Boards Prep: Ocular Physiology Video Flashcards
Orbital Portion: Orbicularis Oculi
- Outer or inner portion of muscle?
- What word should come to mind?
- When you blink Spontaneously/Reflex portion is done by what portion?
- What’s the Antagonist muscle to the Orbicularis Muscle?
a. This muscle compensates for what? - Forced Blinking causes what?
a. What direction is this movement? - What’s Antagonist to the Palpebral Portion?
- Outer
- FORCED (Forced Closure)
- Palpebral Portion
- Frontalis (Runs Vertically)
a. For a PTOSIS - Bell’s Phenomenon
a. Up and Out movement - the Levator.
- Reflex Blinking: Immediately think of what?
a. Dazzle/Menace?
b. Cotton Swab?
- SENSORY STIMULUS (not CN 7!)
a. CN 2
b. V-1 (HSV: dendrite)
Lacrimal Pump Theory
- People Cry: blink more often. Decreases tear drainage onto the cheek. Why?
a. How does the Orbicularis Oculi Help everytime you blink?
- 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)
- 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? - Apocrine Glands (2)
- Which tear film layer is increased with blinking?
- 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
- Type of Gland?
- What test isolates the Accessory Lacrimal Glands?
- ALGs are responsible for what type of tearing?
- What’s the main responsibility of the Glycocalyx?
- Merocrine Gland (Glands of Krause and Wolfring)
- Schirmer 2
- Basal Tearing
- Absorbing the MUCOUS! (Part of Mucous Layer: Outer Mucin and Inner Glycocalyx (made from corneal epithelium)
Goblet Cells
- What Vitamin do they NEED for development?
a. Deficiency causes what?
- VITAMIN A.
a. Bitot Spots
Vitamins
- What 2 vitamins in Excess will not hurt you?
- Which Vitamins are Fat Soluble?
- Which Vitamins are Antioxidants?
- Vitamins E and K
- DEAK
- ACE
Properties of Tears
- What Ions are the highest in tears?
a. Which one is way higher in the tears than in your plasma? - What happens to pH of tears during Sleep?
a. During Dry Eye?
- Sodium and Chloride (High in tears and in blood)
a. POTASSIUM (K+) - Less O2…so More Lactic Acid Production…so LOWER pH.
a. Decrease…More ions d/t evaporation! so decreased pH.
VOR: Review
- Purpose of VOR?
- What part of the Brain is responsible for the Pursuit and Saccade Eye Movement?
- match eye movement w/Head movement.
- 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
*So STAPES!
UV Light Review:
- Shorter wavelengths = what energy level?
- What UV light is most dangerous?
- UVC: Wavelength range?
a. Danger?
b. Absorbed by what area of they eye? - UVB: Wavelength range?
a. Most likely cause of what cancer? - UVA: Wavelength range?
a. 2 locations in the eye that absorb UVA light?
- Higher energy per photon
- UVC!!
- 200-290 nm
a. Most dangerous
b. Epithelium and Bowmans. (Tanning, welding, skiing) (damage = Diffuse SPK!) - 290-320 nm
a. Basal Cell Carcinoma - 320-400 nm
a. Lens. (300-350 absorption = Vitreous)
Corneal Deturgescence
- What does Deturgescence mean?
- How does the cornea maintain water concentration via the epithelium?
a. What about w/the Endothelium?
- Dehydration…of the cornea.
- 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
- Open eye?
- Closed Eye?
- TEARS do ALL LAYERS of the CORNEA (including the Endothelium)
- Palpebral conjunctiva and Aq. Humor do this.
Neurotrophic Keratopathy
- CN Issue?
- 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? - What’s the Purpose of Basal Cells?
- What are the 2 layers of the cornea that thicken over time?
- What enzyme makes corneal growth or healing to take longer?
a. What can be prescribed to attack these enzymes and help the healing process?
- V1 issue.
- 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
- Matrix Metalloprotinases (MMPs)
a. Doxycycline and Topical Steroids
Pentose Phosphate Shunt
- What does it Make?
- What does this do for the eye?
- Aging Changes in the Lens
a. What increases? What does this do? What drug Causes a Myopic Shift?
b. What decreases? - Sorbital = ? to the lens?
- Calcium: level needed?
- What drives the Na/K Pump in the Lens?
- What Vitamins do you want for the Lens?
- What produces the Embryonic Nucleus?
- NADPH: What else does it do?
* Stopped at ~31:50 Pg 3/7. (Uvea)
- NADPH!!!!!
- NADPH reduces GLUTATHIONE…makes it ACTIVE…so it becomes a FREE RADICAL SCAVENGER
- a. Calcium, NS; Causes a Myopic Shift; DIAMOX!
b. Crystallins (Alpha Crystallin), Glutathione - Think Diabetic Cataract; If HEXOKINASE is NOT PRESENT, you will have problems!
- Too much, and too little is problematic for the lens (Causes Cataracts)
- Anaerobic Glycolysis (Lactic Acid being produced…–> Lots of Lactic acid in Aq. Humor
- Vitamins ACE (Lens is PACKED with VITAMIN C)
- 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!!! - Fatty Acid Steroid Synthesis.