*topic 6 aq humour (part 1)

Question 1

where is aq humour produced?

Answer 1

inner non-pigmented ciliary epithelium on the ciliary processes (pars plicata region) which is located in the ciliary body

Question 2

what is the RI of aq humour? how does aq humour move in the eye?

Answer 2

1.336

it moves according to convection currents

Question 3

What is the source of aq humour (what is it made from)?

Answer 3

source: the ciliary arterial system
aq humour is made from the ciliary arterial blood where the blood plasma (made up of mainly water and plasma proteins) gets converted into aq humour (mainly made of water).

Question 4

where is aq humour produced? what are the 3 processes that produce it?

Answer 4

production of aq humour occurs in the inner non-pigmented ciliary epithelium in the ciliary processes.

the three processes are: diffusion, ultrafiltration and active transport

Question 5

what happens during diffusion? what type of molecules is being transported?

Answer 5

diffusion is the movement of molecules ALONG a concentration gradient
lipid soluble particles are bring transported

Question 6

what happens during ultrafiltration? what type of molecules is being transported?

Answer 6

Ultrafiltration is the movement of smaller molecules across a semi-permeable membrane via hydrostatic force
smaller water soluble particles are being transported

Question 7

what happens during active transport? what type of molecules is being transported?

Answer 7

It is the movement of larger molecules AGAINST a concentration gradient using ATP (requires energy)
larger water soluble particles are being transported

Question 8

what happens after the molecules exit the ciliary processes?

Answer 8

1. transported to the posterior chamber and water follows, forming aq humour
2. aq humour is then transported to anterior chamber via pupil and circulates in the anterior chamber

Question 9

what is the function of aq humour?

Answer 9

provides nutrients and removes waste products from the cornea, iris and crystalline lens (CIC)

Question 10

where is the aq humour drained?

Answer 10

anterior chamber angle

Question 11

what are the structures of the anterior chamber angle in order? (TSSCS)

Answer 11

1. trabecular meshwork (TM) (aq humour exits eye from the ant chamber angle and into TM)
2. schlemm’s canal (SC)
3. scleral spur (SS)
4. Ciliary body (CB)
5. schwalbe’s line (SL) (not really a structure, more like an anatomical landmark)

Question 12

what structures are seen in wide open angle (grade 0/1) and closed angle (grade 3/4)?

Answer 12

wide open angle (grade 0/1):
all structures visible

closed angle (grade 3/4):
only TM or none are visible

Question 13

what is the conventional drainage pathway where 80-90% of aq humour is drained? (ATSCAEA)

Answer 13

1. anterior chamber angle
2. trabecular meshwork
3. schlemm’s canal
4. collector channel
5. aqueous veins
6. episclera
   7/ ant. ciliary veins

Question 14

what is the uveoscleral drainage pathway where 10-20% of aq humour is drained?

Answer 14

1. aq humour drains through face of ciliary body into region posterior to scleral spur (located in apex of anterior chamber)
2. aq flows though ciliary body into suprachoroidal space

Question 15

what is blood aq barrier? where is it found?

Answer 15

it is an anatomical mechanism that prevents exchange of materials between chambers of the eye and blood vessels.
it is found in the non-pigmented ciliary epithelium

Question 16

what are the 2 constituents of the blood aq barrier?

Answer 16

1. tight junctions of the non-pigmented ciliary epithelium

2. junctions of the iris tissues and iris blood vessels

Question 17

what are the 2 functions of the blood aq barrier?

Answer 17

1. maintain clarity of aqueous humour
   this is required for optical integrity of the eye
2. restrict movement of sodium, larger water soluble ions, proteins and other large and medium sized molecules in aq humour