Flashcards in Boards Prep: Ocular Physiology Video Flashcards Deck (30):
Orbital Portion: Orbicularis Oculi
1. Outer or inner portion of muscle?
2. What word should come to mind?
3. When you blink Spontaneously/Reflex portion is done by what portion?
4. What's the Antagonist muscle to the Orbicularis Muscle?
a. This muscle compensates for what?
5. Forced Blinking causes what?
a. What direction is this movement?
6. What's Antagonist to the Palpebral Portion?
2. FORCED (Forced Closure)
3. Palpebral Portion
4. Frontalis (Runs Vertically)
a. For a PTOSIS
5. Bell's Phenomenon
a. Up and Out movement
6. the Levator.
1. Reflex Blinking: Immediately think of what?
b. Cotton Swab?
1. SENSORY STIMULUS (not CN 7!)
a. CN 2
b. V-1 (HSV: dendrite)
Lacrimal Pump Theory
1. People Cry: blink more often. Decreases tear drainage onto the cheek. Why?
a. How does the Orbicularis Oculi Help everytime you blink?
1. Orbicularis Oculi: Helps tears drain off the ocular surface.
a. Orbicularis Oculi WIDENS LACRIMAL SAC (negative pressure) and Helps pumps tears into the sac (Muscle of Horner (Pars Lacrimalis is Muscle of Horner!)...shortens canaliculi)
Meibomian Glands (Holocrine)
1. Type of Gland?
a. What surrounds them?
b. What is a Dz of the sebaceous glands?
c. W/this u see Telangiectasia...what kind of lid cancer has this?
2. Apocrine Glands (2)
3. Which tear film layer is increased with blinking?
1. Sebaceous Glands
a. Collagen (Tarsal Plate)
b. Acne Rosacea (Thickened nose...pustules/Papules)
c. BASAL CELL Carcinoma, or Acne Rosacea
2. Glands of Moll, Goblet Cells
3. Lipid Layer
Acessory Lacrimal Glands
1. Type of Gland?
2. What test isolates the Accessory Lacrimal Glands?
3. ALGs are responsible for what type of tearing?
4. What's the main responsibility of the Glycocalyx?
1. Merocrine Gland (Glands of Krause and Wolfring)
2. Schirmer 2
3. Basal Tearing
4. Absorbing the MUCOUS! (Part of Mucous Layer: Outer Mucin and Inner Glycocalyx (made from corneal epithelium)
1. What Vitamin do they NEED for development?
a. Deficiency causes what?
1. VITAMIN A.
a. Bitot Spots
1. What 2 vitamins in Excess will not hurt you?
2. Which Vitamins are Fat Soluble?
3. Which Vitamins are Antioxidants?
1. Vitamins E and K
Properties of Tears
1. What Ions are the highest in tears?
a. Which one is way higher in the tears than in your plasma?
2. What happens to pH of tears during Sleep?
a. During Dry Eye?
1. Sodium and Chloride (High in tears and in blood)
a. POTASSIUM (K+)
2. Less O2...so More Lactic Acid Production...so LOWER pH.
a. Decrease...More ions d/t evaporation! so decreased pH.
1. Purpose of VOR?
2. What part of the Brain is responsible for the Pursuit and Saccade Eye Movement?
1. match eye movement w/Head movement.
2. Rotate OKN Counterclockwise: (Pursuit in right, then saccade to left)
a. Rt eye: Rt Frontal Lobe and Rt Superior Colliculus controls saccades to the Left; Right pursuits are controlled by the Right Parietal Lobe.
Middle Ear bone is closest in proximity to Oval Window?
Outer ear (Tympanic Membrane) Middle Ear (Oval Window) --> Inner Ear
Malleus --->Incus --> Stapes
UV Light Review:
1. Shorter wavelengths = what energy level?
2. What UV light is most dangerous?
3. UVC: Wavelength range?
b. Absorbed by what area of they eye?
4. UVB: Wavelength range?
a. Most likely cause of what cancer?
5. UVA: Wavelength range?
a. 2 locations in the eye that absorb UVA light?
1. Higher energy per photon
3. 200-290 nm
a. Most dangerous
b. Epithelium and Bowmans. (Tanning, welding, skiing) (damage = Diffuse SPK!)
4. 290-320 nm
a. Basal Cell Carcinoma
5. 320-400 nm
a. Lens. (300-350 absorption = Vitreous)
1. What does Deturgescence mean?
2. How does the cornea maintain water concentration via the epithelium?
a. What about w/the Endothelium?
1. Dehydration...of the cornea.
2. Epithelium absorbs Na+ from Tears...cascade that leads to a Cl- ion to be secreted out into the tears w/WATER FOLLOWING (lets Epithelium be effective in maintaining water)
a. Na+ Absorbed which kicks out a CL- ion to the Aq. Humor w/Water Following. Bicarb also works in endothelium as well.
