac cycle.
structure A
role of structure A

[ 3 ]

[Maximum number: 3]

Fig. 4.1 is a diagram of a section through a mammalian heart.

Fig. 4.1

(a)

Use a label line and the appropriate letter to label each of the following on Fig. 4.1:

W right atrium
X tricuspid valve
Y aorta.

[ 3 ]

[Maximum number: 4]

Some people who are infected with HIV develop HIV/AIDS.

(a)

A person infected with HIV may develop a heart condition called cardiac tamponade.

The pericardium is a thin sac surrounding the heart, as shown in the healthy heart in Fig. 4.2. When a person develops cardiac tamponade, the pericardium starts to fill with blood. This prevents the ventricles functioning efficiently.

Fig. 4.2

People with cardiac tamponade experience a variety of symptoms including low blood pressure and an increased breathing rate.

Suggest why a person with cardiac tamponade would experience symptoms of low blood pressure and an increased breathing rate.

[ 4 ]

(a)

Fig. 5.1 shows a drawing of an external view of a mammalian heart.

Two cross-sections were made of the heart:
- section 1 was made across the line A-B.
- section 2 was made across the line C-D.

Drawings of the two sections were viewed from above as shown by the arrow on Fig. 5.1. Fig. 5.2 is a drawing of section A-B. Fig. 5.3 is a drawing of section C-D.