They surround the follicle's outermost layer, the basal lamina, and undergo cytodifferentiation to become the theca externa and theca interna.
Diseases which may be diagnosed by an otoscope include otitis media and otitis externa, infection of the middle and outer parts of the ear, respectively.
Ear mites can cause otitis externa; ticks and fleas can also live in dogs' ear canals.
The first layer is the lamina rara externa, adjacent to the podocyte processes.
It lies between the tunica intima on the inside and the tunica externa on the outside.
The theca are divided into two layers, the theca interna and the theca externa.
The host soon moults and a new young externa, budded from the interna, emerges from the host's body.
The host treats the externa as if it were its own egg sac.
