Anatomy 2 Exam 2
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Questions and Answers

What vitreous attachment could most likely cause a retinal tear?

  • Optic disc
  • Macula
  • Vitreous base (correct)
  • Posterior lens

    • Where are hyalocytes located in the vitreous chamber?

  • At the cortex near the vitreal surface (correct)
  • Around the lens patellar fossa
  • Within the collagen fibrils
  • At the center of the anterior surface

    • What percentage of the vitreous is composed of water?

  • 97.5-98.0%
  • 96.7-98.5%
  • 98.5-99.7% (correct)
  • 96.7-98.2%

    • Which is not considered a component of the vitreous?

    <p>Type 3 collagen</p> Signup and view all the answers

    As we age, the vitreous becomes more jelly like.

    <p>False</p> Signup and view all the answers

    What is the space between the posterior surface of lens and the vitreous?

    <p>Berger's space</p> Signup and view all the answers

    The Cloquet's canal is remnants of the secondary vitreous.

    <p>False</p> Signup and view all the answers

    Which is not correct regarding the functions of the vitreous

    <p>A transparent medium with a 1.38 refractive index</p> Signup and view all the answers

    What clinical application is due to a vitreous detachment near the optic nerve?

    <p>Weiss ring</p> Signup and view all the answers

    The appearance of asteroid hyalosis is due to accumulation of calcium in the vitreous.

    <p>True</p> Signup and view all the answers

    Synchysis scintillants is the presence of cholesterol crystals in younger patients and occurs unilateral.

    <p>False</p> Signup and view all the answers

    At what time frame does the layer of Chievitz separate from inner and outer neuroblastic layers of primary retina?

    <p>2.5 months</p> Signup and view all the answers

    What cells are NOT differentiated from the innermost layer of Chievitz?

    <p>Bipolar cells</p> Signup and view all the answers

    Which cells are not differentiated from the outer layer of Chievitz?

    <p>Amacrine cells</p> Signup and view all the answers

    Which retinal layer eventually develops from the layer of Cheivitz?

    <p>IPL</p> Signup and view all the answers

    What is the correct time frame for the normal retinal vascular development to occur?

    <p>16 weeks gestation</p> Signup and view all the answers

    What layer of the retina in a newborn is thinner but still has synapses established?

    <p>OPL</p> Signup and view all the answers

    During macula development, the cones synapse with cells from inner nuclear layer to form what layer?

    <p>Henle's layer</p> Signup and view all the answers

    What is the space between the neural retina and the RPE?

    <p>Subretinal space</p> Signup and view all the answers

    What part of a photoreceptor cell that takes place in photo pigmentation?

    <p>Outer segment</p> Signup and view all the answers

    What area does metabolic activity and photopigment synthesis occur on a photoreceptor cell?

    <p>Inner segment</p> Signup and view all the answers

    The outer layer of the inner segment of a photoreceptor cell is called the myoid.

    <p>False</p> Signup and view all the answers

    The myoid region of a photoreceptor cell is the location of protein synthesis.

    <p>True</p> Signup and view all the answers

    Rods are used to detect objects in low levels of illumination.

    <p>True</p> Signup and view all the answers

    Rod discs contain rhodopsin, that absorb protons maximally at what wavelength?

    <p>507 nm</p> Signup and view all the answers

    Cones are used in photopic vision.

    <p>True</p> Signup and view all the answers

    What is the correct wavelength and color that correspond to short, medium, and long cones?

    <p>Blue=420 nm, green=531 nm, red=588 nm</p> Signup and view all the answers

    Which retinal layer acts as a barrier for large metabolites and contains desmosomal attachments between Muller and photoreceptor cells?

    <p>OLM</p> Signup and view all the answers

    What retinal layer contains cell bodies of rods and cones?

    <p>ONL</p> Signup and view all the answers

    What is the only layer of the retina that received blood supply from the choroid and the central retinal artery?

    <p>OPL</p> Signup and view all the answers

    What cells do the photoreceptor cells synapse with in the outer plexiform layer?

    <p>Horizontal and Bipolar</p> Signup and view all the answers

    The synaptic area of a rod is called a pedicle.

    <p>False</p> Signup and view all the answers

    What cell bodies are found in the inner nuclear layer?

    <p>Horizontal, Bipolar, Amacrine, Muller, Interplexiform</p> Signup and view all the answers

    How do horizontal cells modify the information that reaches the bipolar cells?

