Rapid Diffusion of Hydrogen Protects the Retina: Administration to
... of the eye, passing through the optic nerve head, and were stained ...
... of the eye, passing through the optic nerve head, and were stained ...
FM 8-50 - Operational Medicine
... between the lens and the retina. It is transparent to both visible and near-infrared radiation. The vitreous humor also serves as a structural support for the retina. b. The Light Absorption and Transduction System. The retina comprises this system which lines the inside of the eyeball. The retina c ...
... between the lens and the retina. It is transparent to both visible and near-infrared radiation. The vitreous humor also serves as a structural support for the retina. b. The Light Absorption and Transduction System. The retina comprises this system which lines the inside of the eyeball. The retina c ...
An introduction to Albinism
... To have normal pigmentation, the cell must make melanosomes and enough melanin must be found in of these vesicles. In all of us the colour of our skin and eyes is determined by the amount of melanosomes each cell has rather than the number of pigmented cells we have. ...
... To have normal pigmentation, the cell must make melanosomes and enough melanin must be found in of these vesicles. In all of us the colour of our skin and eyes is determined by the amount of melanosomes each cell has rather than the number of pigmented cells we have. ...
File
... Rods are extremely sensitive to light, but they do not distinguish different colors, only black and white. Cones are less sensitive than rods, but they do respond to different colors, producing color vision. Cones are concentrated in the fovea, the site of sharpest vision. ...
... Rods are extremely sensitive to light, but they do not distinguish different colors, only black and white. Cones are less sensitive than rods, but they do respond to different colors, producing color vision. Cones are concentrated in the fovea, the site of sharpest vision. ...
PDF
... cycle parameters were derived graphically (Quastler & Shermann, 1959). Fourday-old rats received a single injection of [3H]thymidine, and then the fraction of labelled mitoses (FLM) was plotted as a function of time. Mitotic figures from middle prophase to telophase were scored (30-60 mitoses per ey ...
... cycle parameters were derived graphically (Quastler & Shermann, 1959). Fourday-old rats received a single injection of [3H]thymidine, and then the fraction of labelled mitoses (FLM) was plotted as a function of time. Mitotic figures from middle prophase to telophase were scored (30-60 mitoses per ey ...
The Ear
... • 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 ...
The spectral transmission of ocular media suggests ultraviolet
... Figure 1. The absorption spectra of the visual pigments of the ferret and the spectral transmission of its lens. The absorption maxima of the visual pigments (rods—505 nm; cones—430 and 558 nm) are taken from Calderone & Jacobs [28] and the visual pigments templates of Govardovskii et al. [29] (soli ...
... Figure 1. The absorption spectra of the visual pigments of the ferret and the spectral transmission of its lens. The absorption maxima of the visual pigments (rods—505 nm; cones—430 and 558 nm) are taken from Calderone & Jacobs [28] and the visual pigments templates of Govardovskii et al. [29] (soli ...
Ethacrynic acid induces reversible shape and cytoskeletal
... 5% CO2 environment. Cell shape and cytoskeletal studies were conducted on trabecular meshwork cells from passages 1-5. Human trabecular meshwork: The H-l cell line we used was derived from a 16-year-old girl. The intact enucleated eyes were shipped by overnight mail on ice by the National Disease Re ...
... 5% CO2 environment. Cell shape and cytoskeletal studies were conducted on trabecular meshwork cells from passages 1-5. Human trabecular meshwork: The H-l cell line we used was derived from a 16-year-old girl. The intact enucleated eyes were shipped by overnight mail on ice by the National Disease Re ...
Anatomy of the eye of the sperm whale
... rete is to maintain a high temperature of the optic nerve and the retina (Dawson, 1980), but it is unclear if a massive rete is needed for this. Seals, some of which dive deeper and longer than most cetaceans do not possess an optic rete and are thus apparently able to maintain retinal temperature b ...
