Anatomy Outline Test #3
... Lec. 26: Development of the Eye Week 4 (Day 22)-Week 20 (not able to see well at birth) Eye development Comes from neuroectoderm (forebrain) = retina, optic n. o optic stalkoptic nerve o optic cup retina Mesenchyme = choroid, sclera Surface ectoderm of head= cornea, lens Optic grooves/su ...
... Lec. 26: Development of the Eye Week 4 (Day 22)-Week 20 (not able to see well at birth) Eye development Comes from neuroectoderm (forebrain) = retina, optic n. o optic stalkoptic nerve o optic cup retina Mesenchyme = choroid, sclera Surface ectoderm of head= cornea, lens Optic grooves/su ...
NO-induced regulation of human trabecular meshwork cell volume
... distinct cell populations (13). The cellular mechanisms underlying changes in aqueous humor outflow through the TM are not well understood; however, several cellular mechanisms have been proposed (18). The TM is thought to be a smooth muscle-like tissue with contractile properties (5, 33). Contracti ...
... distinct cell populations (13). The cellular mechanisms underlying changes in aqueous humor outflow through the TM are not well understood; however, several cellular mechanisms have been proposed (18). The TM is thought to be a smooth muscle-like tissue with contractile properties (5, 33). Contracti ...
Improving Vision Naturally
... size as the iris contracts and expands to modulate the amount of light entering the eye. Behind the iris the choroid forms a muscular appendage known as the ciliary body. The ciliary body is where some of the fluid of the eye is produced. Behind the pupil lies another structure which should be trans ...
... size as the iris contracts and expands to modulate the amount of light entering the eye. Behind the iris the choroid forms a muscular appendage known as the ciliary body. The ciliary body is where some of the fluid of the eye is produced. Behind the pupil lies another structure which should be trans ...
Document
... • Originates as outpocketing of brain • Delicate two-layered membrane – Outer Pigmented layer ...
... • Originates as outpocketing of brain • Delicate two-layered membrane – Outer Pigmented layer ...
The Parasympathetic Pathways to Internal Eye Muscles
... nucleus, but this is by no means the only site yielding accommodation responses. Frequencies of 400 to 500 Hz. are most effective and frequencies below 200 Hz. progressively less so. In the site mentioned, stimulation results in the full near triad, with symmetrical convergence and pupil constrictio ...
... nucleus, but this is by no means the only site yielding accommodation responses. Frequencies of 400 to 500 Hz. are most effective and frequencies below 200 Hz. progressively less so. In the site mentioned, stimulation results in the full near triad, with symmetrical convergence and pupil constrictio ...
acute visual loss
... A 30 -year-old woman presents with sudden vision loss of the right eye and mild pain on upgaze movement. Examination reveals that vision is 20/50 on the right and 20/20 on the left. There is a +RAPD on the right and a Visual field testing showed an inferior altitudinal defect on the same side. The l ...
... A 30 -year-old woman presents with sudden vision loss of the right eye and mild pain on upgaze movement. Examination reveals that vision is 20/50 on the right and 20/20 on the left. There is a +RAPD on the right and a Visual field testing showed an inferior altitudinal defect on the same side. The l ...
Optic nerve and visual pathway
... • It is a segmental infarction of the anterior part of the optic nerve, caused by the occlusion of short posterior ciliary arteries. • Symptoms : Headache, scalp tenderness, jaw claudication, pain and stiffness of the proximal muscles. ...
... • It is a segmental infarction of the anterior part of the optic nerve, caused by the occlusion of short posterior ciliary arteries. • Symptoms : Headache, scalp tenderness, jaw claudication, pain and stiffness of the proximal muscles. ...
Visual Function and Cortical Organization in Carriers of Blue Cone
... is smaller because foveal underdevelopment leads to ganglion cell loss; this is supported by the narrowing of the width of the optic nerves, chiasm and tracts observed in the albino retina [17]. In contrast, Adams & Horton [18] mapped the cortical representations of angioscotomas in the squirrel mon ...
