Vision

A comprehensive set of flashcards summarizing key vocabulary and definitions related to the topic of vision, covering anatomy, physiology, and visual processing concepts.

Vitreous Humor

A gel-like substance that fills the space between the lens and the retina in the eye.

Retina

The light-sensitive layer at the back of the eye that contains photoreceptors.

Photoreceptors

Cells in the retina (rods and cones) that convert light into neural signals.

Emmetropia

Normal vision occurring when light rays focus directly on the retina.

Myopia

Nearsightedness; a condition where light rays focus before the retina.

Hyperopia

Farsightedness; a condition where light rays focus behind the retina.

Accommodation

The process by which the lens changes shape to focus light onto the retina.

Ciliary Muscles

Muscles that control the shape of the lens for focusing.

Cornea

The transparent outer layer of the eye that refracts light.

Cones

Photoreceptor cells responsible for color vision and visual acuity.

Rods

Photoreceptor cells that are sensitive to low light levels.

Action Potentials (APs)

Electrical impulses that transmit signals through neurons.

Optic Nerve

The nerve that transmits visual information from the retina to the brain.

Fovea Centralis

The area of the retina with the highest concentration of cones and best visual acuity.

Lateral Geniculate Nucleus (LGN)

A relay center in the thalamus for visual information received from the retina.

Optic Chiasm

The point where optic nerves cross, allowing visual information from both eyes to be processed.

Transduction

The conversion of light signals into electrical signals in photoreceptors.

Lateral Inhibition

A mechanism in the retina that sharpens contrast in visual perception.

Glutamate

A neurotransmitter released by photoreceptors in the absence of light.

Hyperpolarization

The process that decreases the membrane potential of a neuron.

Dark Adaptation

The process of the eyes adjusting to low light levels.

Light Adaptation

The process of the eyes adjusting to bright light levels.

Retinal Pigments

Substances in photoreceptors that absorb light and initiate phototransduction.

Visual Acuity

The clarity or sharpness of vision, primarily determined by cones.

Blind Spot

A small area on the retina where no photoreceptors are present, leading to a gap in vision.

Cataracts

An eye condition characterized by clouding of the lens, affecting vision.

Astigmatism

A refractive error caused by an irregular shape of the cornea or lens.

Glaucoma

Increased pressure within the eye, potentially damaging the optic nerve.

Color Blindness

The inability to perceive colors accurately due to absent or malfunctioning cones.

Phototransduction

The process through which light is converted into electrical signals in the retina.

Retinal Isomerase

An enzyme that converts trans-retinal back to cis-retinal during the photopigment regeneration process.

Neural Layer

The layer of the retina containing the photoreceptors and other neuron types.

Pigmented Layer

A layer of the retina that absorbs excess light and prevents scattering.

Accommodation

The eye's ability to change focus from distant to near objects.

Aqueous Humor

The fluid in the anterior segment of the eye that maintains intraocular pressure.

Cone Types

Three types of cones (S, M, L) that correspond to short, medium, and long wavelengths of light.

Pupil

The adjustable opening in the center of the iris that regulates light entry.

Iris

The colored part of the eye that controls the size of the pupil.

Ciliary Body

The structure in the eye that includes the ciliary muscles and produces aqueous humor.

Optic Disc

The location where the optic nerve exits the retina, creating a blind spot.

Retinitis Pigmentosa

A genetic disorder that results in progressive loss of photoreceptors, causing vision loss.

Diabetic Retinopathy

Damage to the retina caused by complications from diabetes, leading to vision issues.

Photopigment Regeneration

The process of converting photopigment back to its functional form after bleaching.

Color Perception

The interpretation of wavelengths of light as distinct colors in the brain.

Visual Pathway

The route visual information takes from the retina to the visual cortex in the brain.

Frequency

The number of cycles of a wave in a given period, related to the color perceived.

Amplitude

The height of a wave that corresponds to brightness in visual perception.

Contrast Sensitivity

The ability to detect differences in light and dark areas in visual stimuli.

Temporal Retina

The part of the retina closest to the temples, processing visual information from the central field of vision.

Nasal Retina

The part of the retina closest to the nose, processing visual information from the peripheral field.

Extrastriate Cortex

Areas surrounding the primary visual cortex that process additional visual information.

Synaptic Potential

A change in the membrane potential of a postsynaptic neuron in response to neurotransmitter release.

Graded Potentials

Small changes in membrane potential that can vary in size and are not all-or-nothing.