# Explain how the structure of an artery is adapted to withstand and regulate the high-pressure blood flow it receives from the heart.

> IB DP Biology Higher Level (2023 syllabus) — B3.2 Transport · Explain · 4 marks

## Mark scheme (4 marks)

1. Thick muscular (smooth muscle) wall / tunica media is thick, allowing the artery to withstand high pressure without rupturing
2. Abundant elastic fibres / elastic tissue in the wall allows the artery to stretch (recoil) as pressure pulses pass, dampening the pulse and maintaining continuous flow
3. Smooth muscle in the wall can contract (vasoconstriction) or relax (vasodilation) to regulate blood flow / blood pressure to different organs
4. Narrow lumen (relative to wall thickness) maintains high pressure / a smooth endothelium (tunica intima) reduces friction to allow efficient blood flow

## Related

- [Revision notes for IB DP Biology Higher Level (2023 syllabus)](https://www.gradenine.co.uk/learn)
- [How to answer "Explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
- [Practice this with AI marking (free)](https://www.gradenine.co.uk/start)

---
Source: [GradeNine](https://www.gradenine.co.uk/q/explain-how-the-structure-of-an-5ae68e7b) · Published by Druglandscape Ltd.