Oxygen for the Cornea
1. Open eye?
2. Closed Eye?
1. TEARS do ALL LAYERS of the CORNEA (including the Endothelium)
2. Palpebral conjunctiva and Aq. Humor do this.
1. CN Issue?
2. Corneal Epithelium replaces itself every (how many days)?
a. Trigger to start replacement is d/t which CN?
b. If you damage this trigger, what happens?
3. What's the Purpose of Basal Cells?
4. What are the 2 layers of the cornea that thicken over time?
5. What enzyme makes corneal growth or healing to take longer?
a. What can be prescribed to attack these enzymes and help the healing process?
1. V1 issue.
2. Every 7 days.
a. V1! ("feels loss" to trigger stimulating new cell growth)
b. new cell growth is impaired...ulcer forms...
3. Palisades of Vogt (Limbus). Basal Cells (Only mitotic cells) make Wing Cells (anterior to them) and Basal cells also make membrane behind it.
4. Basement Membrane and Descemet's Membrane
5. Matrix Metalloprotinases (MMPs)
a. Doxycycline and Topical Steroids
Pentose Phosphate Shunt
1. What does it Make?
2. What does this do for the eye?
3. Aging Changes in the Lens
a. What increases? What does this do? What drug Causes a Myopic Shift?
b. What decreases?
4. Sorbital = ? to the lens?
5. Calcium: level needed?
6. What drives the Na/K Pump in the Lens?
7. What Vitamins do you want for the Lens?
8. What produces the Embryonic Nucleus?
9. NADPH: What else does it do?
*Stopped at ~31:50 Pg 3/7. (Uvea)
2. NADPH reduces GLUTATHIONE...makes it ACTIVE...so it becomes a FREE RADICAL SCAVENGER
3. a. Calcium, NS; Causes a Myopic Shift; DIAMOX!
b. Crystallins (Alpha Crystallin), Glutathione
4. Think Diabetic Cataract; If HEXOKINASE is NOT PRESENT, you will have problems!
5. Too much, and too little is problematic for the lens (Causes Cataracts)
6. Anaerobic Glycolysis (Lactic Acid being produced...--> Lots of Lactic acid in Aq. Humor
7. Vitamins ACE (Lens is PACKED with VITAMIN C)
8. Primary Lens Fibers (aka Posterior Lens Fibers...Act First..and Create the EMBRYONIC NUCLEUS and that is IT!) (RI of Embryonic Nucleus = 1.41)
*Rest of the nucleus is made by Secondary Lens FIBERS!!!
9. Fatty Acid Steroid Synthesis.
Aging Changes of the Uvea
1. CB: What happens to Aq. Humor formation and ciliary muscle contraction with age?
2. Choroid: What happens to Bruch's Membrane and Choriocapillaris with age?
3. Where is the highest BF rate in the eye?
4. What does a high amt of protein in the choroid do?
5. Which has a Higher Oxygen Content: Choroid or Retina?
1. Decreases with Age.
2. Bruch's: GETS THICKER. (It's Hydrophilic in a healthy Pt.) When it becomes Hydrophobic, it can't pass nutrients to the the outer retina.
4. Sets up a gradient to pull retinal Edema Across the RPE and into the CHOROID.
1. What's the #1 risk factor for a PVD?
2. Where is Collagen Concentration highest in the Vitreous?
b. Where is Vitreal breakdown most common?
3. Collagen in the Vitreous: Does it increase or decrease with age?
4. Attachment at the Macula: What 2 Dz conditions should u think about?
1. Vitreous Syneresis
2. At the Vitreous BASE
a. At the CENTER of the Vitreous
b. At the center of the vitreous.
3. NEITHER! It just clumps together, which is what we see as floaters.
4. Macular Holes and ERMs! (#1 risk factor for them are Vitreous Traction!)
BF in the eye.
1. 2 ways we can alter BF in the eye?
3. What's the number 1 THREAT to VISION from really HIGH PRESSURES? (like in Angle Closure)?
1. Autoregulation (happens at the ON and the Retina) (
2. Autonomic Control (via Iris, CB, and Choroid). (aka...the UVEA...PSNS and SNS regulation)
3. CRAO! (pressure pushes on the ONH, causing compression on the CRA...which then prevents BF into its branches...thus loss of vision and death of parts of the retina).
