Trace events following sinoatrial excitation and interpret pressure changes during contraction and relaxation.
Tę umiejętność sprawdza 14 zadań wzorowanych na arkuszach IB z lat 2022–2025.
During a blood-pressure measurement the cuff is gradually deflated. The graph includes the arterial pressure oscillations. Which pair gives the systolic pressure followed by the diastolic pressure? A. 148 mmHg, then 58 mmHg B. 82 mmHg, then 128 mmHg C. 128…
Explain how specialized heart-muscle cells initiate the heartbeat.
For approximately how long is the left atrioventricular valve open during the 0.90-second model cycle? A. 0.90 s B. 0.54 s C. 0.36 s D. 0.12 s
Two main sounds occur during a cardiac cycle. Outline their causes.
State its function.
Describe the cause of the sound as the ventricles begin to relax.
Explain how stimulation brings about atrial and ventricular contraction.
What is the immediate role of the sinoatrial node in initiating a normal heartbeat? A. It receives each heartbeat from ventricular muscle and then activates the atria B. It prevents nervous or hormonal adjustment of heart rate C. Its excitation spreads through…
The schematic shows the chambers and major connections of a human heart. What are the functions of the structures labelled X and Y? A. X carries blood high in oxygen to the body; Y prevents backflow from the body into the aorta B. X carries blood low in oxygen…
Electrical conduction through the atrioventricular node includes a brief delay. Outline why this delay is useful.
(a) Explain how changes in regulation of the cell cycle can lead to a tumour. (b) Outline the role of the right atrium during the cardiac cycle. (c) Describe carbon-cycle processes that release or consume carbon dioxide.
Calculate the duration for which all four chambers are simultaneously in diastole.
Describe the state of the atrioventricular and semilunar valves at 0.25 s.
This schematic looks across the heart at the level of its valves. During ventricular ejection, what is the state of P, Q and R? A. P open; Q open; R closed B. P closed; Q open; R closed C. P closed; Q closed; R open D. P open; Q closed; R open
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