42. Upper visual field
Lower half of retina
Lateral geniculate body
Lateral fibres of optic
radiation(Meyers loop
through temporal lobe)
Lowerlip of calcarine
sulcus (LLLL)
Lower field upper retina
medial part of LGB medial
fibres of optic
radiation(parietal fibres)
upper lip of calcarine sulcus
43.
44.
45.
46.
47.
48. Macular sparing
• Fibres from macula lutea project on posterior lip of calcarine
fissure (last damaged) macular sparing
58. • A Marcus Gunn pupil is a pupil that does not respond very well to
light when the light is shined that eye. For example, when light is
shined in one normal eye (only), both pupils will constrict or get
smaller. If the light is then moved rapidly to the affected, Marcus
Gunn, eye even though the light is shining in the affected eye BOTH
pupils dilated or get larger. The patient usually does not know that
he/she has a Marcus Gunn pupil.
59. • Holmes-Adie syndrome or disease is a tonic pupil combined with
reduced deep tendon reflexes. A tonic pupil is one that does not
chance very much with changes with brightness or illumination.
Typically, the pupils constrict in brightness and dilate or grow larger in
darkness. In Holmes-Adie syndrome, the pupil(s) don't react to
changes in illumination. There may also be problems with
accommodation - close-up objects may appear blurry.
60. • Argyll Robertson pupils are bilateral small pupils that constrict when
the patient focuses on a near object (they “accommodate”), but do
not constrict when exposed to bright light (they do not “react” to
light).
• A pupil that fails to respond to light but does respond to
accommodation and is also very small (an Argyll Robertson pupil) is
an important diagnostic sign of central nervous system disease—
often syphilis.
61.
62.
63.
64.
65. Fibres terminating in visual cortex
• All fibres of optic radiation
terminate in layer 4 of primary
visual cortex
• Except colour vision fibres terminate
in layer 2 & 3
• Terminate in layer 2 & 3 (BLOBS)
66.
67.
68.
69. Colour blindness
• Trichromats
• Normal person with 3 cones but weakness of any one cone
• Protanomaly red cones are weak
• Deutranomaly weak green cones
• Tritanomaly weak blue cone
• Dichromats
• Have only 2 functional cones one is absent
• Protanopia absent red cone
• Deutranopia absent green cone
• Tritanopia absent blue cones
70. • Deutranopia
• Green blind
• when defective
deutranomaly
• Protanopia (most common)
• Red blind
• When vision is
defective(appreciate colour
but weak) protanomaly
• Tritanopia (rare)
• Blue blind
• Whwn defective
71.
72. Red green colour blindness
• Most common type of colour blindness
• Unable to differentiate b/w red & green colours
73. • Congenital color blindness or achromatopsia occur in two forms;
• total and partial.
• Total form
• rare and is associated with nystagmus and central scotoma.
• All colors appear grey with different brightness.
• partial form
• is seldom discovered unless special tests are made because the patient compensates
the defect by giving attention to shape, texture and by experience.
• Gross cases occurs in 3-4% of males but is rare in females.
• Slighter cases are more common in males. In most cases red and green Q colors
are confused.
• It can be tested by Ishihara chart.
74. • Color vision V8 area
• Lesions of V8 achromatopsia
• Color blindness à x-linked recessive disorder
84. • Endolymph is rich in K by striae
vascularis
• Potential difference b/w
endolymph & perilymph
+80mV
• Potential difference b/w
endolymph & hair cell 140
mV
• Inner hair cells
• RMP = - 60mV
85.
86.
87.
88. • Inner hair cells are sensory
• Inner hair cells are responsible
for hearing
• Not in contact with tectorial
membrane
• Single row
• Outer hair cells are motor in
touch with tectorial membrane
moves tectorial membrane
to dampen waves
• 3 rows modulation of sound
89. Only sterocilia in inner hair cells
But stereocilia & kinocilia in hair cells of
membranous labyrinth
90.
91. • The outer hair cells, on the other hand, respond to sound like the
inner hair cells, but depolarization makes them shorten and
hyperpolarization makes them lengthen. They do this over a very
flexible part of the basal membrane, and this action somehow
increases the amplitude and clarity of sounds.
• These changes in outer hair cells occur in parallel with changes in
prestin, a membrane protein, and this protein may well be the motor
protein of outer hair cells
111. • Maximum number of taste receptors in circumvallate papillae (abt
100)
• Fungiform (5 /papillae)
• Taste receptors are absent in filiform papillae
121. • Olfactory receptor itself is a
neuron
• Olfactory receptor has cilia
projecting in nasal mucosa
acting as receptor for olfaction
• Dendrites of neuron among
supporting cells
122. • Axons form olfactory nerve & pierce cribriform plate & terminates in
olfacrory bulb
• Synapses with mitral cells to form olfactory glomeruli
• Mitral cells are principal out put neurons & axons of mitral cells form
olfactory tract
128. Synapse with 5 different regions of brain
• Processing of olfaction
Anterior olfactory nucleus
• Emotional response to olfaction
Amygdala
• Sniffing
• Well developed in dogsPyriform cortex
• Processing of olfactory nerves
Entorrhinal cortex
• Final processing of smell
Orbitofrontal cortex
