3.2 Pathophysiology of the Eye - Brisket

booooo

sebaceous glands produce the ____ components of tears

protective lipid

________ glands produce the protective lipid components of tears

sebaceous

name the three sebaceous glands that make tears

glands of zeis

glands of moll

meibomian glands

wehre are glands of zeis found

base of eyelash hair follicle

where are glands of moll found

base of eyelash

where are meibomian glands found

inner rim of the eyelid

eyelids function

protection, moisture, tear production, tear spreading

the bulbar conjunctiva cover the …

sclera

the palpebral conjunctiva lines the …

eyelid

the palpebral conjunctiva is continuous with …

the corneal epithelium

what is the fornix

the space formed at reflection of bulbar and palpebral conjunctivae

what part of the eye makes the aqueous component of tears?

Lacrimal apparatus

what part of the eye drains tears from eyes?

Lacrimal apparatus

function of the Lacrimal apparatus

Produces the aqueous component of tears; drains tears from eye

tears have layers (like ogres), describe the outer layer

lipid layer made by the eyelid sebaceous glands

tears have layers (like ogres), describe the aqueous layer

thick, made by the lacrimal gland

contains salts, lysozymes and other proteins

tears have layers (like ogres), describe the inner layer

mucin layer made by specialized cells in the conjunctiva and corneal epithelium

what is the purpose of tears

Protects, cleans, lubricates, and moistens the eyeball

what type of innervation controls tears

parasympathetic

anticholinergic drugs can ____ tear production

decrease

tears pathway

pass through two lacrimal puncta into canaliculi which drain into the lacrimal sac; the nasolacrimal duct carries tears to the nasal cavity

the eye is made of ____ layers (tunics)

3

the outside layer is called the …

fibrous tunic

what two structures make up the fibrous layer of the eye

the sclera and the cornea

describe the sclera

avascular

white of the eye

dense with collagen fibers

protective

site of muscle attachment

what part of the eye is the site of muscle attachment?

sclera

describe the cornea

1. vascular

2. physical characteristics

1. avascular

2. transparent and made of five layers

what part of the eye is the major refractory structure?

cornea

what part of the eye is responsible for the majority of the eye focusing?

cornea

what is the role of the cornea?

major refractory structure

majority of the eye focusing

what is the limbus

transitional zone where the cornea meets the sclera

the limbus contains which structures (3)

bulbar conjunctiva

Trabecular meshwork

Canal of Schlemm

what is the middle layer of the eye called

the vasucalr/uvea layer

the vascular/uvea layer of the eye contains what three structures

choroid, ciliary body, and iris

describe the choroid characteristics

hella vascular

melanocyte produced melanin absorbs light rays

what part of the eye prevents light scattering?

choroid

function of the choroid?

prevent light scattering

describe ciliary bodies

makes the aqueous humor

zonular fibers that attach to the lens

ciliary muscle that alters the shape of the lens

where is the lens

posterior to the iris/pupil

describe the lens

crystallin proteins arranged like onion layers

held in place by zonular fibers;

describe the iris

Stroma consisting of melanocytes (number determines eye color)

which part of the eye has the pupille muscles?

iris

function of pupillae muscles

control the size of the pupils

which part of the eye is responsible for fine focusing?

the lens

what is the function of the lens?

fine focus

decreased ability to fine focus by the lens is a condition called…

presbyopia

what is presbyopia?

decreased ability to fine focus by the lens

describe the Pupil

hold defined by the iris

appears black due to pigmentation of choroid and retina

size is controlled by pupillae muscles

the interior of the eye consists of two fluid filled cavities, what are tehy

anterior and posterior cavity

the anterior cavity contains a ____ fluid called the ________

clear watery

aqueous humor

the anterior cavity is divided into _____ chambers

2

the anterior cavity is divided into two chambers, name them

anterior and posterior

where is the anterior chamber of the anterior cavity

bt the cornea and iris

where is the posterior chamber of the anterior cavity

between the iris and the vitreous/posterior chamber

the posterior cavity is the _____

vitreous chamber

which cavity of the eye is divided into two chambers?

anterior

the posterior cavity is filled with…

the vitreous humor

describe the vitreous humor

jelly/watery

contains hyaluronic acid and collagen fibers

the posterior cavity of the eye occupies _____ of the eyeball

4/5

the posterior cavity of the eye maintains…

eye shape

the posterior cavity of the eye holds the ______ against the _______

retina against choroid

the posterior cavity of the eye contains ____to clear debris

phagocytic cells

describe the Aqueous humor physical characteristics

clear fluid

serum ultrafiltrate

Aqueous humor fills the…

anterior and posterior chambers (anterior compartment) of the eye

Aqueous humor is made by…

ciliary body epithelium

Aqueous humor function

Provides nutrients, removes wastes, transports neurotransmitters to avascular lens and cornea.