Capillaries in the Eye
1. Fenestrated Capillaries: 2 Locations in the eye?
2. Non-Fenestrated Capillaries: 2 main locations?
1. Choroid and CB
2. Iris and Retina
Blood Aq. Barrier and Blood Retinal Barrier
1. Blood Aq. Barrier: Tight junctions: Found in 3 PLACES
2. Blood/Retinal Barrier: Tight Junctions: Found in 2 Places.
1. NPCE, Iris Vessels, Schlemm's Canal
2. B/W RPE Cells, and Retinal Vessels
1. As we are sleeping, Na+ enters into what?
a. Why does this occur?
b. Membrane Potential in the dark?
c. Na entry causes what? This leads to release of what?
d. Type of Potential created by photoreceptors?
e. What cell types perform APs?
f. What occurs when the light comes on? What does this cause?
1. Into the Outer segment in the DARK...hence it's the DARK CURRENT
a. due to cGMP keeping the Na+ channels open in the OS.
b. ~-50 mV
c. Depolarization (in the dark); Leads to GLUTAMATE RELEASE (in the dark)
d. ADD: GRADED!
e. Amacrine and Ganglion cells
f. PHOTOTRANSDUCTION; Light absorption causes a change from 11 cis-retinal to all-trans retinal.
Major Neural Pathways
1. Ascending Pathways: 2 of them?
a. What does each do?
2. Descending Pathways carry what info?
1. Spinothalamic and Trigeminothalamic Pathways (Spy and Try)
a. Spy: More sophisticated...carries PAIN and TEMP info from the BODY.
b. Try: "Tries Hard" but can only do PAIN and TEMP for the FACE!
2. Motor info from Brain to MUSCLES!
Major Neural Pathways:
1. If the lesion is ABOVE the crossover point (regardless of if it's carrying sensory or motor info), this will RESULT in what kind of PATHOLOGY?
1. a CONTRALATERAL PATHOLOGY!!!
Major Neural Pathways:
1. Most neural pathways cross at what Brainstem location?
a. Name 2 of them.
1. at the MEDULLA!!
a. Pyramidal Pathway (PyraMEDULLA Pathway)
Medial Lemniscus Pathway (MEDULLA Lemniscus Pathway)
Neuroimaging: CT/MRI/PET Scans
1. CT does what?
2. PET does what?
3. MRI does what?
1. Compares Calcium density
2. compares glucose uptake
3. Mobile Proteins
2. Which layers of the Left LGN receives info from what part of the retina?
3. Which layers of the Left LGN receives info from what part of the retina?
4. Retinitis Pigmentosa? Number one symptom? Number 2?
4. #1: Night Blindness; #2: Peripheral Vision Loss
1. EOG: Think what?
a. Arden Ratio: What's the cut-off for Normal/Abnormal?
2. ERG: Think what Dz?
a. What does the A-Wave, B-Wave, and C-Wave evaluate?
b. Peripheral Vision loss is most commonly seen in which location? Why?
c. What else can RP have ABNORMAL ERG? (3)
3. VER: Think what Dz?
a. normal peak should occur at what time?
b. VER levels should correspond to what VA for babies?
1. BEST's Dz (Stage 1)
a. 1.50 is cut off
2. Retinitis Pigmentosa (RP)
a. A-Wave: Photoreceptor
B-Wave: Bipolar, Mueller Cells
b. in the SUPERIOR location (d/t Inferior Retina being involved FIRST)
c. Photopsia, Central Issues (PSC, CME), High Myopia
a. ~110 msec
b. 20/20 VA for babies, even though their Snellen VA is ~20/600.
1. Light response: % of fibers from ON exits prior to LGN and goes to what nuclei?
2. Near Response: Pathway?
3. Does the NEAR RESPONSE need the PRETECTAL NUCLEUS?
a. Lesion of the Pretectal Nucleus would result in what?
4. 2 Systemic things with Adie's Tonic Pupil?
1. ~1/3; --> Pretectal Nucleus --> EW Nucleus --> Ciliary Ganglion
2. V1 Activates Frontal Eye Fields --> EW Nucleus --> Ciliary Ganglion
a. Abnormal Response to light, normal response to near object. (ARP, Adie's Tonic Pupil: Acute Dilated Pupil...BETTER with ACCOMMODATION!)
2. 0.125% diluted pilocarpine...Causes affected eye to become VERY MIOTIC! Loss of Deep Tendon Reflexes (like in KNEE) and Increased Sweating
1. Goldmann Applanation Tonometry
a. Based on what Law?
b. Indirectly Measures IOP thru what?
c. What's the Corneal Thickness number that is assumed on all corneas with this method?
2. Non-Contact Tonometry
a. Based on what?
3. PASCAL Tonometry (Think CONTOUR Tonometry)
a. May provide benefit in doing what?
1. Imbert-Flick's Law
b. thru Measuring Corneal Elasticity
c. 520 um.
d. Thick Mires/Thick Corneas: OVERESTIMATE IOPs!!! (so u have to subtract)
2. a. on a Time Interval
3. a. Supposed to negate Corneal Thickness