Anatomy

1. BY
Azmat jehan

3.  Aqueous is a clear watery secretion produced
by ciliary processes of ciliary body in the
posterior chamber.
 It fills the anterior and posterior chambers
 It has got a specific composition and it is in a
continues flow

4.  Aqeous humour is formed from blood plasma and
secreated by the nonpigmented cilliary epithelium
.ocular fluid are seperated from blood by barrier
formed by tight junction between epithelial and
endothelial cells called blood aquoes barrier..
 Carbonic anhydrase in humour is present in pigmented
and nonpigmented cilliary epithelium.its inhibits cause
a retention in the rate of entery of sodium and
bicarbonate in to the aquoes ,leading to reduction in
aquoues flow.
 The high level of ascorbic acid in the aqeous humour
sugests that there is an active pump mechanism for its
secretion in to the aqeous.

5. The mechanism of production involves the
following process
 Active transport
 Ultra filtration
 Diffusion

6.  It is a kind of transport that needs energy to
move a substance against its
concentration/electric gradient and requires
celluar energy in the form of adenosine
triphosphate (ATP).
 80% of the production of aqueous is through
this process
 The rate of formation of aques humour is 1 - 2
Ul per mint

7.  The substances transported through active transport in
aqueous are;
 Sodium (Na+)
 Chloride
 Bicarbonate it is produced in the cell (ciliary
epithelium) by the reaction
 CO2+H2O-------------HCO-3+H
 The HCO-3 formed as a result of this secretion moves
in to the aqueous probably through active transport

8.  Amino acids
 Ascorbic acids
 The active transport is not affected by pressure
but is affected by low oxygen, low temperature
and drugs, which inhibit the pump enzymes

9.  It is movement of a substance across a surface
under pressure
 20% of aqueous synthesis is carried out by this
mechanism
 It is a pressure dependent process

10.  In this process substances are pushed out of the
blood across the ciliary epithelium in to the
aqueous
 It depends upon the balance of forces acting on
the blood vessel wall i.e
 Forces moving the substances out

11.  Forces trying to move the substances in
 Blood pressure in ciliary capillaries
 Intraocular pressure
 Pressure of blood proteins

12.  Increased intraocular pressure does not
normally affect the active transport but it does
affect the rate of ultrafiltration

13.  It is a process in which substances move along
their concentration gradient i.e. from higher
concentration to lower concentration
 It plays a minor role in aqueous synthesis

14.  Important substances moved across the
epithelium in this manner are;
 Glucose
 oxygen and
 potassium

15. Substances are secreted by ciliary epithelium in
to posterior chamber through the process of;
1 Active transport
2 Ultrafiltration
3 Diffusion

16.  As it flows along its path substance from the
aqueous get absorbed in to the tissues that it
bathes & supply the metabolic needs to the
following, like the cornea, anterior vitreous, iris
and lens.
 Some substances are added to the flowing
aqueous by these tissues

17.  Therefore the composition of aqueous changes
from one site to another
 On the average it has got the following
composition
 The components can be divided in to
1) Inorganic substances
2) Organic substances

18.  Sodium
 Its concentration is slightly more then that in
plasma
 Potassium
its concentration is almost the same as in plasma
 Chloride
its concentration is higher than that in the plasma

19.  Hydrogen ion
almost the same
 Bicarbonate
slightly less
 Oxygen
less than blood

20.  Glucose
its amount in aqueous is 80% of its concentration
in plasma
 Lactic acid higher than plasma

21.  Proteins
 less than 1% of plasma
 Proteins are big higher molecular weight
substance
 Amino acids
 slightly higher concentration than plasma

22. Aqueous flows through two routes
 Trabecular route (main route)
 Uveoscleral route (minor route)

23. The main anatomical landmarks along the
aqueous outflow tract are
 Trabecular meshwork
 Canal of schlemm(sinus venosus sclera)
 Both located in the iridocorneal angle

24.  It encircles the circumference of anterior
chamber
 It is a meshwork of channels meant for
aqueous outflow
 These channels occupy the angle like a piece of
sponge wedged between the cornea and iris
root,
 The apex is situated at the end of descemets
membranne and the base at the scleral spur.
 Scleral spur is the part of sclera in to which
cilliary muscle inserted.

25.  The trabecular meshwork is a circular
spongyworle of connective tissue lined by
trabeculocytes.theses cells have contactile
properties which may influence outflow
resistance .the also have pagocytic properties .

26.  These channels
communicate with
the anterior chamber
on inner side and
the canal of
schlemm on the
outer side

27.  It is a small channel that runs circularly around
the eyeball at the corneoscleral junction
 On its inner surface the canal of schlemm
communicates with the anterior chamber
through the trabecular meshwork its outer wall
is burried in the stroma of the corneoscleral
limbus.
 The canal of schlemm communicates with the
scleral plexus of veins through small channels

29.  About 25-30 collector chanels arises from
schelms canals and drain in to the deep and
midel scleral venous plexus.about upto 8 of
these chanels drain directly in to the episcleral
venous plexus as aqueous vein

30.  Aqueous after being poured in to the posterior
chamber passes through the pupil to enter the
anterior chamber
It drains through two routes
 Trabecular route
 Uveoscleral route

31.  Most 90% of aqueous flows through this route
 Posterior chamber--------------Anterior chamber-
--------Trabecular meshwork-------Canal of
schlemm------Episcleral veinous plexus

32.  Flow along this route is pressure sensitive
therefore
 Increase episcleral veinous pressure decrease
the flow
 Increase IOP also decreases the flow by making
the canal of schlemm and trabecular meshwork
collapse

33.  It accounts for 10% of aqueous flow
 Along this route aqueous flow from posterior
and anterior chamber and than at the iris root it
trickles down through the ciliary body to the
space between the choroids and sclera

34.  From here aqueous gets absorbed in to veins of
choroids, sclera and cilliary body
 Some aqueous also drains through the iris
 This route is relatively pressure independent
and is not much affected by pressure changes
in IOP and episcleral veinous plexus

35.  Rate of aqueous synthesis 2-3l/min
 Rate of aqueous outflow 2l/min
 Episcleral veinous pressure 20 mm Hg
 Intraocular pressure 11-21 mm Hg

36.  The aqueus humour supplies the metabolic
need of the avascular lens and the cornea.
 It imparts an intraocular pressure to the eyeball
to maintain its shape
 It supplies nourishment to the tissues it baths --
--lens, anterior vitreous, corneal endothelium
and stroma

37.  Provides an optically clear medium of light to
pass through
 In this regard it is part of refractive media of
the eye
 Others are cornea, lens vitreous

38.  Because of its immunological components (e.g
immunoglobulins) it helps in fighting against
infections
 Junction between the cells of ciliary epithelium
and the cells of iris blood vessels do not allow
harmful substances to enter the aqueous and
together make up the blood aqueous barrier