Question 22M.1A.SL.TZ2.26
| Date | May 2022 | Marks available | [Maximum mark: 1] | Reference code | 22M.1A.SL.TZ2.26 |
| Level | SL | Paper | 1A | Time zone | TZ2 |
| Command term | Question number | 26 | Adapted from | N/A |
The light micrograph shows two blood vessels, an artery and a vein, in transverse section.
[Source: Columbia Center for New Media Teaching and Learning, n.d. Epithelium: Simple Squamous Epithelium. [image online] Available at: http://www.columbia.edu/itc/hs/medical/sbpm_histology_old/lab/lab02_squamous.html [Accessed 29 November 2019].]
What explains the different shapes of these blood vessels?
A. Arteries do not have valves.
B. Muscle cells are found only in the walls of veins.
C. Arteries have a larger lumen-to-wall thickness ratio.
D. There are fewer elastic fibres in the walls of veins.
[1]
D
Very few candidates answered this correctly with many incorrectly answering C, that arteries have a larger lumen-to-wall thickness ratio than veins. The question was taken from 6.2 Identification of blood vessels as arteries, capillaries or veins from the structure of their walls.