    <p>Lateral inhibition</p> Signup and view all the answers

    What layer of the retina is the location for the synapses between the second and third order neurons in visual pathway?

    <p>IPL</p> Signup and view all the answers

    What cells modify the synapses between ganglion and bipolar cells?

    <p>Amacrine cells</p> Signup and view all the answers

    Bipolar cells increase stimulation of ganglion cells.

    <p>True</p> Signup and view all the answers

    Amacrine cells increase stimulation of ganglion cells.

    <p>False</p> Signup and view all the answers

    What is the thickness of the ganglion cell layer in the macular region?

    <p>4-7 layers</p> Signup and view all the answers

    Where do each ganglion cell axons terminate at?

    <p>Lateral geniculate nucleus</p> Signup and view all the answers

    Midget cells are sensitive to dim changes in illumination.

    <p>False</p> Signup and view all the answers

    Magnocellular cells are sensitive to dim changes in illumination.

    <p>True</p> Signup and view all the answers

    Which retinal layer is not present in the fovea?

    <p>Nerve fiber layer</p> Signup and view all the answers

    Which retinal layer is absent over the optic disc?

    <p>Internal limiting membrane</p> Signup and view all the answers

    Which neuroglial cell has the main function of glycogen metabolism?

    <p>Muller cells</p> Signup and view all the answers

    Which retinal layer does not receive blood from the choroid via the short posterior ciliary arteries?

    <p>Inner plexiform layer</p> Signup and view all the answers

    Which retinal layer received blood from the superficial capillary networks of the CRA?

    <p>NFL</p> Signup and view all the answers

    Which retinal artery can allow the macula to be spared in a CRAO?

    <p>Cilioretinal artery</p> Signup and view all the answers

    Which is NOT true regarding xanthophyll pigments in the macula?

    <p>Absorb long wavelength visible light</p> Signup and view all the answers

    What is the correct diameter of the fovea?

    <p>1.5 mm</p> Signup and view all the answers

    What part of the macula has the highest concentration of cones?

    <p>Foveola</p> Signup and view all the answers

    Which part of the macula contains largest amount of bipolar and ganglion cells?

    <p>Parafovea</p> Signup and view all the answers

    The neural retina continues forward as the pigmented epithelium of the ciliary body.

    <p>False</p> Signup and view all the answers

    What is the function of the A2E substance identified in lipofuscin accumulation?

    <p>Contributes to RPE cell death</p> Signup and view all the answers

    Which type of vision does vitamin A, metabolized and stored by RPE cells, primarily support?

    <p>Scotopic vision</p> Signup and view all the answers

    What is the product of anaerobic metabolism in the RPE?

    <p>Lactate</p> Signup and view all the answers

    What is the vitamin A called that is stored in the RPE and used for disc renewal?

    <p>All-trans-retinol</p> Signup and view all the answers

    Which growth factor, produced by the RPE, helps maintain choriocapillaries function?

    <p>VEGF</p> Signup and view all the answers

    What retinal disease is associated with the degeneration of photoreceptors?

    <p>Retinitis pigmentosa</p> Signup and view all the answers

    What is responsible for maintaining the slight negative electrical charge in photoreceptors during darkness?

    <p>Active transport of cations like sodium and calcium</p> Signup and view all the answers

    At what voltage is the electrical charge maintained in photoreceptors in the dark?

    <p>-40 mV</p> Signup and view all the answers

    Which cells are activated first by the hyperpolarization of photoreceptors during phototransduction?

    <p>Horizontal cells</p> Signup and view all the answers

    What triggers the start of vision in the phototransduction process?

    <p>Light absorption by rhodopsin</p> Signup and view all the answers

    What is the role of cyclic GMP-gated channels in photoreceptors?

    <p>Responsible for light-induced changes in electrical activity</p> Signup and view all the answers

    Which protein determines the wavelength absorption in the visual pigments?

    <p>Opsin</p> Signup and view all the answers

    What allows for electrical synapses to pass directly between cells in the retina?

    <p>Gap junctions</p> Signup and view all the answers

    Which transporter is responsible for moving lactate across the RPE, a product of anaerobic metabolism?

    <p>Proton-Lactate water co-transporter</p> Signup and view all the answers

    What is the significance of aquaporins in the physiology of the RPE cells?

    <p>Regulating the movement of water</p> Signup and view all the answers

    Which family of glucose transporters is mainly utilized in the retina for glucose transport?

