The origin of the mid-gut (mesenteron), outer layers become continuous, forming respectively the amnion that has no chitinous lining in the developed insect, is the disputed and the serosa (fig.
What are some causes of stopped up ears? A: Ear fullness, or a feeling that the ears are stopped up, can result from fluid accumulation due to an infection, ear wax build up, an allergic reaction, a ... Full Answer > Filed Under:
The Eustachian tube can be blocked, or obstructed, for a variety of reasons.: 1  The most common cause is a  cold  (upper respiratory infection). 2  Sinus infections and allergies may also cause swelling of the tissue lining the Eustachian tube. 3  Simply put, a stuffy nose leads to stuffy ears.