Ciliary Body

Question 1

What is the ciliary body in general?

Answer 1

Ring like structure behind the iris and surrounding the crystalline lens

Question 2

What are the two regions of the ciliary body?

Answer 2

• pars plicata

- pars plana

Question 3

Describe the pars plicata location and what it contains

Answer 3

• wider, anterior portion
• contains ciliary processes that extend into the posterior chamber, space between the processes is called valleys of Kuhn

Question 4

What are the valleys of kuhnt?

Answer 4

Regions between the ciliary processes

Question 5

Where is the pars plana?

Answer 5

• it is the flatter region

- extends from posterior of the pars plicata to the ora serrata

Question 6

What are the dentate processes of the ora serrata? What are oral bays?

Answer 6

• dentate processes are forward pointing spices of the ora serrata (serrated pattern). They are elongation of retinal tissue that expand into the pars plana
• oral bays are the regions between the dentate processes

Question 7

What are zonule fibers? How do they attach? What do they assist in?

Answer 7

• fibers attach the ciliary body and the lens
• some insert into internal limiting membrane of pars plana and travel through valleys of kuhnt of plicata.
• some attach directly to valleys
• assist in lens change in accommodation

Question 8

What are the layers of the ciliary body from superficial to deep?

Answer 8

1. Supraciliaris
2. Ciliary muscle
3. Ciliary stroma
4. Ciliary epithelium

Question 9

What kind of tissue/ cells is supraciliaris?

Answer 9

• loose connective tissue

- pigmented melanocytes, fibroblasts, and collagen bands

Question 10

What is the advantage of the arrangement od the supraciliaris? Disadvantage?

Answer 10

Advantage: allows ciliary body to slide against the sclera without detachment from or stretching the tissue
Disadvantage: allows for the accumulation of fluid within its spaces which could lead to displacement

Question 11

What kind of muscle is the ciliary muscle?

Answer 11

Smooth

Question 12

What are the three directions the ciliary muscle fibers are arranged?

Answer 12

Longitudinal, radial, circular

Question 13

Where does the longitudinal muscle lie?

Answer 13

-adjacent to supraciliaris, parallel to sclera

Question 14

What is the shape of the longitudinal muscle bundles?

Answer 14

• long narrow V
• base is at the scleral spur
• apex is in the choroid

Question 15

Where is the longitudinal ciliary muscle insertion?

Answer 15

-in anterior 1/3 of choroid (muscle stars)

Question 16

Describe the radial ciliary muscle fibers

Answer 16

• wider, shorter Vs

- originate at scleral spur and insert into connective tissue near the base of the ciliary processes

Question 17

Describe circular muscle

Answer 17

• innermost region
• circular bundles with sphincter action
• located near the major circle of the iris

Question 18

Describe the innervation of the ciliary muscle

Answer 18

• para: activates muscle for contraction

- sym: inhibitory effect

Question 19

What type of tissue is the ciliary stroma?

Answer 19

-highly vascularized loose connective tissue

Question 20

Where is the ciliary stroma located? What does it form?

Answer 20

-located between ciliary muscle and epithelial layers and forms the core of each ciliary process

Question 21

What is the ciliary stroma continuous with anteriorly? Posteriorly?

Answer 21

• Anteriorly: continuous with iris stroma

- Posteriorly: thins in the pars plana is continues as choroidal stroma

Question 22

Where is the major arterial circle of the iris located?

Answer 22

-in ciliary stroma anterior to the circular muscle and near the iris root

Question 23

What forms the major arterial circle of the iris?

Answer 23

-anastomoses of the long posterior ciliary arteries and the anterior ciliary arteries

Question 24

Where are the ciliary stromal capillaries located?

Answer 24

• near the pigmented epithelium

- they are large and fenestrated, especially in ciliary processes

Question 25

What structures does the ciliary epithelium line?

Answer 25

-the posterior chamber and vitreous chamber

Question 26

How are the two epithelial layers positionsed?

Answer 26

-apex to apex because of invagination of the neural ectoderm forming the optic cup

Question 27

What connect the two layers of epithelium?

Answer 27

-intercellular junctions, desmosomes, tight junctions

Question 28

What is so important about the gap junctions in the epithelium?

Answer 28

-cellular communication between the layers to form blood aqueous layer

Question 29

What kind of cells are in outer layer of ciliary epithelium?

Answer 29

Pigmented cuboidal joined by desmosomes and gap junctions

Question 30

What kind of cells are in inner layer of ciliary epithelium??

Answer 30

Nonpigmented!

• columnar cells in pars plana
• cuboidal cells in pars plicata

Question 31

Which layer of epithelium forms a site of the blood aqueous barrier? How?

Answer 31

• inner layer
• inter-digitations
• desmosomes, gap junctions, zonula occludens

Question 32

Which layer has cells that are more metabolically active? Why? What does that help?

Answer 32

• inner
• nonpigmented cells are more metabolically active so they secrete more of aqueous humor components and serve as diffusion barrier between blood and aqueous
• non pigmented have more mitochondria!!!!

Question 33

What is the function of the ciliary body?

Answer 33

Produces and secretes aqueous humor

-musculature causes accommodation and can affect aqueous outflow