... rete is to maintain a high temperature of the optic nerve and the retina (Dawson, 1980), but it is unclear if a massive rete is needed for this. Seals, some of which dive deeper and longer than most cetaceans do not possess an optic rete and are thus apparently able to maintain retinal temperature b ...
Human limbal progenitor cell characteristics are maintained in tissue
... rim after enzyme treatment and scraping revealed only stromal structure at the limbal region. Morphology of Cultured Limbal Epithelial Cells In human limbal tissue, the epithelium consisted of 8 to 10 layers of cells. Basal cells were small, columnar and tightly arranged. Application of antibodies t ...
... rim after enzyme treatment and scraping revealed only stromal structure at the limbal region. Morphology of Cultured Limbal Epithelial Cells In human limbal tissue, the epithelium consisted of 8 to 10 layers of cells. Basal cells were small, columnar and tightly arranged. Application of antibodies t ...
HUMAN FUNCTIONAL ANATOMY 213 CRANIAL NERVES
... I - Olfactory nerve. Bipolar cells are also the receptor cells for smell. They pass through the cribriform plate to connect the nasal mucosa to the olfactory bulb (which is actually part of the brain) II – Optic nerve. Bipolar cells in the retina connect the photo receptors to other nerve cells of t ...
... I - Olfactory nerve. Bipolar cells are also the receptor cells for smell. They pass through the cribriform plate to connect the nasal mucosa to the olfactory bulb (which is actually part of the brain) II – Optic nerve. Bipolar cells in the retina connect the photo receptors to other nerve cells of t ...
Optic Nerve Hypoplasia
... With Optic Nerve Hypoplasia photophobia and a nystagmus may occur. As the brain matures there may be a mild improvement in visual function and in some cases, reduced nystagmus may also occur. A person with Optic Nerve Hypoplasia has optic nerves which are small and poorly developed. Instead of havin ...
... With Optic Nerve Hypoplasia photophobia and a nystagmus may occur. As the brain matures there may be a mild improvement in visual function and in some cases, reduced nystagmus may also occur. A person with Optic Nerve Hypoplasia has optic nerves which are small and poorly developed. Instead of havin ...
Umbruch 406..407
... 17 Intermediate nerve. Nonmotor portion of the facial nerve. It emerges from the brainstem between the facial and vestibulocochlear nerves and conveys autonomic and taste fibers. After various anastomoses, it merges with the facial nerve in the petrous part of the temporal bone. D 18 Geniculate gang ...
... 17 Intermediate nerve. Nonmotor portion of the facial nerve. It emerges from the brainstem between the facial and vestibulocochlear nerves and conveys autonomic and taste fibers. After various anastomoses, it merges with the facial nerve in the petrous part of the temporal bone. D 18 Geniculate gang ...
PDF - Molecular Vision
... the stroma, and the innermost endothelium cell layer. The corneal epithelium is pluristratified, made out of cuboidal basal cells that gradually become flatter as they differentiate toward the surface [1,2]. Basal cells rest on a basement membrane to which they attach by the formation of hemidesmoso ...
... the stroma, and the innermost endothelium cell layer. The corneal epithelium is pluristratified, made out of cuboidal basal cells that gradually become flatter as they differentiate toward the surface [1,2]. Basal cells rest on a basement membrane to which they attach by the formation of hemidesmoso ...
from 632.8 to 1070 nm
... The experimental apparatus for measuring ocular aberrations was essentially compounded by a Hartmann-Shack wavefront sensor, three different light sources and appropriate optics for conjugating the eye´s exit pupil onto the sensor. It is conceptually similar to a wavelength tunable wavefront sensor ...
... The experimental apparatus for measuring ocular aberrations was essentially compounded by a Hartmann-Shack wavefront sensor, three different light sources and appropriate optics for conjugating the eye´s exit pupil onto the sensor. It is conceptually similar to a wavelength tunable wavefront sensor ...
