Solved 2017 Question Paper ICSE Class 10 Biology — Question 9
Back to all questionsQuestion 6(a)
The diagram given below represents a section of the human heart. Answer the questions that follow: [5]
(i) Which parts of heart are in the diastolic phase? Give a reason to support your answer.
(ii) Label the parts numbered 1 and 2 in the diagram. What type of blood flows through them?
(iii) What causes the heart sounds 'LUBB' and 'DUP'?
(iv) Name the blood vessels that supply oxygenated blood to the heart muscles.
(v) Draw neat labelled diagrams of a cross section of an artery and a vein.
(i) In the diagram, ventricles are in the diastolic phase. The reason is that the arrows are shown from atria to the ventricles. It indicates that tricuspid and bicuspid valves are open and the blood is flowing from the atria to the ventricles. During this, the pressure in the ventricles falls and hence they are in the diastolic phase.
(ii) The parts numbered 1 and 2 are:
- 1 → Pulmonary artery, Deoxygenated blood.
- 2 →Pulmonary veins, Oxygenated blood.
(iii) The first sound "LUBB" is produced when the atrio-ventricular (tricuspid and bicuspid) valves get closed sharply at the start of ventricular systole. The second sound "DUP" is produced when at the beginning of ventricular diastole, the semilunar valves at the roots of aorta and pulmonary artery get closed.
(iv) Coronary arteries supply oxygenated blood to the heart muscles.
(v) Below diagrams show the cross section of an artery and a vein:
