Random Pile of Done Flashcards
Which type of glial cell lines the cavities of the CNS as well as the walls of the ventricles in the brain?
Ependymal Cells
NOTE: they also form the epithelium of the choroid plexus, which secretes CSF
Which type of glial cells are considered non-neuronal cells of the CNS and serve to coat axons in a myelin sheath, which greatly increases the speed of conduction?
Oligodendrocytes NOTE: these cells also wrap numerous axons simultaneously, while Schwann cells insulate on a one-to-one ratio for cellular axons in the PNS
Which glial cells are the most numerous and offer support and structure to the brain?
Astrocytes NOTE: these cells also play a large role in the formation of the BRB, which serves to inhibit toxic substances of the blood from entering the brain. These cells play an important part in removing NTs from synaptic zones as well as the removal of excessive etracellular potassium.
Which type of glial cell are a type of macrophage that are called into action in the event of injury, disease or infection?
Microglia NOTE: these cells are capable of phagocytosis
The primary absorption pathway for large, hydrophilic drugs is where?
Transconjunctival Route
The primary absorption pathway for small, lipophilic drugs is where?
Transcorneal route
Which 2 of the following ocular elements pass through the optic foramen before reaching the eye?
Opthalmic Artery and CN 2
What is the average diurnal variation of IOP for a normal person who does not suffer from glaucoma?
3-5 mmHg NOTE: The average intraocular pressure (IOP) is around 15 mmHg (+/- 2.57 mmHg) for people without glaucoma or ocular hypertension. Pressures for most people also fall within 10.5-20.5 mmHg. IOP can fluctuate between 3-6 mmHg on a daily basis, most likely resulting from a change in aqueous production rather than aqueous drainage. A fluctuation of greater than 10mmHg is usually indicative of glaucoma.
What is coat’s white ring?
A small, white, oval ring at the level of Bowman’s membrane that is associated with a previous corneal FB
Which HA’s are most commonly caused by stress and may be attributed to poor posture, hunger, and fatigue?
Tension HA’s NOTE: this type of HA is associated w stiffness of the muscles in the neck region and pain around the occipital region or a vice-like pain in the frontal area. CC: “throbbing”
Which HA’s are more commonly “associated acute” rather than “chronic nasal sinusitis” and usually present with a deep and constant pain in the frontal region of the head?
Sinus HA NOTE: pain in these cases is usually associated w/ other sinus symptoms such as rhinorrhea, feeling of fullness in the ears, fever, facial swelling, and lacrimation. CC: transient loss of smell. Majority will note an increase in pain/pressure when bending down
Which thyroid hormone is released from the hypothalamus?
Thyrotropin-Releasing Hormone (TRH)
Where is Thyroid Stimulating Hormone (TSH) produced?
Pituitary glands
As demarcation lines, or high water marks, occur due to the proliferation of retinal pigment epithelial cells (3 months), what configuration do they make with respect to the ora serrata?
Convex NOTE: this represents sites of increased adhesion. With time, the demarcation line tends to lose its pigment and can be less obvious upon fundus examination
What is or are the MOA(s) for Brimonidine (Alphagan) and Apraclonidine (Iopidine)?
- INC Uveoscleral outflow 2. DEC Aqueous production
What are the 3 photopigments contained within the human cones?
Erythrolabe (565 nm), chlorolabe (535 nm), and cyanolabe (430 nm)
What is the flow of aqueous out of the eye via trabecular outflow?
Uveal layer –> corneoscleral layer –> Juxtacanalicular layer –> Schlemm’s canal –> distal collector channels –> Aqueous veins –> Episcleral venous system
For Keratometry, to extend the ranges down, what lens would you use and what range does it create?
-1.00 Lens Subtract 6D from the drum reading for flatter corneas
What does adding a +1.25D lens to a keratometer do?
Add a range of 8-9D for steeper corneas
According to the American Diabetes Association, asymptomatic pts who do not possess any RFs for DM should be screened at what age?
45 years old
What is the reversible replacement of one differentiated cell type with another mature differentiated cell type (i.e. Barrett’s esophagus) known as?
Metaplasia NOTE: most common in epithelial tissues (can be from normal maturation or abnormal signaling). Original cells may not be robust enough to withstand harsh environments and thus change to a cell that is better suited
What is this referring to: - Disorderly arrangement of cells due to an alteration of size, shape, and organization -Epithelial cells -Reversible* -Immature cells > Mature -Pap smears
Dysplasia
What is an alteration of differentiation? -Poorly differentiated or undifferentiated -Divide rapidly but do NOT resemble normal cells structurally or functionally
Anaplasia (Ana is the weird kid, she is not differentiating the same as the other kids)
What is protective against progression of diabetic retinopathy?
High Myopia NOTE: proliferation of DR can be triggered by traction of the retina caused by incomplete detachment of the vitreous –> fibrovascular tissue formation. Myopic pts w/ a PVD possess a DEC risk of traction & therefore a DEC risk of progression of DR.
What is the ideal clearance to be attained over the steepest region of the cornea when fitting a scleral CLs?
100-300 um
What is called when the ability to recognize faces is impaired while other aspects of visual processing remain intact?
