Title: Anatomy / 12 Eye

Q: Eyeball (Layers, optic apparatus, Aqueous fluid)
A: The eyeball is a 3 layered hollow sphere
Layers:
- Tunica fibrosa bulbi (Outer layer): sclera, cornea, and conjunctiva;
- Tunica vasculosa bulbi (Middle layer): choroidea, iris, and ciliary body.
- Tunica interna bulbi (Inner layer): retina
Optic apparatus:
- Cornea
- Anterior eye chamber
- Iris
- Posterior eye chamber (including the lens and ciliary body with zonular fibers)
- Vitreous body
Aqueous fluid (humor):
- Is essential for maintaining intraocular pressure within the eye

Q: internal
eye muscles and their tasks
A: Dilatator pupillae muscle: task is to cause mydriasis (= Pupillenerweiterung);
Sphincter pupillae muscle: task is to cause miosis (= Pupillenverengung);
Ciliar muscle: primary task is accommodation, which allows the eye to change its focus between distant and near objects.

Q: Retina (Parts/Regions, Cells)
A: Parts/Regions:
Central Fossa: located at the background of the eye, highest concentration of cone cells, aligned with the visual axis;
Papilla (= Blindspot): papilla of the optic nerve, packed with nerve fibers --> no photoreceptors
Cells of the retina:
- Rod cells: for dim light & black-white vision;
- Cone cells: for bright light and colors;
- bipolar cells: transmit signals from photoreceptors to ganglion cells;
- ganglion cells: axons from the optic nerve;

Q: external eye muscles
A: Muscles
- 4 recti muscles (superior, inferior, lateral, medial);
- 2 oblique muscles (superior, inferior);
- levator palpebrae superioris

Q: Accessory structures (eyelid structures, lacrimal glands and lacrimal structures)
A: Eyelid Structures
- Tarsus: The plate of dense connective tissue that gives the eyelids their shape and firmness;
- Glands of the eyelid:
- Meibom glands: Talg-glands at the rim of the eyelids;
- Zeis glands: Talg-glands associated with the eyelashes;
Lacrimal Glands & Structures
- Lacrimal glands: Produce tears to lubricate the eye;
- Lacrimal structures: The system of ducts and canals responsible for the drainage of tear fluid;