Combo with "Eye Histology" and 1 other
3 Layers (Tunics) of Eye
i. Fibrous (external) tunic ii. Vascular (middle) tunic or uvea iii. Nervous tunic (retina)
amacrine and horizontal cells
lateral processing in plexiform layers ________ cells interconnect bipolar and ganglion cells ________ cells interconnect receptor and bipolar cells
crytstallins
lens fibers are filled with groups of proteins called _____.
What are the four parts of the neural retina
outer segment (OS) inner segment (IS) nuclear region and synaptic region What are the four parts of the neural retina
Melanocytes
prevent distortion of image formation by scattered light
pigment epithelium layer of rods and cones outer limiting membrane outer nuclear membrane outer plexiform layer inner nuclear layer inner plexiform layer ganglion cell layer layer of optic nerve inner limiting membrane 1. muller cell 2. bipolar cell 3. horizontal 4. amacrine 5. ganglion
top to bottom then 1-5
-Outer pigment epithelium (non- sensory) -Inner sensory retina or neural retina
what are the 2 layers of the retina?
mitochondria
what do the inner segments have an abundance of?
fovea centralis
what is a shallow depression located about 2.5mm lateral to the optic disc and is the area of the greatest visual acuity
ectoderm
what is the retina derived from?
optic disc or papilla
what is the site where the optic nerve emerges from the retina ans called the blind spot because of the lack of receptors
ganglion neurons
what is the source of axons in the optic nerve?
macula lutea
what is the yellow pigmented zone surrounding the fovea centralis
outer segments
what part of the rods are embedded in the microvilli of pigmented epithelial cells
Iris
*Anterior extension of choroid *Covers lens *FORMS DIAPHRAGM with an APERTURE (PUPIL) *DELINEATES ANTERIOR FROM POSTERIOR CHAMBER
Cornea
A
Cone
Animals that are mainly active at night have retinas with fewer ________ cells than those of animals active during the day.
Anterior Surface
Anterior or posterior surface of the iris ? *Incomplete, fenestrated *Stellate fibroblasts
Posterior surface
Anterior or posterior surface of the iris ? *Inner epithelium - pigmented *Outer layer - dilator pupillae muscle
Stroma
Area of the ciliary body composed of loose connective tissue( elastic fibers, vessels & melanocytes) & ciliary muscles
ganglion cells
Axons of __________ form nerve fiber layer and converge at the optic papilla. They then leave the eye at the optic nerve. (8)
Anterior compartment
B
Bruch's membrane
BETWEEN CHOROID AND RETINAL PIGMENT EPITHELIUM
Lens
C
lens fibers
Cells of the lens elongate to form __________ which comprise the lens
Iris
Contains sphincter pupillae and dilator pupillae muscles in its stroma which control pupillary size.
Accomodation
Continuous changes in the shape of the lens keep images focused on the retina. (a) The lens flattens for distant vision when the ciliary muscles are relaxed and the shape of the ciliary body holds the ciliary zonule taut. (b) To see closer objects, the ciliary muscle fibers contract, changing the shape of the ciliary body, relaxing tension on the ciliary zonule, and allowing the lens to assume the more rounded shape.
1. Canal of Schlemm 2. trabecular meshwork 3. Ciliary muscles
Cut a hole in that box
Posterior compartment
D
cataract -increased opacity of lens-change in solubilty of lens proteins presbyopia -Reduced elasticity of lens, Accommodation for near objects becomes difficult- form of hyperopia
Describe how cataracts and presbyopia differ.
1. Cornea 2. Anterior chamber 3. Pupil 4. Lens 5. Vitreous body 6. Retina
Describe the pathway light travels through the eye.
Retina
E
capsule
Entire lens is contained in a ______________
anterior epithelium
Epithelium is only present in the anterior portion of the lens called the ________________
Optic nerve
F
Retina
Identify R
Sclera
Identify S
Tapetum lucidum
Identify the layer of the choroid that is most central in this slide.
conjunctivitis
Inflammation of the conjunctiva - red eye is called...
Yep
Is the constrictor pupillae a circumfrential muscle located at the pupillary margin?
zonules
Lens held in place by a radially oriented group of fibers, the _____.
photoreceptor cells in rods and cones
Light passes through layers of retina and stimulates __________ (2 and 4)
Anterior corneal epithelium, anterior limiting lamina, substantia propria, posterior limiting lamina, posterior epithelium of the cornea
List the 5 layers of the cornea
ANTERIOR CORNEAL EPITHELIUM BOWMAN'S MEMBRANE CORNEAL STROMA: DESCEMET'S MEMBRANE CORNEAL ENDOTHELIUM
Name the layers of the cornea.
10 - 22 mmHg
Normal intraocular pressure?
