Quiz
Vision and visual pathway
Questions in this quiz (50)
1Vision - choose correct
- AElectromagnetic radiation in this range of wavelengths is called visible light or simply light.
- BThe optical spectrum is the portion of the electromagnetic spectrum that is visible to the animal eye.
- CThe visible spectrum is approximately between 400nm to 750nm
- D8% of men are colour blind, it's a Y-linked disease
2Retina - rods & cones - choose correct
- ABoth photoreceptors are found in the inner nuclear layer of the retina at the back of each eye
- BBipolar and ganglion cells send information from photoreceptors to the brain are in front of the cones and rods
- CThe human eye have 6 million cones and 120 million rods
- DCones and rods are types neurons
3Albinism; choose correct
- AAlbinos don't have colour vision
- BAlbinos have reduced pigment epithelium in sclera and choroid
- CAlbinos have colour vision
- DAlbinos have increased visual acuity, due to intra-ocular reflection of light
4Vision - choose correct
- ARetinal ganglion cells that express the photopigment melanopsin.
- BIn the absence of rods and cones, mammals retain the ability to detect light for various non-image-forming visual functions.
- CPhototransduction is conducted only by cones and rods
- DCones have rhodopsin and rods have fotopsin
5Retino-hypothalamic tract - choose WRONG
- APhotosensitive ganglion cells seem to serve as photoreceptors for the photic synchronization of circadian rhythms.
- BCones innervate the midbrain pupillary control center.
- CThey project to the circadian pacemaker of the brain - the suprachiasmatic hypothalamic nucleus
- DPhotosensitive ganglion cells contribute to the pupillary light reflex and other behavioral and physiological responses to environmental
6Neurotransmitters; choose WRONG
- ARods/cones - Glutamate
- BAmacrine cells - Inhibitory neurotransmitters (GABA, Glycine, Dopamine, Ach, Indolamine)
- CHorizontal cells - Excitatory neurotransmitters.
- DHorizontal cells - Inhibitory neurotransmitters.
7Retina; Choose correct
- AGanglion cells - the only retinal cell of the pathway transmitting signals by mean of action potential.
- BAmacrine cells - Occasionally action potential is recorded in.
- CRemaining cells of the retina - conduct their visual signals by electrotonic conduction (graded conduction).
- DGanglion cells - conduct their visual signals by electrotonic conduction (graded conduction).
8Photoreceptors; choose correct
- ARods are used to determine color, depth, and intensity.
- BEach particular photosensitive cell responds to monochromatic spectral stimuli
- CAll 3 types of photoreceptors transduce light into a change in membrane potential through different signal transduction pathway.
- DAll 3 types of photoreceptors differ in the nature of the opsin they contain and therefore in their function.
9Vision; choose correct
- ACones are divided into red, blue and green
- BVisual imaging occurs in the visual cortex, occipital lobe
- CFovea has the lowest visual acuity
- DRods are trichromatic
10Generator potential; choose correct
- ADark current - the voltage-gated sodium channels in the outer segment are opened due to cGMP bound to them.
- BDark current - depolarising sodium channels to - 40mV, in dark conditions
- CRods are also de-polarising in light conditions
- DCones de-polarise in dark conditions
11Signal tranduction pathway; choose correct
- AThe opsin in the outer segment absorbs a photon, changing the configuration of a molecule inside the cell from the less- energetic cis-form to the more-energetic trans-form.
- BNight blindness can be caused by deficiency of vitamin E
- CThe light acts as a ligand
- DLight is absorbed by rhodopsin or by one of the photopsins of cones, changing shape of the retina.
12Signal transduction pathway; choose correct
- AEach photo-activated rhodopsin triggers activation of about 100 transducins
- BPDE inhibits the hydrolysis of cGMP
- CEach transducin then activates the enzyme cGMP-specific phosphodiesterase (PDE)
- DcGMP was keeping the Na(Ca channels closed
13Signal transduction pathway ; choose correct
- AA photoreceptor actually releases less neurotransmitter when stimulated by light.
