Page 362 - Color_Atlas_of_Physiology_5th_Ed._-_A._Despopoulos_2003

A. Visual acuity

1.5mm
(at distance of 5 m) α=1’
Visual Acuity, Photosensors I
5m

Landolt 8.5m
rings
5m 3.3m

B. Retina: Photosensor distribution, sensitivity in darkness and visual acuity
Optical axis
Plate 12.20
Nasal Temporal
1 Photosensor distribution 90° Blind 90° 2 Visual acuity, sensitivity in
spot darkness
Rods Cones 60° (15°) 60° Sensitivity in Visual
acuity
darkness (%)
Sensor density (10 3 /mm 2 ) 100 30° Fovea centralis (5°) 60 1/2
150
1/1
80
30°
0
40
50
20
1/4
90° 60° 30° 0 30° 60° 90° 90° 60° 30° 0 30° 60° 90° 1/8
Blind spot Fovea centralis Blind spot Fovea centralis
C. Photosensors
1 Cone Rod Rhodopsin Cytoplasm of
Disks 2 C outer segment
Outer segment Disk

membrane
Cilia Inner
Mito-
Cyto-
Inner segment plasm chondria Opsin 3 N 11 space of disk O
Nuclei
Sensor
membrane
pedicle Plasma O
11-cis-retinal All-trans-retinal 349
Light energy
Despopoulos, Color Atlas of Physiology © 2003 Thieme
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