Maintains structural integrity of ocular structures via intraocular pressure (IOP)

How is the Aqueous humor made:

step 1:

ciliary body epithelial cells actively secrete Na and bicarbonate

How is the Aqueous humor made: ;

step 1: ciliary body epithelial cells actively secrete Na and bicarbonate

step 2:

osmotic gradient is formed

How is the Aqueous humor made: ;

step 1: ciliary body epithelial cells actively secrete Na and bicarbonate

step 2: osmotic gradient is formed

step 3:

pulls water from the ciliary stromal ultrafiltrate

How is the Aqueous humor made: ;

step 1: ciliary body epithelial cells actively secrete Na and bicarbonate

step 2: osmotic gradient is formed

step 3: pulls water from the ciliary stromal ultrafiltrate

step 4:

puts water into the posterior chamber of the anterior cavity

How is the Aqueous humor made: ;

step 1: ciliary body epithelial cells actively secrete Na and bicarbonate

step 2: osmotic gradient is formed

step 3: pulls water from the ciliary stromal ultrafiltrate

step 4: puts water into the posterior chamber of the anterior cavity

step 5:

the AH is made! (woo!)

Carbonic anhydrase (primarily isoenzyme type II), α and β adrenergic receptors, and sodium- and potassium-activated adenosine triphosphatases are expressed by __________ and are involved in sodium and bicarbonate secretion.

ciliary epithelium

which receptors does the ciliary epithelium express that are involved in Na and bicarb secretion?

Carbonic anhydrase (primarily isoenzyme type II),

α and β adrenergic receptors

sodium- and potassium-activated adenosine triphosphatases

what is the major contributor to aqueous humor formation?

Active transport by non-pigmented epithelial cells

Energy required for active transport is generated by ATP hydrolysis to ADP, mediated by the enzyme Na-K-ATPase, where is this enzyme found?

on both pigmented and non-pigmented ciliary epithelia

Carbonic anhydrase, an enzyme also found in pigmented and non-pigmented ciliary epithelia, mediates ______

bicarbonate transport across ciliary epithelium

How does Carbonic anhydrase, an enzyme also found in pigmented and non-pigmented ciliary epithelia, mediates bicarbonate transport across ciliary epithelium?

via hydration of CO₂, forming HCO₃⁻ and protons

Bicarbonate formation regulates pH for optimal active ion transport, which influences________ by affecting sodium.

fluid transport

molecules actively transported across epithelium via chloride channels include…

Chloride

ascorbic acid

certain amino acids

Active transport produces an _____ across the ciliary epithelium

osmotic gradient

Active transport produces an osmotic gradient across____

the ciliary epithelium

Active transport produces an osmotic gradient across the ciliary epithelium, promoting _______ via ultrafiltration and diffusion

the movement of other plasma components

Active transport produces an osmotic gradient across the ciliary epithelium, promoting the movement of other plasma components via ________

ultrafiltration and diffusion

Aqueous humor exits the anterior chamber by two routes, what are they?

conventional and unconventional

describe the conventional outflow pathway for the AH

trabecular network to the canal of schlemm

describe the unconventional outflow pathway for the AH

through ciliary body and suprachoroidal pathway

Cholinergic agents (pilocarpine) ______ outflow by physically opening the meshwork pores secondary to ciliary muscle contraction

increase

how do Cholinergic agents (pilocarpine) increase outflow?

by physically opening the meshwork pores secondary to ciliary muscle contraction

ROCK inhibitors enhance the _____ outflow through trabecular meshwork.

aqueous humor

Prostaglandins remodel meshwork extracellular matrix, ______ mainly uveoscleral outflow.

increasing

Uveoscleral aqueous humor outflow is increased by ______

prostaglandin analogs and α2 adrenergic agonists.

Novel adenosine receptor agonists, cannabinoids, serotonin agents, and dopamine agonists increase aqueous humor outflow, ________ IOP.

reducing

IOP is not constant and changes with ….

pulse, blood pressure, forced expiration or coughing, neck compression, and posture.

T or F:

IOP is constant

F

name drugs that can increase IOP

all steroids

anticholinergics

succinylcholine