Answer to Case 694

The following excellent answer to this week ' s case is by our guest author, Jacob Rattin (@eternalstudying), medical student and future pathologist. Hopefully we will be able to recruit him to my residency program at Mayo Clinic!Answer to Parasite Case of the Week694: BAL showing a ciliated respiratory epithelial cell exhibiting ciliary movement.If you reach back into your memories from undergrad cell bio, motile cilia contain “9+2” axonemes made up of 9 doublet microtubules and a central pair of microtubule singlets. The peripherally located “9+2” doublets are associated with several accessory proteins, with dynein arms being most relevant to us in this case. The dynein arms provide ATP-dependent motor function, with hydrolysis of ATP resulting in sliding of the axoneme and ciliary movement, which is what you are seeing in the video. The respiratory epithelial cell does not have to be a part of the tissue to exhibit their back-and-forth motion. If ATP is available for hydrolysis, the dynein arms will provid e ciliary movement!As a reminder, ciliated epithelium can be found in the following regions:• Upper respiratory tract• Fallopian tube and parts of the endometrium • Ependymal cells that line the ventricles in the brain • Caput epididymis/efferent ducts• Locations in which ciliary metaplasia has occurredSome folks on Twitter, LinkedIn, and in the comments section of this blog were thinkingLophomonas blattarum, a multiflagellate protozoan that o...
Source: Creepy Dreadful Wonderful Parasites - Category: Parasitology Source Type: blogs