T8.3: Visual Systems & Retina Flashcards
Zombie Goldilocks lost her eyeballs so she was plucking eyballs out of corpses to replace hers. The first set of eyeballs were too short. What condition does this characterize? (MG)
A. Myopia
B. Hyperopia
C. Emmetropia
D. Ursaopia
B. Hyperopia
Far-sightedness
Zombie Goldilocks lost her eyeballs so she was plucking eyballs out of corpses to replace hers. The first set of eyeballs were too long. What condition does this characterize? (MG)
A. Myopia
B. Hyperopia
C. Emmetropia
D. Ursaopia
A. Myopia
Near-sightedness
Zombie Goldilocks lost her eyeballs so she was plucking eyballs out of corpses to replace hers. The first set of eyeballs were just right. What condition does this characterize? (MG)
A. Myopia
B. Hyperopia
C. Emmetropia
D. Ursaopia
C. Emmetropia
Normal vision, normal eyeball length
Ryan Averill, age 27, was listening to a podcast and jazz music simultaneously, when suddenly he hears some rough sex happening in the distance. This immediately triggers Ryan’s sympathetic response, dilating his iris muscles, as he sprints upstairs hoping to catch Adam Mamo doing the sex. Which iris muscle and innervation is paired correctly?
A. Sphincter pupillae are radial muscles whose contraction is controlled by parasympathetic response.
B. Spincter pupillae are circular muscles whose contraction is controlled by sympathetic response.
C. Dilator pupillae are circular muscles whose contraction is controlled by the parasympathetic response.
D. Dilator pupillae are radial muscles whose contraction is controlled by the sympathetic response.
E. Dilator pupillae are circular muscles whose contraction is controlled by the sympathetic response.
AA
CORRECT ANSWER = D. Dilator pupillae are radial muscles whose contraction is controlled by the sympathetic response.
Dilator pupillae are RADIAL muscles whose contraction DILATES the pupil. It is innervated by sympathetic nerves from the superior cervical gangelion. Therefore, options C and E are incorrect.
Spincter pupillae are CIRCULAR muscles whose contraction REDUCES pupil size. It is controlled by parasympathetic nervous system. Therefore, options A and B are incorrect.
Ahmee Ashai’s dark, black, sexy Wesley Snipes shade skin allows him to be invisible in the dark of the night. During darkness, the eye is _______, causing ______ binding to a gated channel resulting in the ______ of sodium.
A. Depolarized, cGMP, influx B. Depolarized, cGMP, efflux C. Depolarized, cAMP, influx D. Depolarized, cAMP, efflux E. Hyperpolarized, cGMP, influx F. Hyperpolarized, cGMP, efflux G. Hyperpolarized, cAMP, influx H. Hyperpolarized, cAMP, efflux
AA
ANSWER = A. Depolarized, cGMP, efflux.
The ‘dark current’ is the mechanism in which photoreceptors, unlike any other sensory receptor, stay depolarized during periods of darkness. In other words, when light is not hitting photoreceptors, they stay depolarized.
During darkness, the G-protein does not activate the enzyme cGMP phosphodiesterase. As a consequence, there is plenty of cytoplasmic cGMP available, which keeps the cGMP gated channels in the photoreceptor membrane open. This allows a continuous INFLUX current of sodium ions, which keeps the photoreceptors DEPOLARIZED in the dark.
Similar to other sensory neurons, or any neurons in general, photoreceptors release their neurotransmitter (glutamate) while they are depolarized.
Adam Mamo, age 24, suddenly finds himself with throbbing erections whenever he sees swole guys at the gym. He rushes himself to the doctor’s office to see if there is something wrong with his eyes. The local ophthalmologist sadly doesn’t speak arabic and mistakenly believes that Adam Mamo is requesting an Ishihara vision test.
The Ishihara vision test and subsequent vision tests results are conclusive, revealing Adam is insensitive to red light and has defective long wavelength cones (L-cones). Adam is revealed to have difficulties in distinguishing between blue and green and between red and green colours. What color blindness does Adam Mamo have?
A. Dichromat Protanopia B. Protanopia C. Deuteranopia D. Dichromat Deuteranopia E. Anomalous trichromats F. Achromatopsia
AA
ANSWER = B. Protanopia.
Protanopia: insensitivity to red light and have defective long wavelength cones (L-cones). Patients have difficulties in distinguishing between blue and green and between red and green colours.
Deuteranopia: insensitive to GREEN light. Red and green are the most difficult to detect, with gray, purple, and greenish blue-green hues replacing them.
Anomalous trichromats: type of deuteranopia, with medium-wavelength cones missing due to defective green cones.
Dichromat: have a total lack of L-cones. Dichromat Protanopia would not be able to see red light at all. Dichromat deuteranopia would not be able to see green light at all.
Achromatopsia (Cortical Color Blindness) is an inability to distinguish color hues due to cortical lesions in Brodmann’s Areas 18 or 37. Inferior temporal cortical lesions can cause color blindness. This would result in a complete color blindness, not partial.
Jim is hit in the head with a soccer ball and now lost central vision. What was damaged?
A. Macula
B. Fovea
C. Optic Disk
D. Lens
RFA
Ans. A Macula is the best answer. while the Fovea is contained in in it the Macula is the area of the retina dedicated to central vision
Amblyopia is a issue stemming from?
A. Receptor Density
B. Retina Function
C. Cortical processing
D Optical Factors
RFA
Ans C- Amblyopia( lazy eye)- is due to cortical processing issues along with TBI and stroke
A. Receptor Density- central vs. peripheral issues
B. Retina function- Retinal detachment, Macular Degeneration
D. Optical Factors- sharpness of retinal focus in the eye.
Jerry comes into the with dilated pupils. It is found he has damage to his nervous system at the origin of fibers responsible for constriction .
A. Ciliary Ganglion
B. Edinger- Westphal Nucleus
C. Intermediolateral cell column in the upper thoracic region of the spinal cord
D. Otic Ganglion
RFA
Ans B- Edinger-Westphal Nucleus is PNS origin for CNIII responsible for pupil constriction
A. Ciliary Ganglion- is involved pupil constriction but is not the origin
C This is the SNS origin, dilation action
D. Ganglion for Parotid gland secretion
What type of lens corrects hyperopia?
convex glass lens in front of eye
What type of lens corrects myopia?
concave glass lens in front of eye
A patient complains of his upper right eye field being slightly black and a floating baby worms in his vision. which eye sight problem is he experiencing?
A) Retinal Detachment B) Age Related Macular Degeneration C) Diabetic Retinopathy D) Night Blindness E) Color Blindness
Answer = A
B- blurry fovea
C- scars and diabetic
d- vit a defic
