OPTM4102 Ciliary Body and Aqueous Humour PDF

O PTM4102 Ciliary body and a que ous humour Dr. Jason Charng [email protected] A cknowle d g e m ent of country Th e Univ ersity o f W est ern A ustr a li a a c kn o wl e d g es th a t its c a m p us is situ a t e d o n N o o n g...

O PTM4102 Ciliary body and a que ous humour Dr. Jason Charng [email protected] A cknowle d g e m ent of country Th e Univ ersity o f W est ern A ustr a li a a c kn o wl e d g es th a t its c a m p us is situ a t e d o n N o o n g a r l a n d , a n d th a t N o o n g a r p e o p l e r e m a in th e sp iritu a l a n d c ultur a l c ust o di a ns o f th e ir l a n d , a n d c o ntin u e t o pr a c tis e th e ir v a lu es, l a n g u a g es, b e li e fs a n d kn o wl e d g e. Artist: Dr Richard Barry Walley O AM Objectives Ciliary body anatomy Accommodation Aqueous humour production and drainage Ciliary body ** AT Part of O middle layer of the eye. uvea Anterior aspect at corneoscleral junction and attached to iris Beneath the sclera 5 layers (superficial → deep): supracillaris, ciliary muscle, ciliary stroma, pigmented epithelium, non-pigmented epithelium (inners (outer). Ciliary body – Pars plicata Anterior ciliary body Contains ~70 ciliary processes (each ~2 mm long, 0.5 mm wide, 1 mm deep), arranged radially Produces aqueous humour Ciliary body – Pars plana Connection between pars plicata Posterior ciliary body & Ora serrata. Flatter, extends from pars plicata to ora serrata Retinal extension into the pars plana is called dentate - ( process - Ora serrata => eyed of the retina - it's part of the retina but does not provide vision. Serrated junction between retina and ciliary body ~5 mm anterior to equator https://entokey.com/retinal-detachment-9/ Ciliary body – supraciliaris => most anterior layer of the ciliary Junction between ciliary body and sclera body. Ribbons of connective tissue Contains large amount of CT. Also contains fibroblasts, melanocytes Allows contraction of the ciliary muscle without detachment from sclera Ciliary body – ciliary muscle 3 muscle groups ~ Longitudinal/meridional/Brucke’s muscle Closest to sclera Tendon attaches to scleral spur ~ Radial ~ Circular/Muller’s muscle O Anterior and inner portion of ciliary body Work in unisen Closest to lens to move the Sphincter in muscle In accommodation ciliary to shift genal parasympathetic >> sympathetic the muscle twards the less - innervation ~ Ciliary muscles move anterior to lens, less zonular fibre contraction, lens bulge (accommodate) Accommodation => the process allows us to focus that are close on the object - F lead to the tension muscles contract towards the lens - in the lens allows it ciliary all zonules relaxation of. subsequently allow to bowge 1343). Lens Zonules/Zonule of Zinn Gateene Connect ciliary body to lens the Posteriorlen actingon Forces captural.. Originate from pars plana anterior AZ, anterior zonule; EZ-MZ, equatorial and meridional zonule; PZ, posterior zonule; ( AHM, anterior hyaloid membrane; PZ-HM, posterior zonule embedded in the hyaloid Consists of fibrillin fibres membrane. ThechangespanthePosteriolrensarr in ee the anterior anterior part. Tonules. directly linked btw Az is L & CB , :. any contraction or relaxation of CB will captural directly act on anterior lens. ↓ in contrast force transmitted from the The CB to the posterior lens via the pz https://pubmed.ncbi.nlm.nih.gov/17065477/ will be mediated by the hyaloid membrane. Neural control of accommodation. through convergence travel Medial Visual pathway e signal to the result travel through Blur signal → primary visual CHI Then ~ rectics , adducting cortex → pretectal area→ eye I Edinger Westphal nucleus Lin the Mid-biain). O Two signals are then sent then activate ciliary muscle in the anterior eye. Then start accommodation * ~ One signal via parasympathetic Prosses Similar with L pathway to the ciliary ganglion and signal will travel > - eye construction. ciliary muscle (accommodation), through CNII also results in pupil constriction A ~ Other signal via CNIII to medial rectus (convergence) Accommodation/near reflex (accommodation + pupil + convergence) https://www.youtube.com/wat ch?v=-BMW3vBTFLk Accommodation and Pupil reflex convergence reflex  Ciliary muscle receptors parasympathetic W Muscarinic Ms Receptor Tris sphincter muscle contains dilator muscle adrenergiz & receptor Dominated by muscarinic sympathetic iris contains , M3 receptors with adrenergic β2 receptor input In clinic, three common effects Pupil dilation blocking diagnostic drugs are: greater than O are muscrinic accomandation antagonist~Tropicamide (anticholinergic, effect - -. - for pupil dilation > cycloplegic) ↓ - muscrinic ~Cyclopentolate => as greater cycloplegi ceffectionen https://www.kemunited.com/2020/03/ophthalmology-drugs.html