8.3. The heart
A subsection of Biology, 9700, through 8. Transport in mammals
Listing 10 of 173 questions
The sinoatrial node (SAN) and the atrioventricular node (AVN) are two regions of the heart. Outline the roles of the SAN and the AVN in the initiation and control of heart action. shows features that are observed in transverse sections of the three main types of blood vessel. blood vessel wall of three layers thin wall relative to lumen diameter thick wall relative to lumen diameter wall of one layer D E F Complete by stating the type of blood vessel indicated by D, E and F. The inner layer of the walls of D and E is composed of endothelial tissue. List two structural features of this tissue.
9700_m18_qp_22
THEORY
2018
Paper 2, Variant 2
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The diagram shows pressure changes in the left side of the heart and aorta over time. The length of this cardiac cycle is 0.6 s. Points 1, 2, 3 and 4 indicate when atrio-ventricular valves and semi- lunar valves either open or close. 0.6 0.5 0.4 0.3 0.2 0.1 time / s pressure / kPa key left ventricle aorta left atrium What is the total time during one cardiac cycle that the atrio-ventricular valves and the semi-lunar valves are both closed at the same time?
9700_s06_qp_1
MCQ
2006
Paper 1, Variant 0
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Questions Discovered
173