8. Transport in mammals
A section of Biology, 9700
Listing 10 of 589 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
View
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
View
shows four types of cell that can be seen in a prepared slide of blood taken from a mammal. Identify the four types of cell shown in . Write the name of the cell type on the answer line provided by each cell in . During systole and diastole of the cardiac cycle, changes in blood pressure occur in the four chambers of the heart. shows changes in the blood pressure in the left side of the heart and the aorta during one cardiac cycle. blood pressure / kPa time / s –2 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 With reference to the blood pressure changes shown in : • state the maximum blood pressure reached in the left ventricle kPa • state the time at which the bicuspid (left atrioventricular) valve closes. s Chronic obstructive pulmonary disease (COPD) can cause a condition known as pulmonary hypertension. This involves an increase in systolic blood pressure in the right ventricle and in the pulmonary arteries. is a summary of some of the events that can result from COPD. COPD chronic alveolar hypoxia blood vessels leading to gas exchange areas decrease in lumen diameter (pulmonary vasoconstriction) pulmonary hypertension loss of alveolar capillaries Chronic alveolar hypoxia describes a condition where the partial pressure of oxygen in the gas exchange regions of the lungs is always lower than normal. Explain how COPD leads to chronic alveolar hypoxia. Explain how the loss of alveolar capillaries affects the functioning of the lungs in a person with COPD.
9700_s21_qp_23
THEORY
2021
Paper 2, Variant 3
View
Questions Discovered
589