Subcapsular epithelium
Part of the lens. Single layer of cuboidal epithelial cells present only on the anterior surface of the lens
Capsule
Part of the lens. Thick basement membrane consists mainly of collagen type IV and glycoprotein
retinal detachment
Pressure in vitreous chamber keeps neural and pigmented areas apposed. Splitting of retina Separation of the photoreceptors from the pigmented epithelium If not re-attached rods and cones degenerate What is your diagnosis???????????????????
lacrimal
Secrete tears to provide: Lubrication Protection of cornea from infectious agents Promotes osmotic balance
between episcleral layer and substantia propria
Tenon's space is the Site of attachment of the extra-ocular muscles. Where is it?
outer fibrous tunic, middle vascular tunic, and the inner retinal tunic
The eye is composed of a lens and three layers: ______, ______, and ____________
vascular supply
The lens loses its ___________ after development
1. stratified columnar epithelium 2. becomes squamous near cornea
The mucin secreting conjunctiva is lined by ____ and becomes the ____ near the cornea.
Outer Limiting Layer
The outer limiting layer is the line of adherent junctions that attach the rod and cone inner segments to the distal ends of the Muller glial cells (red outline).
cilia
The photoreceptor outer segment (OS) of the neural retina are modified ______
Iris
The stroma also contains pigmented cells, melanocytes. Both ciliary processes and the inner surfaces of the iris are covered by a pigmented layer & are continuation of the retina.
tarsal plate
The substance of the eyelid is formed by a thick connective tissue called ____ _____.
Muller cells - glia-like cells
These are supporting cells that extend from the external to internal limiting membranes Support, nourish, and insulate the retinal neurons and fibers
Glaucoma
This condition is associated with : ABNORMALITIES OF DRAINAGE INCREASED INTRAOCULAR PRESSURE
pigmented retinal layer
This layer is a... -Single layer of cells -Esterification of Vitamin A -Synthesize melanin -Connected to adjacent pigment cells by a junctional complex: Blood-retinalbarrier -Phagocytosis of shed tips of rods and cones
anterior corneal epithelium
This layer of the cornea has 5-6 LAYERS OF CELLS, stratified squamous epithelium, Microvilli on superficial cells, Turnover time is 7 days
CORNEAL STROMA
This layer of the cornea has Many layers of regularly organized collagen fibrils (chiefly tropcollagen type I, but also types III, V, and VI collagen). The regular parallel arrangement of the collagen fibers and their small diameter (20 - 60 nm) account for the transparency of the cornea
BOWMAN'S MEMBRANE
This layer of the cornea has homogeneous, collagen fibers, no cells, and provide stability and strength of cornea
CORNEAL ENDOTHELIUM
This layer of the cornea has simple squamous epithelium and dehydrated stroma
DESCEMET'S MEMBRANE
This part of the cornea is posterior limiting lamina with homogeneous, collagen filaments
sclera
This part of the eye is Dense, irregular connective tissue - extension of dura around the brain
orbicularis oculi and levator palpebrae superioris
What 2 muscles are associated with the eyelid?
sclera, cornea, limbus
What 3 things make up the fibrous tunic?
lacrimal glands, lacrimal sac, nasolacrimal duct
What 3 things make up the lacrimal (tear) apparatus?
iridocorneal angle, iris, ciliary body, choroid
What 4 things make up the vascular tunic?
conjunctiva
What Lines the inside of the eyelids and the visible part of the sclera?
lenticular sclerosis and cataracts
What are common defects of the sclera?
rods
What are named for their cylindrical outer segments, have broad receptive fields, Detect motion, and most active at scotopic levels, i.e., when levels of light are low, e.g., night-time or dusk.
Outer Fibrous Middle Vascular Inner nervous
What are the 3 general sections of the eye?
retinal pigmented epithelium, the rods and cones, the ganglion cell layer
What are the 3 most important cell layers of the retina? (out of 10)
Sensory/optical part, non-sensory/ciliary part, iridal
What are the 3 parts of the retina?
oily, aqueous, and mucous portions
What are the 3 portions of tear film?
Suprachoroid layer, vascular layer, tepetum lucidum, choriocapillary layer, basal complex (bruch's membrane)
What are the 5 layers of the choroid?
palpebrae (eyelids), third eyelid and conjunctiva, and the lacrimal apparatus
What are the adnexa or accessory ocular structures?
Area cribrosa
What are the perforations called where the optic nerve penetrates the sclera?
Episcleral layer Substantia propria Suprachoroidal lamina
What are the three layers to the sclera?
bipolar neurons
What connect receptor cells to ganglion neurons?
cones
What contain pigments known as iodopsin, have narrow receptive fields (important for visual acuity), best at detecting static cues, are sensitive to photopic light conditions, and provide color vision?
Gland of 3rd eyelid
What contributes to 30-50% of the aqueous portion of the tear film via multiple very small ductules?
Dilator and sphincter pupillae muscles
What controls the amount of light to which the retina is exposed?
rhodopsin (visual purple)
What do the flattened disks associated with rods contain?
lacrimal gland
What glands produce tears and have tuboalveolar acini composed of secretory cells filled with small granules and myoepithelial cells at the base?
Aqueous humor
What glucose rich substance nourishes the cornea and maintains intraocular pressure?
Choroid
What is Ch? This is the thick highly vascular layer that in its anterior part is continuous with the stroma of the ciliary body. It supplies the retina.