- BHyper-polarization means that less glutamate is released to the bipolar cell than before.
- CGTP provided by the inner segment powers the sodium- potassium pump.
- DThe opening of Na+ channels hyperpolarizes the cell
14Which of these neurons do not belong to the visual pathway?
- ANeurons of layer 4 of the visual cortex (Brodman’s area 17).
- BBipolar cells, Photosensitive cells and Ganglion cells.
- CHorizontal and amacrine cells
- DCells of the lateral geniculate body of the thalamus.
15Visual pathway; choose correct
- AOld system - Suprachasmatic nucleus of hypothalamus – SCN (circadian rhythms)
- BOld System - Lateral geniculate nucleus of thalamus (LGN)
- COld system - Visual cortex (4th neuronal of Brodman’s field 17)
- DOld system - Pretectal nuclei of the midbrain (pupillary reflexes) & Superior colliculi (rapid eye movement of both eyes)
16Functions of the lateral geniculate body (nucleus); choose correct.
- AParvocellular portion of LGN - (shape, color, texture, fine detail).
- BInterlaminar path - conduct impulses from ipsilateral eye.
- CMagnocellular portion of LGN - (spatial organisation, movement, location)
- DLayers 1,4,6 - colour
17Vision; Choose wrong
- ARight retina - Left hemisphere, calcarine fissure
- BLeft retina - Right hemisphere, cuneus gyrus fissure
- CTemporal vision crosses at the optic chiasm
- DNasal vision crosses at the optic chiasm
18Functions of visual projection areas of the visual cortex - Choose wrong match
- AV2, V3, VP – Motion, control of movement.
- BV3A , MT/V5 – Continued processing – larger visual field.
- CV1 – Primary visual cortex – receives input from the LGN – processing in terms on orientation edges, etc.
- DLO – Recognition of large objects.
- EV8 – Color vision.
19Refraction;
- ALight, passing from one transparent medium to another, changes its speed, and bends.
- BAngle of refraction - The angle between the light ray and the normal, as it leaves a medium.
- CEach medium has its own refractive index
- DAngle of incidence - The angle between the light ray and the normal as it enters a medium
20Rate of bending of light depends on;
- AStrength of the light ray
- BThe angle between the light ray and the line perpendicular to the surface separating both media
- CThe refractive index of the media
- DAbsence of other sources of light
21Refraction;
- AParallel light rays are bent to pass through a single point behind the lens (focal point)
- BRays striking perpendicular lens surface pass the lens by bending
- CConvex lenses diverge light rays
- DRays striking perpendicular lens surface pass the lens without being bent
22Refraction;
- AIn the focal length distant sources of light rays are parallell
- BIn the focal length distant sources of light rays are converged
- CIn the focal length the close source is parallell
- DFocal length - distance beyond midpoint of a convex lens, and the focal point
23Refracted image of objects;
- AReversed - Upside-down, left side-right
- BInversed - Downside-up, left side-right
- CEach point source of light on the object comes to a separate point focus on the opposite side of the lens in line with the lens centre
- DOnly one source of light on the object comes to a separate point focus on the opposite side of the lens in line with the lens centre
24Power of lens;
- AExpressed in diopters
- BSpherical Convex lenses = -1 power
- CSpherical Concave lenses = +1 power
- DSpherical Convex lenses = + 10 power
25Optics of the eye;
- AInterface between posterior surface of the cornea and aqueous humour is a part of the optic system
- BInterface on both sides of the lens are parts of the optic system
- CInterface between the retina and the optic nerve is a part of the optic system
- DInterface between air and the anterior surface of the cornea is a part of the optic system
26Choose correct match of indexes of refraction to their medium;
- AAir = 1.0
- BThe lens = 1.40
- CThe cornea = 1.33
- DThe aqueous humour = 1.38
- EThe vitreous humour = 1.34
27Optics of the eye;
- A1/3 of all the refractive power of the eye is provided by the anterior surface of the cornea.
