This 60-year-old patient presented with complaints of a one-year history if intermittent pain and discomfort (burning and shooting) involving bilateral feet, legs and hands, and progressive distal leg muscle weakness.
What are the multiple small circular structures (several marked with arrows) within the cross section of the this axon?
A. Neurofilaments
B. Myosin
C. Centrioles
D. Microtubules
Figure 1: electron microscopy 15000x original magnification
Answer: Microtubules
The structures indicated by arrows are microtubules. Microtubules are part of the intracellular transport machinery involved in the delivery and distribution of cellular cargos, including anterograde and retrograde transport within peripheral nerve axons. Please see references / additional reading.
Reference(s) / additional reading:
Dent EW, Baas PW. Microtubules in neurons as information carriers. J Neurochem. 2014 Apr;129(2):235-9. doi: 10.1111/jnc.12621. Epub 2013 Dec 11. PMID: 24266899; PMCID: PMC3979999.
Barlan K, Gelfand VI. Microtubule-Based Transport and the Distribution, Tethering, and Organization of Organelles. Cold Spring Harb Perspect Biol. 2017 May 1;9(5):a025817. doi: 10.1101/cshperspect.a025817. PMID: 28461574; PMCID: PMC5411697.
Roll-Mecak A. How cells exploit tubulin diversity to build functional cellular microtubule mosaics. Curr Opin Cell Biol. 2019 Feb;56:102-108. doi: 10.1016/j.ceb.2018.10.009. Epub 2018 Nov 20. PMID: 30466050; PMCID: PMC7214606.
Quick note: This post is to be used for informational purposes only and does not constitute medical or health advice. Each person should consult their own doctor with respect to matters referenced. Arkana Laboratories assumes no liability for actions taken in reliance upon the information contained herein.