    <p>Facilitated-diffusion glucose transporter family (GLUT)</p> Signup and view all the answers

    What is the primary function of the retinal pigment epithelium (RPE) in maintaining the health of the choriocapillaris?

    <p>Secreting vascular endothelial growth factor (VEGF)</p> Signup and view all the answers

    What is the primary function of the pigment granules within the RPE cells?

    <p>Absorbing excess light to reduce scatter</p> Signup and view all the answers

    Which of the following statements about the relationship between the RPE and photoreceptors is correct?

    <p>The RPE and photoreceptors have a reciprocal relationship, where dysfunction in one affects the other.</p> Signup and view all the answers

    What is the primary function of the gap junctions in the retina?

    <p>To facilitate the transmission of electrical signals between cells without the need for chemical mediators</p> Signup and view all the answers

    Which of the following neurotransmitters is excitatory in the retina?

    <p>Glutamate</p> Signup and view all the answers

    What is the primary function of the RPE in the visual cycle?

    <p>Oxidizing vitamin A to produce retinal for photopigment regeneration</p> Signup and view all the answers

    Which of the following statements about the shedding of photoreceptor outer segments is correct?

    <p>Rod outer segments are shed in the morning, while cone outer segments are shed in the morning.</p> Signup and view all the answers

    Which cell is not considered an excitatory cell in the retina?

    <p>Muller</p> Signup and view all the answers

    Which retinal cells are considered to be inhibitory, that release GABA and Glycine?

    <p>Amacrine and Horizontal</p> Signup and view all the answers

    Which of the following proteins is responsible for transporting all-trans retinol from the photoreceptor to the RPE?

    <p>IRBP (Interphotoreceptor retinol-binding protein)</p> Signup and view all the answers

    During dark photo transduction, what is released from the depolarized photoreceptors?

    <p>Glutamate</p> Signup and view all the answers

    Which type of retinal cells are responsible for the center-surround organization of receptive fields?

    <p>Bipolar cells</p> Signup and view all the answers

    What is the primary function of horizontal cells in the retina?

    <p>To provide lateral inhibition and contribute to spatial summation</p> Signup and view all the answers

    What is the primary mechanism by which ON-center bipolar cells respond to light stimulation?

    <p>They depolarize in response to light</p> Signup and view all the answers

    What does the RPE convert all-trans-retinol to?

    <p>11-cis-retinol</p> Signup and view all the answers

    Which type of retinal cells are responsible for relaying visual information to the lateral geniculate nucleus (LGN) of the thalamus?

    <p>Ganglion cells</p> Signup and view all the answers

    Which type of retinal cells are responsible for modulating the synaptic connections between bipolar cells and ganglion cells?

    <p>Amacrine cells</p> Signup and view all the answers

    What is the primary function of Müller cells in the retina?

    <p>To provide structural and metabolic support for retinal neurons</p> Signup and view all the answers

    In a dark response, the photoreceptor is hyperpolarized.

    <p>False</p> Signup and view all the answers

    Light adaptation can take up to 30 minutes for retina to adapt.

    <p>False</p> Signup and view all the answers

    Exposure to 400-500 nm light at night can disrupt circadian rhythm.

    <p>True</p> Signup and view all the answers

    The pituitary gland releases melatonin, which is important for circadian rhythm.

    <p>False</p> Signup and view all the answers

    Glutamate is released in a light response.

    <p>False</p> Signup and view all the answers

    What is not a treatment regimen for a retinal detachment?

    <p>AREDS 2 vitamins</p> Signup and view all the answers

    What retinal layer will you find flame-shaped hemorrhages?

    <p>NFL</p> Signup and view all the answers

    What type of hemorrhage involves the rupture of deep capillaries?

    <p>Dot hemorrhages</p> Signup and view all the answers

    Which is NOT a systemic condition that causes boat hemorrhages?

    <p>Diabetes</p> Signup and view all the answers

    What retinal layer will you find hard exudates?

    <p>Outer plexiform layer</p> Signup and view all the answers

    What condition is not associated with cotton wool spots?

    <p>Multiple Sclerosis</p> Signup and view all the answers

    What retinal application is associated with metabolic debris from RPE?

    <p>Drusen in ARMD</p> Signup and view all the answers

    What is not as associated cause of Hollenhurst plaques?

    <p>Sarcoidosis</p> Signup and view all the answers

    What are some conditions that present with retinal vasculitis?

    <p>Sarcoidosis, Behcet's Disease, Multiple sclerosis, Idiopathic conditions</p> Signup and view all the answers

    What ocular condition is secondary to an increase in intracranial pressure?

