The sinus (paranasal sinuses) are air cavities within the facial bones They are lined by mucous membranes similar to those in other parts of the airways
The circulation system of the leech is a little bizarre I mean who's ever heard of an animal that sticks its nervous system inside itse blood vessels?? Yet that's exactly how it is The ventral sinus of the leech is made of a tough fibrous material that appears dark green
A connection from one cavity to another or a cavity that is connected to another cavity; usually refers to the air spaces in the skull that connect to the back of the nose
The sinuses (paranasal sinuses) are air cavities within the facial bones They are lined by mucous membranes similar to those in other parts of the airways
{i} (Anatomy) any of several hollow cavities or passages in the body; one of the hollow cavities in the skull that connects to the nasal passages