💢فسيو العصبي 5 الرؤيه
#physiology_of_CNS 5
#CNS
#⃣Vision :
🔷راح نشرح اليوم عن الرؤية بالتفصيل باذن الله👌😍💪
1⃣Optics :👇👇👇
A:Refractive power of a len :👇
■ is measured in diopters
■ equals the reciprocal of the focal distance in meters.
■ Example: 10 diopters = 1/10 m = 10 cm .👌
B:Refractive errors :👇
##كل اللراح اذكره تحت👇 عبارة عن
Errors 👌👇
##👆 لازم نحفظها ي حلوين تمام😄👌💪👇👇👇
(1) Emmetropia—normal. Light focuses on the retina 👌
(2) Hypertropia—farsighted. Light focuses behind the retina and is corrected with a
convex lens👌
3) Myopia—nearsighted. Light focuses in front of the retina and is corrected with a
biconcave lens 👌
(4) Astigmatism. Curvature of the lens is not uniform and is corrected with a cylindric
lens👌
(5) Presbyopia is a result of loss of the accommodation power of the lens that occurs
with aging 👌
##👆👆 وهيك خلصنااا كل ال 👇
Errors👌👌👌
🔷👆👆واكيد مو راح يصعب عليكم شيء!💪👏😍 احفظوهم اوك😄💪
2⃣Layers of the retina :👇👇
A:Pigment epithelial cells 👇
##وهذه الخلايا وظيفتها 👇👇
■ absorb stray light and prevent scatter of light.
■ convert 11-cis retinal to all-trans retinal👌
B: Receptor cells are rods and cones :👇👇👇
■ Rods and cones are not present on the optic disk; the result is a blind spot👌
C:Bipolar cells:👇👇👇
*⃣The receptor cells (i.e., rods and cones) synapse on bipolar cells, which synapse on the ganglion cells👌👇👇
(1) Few cones synapse on a single bipolar cell, which synapses on a single ganglion cell👌😎💪
(2) Many rods synapse on a single bipolar cell👌😎💪
D:Horizontal and amacrine cells form local circuits with the bipolar cells 👌👌👌and
E: Ganglion cells :👇👇👇
##اللهي عبارة عن 👇👇👇
🔷are the output cells of the retina👌👌😎
🔷 Axons of ganglion cells form the optic nerve 👌👌😎
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