22. Neuroanatomy of vision. Visual pathway, visual recognition, orientation in space. Flashcards
3 parts of the inner coat
- Optic part of the retina
- Non-visual part of the retina: ciliary part and iridium part
Layers of the optic part of the retina
- Pigmented layer (pigment epithelium)
- Neural layers: 9 layers of neural and glial elements
Layers of the iridial part of the retina
2 layers of pigmented epithelium
Characteristics of the ciliary part of the retina
- Pigmented epithelium outside
- Nonpigmented epithelium insideelements
Name these parts of the retina
Components of visual pigment
opsin protein + retinal as a chromophor
The visual pigments: the opsin family
-> List the pigment(s) included in rods
rhodopsin
The visual pigments: the opsin family
-> List the pigment(s) included in cones
- short wavelength sensitive opsin in β (blue) or S cones
- medium wavelength sensitive opsin in γ (green) or M
- long wavelength sensitive opsin in ρ (red) or L cones
- The visual pigments: the opsin family
-> Absorption properties of the visual pigments are exclusively determined by ______
The highly variable opsin peptides,
What is the chromophore?
the retinal in all the four types of human photoreceptors
Identify
Identify these 10 layers
What types of cell bodies are included in 6. Internal nuclear layer?
cell bodies of bipolar, horizontal, amacrine and Müller cells
The role of Horizontal and amacrine cells
Horizontal and amacrine cells are predominantly inhibitory (GABAergic) and contribute to contrast enhancement.
What is Receptive field of ganglion cells?
a spot within the whole visual field perceived by those photoreceptors which converge on the particular ganglion cell.
Blood supply of the retina for outer layers
Choroid
Blood supply of the retina for inner layers
central retinal artery
- branch of ophthalmic artery of internal carotid artery
- superior and inferior, nasal and temporal and macular branches
Parts of the inner coat of the eyeball include…
: optic, ciliary and iridial parts of the retina
What are the Cell types of the retina?
cones/rods, bipolar cells, amacrine and horizontal cells, ganglion cells, Müller cells
What are the 4 parts of the optic nerve?
a) Pars intraocularis (2 mm)
b) Pars orbitalis (25-30 mm)
c) Pars canalicularis (5 mm)
d) Pars intracranialis (13 mm)
List the layers of Optic nerve
- Ext. vagina (Dura mater), towards the inside
- Arachnoid; below:
intervaginale subarachnoideal space, below: - Int. vagina (Pia mater) → Septa, 800-1200 fascicles
Optic nerve
-> Identify
Blood supply for the optic nerve
Blood supply from the ophtalmic a. (1.st branch of the ICA)
Identify 2, 3, 4, 7, 8
2: Sclera ring
3: Excavation
4: Pigmental ring
7: macula lutea
8: central fovea
3 things that constitute optic nerve papilla
7: macula lutea
8: central fovea
Visual pathway
-> What are The first 3 neurons are in the retina?
- Rods and cones (Str. neuroepitheliale et granulosum externum)
- Bipolar neurons (Str. granulosum internum)
- (multipolare) Ganglionic layer (Str. ganglionare), The axons are gathering (Str. neurofibrarum) to the optic nerve
Visual pathway
-> Where does the information come from?
Informations from the fields of vision of two eyes
Visual pathway
-> Informations from the fields of vision of two eyes
-> Characteristics of this information
will be in strict, point-to-point retinotopic arragement to the visual cortex.
determinated
Visual pathway
-> What is the visual field?
Part of the view that with unmoved eye caught can be.
Visual pathway
-> What is the Retinotopy?
The spacial relationships in the position relationships of the nerve tracts.
Visual pathway
(1) Axons from the nasal retina halves cross ___
(2) Axons from the temporal halves stay ___
- in the chiasm.
- ipsilateral.
Types of projections of fibers from the sharpened vision
Fibers from the sharpened vision have bilateral projection. (Basics of „macular sparing“)
The path of Projecting fibers from the lower halves of the retina
Projecting fibers from the lower halves of the retina projects on the upper lip of the sulcus calcarinus.
-> The periphery is at the front, the center more at the occipital pole.
What is suprasellar pyramid?
Optic nerve and tract with the chiasma are forming the so-called suprasellar pyramid (e.g., suprasellar growing pituitary tumors can compress these structures).
Bifurcation of ACI, AcomA, AcomP surround the pyramid.
Visual pathway
-> Identify
Visual pathway
-> What does the optic tract divide into?
It divides into a medial and lateral crus
Visual pathway
-> Pathway of medial crus of optic tract
- Medial crus goes into the superior colliculus via the brachium of the superior colliculus
Visual pathway
-> Pathway of the lateral crus of the optic tract
It goes into the LGB
Visual pathway
-> Characteristics of 4th neurons?
Lateral geniculate body
Visual pathway
-> 4th neurons
-> The role of 1 - 2. Lamina: pars magnocellularis
Motion perception
Visual pathway
-> 4th neurons
-> The role of 3-6. Lamina: pars pavocellularis
Color, shape, texture, spatial resolution
Visual pathway
-> Axons of the ggl. cells (3rd neurons) in the optic nerve and in the tracts optics reach ___
the 4th neurons in LGB
Visual pathway
-> Axons of the ggl. cells (3rd neurons) in the optic nerve and in the tracts optics reach the 4th neurons in LGB
-> From here, they take the further course to the ___
Cortex (5th neuron)
Visual pathway
-> Fibers from ____ become a temporal bundle beside the lateral horn
the upper visual field
Visual pathway
-> Fibers from the upper visual field become a temporal bundle beside the lateral horn
-> Forming a loop which is called…
Meyer-loop (lower lip of the calcimine sulcus)
Visual pathway
-> Fibers from the lower visual field above the parietal part of lateral ventricle to ___
the cortex (upper lip of the calcarine sulcus)
Visual pathway
-> What is Gratiolet-optic radiation?
the optic radiation from the metathalamus, in the posterior crus of the internal capsule
Explain Pupillenreflex
Fibers from the medial branch of the optic tract pull through brachium coll. sup. to the nuclei praetectales, which switch to the Edinger Westphal nucleus:
The M. sphincter pupillae contracts when exposed to light.
on the side of the incidence of light: direct reaction
on the other side: indirect reaction