Prosopagnosia
What is the condition in which patients cannot perceive motion but can acknowledge stationary objects without trouble?
Akinetopsia (AKA “motion blindness”)
Which side of the temporal lobe maintains an image library of all faces one has remembered and recognizes?
Right
Which side of the temporal lobe maintains a library of the shapes and objects one expects to recognize in everyday life?
Left
What is the MOA of Heparin?
It binds to antithrombin –> causing inactivation of thrombin NOTE: Heparin is a blood thinner and is used to treat and prevent deep vein thrombosis, pulmonary embolism, and arterial thromboembolism & also myocardial infarction and unstable angina.
When do vertical saccades mature and emerge in a baby?
2 months
How long does it take for horizontal saccades to emerge and develop?
Emerge: Birth Develop until 24 months
When are pursuits seen in babies?
2-4 months
When does stereopsis occur in babies?
3-5 months some say 4-6 months Reaches adult: 5-7 years old
What should LASIK refractive surgery patients be educated on?
- No eye rubbing - Eye shields should be worn at night while sleeping for approx. 1 week - Swimming in ocean, lakes, rivers, hot tubs, swimming pools, etc. should be avoided for at least 1-2 weeks - No excessive working out for approx. 1 week (especially those with head below the heart or involving Valsalva maneuver) - Eye makeup should be avoided for approx. 1 week - Patients can read, go on the computer, watch TV, etc., but excessive use may cause dryness, so it is advised to use artificial tears often
What are some factors that influence the risk for the development of DR? Which is the greatest RF?
Pregnancy, HTN, nephropathy, obesity, hyperlipidemia, and anemia
GREATEST: Duration
What is the functional unit of a muscle contraction?
Sarcomere
What do multiple sarcomeres make?
A myofibril
What is within one sarcomere?
Small filaments called actin and myosin that slide past each other resulting in motion
Which of the following topical NSAIDS must be used with caution in a person who is allergic to medications that contain sulfa? Ocufen® (flurbiprofen) Xibrom® (bromfenac) Nevanac® (nepafenac) Acular® (ketorolac)
Xibrom® (bromfenac) NOTE: this drug contains BAK and sodium sulfite. It is important to know medications as well as their preservatives bc sometimes the therapeutic effect is not achieved due to sensitivity to preservatives that are contained w/in the medication
Which test relies on birefringence pattern of the macula in order to evaluate an anomaly associated with strabismus and amblyopia?
Haidinger’s brushes NOTE: The patient will then see a small rotating bow-tie pattern. This rotating object represents where the fovea projects in object space. It is most commonly accepted that this phenomenon is caused by the birefringence pattern of the radially oriented fibers of Henle’s layer around the fovea. Haidinger’s brushes are very helpful in the diagnosis of eccentric fixation.
IN what situation would a X-chrome contact lens be MOST beneficial?
A Dichromat NOTE: Essentially an X-Chrome contact lens is a red contact lens that acts as a long-pass filter that blocks short wavelengths and allows longer wavelengths to pass through. Patients with abnormal color vision such as dichromats can benefit from this lens in that it aids in color distinction. Wearing the contact lens in one eye effectively shifts the color absorption curve of that eye so that it is different from the other eye; thus allowing the confusion lines of the patient to be altered between the eyes. In order for the lens to work properly, it is essential that the patient be able to easily alternate vision between the eyes for comparison. One of the drawbacks of the lens is that many patients will suppress the eye with the red lens or fuse the images, thereby reducing its effectiveness.
A positive plastic spherical surface (n= 1.50) in air has a secondary focal length of 28.52 cm. What equation would correctly solve for the power of the plastic surface?
P=1.50/0.2852 m P= n’/f’. For the above problem, the correct solution would be P= 1.50/0.2852 m, or P= +5.259 (because the surface is positive) or +5.25 D (when rounded to the nearest 0.25 D).
What HbA1c is considered normal?
5.7%
What HbA1c is pre-diabetic?
5.7 to 6.4%
What HbA1c is considered diabetic?
>6.5%
What is the normal postprandial glucose measures in pregnant women to assist in the Dx of gestational DM?
70-141 mg/dL
What is the pre-diabetes range for postprandial glucose measures?
141-200 mg/dL
What is the diabetic range for postprandial glucose measures?
>200 mg/dL
What is the normal FBS, pre-diabetic FBS, and diabetic FBS?
Normal = <100 mg/dL Pre-diabetic = 100-125 mg/dL Diabetic = >125 mg/dL
What are the 3 muscular boundaries of the superior carotid traingle?
- omohyoideus 2. Sternocleidomastoideus 3. Posterior belly of the digastricus
A patient with a very dense central corneal scar of his right eye requires his intraocular pressure (IOP) to be measured. Which instruments will yield the MOST accurate reading of his IOP?
Tonopen NOTE: Conditions that can alter central corneal elasticity, such as corneal edema or scarring, may decrease the accuracy of IOP measurement. For these situations it is best to use a McKay-Marg or Tonopen tonometer, which were constructed to better measure corneas with abnormal rigidity. The design of this instrument was created such that the forces of corneal rigidity and surface tension are decreased substantially.
What is the approximate volume of the vitreous?
4 mL
What is the equation for the optical density of a ND filter?
OD= log(1/T)