... is smaller because foveal underdevelopment leads to ganglion cell loss; this is supported by the narrowing of the width of the optic nerves, chiasm and tracts observed in the albino retina [17]. In contrast, Adams & Horton [18] mapped the cortical representations of angioscotomas in the squirrel mon ...
Ophthalmic Examination Made Simple
... light, stand far enough away from the patient to visualize both pupils simultaneously, using the tapetal reflection. The tapetal reflection also serves to highlight (by means of retroillumination) any ocular opacities, particularly in the lens or vitreous humor. Next, use a bright light to evaluate ...
... light, stand far enough away from the patient to visualize both pupils simultaneously, using the tapetal reflection. The tapetal reflection also serves to highlight (by means of retroillumination) any ocular opacities, particularly in the lens or vitreous humor. Next, use a bright light to evaluate ...
Conjunctival epithelial wound healing.
... origin of goblet cells cannot be determined in these experiments so that neither explanation for the disappearance of goblet cells during conjunctival healing can be verified. ...
... origin of goblet cells cannot be determined in these experiments so that neither explanation for the disappearance of goblet cells during conjunctival healing can be verified. ...
Ocular surface reconstruction in limbal stem cell deficiency
... Davanger and Evensen [9] proposed that the corneal epithelium is renewed from a source of cells located at the limbus. They were the first in proposing the stem cell theory. Corneal stem cells are located peripherally at the limbus, in the basal cell layer, in pigmented crypts called the palisades o ...
... Davanger and Evensen [9] proposed that the corneal epithelium is renewed from a source of cells located at the limbus. They were the first in proposing the stem cell theory. Corneal stem cells are located peripherally at the limbus, in the basal cell layer, in pigmented crypts called the palisades o ...
Document
... • Three small bones in middle ear cavity: the malleus, incus, and stapes • Transmit vibratory motion of the eardrum to the oval window • Tensor tympani and stapedius muscles contract reflexively in response to loud sounds to prevent damage to the hearing receptors ...
... • Three small bones in middle ear cavity: the malleus, incus, and stapes • Transmit vibratory motion of the eardrum to the oval window • Tensor tympani and stapedius muscles contract reflexively in response to loud sounds to prevent damage to the hearing receptors ...
Thorax - Dr James Mitchell
... colon. Most vagal fibres are afferent, there is a very large ratio of postganglionic to preganglionic efferent fibres. S2-4 Anterior rami → sacral spinal nerves → pelvic viscera and pelvic plexus → bladder, erectile tissue, gonads, uterus and uterine tubes, hindgut from mid transverse colon to rectu ...
... colon. Most vagal fibres are afferent, there is a very large ratio of postganglionic to preganglionic efferent fibres. S2-4 Anterior rami → sacral spinal nerves → pelvic viscera and pelvic plexus → bladder, erectile tissue, gonads, uterus and uterine tubes, hindgut from mid transverse colon to rectu ...
The Parasympathetic Ganglia in the Head and Neck
... How are the Visceral Structures Supplied by Autonomic (Motor) Fibers? The autonomic supply to the visceral structures in two points: 1. Most of the visceral structures have two nerve supply: one sympathetic and one parasympathetic. One of these nerves acts "stimulator" while the other acts "inhibit ...
... How are the Visceral Structures Supplied by Autonomic (Motor) Fibers? The autonomic supply to the visceral structures in two points: 1. Most of the visceral structures have two nerve supply: one sympathetic and one parasympathetic. One of these nerves acts "stimulator" while the other acts "inhibit ...
Leading 2nd version.PM
... Most investigations of the toxicity of intraocular iron foreign body were carried out in the 1970s. Since then, our knowledge of the biochemistry of iron toxicity and the basic pathology of the retina, as well as the mechanism of cell death has greatly increased. Apoptosis has been shown to be the m ...
