1. Aqueous Humor, Endolymph, and
Perilymph
By: Christian Kroll

2. What is Aqueous Humor?
• 99.9 % Water
• .1 % Proteins, Glucose, and Electrolytes
• Cellular Debris

3. Functions of Aqueous Humor
• Bringing Oxygen to cells
• Clear medium
• Maintains IOP
• Helps to fight infection

4. Formation of Aqueous Humor
• Diffusion
• Ultrafiltration
• Active Secretion
Pars Plicata
Ciliary Body
Lens
Posterior
Chamber
Suspensory Ligaments

5. Aqueous Humor Flow
Trabecular outflow 90%
Uveoscleral outflow 10%
Anterior
Chamber
Angle

6. Outflows

7. Trabecular Outflow
Guyton R, Hall Textbook of
Medical Physiology
Trabecular
Meshwork
Anterior Chamber
Anterior Chamber
AngleSchlemm’s
Canal
Ciliary
body
Posterior
Chamber
Episcleral v.

10. Uveoscleral outflow- 2 sub flows
Uveoscleral Uveovortex
Passage through
• Root of Iris
• Interstitial Spaces
• Suprachoroidal Space
Passage through
• Iris
• Ciliary Muscle
• To Vortex Veins
Used earlier in life
Pressure Independent

11. Image taken
from Rohit
Rao’s
Presentaion
“Physiology of
Aqueous Humor

12. Clinical Application
Glaucoma
Primary
• Open Angle Glaucoma
• Angle Closure Glaucoma
Symptoms
• Enlarged Eye Ball
• High IOP
• Vision Loss
• Redness
Treatment
• Beta Blockers
• Steroid Eye Drops
• Surgery?
Miller-Keane
Encyclopedia and
Dictionary of Medicine,
Nursing, and Allied
Health

13. Endolymph
Source: Controversial
Created from perilymph
Flow: Controversial
Known Location:
Membranous Labyrinth
High K+
Perilymph
Source: cochlea?
Derived from CSF?
Known Location:
Bony Labyrinth
High Na+

14. Image from
Gilroy et. al
Atlas of
Anatomy 2
ed.

15. Endolymphatic Sac
Oval Window
Ampulla
Endolymphatic Duct
Image from
Gilroy et. al
Atlas of
Anatomy 2
ed.

16. Image from
Gilroy et. al
Atlas of
Anatomy 2 ed.

17. Scala Vestibuli
Scala Media
Scala Tympani
Reissner’s Membrane
Image from Gilroy et.
al Atlas of Anatomy 2
ed.

18. Organ of Corti is bathed
in endolymph
Perilymph different
Why endolymph?
Regulates potassium
flow without using ATP

19. Clinical Application
Meniere’s Disease
Symptoms:
• Vertigo
• Hearing loss
• Ringing in ears
• Pressure in ear
Causes:
Abnormal volume of inner ear?
Treatment:
Medications such
as motion sickness
Fluid Retention Reduction

20. References
Leonard LA, Nilsson SFE, Hoeve JV, Wu S, Kaufman PL, Alm A. 2011. Adler's Physiology of the Eye, 11th
ed, Saunders Elsevier, Philadelphia.
Harris JP and Nguyen QT. 2010. Volume 43, Issue 5. Otolaryngologic Clinics of North America. Saunders,
Philadelphia.
Llobet A , Gasull X , Gual A. 2003. Vol. 18. No. 5. Understanding Trabecular Meshwork Physiology: A Key
to the Control of Intraocular Pressure American Physiological Society., APS, Bethesda.
Ghanem TA, Breneman KD, Rabbitt RD, Brown HM. 2008. Ionic composition of endolymph and perilymph
in the inner ear of the oyster toadfish, Opsanus tau. US National Library of Medicine National Institutes of
Health. 214(1):83-90.
Nin F, Hibino H, Murakami S, Suzuki T, Hisa Y, and Kurachia Y. 2011. Computational model of a circulation
current that controls electrochemical properties in the mammalian cochlea. Proceedings of the National
Academy of Sciences of the United States of America, 10.1073/pnas.1120067109.
Villamarina A, Roya S, Hasballaa R, Vardoulisa R, Reymonda P, Stergiopulosa N. 2012. 3D simulation of the
aqueous flow in the human eye. Medical Engineering and Physics Vol 34. Issue 10.

21. Questions?????