A patient is found to have a systolic blood pressure of 160 mm Hg and a diastolic pressure of 100 mm Hg. (i) What condition does this indicate? (ii) If the arterioles are constricted, explain the mechanism by which this leads to the observed readings.
Generated by claude-sonnet-4-6 · 2026-06-26 01:01 · grounding rag
Model Answer
(i) The readings (systolic: 160 mm Hg, diastolic: 100 mm Hg) are above the normal range (120/80 mm Hg). This condition is called hypertension (high blood pressure).
(ii) Constriction of arterioles increases resistance to blood flow. The heart must pump blood with greater force against this resistance. As a result, the pressure exerted by blood on arterial walls increases during both ventricular contraction (systole) and relaxation (diastole), leading to elevated systolic and diastolic readings.
Source: Chapter 5, Section 5.4.1 — Blood pressure (More to Know box)
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Explanation
- Examiners expect the term hypertension in part (i) — one word/phrase is sufficient for 1 mark.
- For part (ii) (2 marks), two logical steps are needed: (1) constriction → increased resistance, and (2) increased resistance → heart exerts greater force → higher blood pressure. The passage directly states "high blood pressure is caused by constriction of arterioles, which results in increased resistance to blood flow."
- Do not confuse arterioles with arteries; use the correct term from the passage.