... Most investigations of the toxicity of intraocular iron foreign body were carried out in the 1970s. Since then, our knowledge of the biochemistry of iron toxicity and the basic pathology of the retina, as well as the mechanism of cell death has greatly increased. Apoptosis has been shown to be the m ...
Cortical Organization
... The “What” stream is a giant module. The “Where/How/Action” stream is a second giant module. But are there more specific modules? Are there specialties within the streams – streams within streams? Evidence for specialized modules – from the past 20 years of research. 1. Area V4: A module for process ...
... The “What” stream is a giant module. The “Where/How/Action” stream is a second giant module. But are there more specific modules? Are there specialties within the streams – streams within streams? Evidence for specialized modules – from the past 20 years of research. 1. Area V4: A module for process ...
neurology_lab9_3_5_2011 - Post-it
... cross to opposite side posteriorly to emerge from post aspect of midbrain "the decussation will be post to cerebral aquiduct " Medial lemniscus tracts & lateral lamniscus & trigeminal lemniscus run post to substantia nigra . Crus cerebri "ant to substantia nigra" contain a lot of fibers . 1. middle ...
... cross to opposite side posteriorly to emerge from post aspect of midbrain "the decussation will be post to cerebral aquiduct " Medial lemniscus tracts & lateral lamniscus & trigeminal lemniscus run post to substantia nigra . Crus cerebri "ant to substantia nigra" contain a lot of fibers . 1. middle ...
outline24074
... ii. Heteronymous: Involves opposite sides of visual fields 1. Optic chiasm produces bitemporal defect iii. Homonymous: Involves same side of visual field in each eye 1. Lesions of retrochiasmal pathway d. Quadrantopsia: Complete defect involving a quadrant of each visual field. i. Heteronymous or Ho ...
... ii. Heteronymous: Involves opposite sides of visual fields 1. Optic chiasm produces bitemporal defect iii. Homonymous: Involves same side of visual field in each eye 1. Lesions of retrochiasmal pathway d. Quadrantopsia: Complete defect involving a quadrant of each visual field. i. Heteronymous or Ho ...
Biomechanics of Schlemm`s canal endothelium and intraocular
... At the level of SC, however, several changes in glaucomatous eyes have been observed with the potential to be a significant contributor to the increased outflow resistance. The dimensions of the lumen of SC are smaller in glaucomatous eyes and these changes correlate with outflow resistance (Allingham ...
... At the level of SC, however, several changes in glaucomatous eyes have been observed with the potential to be a significant contributor to the increased outflow resistance. The dimensions of the lumen of SC are smaller in glaucomatous eyes and these changes correlate with outflow resistance (Allingham ...
F In the Treatment of Glaucoma
... neuroprotectors to prevent secondary degeneration of the unaffected neurones. The neuroprotectors will act to prevent the spread of degeneration from the affected retinal ganglion cells and neurones to the yet undamaged ones. This can be obtained via administration of drugs that are: Vasodilators, a ...
... neuroprotectors to prevent secondary degeneration of the unaffected neurones. The neuroprotectors will act to prevent the spread of degeneration from the affected retinal ganglion cells and neurones to the yet undamaged ones. This can be obtained via administration of drugs that are: Vasodilators, a ...
Visual Attention: The Thalamus at the Centre?
... Critical, but previously unresolved questions include whether such modulation of fMRI signals reflect changes in firing rate of individual LGN neurons rather than feedback signals from cortical areas, and more generally what the precise functional relationship is between the different nuclei that co ...
... Critical, but previously unresolved questions include whether such modulation of fMRI signals reflect changes in firing rate of individual LGN neurons rather than feedback signals from cortical areas, and more generally what the precise functional relationship is between the different nuclei that co ...
Evaluation of Retinal Pigment Epithelial Hamartoma Using Oct – A
... or melanoma [7]. Thus OCT is quite diagnostic in determining the exact anatomical location of the hyperplastic RPE cells located within the retina having their apex at the vitreo retinal surface. To summarize CSHRPE located extrafoveally usually requires no active treatment since the lesion is non p ...
