Vision: When a foreign particle lands on the cormea what prevents it from migrat
ID: 3509162 • Letter: V
Question
Vision: When a foreign particle lands on the cormea what prevents it from migrating to the back of the eye and damaging the optic nerve? Why do you get a runny nose or sniffles when you cry Trace the pathway of lacrimal fluid secretion complete drainage What medical condition develops with blockage of the canal of Schlemm (scleral venous sinus)? What eye region is damaged and how does this happen ? The ciliary body consists of the muscle control? process and the muscle. What does this What region of the eye contains only cones? What visual property is associated with this region? What visual property is lost when rods are not functional? Explain why? Where is the blind spot of the eye? Why is it called a blind spot?Explanation / Answer
1) cornea along with tears plays a protective role in eye,it prevent penetration of microorganisms.
2) Lacrimal gland(tear secretion) => lacrimal punctum => lacrimal canaliculi => lacrimal duct => nasal discharege that is running nose.
3) Glaucoma is associated with this condition
Canal of schlemm is respospible for delivering aqueous humour to episcleral blood vessels.their blackage will cause dry eyes,finally adhesion of lens and cornea.,intraocular pressure also increase which results in narrowing of iridocorneal angle and results into glaucoma.
4)ciliary processes (vary from sixty to eighty in number) and ciliary muscle.
Ciliary muscle helps in accomodation of lens thus help in responding to the intensity of light.
5)they are dense in fovea centralis,they provide the clearest vision and sharpest image of an object.
6)Rod cells function in dim light,if there visual property is lost,night blindness occurs,due to activation of phosphodiesterase enzyme which breaks thousands od cGMP molecules within a second.
7)It is small portion of visual field within the retina of the eye and corresponds to postion of optic nerve also called as optic nerve head.photoreceptor cells are absent here therefore no image is formed at this site and hence called blind spot.
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