Glaucoma
What is caused by an increase in intraocular pressure?
Keratitis
What is inflamation of the cornea called?
Iris
What is located anterior to the lens and separates the anterior and posterior chambers?
Ciliary processes
What is number 3, the aqueous humor forming cells of the eye? (non-pigmented cells form the aqueous humor)
Conjunctiva
What is structure C that lines the eyelids and is continuous with the epithelium of the limbus?
Iris
What is structure I? This has an opening called the pupil that helps the anterior and posterior chambers communicate.
Vascular sclera
What is structure S?
Cornea
What is the anterior portion of the eye that is an avascular, transparent concave lens?
lacrimal glands and glands of the third eyelid
What is the aqueous seromucous material of the tear film produced by?
Descemet's membrane
What is the basal lamina of the Posterior epithelium of the cornea called? It is also refered to as the posterior limiting lamina.
Optic papilla
What is the blind spot or optic disk of the eye?
Protects the eye, maintains shape of the eye, provides insertion points for tendons of extraocular muscles
What is the function of the sclera?
Constrictor pupillae
What is the gay pink arrow pointing to ?
Vitreous body
What is the gelatinous, colorless, viscous fluid mainly water in the eye?
zunular fibers from ciliary processes
What is the lens suspended by?
sends visual images to the brain, nerve fiber layers converge on the optic disk to for the optic nerve
What is the main responsibility of the sensory/optic retina?
goblet cells in the conjuntiva
What is the mucous portion of the tear film produced by?
Meibomian (tarsal) glands
What is the oily superficial layer of the tear film produced by?
Retinal pigmented epithelium
What is the outermost layer of the retina that consists of flat polygonal cells resting on a basement membrane that transport nutrients and metabolites to the rods and cones, absorb light, and phagocytose? (1)
posterior chamber-> through pupil-> anterior chamber-> iridocorneal angle-> past pectinate ligaments-> scleral venous plexus
What is the path of Aqueous humor?
Tapetum lucidum
What is the pink layer of the choroid second from the top with no pigment present?
To absorb stray light and to Reduce diffusion and focus incident light
What is the purpose of pigmented cells?
White, opaque layer of dense irregular connective tissue
What is the sclera?
LImbus
What is the slightly vascular corneoscleral junction where the opaque sclera overlaps the transparent cornea? This provides metabolites for the cornea
Choroid
What is the vascular supply to optical retina that contains pigment; Tapetum lucidum?
hyaline or elastic
What kind of cartilage is present in the third eyelid?
Goblet cells
What kind of cells are in the palpebral (eyelid) conjunctiva?
photosensitive
What kind of pigments do the outer segments modified cilia contain?
Tapetum lucidum
What layer of the choroid is absent in swine?
Anterior corneal epithelium
What layer of the cornea is structure number 1?
anterior limiting membrane
What layer of the cornea is structure number 2 that supports the anterior corneal epithelium?
Substantia propria
What layer of the cornea is structure number 3? This is the stroma of the cornea.
Posterior limiting lamina/membrane
What layer of the cornea is structure number 4 that is also called Descemet's membrane and supports the endothelium?
Posterior epithelium
What layer of the cornea is structure number 5? Also known as the corneal endothelium.
retina
What makes up the neuro-epithelial tunic?
Tapetum lucidum
What minimizes internal reflections and increases light perception under conditions of poor illumination? It increases acuity of vision
Sensory/optical part
What part of the retina contacts the choroid?
Non-sensory/ciliary part
What part of the retina covers the ciliary body, is pigmented, and has secretory cells for aqueous humor?
Iridal
What part of the retina is located on the posterior surface of the iris?
Cornea
What part of they eye is composed of 5 layers and has remarkable regenerative capacity?
Ciliaris Muscle
What smooth muscle is associated with accommodation ?
cornea
What structure Forms the anterior surface of the eye in an area largely corresponding to the pigmented iris. Blood vessels are not normally found here. It is Transparent and has a Rich sensory nerve supply
Choroid, Ciliary body, and Iris
What structures make up the middle vascular section of the eye?
Ciliary Body
What suspends the lens, contains smooth muscle for accommodation, and has processes covered by secretory epithelium?
Vascular Tunic
What tunic does the pink represent?
Nervous tunic
What tunic does the yellow represent?
Fibrous tunic
What tunic does this represent?
Type 1 and some elastic
What types of collagen make of the sclarea?
Top - Retinal pigment epithelium Bottom - Bruch's membrane
What words are hidden behind the black boxes ?
Iridocorneal angle
Where is aqueous humor drained?
Canal of Schlemm
Where is aqueous humor produced?
the orbit
Where is the eyeball located in the skull?
avascular, made up of dense connective tissue with parallel collagen bundles
Why is the cornea transparent?
Cones
________ are responsible for vision in bright light and color vision and contain Iodopsin.
Rods
_________ are responsible for vision in dim light and contain pigment Rhodopsin (aldehyde of vitamin A)
lens fibers
elongated and appear as thin, flattened structures