... or melanoma [7]. Thus OCT is quite diagnostic in determining the exact anatomical location of the hyperplastic RPE cells located within the retina having their apex at the vitreo retinal surface. To summarize CSHRPE located extrafoveally usually requires no active treatment since the lesion is non p ...
R.N. 70269/98 Postal Registration No.: DL-SW-1/4082/15-17 ISSN : 0972-169X
... the lowest and violet having the highest frequency. Hence energy of red light photon is less compared to that of violet light. In simplest terms, primary source of visible light (or any other electromagnetic radiations) is release of energy when electron jumps from its excited state to the stable st ...
... the lowest and violet having the highest frequency. Hence energy of red light photon is less compared to that of violet light. In simplest terms, primary source of visible light (or any other electromagnetic radiations) is release of energy when electron jumps from its excited state to the stable st ...
The glossopharyngeal nerve
... Lesions of the Glossopharyngeal Nerve • Transient or sustained hypertension, reflecting involvement of the carotid branch • Loss of sensation over the ipsilateral soft palate, fauces, pharynx and posterior third of the tongue. • Taste is also lost over the ipsilateral post sulcal portion although ...
... Lesions of the Glossopharyngeal Nerve • Transient or sustained hypertension, reflecting involvement of the carotid branch • Loss of sensation over the ipsilateral soft palate, fauces, pharynx and posterior third of the tongue. • Taste is also lost over the ipsilateral post sulcal portion although ...
Photoreceptor cell
A photoreceptor cell is a specialized type of neuron found in the retina that is capable of phototransduction. The great biological importance of photoreceptors is that they convert light (visible electromagnetic radiation) into signals that can stimulate biological processes. To be more specific, photoreceptor proteins in the cell absorb photons, triggering a change in the cell's membrane potential.The two classic photoreceptor cells are rods and cones, each contributing information used by the visual system to form a representation of the visual world, sight. The rods are narrower than the cones and distributed differently across the retina, but the chemical process in each that supports phototransduction is similar. A third class of photoreceptor cells was discovered during the 1990s: the photosensitive ganglion cells. These cells do not contribute to sight directly, but are thought to support circadian rhythms and pupillary reflex.There are major functional differences between the rods and cones. Rods are extremely sensitive, and can be triggered by a single photon. At very low light levels, visual experience is based solely on the rod signal. This explains why colors cannot be seen at low light levels: only one type of photoreceptor cell is active.Cones require significantly brighter light (i.e., a larger numbers of photons) in order to produce a signal. In humans, there are three different types of cone cell, distinguished by their pattern of response to different wavelengths of light. Color experience is calculated from these three distinct signals, perhaps via an opponent process. The three types of cone cell respond (roughly) to light of short, medium, and long wavelengths. Note that, due to the principle of univariance, the firing of the cell depends upon only the number of photons absorbed. The different responses of the three types of cone cells are determined by the likelihoods that their respective photoreceptor proteins will absorb photons of different wavelengths. So, for example, an L cone cell contains a photoreceptor protein that more readily absorbs long wavelengths of light (i.e., more ""red""). Light of a shorter wavelength can also produce the same response, but it must be much brighter to do so.The human retina contains about 120 million rod cells and 6 million cone cells. The number and ratio of rods to cones varies among species, dependent on whether an animal is primarily diurnal or nocturnal. Certain owls, such as the tawny owl, have a tremendous number of rods in their retinae. In addition, there are about 2.4 million to 3 million ganglion cells in the human visual system, the axons of these cells form the 2 optic nerves, 1 to 2% of them photosensitive.The pineal and parapineal glands are photoreceptive in non-mammalian vertebrates, but not in mammals. Birds have photoactive cerebrospinal fluid (CSF)-contacting neurons within the paraventricular organ that respond to light in the absence of input from the eyes or neurotransmitters. Invertebrate photoreceptors in organisms such as insects and molluscs are different in both their morphological organization and their underlying biochemical pathways. Described here are human photoreceptors.