- BTotal refractive power of the eye is 59 dioptres
- C2/3 of all the refractive power of the eye is provided by the anterior surface of the cornea.
- DTotal refractive power of the eye is 39 dioptres
28Optics of the eye;
- AReduced eye - a simplified design of the ocular optical system, represented as having a single refracting surface and a uniform index of refraction
- BReduced eye - By close object the light rays are diverged and refraction power of the eye should be increased in order to focus eye on object and produce the image exactly on the retina.
- CAccommodation - By close object the light rays are diverged and refraction power of the eye should be increased in order to focus eye on object and produce the image exactly on the retina.
- DAccommodation - a simplified design of the ocular optical system, represented as having a single refracting surface and a uniform index of refraction
29Accommodation;
- ARefraction power of the eye can be increased voluntary by approximately 14 dioptres by changing the shape of the lens from moderately convexed to more convexed.
- BIn normal conditions tension of ligaments of the lens causes its to remain spherically shaped.
- CContraction of the ciliary muscle depend on parasympathetic transmission via III CN.
- DContraction of smooth muscle fibers in the ciliary muscle tenses the ligaments to the lens capsule and the lens assumes a more spherical shape.
30The far point of vision;
- AReduced eye – refraction power 59 D
- BWith age gets farther away
- CLight rays are divergent
- DPicks up 6 m and more distant objects.
31The near point of vision;
- AParallell light rays, and the point of vision comes closer with age
- BAbout 20 cm in front of eyes
- CDoes not require accommodation
- DThe nearest point in front of eye which can be focused on retina
32Choose correct elements of the near response;
- AAccomodation
- BPupillary constriction
- CPupillary dilation
- DDivergence of the visual axes
33Choose correct for normal focusing ability;
- ADistant object - parallel light rays focuses on retina
- BLight rays focus behind the retina
- CClose object - contraction of ciliary muscle provide accommodation – diverge rays are focus on retina
- DLight rays focus in front of the retina
34Defects of focusing;
- APresbypia (senile farsightedness) is caused by decreased lens elasticity
- BPresbypia (senile farsightedness) is caused by decreased power of ciliary muscle
- CAstigmatism is caused by a cornea that isn't spherical
- DAstigmatism is corrected with concave lenses
35Visual acquity does NOT depend on....?
- AFixation of eye (fovea centralis)
- BRefraction index of medium
- CAstigmatism
- DMyopia
36Visual acquity depends on
- AOptical factors (image-forming mechanisms of the eye)
- BDepth of vision
- CRetinal factors
- DStimulus factors (illumination, brightness, contrast, time of exposure)
37Depth of Vision;
- ADistance is perceived by - sizes of known objects, moving parallax and stereopsis
- BDistance is perceived by - sizes of unknown objects and stereopsis
- CDistance is perceived by - relative distance, fast moving close objects and slow moving far objects
- DStereopsis is dependent on mono-ocular vision - image only created on retina
38Photoreceptors;
- ARhodopsin decompose in darkness
- BRhodopsin is combined of scotopsin and retinene-1 (aldehyde of vit. A)
- CThe only retinal neurons that transmit visual signal by means of action potential are the ganglia cells
- DActivated rhodopsin deactivates transducin
39Phototransduction;
- APhoton activates an electron
- BActivated transducin activates rhodopsin
- CActivated transducin activates cGMP
- DPhosphodiesterase hydrolyzes cGMP (which normally causes Na-channels stay open),
and Na-channels close
40Blind spot;
- AFound 15 degrees temporally to visual axis
- BIt is NOT visible through the ophtalmoscope as the optic disc.