Towards a New Ophthalmic Biology and Physiology
... selection [1]. Darwin´s eye definition was as an organ consisting of at least two different cell types: photoreceptor and pigment cells; this is the Darwinian prototype. Early organisms, more than 600 million years ago, (Mya), evolved primitive photoreceptors capable of signaling light. During the C ...
... selection [1]. Darwin´s eye definition was as an organ consisting of at least two different cell types: photoreceptor and pigment cells; this is the Darwinian prototype. Early organisms, more than 600 million years ago, (Mya), evolved primitive photoreceptors capable of signaling light. During the C ...
Protective coatings for intraocular wirelessly controlled microrobots
... from two different materials (Au and Ppy) [Figure 2], were used in corrosion and in cell tests. The microrobots used in vivo had their outer surface coated with Ppy and their inner surface coated with Au (i.e., hollow interior used as a potential drug reservoir). The same coating methods were used a ...
... from two different materials (Au and Ppy) [Figure 2], were used in corrosion and in cell tests. The microrobots used in vivo had their outer surface coated with Ppy and their inner surface coated with Au (i.e., hollow interior used as a potential drug reservoir). The same coating methods were used a ...
Compound developmental eye disorders following inactivation of
... and abnormal patterning of the chamber angle between the cornea and the iris; it is also associated with a high prevalence of glaucoma [1]. Development of the anterior eye segment depends on the proper function of two transcription factors in the periocular mesenchyme, the forkhead/winged-helix fact ...
... and abnormal patterning of the chamber angle between the cornea and the iris; it is also associated with a high prevalence of glaucoma [1]. Development of the anterior eye segment depends on the proper function of two transcription factors in the periocular mesenchyme, the forkhead/winged-helix fact ...
Widefield Enface OCT - Haag
... The Cornea Power Upgrade allows evaluation of patients with prior refractive procedures. Standard topography only calculates the front curvature and then extrapolates posterior curvature. Using the Cornea Power Upgrade option, both the anterior and posterior curvatures are measured directly to obtai ...
... The Cornea Power Upgrade allows evaluation of patients with prior refractive procedures. Standard topography only calculates the front curvature and then extrapolates posterior curvature. Using the Cornea Power Upgrade option, both the anterior and posterior curvatures are measured directly to obtai ...
Uniformity of monkey striate cortex: A parallel relationship between
... from successive cells during a penetration perpendicular to the cortical surface. The amount of variation in receptive-field position was such that the total visual-field area covered by the superimposed receptive fields in one penetration was several times the area occupied by a single field; most ...
... from successive cells during a penetration perpendicular to the cortical surface. The amount of variation in receptive-field position was such that the total visual-field area covered by the superimposed receptive fields in one penetration was several times the area occupied by a single field; most ...
Diseases of the Retinal Pigment Epithelium
... The retinal pigment epithelium is a critical tissue within the eye. It lies directly behind the retina, where it provides metabolic support to the photoreceptors and controls their local environment. As a result, the RPE is vital to retinal function, but also a site of aging and disease that cause d ...
... The retinal pigment epithelium is a critical tissue within the eye. It lies directly behind the retina, where it provides metabolic support to the photoreceptors and controls their local environment. As a result, the RPE is vital to retinal function, but also a site of aging and disease that cause d ...
Blouin (2004) Shifts in the retinal image of a visual scene during
... initial visual environment (i.e. the 08 –128 –368 set of LEDs) could be shifted by 4.58 to the right when peak velocity of the primary saccade was reached (see Fig. 2 for typical raw recordings in this condition). In this case, after the visual scene displacement, the subjects were facing an environ ...
... initial visual environment (i.e. the 08 –128 –368 set of LEDs) could be shifted by 4.58 to the right when peak velocity of the primary saccade was reached (see Fig. 2 for typical raw recordings in this condition). In this case, after the visual scene displacement, the subjects were facing an environ ...
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.