Floaters in the eye

The floaters you see in your field of vision when you get very tired are proteins in your vitreous humor. They cause the dark spots in your vision by blocking the images from reaching your optic disc.

The Eye

There is an anterior and posterior segment. Iris separates the anterior segment into the anterior and posterior chambers.

The eye is covered by the sclera.

We do not make more vitreous humor which is in the posterior segment of the eye.

We do make more aqueous humor which is in the anterior segment of the eye. It is like blood plasma. The body is always making more and it is always circulating.

Parasympathic

The parasympathic preganglion is always excitatory. I think of this as the first is excited to meet the second because they are a "para"(pair).

Vagus

90% of all parasympathic activities are regulated by the Vagus nerve, cranial nerve #10.