8.1. The circulatory system
A subsection of Biology, 9700, through 8. Transport in mammals
Listing 10 of 175 questions
Mammals have a closed double circulation system. Explain what is meant by a closed double circulation. Table 1.1 shows some structures in the mammalian circulatory system. Complete Table 1.1 to show the sequence of structures through which blood flows, starting with the pulmonary vein. Use the numbers 2 to 5 to indicate the correct sequence. Table 1.1 structure sequence of blood flow left ventricle vena cava pulmonary vein aorta right atrium Explain why arteries have thicker walls than veins. Smoking causes carbon monoxide and nicotine to enter the blood. Describe the short-term effects of each of these substances on the cardiovascular system. carbon monoxide nicotine
9700_s17_qp_23
THEORY
2017
Paper 2, Variant 3
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The mammalian circulatory system is described as a closed double circulation. Explain why it is called a closed and double circulation. closed double 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 . is a drawing of section A–B. is a drawing of section C–D. A B C D A B C X Y D Name structures 1, 2 and 3, as shown in . Explain why the wall of chamber Y is thicker than the wall of chamber X, as shown in . Explain how the contractions of the chambers of the heart are coordinated during one cardiac cycle.
9700_s19_qp_21
THEORY
2019
Paper 2, Variant 1
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Questions Discovered
175