    <p>Acute Optic Disc Edema</p> Signup and view all the answers

    Optic disc edema is usually presented unilaterally.

    <p>False</p> Signup and view all the answers

    What type of macular degeneration presents with acute sub-retinal blood in macular region with subtle sub-retinal fluid and is not presented with choroidal neovascular membrane?

    <p>Early wet ARMD</p> Signup and view all the answers

    Dry age-related macular degeneration is also called exudative degeneration.

    <p>False</p> Signup and view all the answers

    Study Notes

    RPE Cells in Retinal Physiology

    • RPE cells phagocytose fragments from the continual shedding of the photoreceptor outer segment discs, which accumulates as lipofuscin.
    • Lipofuscin, a yellow-brown pigment, contains lipid-containing residues of lysosomal digestion and contributes to RPE cell death.
    • RPE cells metabolize and store vitamin A, which is essential for the biochemical process in the rod disc renewal system.
    • Vitamin A is also known as all-transretinol, and it helps in night vision as a precursor of rhodopsin.
    • RPE cells contribute to the formation of the interphotoreceptor matrix (IPM) between the RPE layer and the photoreceptors.
    • The IPM is composed of hyaluronan (HA), which forms a basic scaffold structure, and interacts with HA-binding motifs on cells that border the IPM.

    RPE Functions

    • RPE cells are fundamental to the health of the neural retina and the choriocapillaris.
    • They form a part of the blood-retinal barrier, which isolates the inner retina from systemic influences.
    • RPE cells electively control the movement of nutrients and metabolites from the choriocapillaris into the retina and removal of waste products.
    • Water is eliminated from the subretinal space by active transport through the RPE, involving ion pumps, exchangers, and channels.
    • Glucose transporters in the RPE cells maintain a steady supply of glucose to the active photoreceptors.
    • RPE cells produce growth factors that drive certain cellular processes, including vascular endothelial growth factor (VEGF) and pigmented epithelial-derived factor (PEDF).

    Photoreceptors

    • The relationship between the RPE and photoreceptors is reciprocal, and dysfunction in one layer affects the other.
    • Retinal degenerative diseases often cause changes in the RPE that are clinically visible.
    • Photoreceptors have different types of vision, including scotopic vision (rod-dominated, low light levels) and photopic vision (cone-dominated, high light levels).
    • The composition of visual pigments includes opsins and chromophores, which determine the wavelength absorption of light.

    Visual Pigments

    • Cones have three photopigments, differing in amino acid composition, which are sensitive to different wavelengths of light (red, green, and blue).
    • Rods have a single photopigment, rhodopsin, which is sensitive to low light levels.
    • The formation of visual pigments involves the conversion of 11-cis retinal to all-trans retinal, which is moved into the cytoplasm and reduced to all-trans retinol.

    Retinal Synapses

    • Information transmission between retinal neurons occurs through ion channel activity at gap junctions and chemical synapses.
    • Neurotransmitters, such as glutamate, GABA, and glycine, and neuromodulators, like dopamine and cGMP, play a crucial role in retinal transmission.

    Phototransduction

    • Phototransduction is the process by which light is converted into an electrical signal in photoreceptors.
    • The absorption of light triggers a series of biochemical changes, leading to the hyperpolarization of the photoreceptor and the transmission of the signal to other retinal neurons.

    Retinal Cells

    • Bipolar cells have center-surround receptive fields, responding to spatial antagonism.
    • Horizontal cells receive input from a large number of photoreceptors, contributing to spatial summation.
    • Ganglion cells are activated by the signal from bipolar cells and transmit the message to the brain.

    Vitreous Humor

    • The vitreous humor is a gel-like substance that fills the vitreous chamber, making up 80% of the eye's volume.
    • Its components include 98.5% to 99.7% water, collagen fibers, and hyaluronic acid.
    • The vitreous humor undergoes changes with age, becoming more liquid and forming pockets of fluid.
    • Vitreous attachments, including the vitreous base, posterior lens, optic disc, macula, and annular ring, are important for maintaining the integrity of the retina.

    Vitreous Changes

    • Age-related changes in the vitreous humor include the formation of floaters, aggregation of collagen fibrils, and the formation of pockets of fluid.
    • Vitreous detachments, including posterior vitreous detachment, can occur due to trauma, age, or other factors.
    • Clinical applications of vitreous changes include the diagnosis of vitreous hemorrhage, neovascularization, and retinal detachment.

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