antagonist (anticholinergic, cycloplegic) blockage) use with contains. sometime muscles Tropicamide ~Phenylephrine (adrenergic α to Ciliary 1 M3 furthur dilate Tropicamide - - muscrinergic. eye bu agonist) Dilate = eye activating thereceptor causing via muscle... not X , - sphincter in the dilator act on the (N) & Pheny lephrine be no < , receptor found in ciliary muscledrenergic B2. muscle muscle (x , ). cloplegia dilator act on close because accommodation is. impaired Tropicamide side effect Can't see things up : retraction use when want to preform Cycloplegia Cyclopentolate : ↓ Ciliary stroma the nerves Anterior surface of the i iris has no epithelirial Substances release into the ciliary covering. body stroma will supports. matric that contains loss CT vessels within have access to the chamber by diffusing from ciliary body & blood surface then to the chamber Lies over the ciliary muscle stroma to the Tris. , # Heavily pigmented, How nutrients provided to the cornea. vascularised and innervated The core of each ciliary process unit Is continuous with the choroid posteriorly and the iris anteriorly Ciliary beds within stroma fenestrated – allow exchange between blood and stroma Ciliary epithelium Gap junctions Punctum adherens Site of aqueous production Also facilitates immune privilege of the eye 2 types, pigmented (inner, - cuboidal) and non- - Pigmented cell pigmented (outer, ° ② columnar/cuboidal) ~ Lie apical side to apical side Non pigmented cell ~ Specialized processes between fight junctions btw non-pigmented ocular blood and within layers form the cells ~ Non pigmented cells contain aqueous barrier. zonula occludens (i.e. tight -- - ↓ junctions) prevent leakage, ocular prevent the blood aqueous barrier leakage of proteins & immune cells ~ Gap junctions allow Zonula occludens,...... Desmosome communication between cells gap junctions, zonula adhaerens https://pubmed.ncbi.nlm.nih.gov/100466/ Aqueous production Aqueous humour is turned over every mins. ↓ contains nutrients for the Labornea. avascular) Production rate ~2.5 µL/min. Turnover ~2.4 µL/min Posterior chamber → anterior chamber → canal of Schlemm produced via z 80-90% volume via active secretion, rest via passive diffusion required energy no. energy Three mechanisms: ~ diffusion (passive), ultrafiltration (passive): capillaries → stroma ~ active secretion: stroma → posterior chamber https://pubmed.ncbi.nlm.nih.gov/32341164/  Passive diffusion => Does not molecules. Rely on transportation of require energy down its concentration gradient. Transportation down concentration gradient travel Across lipid portion of the membrane produces Mainly for lipid soluble substances aqueous in the From capillaries to posterior chamber  particles move through Passive ultrafiltration passive ultrafiltration be small and should have neutral charge. allows T Flow of water and water soluble substances Limited by size and charge of particle Via osmotic gradient or hydrostatic pressure (i.e. blood pressure) Bulk movement of blood plasma into ciliary stroma, via fenestrated capillaries Forms plasma ultrafiltrate reservoir in the stroma ultrafiltration perpales the. 2T The pressure gradient tw blood flow & ciliary body Active secretion Requires energy. ~ 90% of total aqueous formation Contributes to the chemical composition and volume of the posterior chamber aqueous Requires energy Transports selected substances against a concentration gradient Via specific transporters Aqueous production – Step 1 NaCl is transferred from stroma by two sets of electroneutral transporters 1. Na+/H+ and Cl-HCO3- 2. Na+/K+ and 2Cl- Aqueous production – Step 2 Passage of NaCl from PE to NPE cells through gap junctions (free movement)  Aqueous production – Step 3 Primary active: 1) Na+K+ Secondary active: 2) Cl− 3) HCO3− via Cl- exchange 4) H2O diffuses out https://www.youtube.com/watch?v=L4Tbi1ql-tU primary vs secondary active transporter Aqueous production 1. Uptake of NaCl from stroma to PE cells by electroneutral transporters 2. Passage of NaCl from PE to NPE cells through gap junctions (free movement) 3. Release of Na+ and Cl- through Na+/K+ activated ATPase and Cl- channels, respectively 4. Water moves via diffusion through aquaporins Neural control Aqueous production interaction between ~secretion-inhibiting adrenergic α 2 receptors ~secretion-stimulating β-adrenergic receptors Glaucoma medications utilize these receptors to decrease aqueous production Aqueous drainage 2 sites of clearance ~Posterior trabecular meshwork → Schlemm’s canal ~Uveoscleral (~10 % outflow) IOP = aqueous production + clearance https://pubmed.ncbi.nlm.nih.gov/32341164/ Summary Ciliary body structures Accommodation Aqueous humour production – movement of ions and water Aqueous humour drainage