The Nervous System Fetal Pig Dissection Part 6 Hyperpolarization The Cranial Nerves (See Packet) The Brain Your Dissection: Brain Anatomy Arbor Vitae: (Tree of Life) branched white matter within the cerebellum Circle of Willis: arteries supplying blood to the base of the brain Hypophysis: pituitary gland Meninges, Dura Mater, Pia Mater, Arachnoid: membranes covering brain and spinal cord The Eye Backside view Your Dissection Eye Anatomy Sclera: White, outer fibrous layer Choroid: many blood vessels, absorbs stray rays of light Ciliary muscle: controls the shape of the lens Iris: regulates the size of the pupil Vitreous Humor: jelly like fluid behind the lens Eye Anatomy Aqueous Humor: watery fluid between cornea and lens Retina: dark shiny layer