- CThe optic nerve leaves the eye at the point 3 mm medial to and slightly above the posterior pole of the globe
- DThere are some photoreceptors in this area
41Choose correct match between cranial nerve and activity of eye structure;
- AOptic N. (CN2) - Mediates vision
- BOculomotor N. (CN3) - innervates superior oblique muscle
- CTrochlear N. (CN4) - innervates superior oblique muscle
- DTrigeminal N. (CN5) - sensory portion of corneal reflex
- EAbducens N. (CN6) - Innervates orbicularis oculi and lacrimal glands
42Visual adaptation;
- ALight adaptation (photopic vision) - regeneration of photopigment, that in turn increases visual sensitivity
- BDark adaptation (scotopic vision) - a reduction in the amount of rhodopsin, which in turn reduces visual sensitivity
- CLight adaptation time is 5min
- DDark adaptation time is 20min
43Visual fields; limitations
- ALaterally = 90 degrees
- BDownward = 50 degrees
- CUpward = 50 degrees
- DMedially 65-70 degrees
44Visual pathway - choose correct order;
1. Geniculate body neurons
2. Bipolar cells
3. Cerebral cortex
4. Rods and cones
5. Ganglia cells- A1, 3, 2, 4, 5
- B4, 2, 5, 1, 3
- C2, 4, 5, 1, 3
- D4, 5, 2, 1, 3
45Visual pathway;
- AAxons of ganglia cells converge and leave eye as the optic nerve through optic disc.
- BThe temporal optic fibers cross at the optic chiasm
- CEach optic tract fibres synapse in ventral lateral geniculate nucleus of lateral geniculate body (LGB) of the thalamus.
- DGeniculocalcarine fibres pass as optic radiation to the primary visual cortex in the calcarine fissure area of the medial occipital lobe (striate cortex)
46Visual pathway;
- AGeniculate body has 6 layers, 2 main parts parvocellular and magnocellular
- BParvocellular -carries signals for colour vision, texture, shape, fine detail
- CParvocellular - carries signals for detection of movement, depth and flicker
- DMajor input comes form the retina
47Visual Cortex;
- APrimary cortex; Brodmann’s area 18 (V2),19
- BSecondary cortex; Brodmann’s area 17 ( also known as V1)
- CArea V8 concern with colour vision
- DDorsal and parietal pathway – motion
- EVentral and temporal pathway – shape and recognition of forms and faces
48Defects of visual analyser;
- AOptic chiasm – right or left homonymus hemianopia (half-blindness in same side half of the visual field
- BInterruption of optic nerve – blindness in the eye
- COccipital lesion – macular sparing (loss of peripheral vision with intact macular vision)
- DOptic tract - bitemporal heteronymous hemianopia (half-blindness in opposite sides of the visual field)
49Reaction of pupil to light
- AAfferent pathway: photoreceptors, bipolar cells, ganglion cells, optic nerve, optic tract, nuleus pretectalis and farther to Edinger-Westphal nucleus bilaterally.
- BEfferent pathway: from Edinger-Westphal nucleus through oculomotor nerve to ciliary ganglion and n.n. ciliares breves to papillary sphincter.
- CEfferent pathway: photoreceptors, bipolar cells, ganglion cells, optic nerve, optic tract, nuleus pretectalis and farther to Edinger-Westphal nucleus bilaterally.
- DAfferent pathway: from Edinger-Westphal nucleus through oculomotor nerve to ciliary ganglion and n.n. ciliares breves to papillary sphincter.
50Choose correct instrument to function;
- ASlit lamp - facilitates examination of the eyelid, sclera, conjunctiva, iris, natural crystalline lens, and cornea
- BOphtalmoscopy - Used to determine the health of retina and the vitreous humour
- COphtalmoscopy - facilitates examination of the eyelid, sclera, conjunctiva, iris, natural crystalline lens, and cornea
- DPerimetry - maps and quantifies the visual field
- ESlit lamp - maps and quantifies the visual field
Information
- Description
- Based on PUM physiology presentations and own notes
- Author
- Soheila Amri
- Language
- English
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