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.

Afferent and Efferent - Keeping Them Straight

I keep these straight by putting it in alpabetical order. The senses come first so they begin with any "A." After you sense something you move. The movement comes second so hence the "E."

Parasympathic Vs. Sympathic

These are both sections of the autonomic nervous system.
The parasympathic is referred to as the rest and digest system. It regulates resting functions such as digesting food or emptying you urinary bladder.

The sympathetic is referred to as the fight or flight system. This system prepares you for physical activity. It prepares you to battle or to run.

The Nervous System Breakdown

The nervous system breaks down into the central nervous system or CNS and the peripheral nervous system or PNS. The CNS contains the brain and spinal cord. The PNS contains the cranial nerves, spinal nerves and peripheral nerves.

The PNS breaks down into the sensory division or afferent pathway and the motor division or efferent pathway. The sensory division brings information in. The motor division sends information out. The motor division breaks down into the Autonomic nervous system and the somatic nervous system or voluntary section. The autonomic breaks down into the sympathetic division and the parasympathetic division.

The Somatic controls the skeletal muscles. The autonomic controls smooth muscle, cardiac muscle, and glands.

The sensory division is the sense it division. When you use your senses you are using this division. The motor division is the response team. It sends a response to your muscles and glands to respond to what you sense.

The spinal cord is the major connector between the PNS and the CNS.