Lecture 11 vision 08.11.24

Vision

The process by which the eyes and brain work together to interpret light information.

Sclera

The tough outer layer of the eye, transparent at the front (cornea).

Choroid

A thin, pigmented layer next to the sclera that contains blood vessels.

Lens

The structure that focuses light onto the retina.

Iris

The colored part of the eye that regulates the amount of light entering the pupil.

Photoreceptor Cells

Specialized cells in the retina that detect light; includes rod cells and cone cells.

Myopia

A vision defect where distant objects appear blurred because they focus in front of the retina.

Hyperopia

A vision defect where close objects appear blurred because they focus behind the retina.

Retina

The innermost layer of the eye containing photoreceptor cells.

Rod cells

Photoreceptor cells that are highly sensitive to light, enabling vision in low light conditions.

Cone cells

Photoreceptor cells that detect color and function best in bright light.

Rhodopsin

The photopigment in rod cells used for vision in dim light.

Photopsins

The photopigments in cone cells that absorb different wavelengths of light.

Accomodation

The process by which the lens changes shape to focus on objects at different distances.

Ciliary body

Part of the eye that produces aqueous humor and controls the shape of the lens.

Vitreous humor

The jelly-like substance that fills the majority of the eye.

Optic disc

The location on the retina where there are no photoreceptors, known as the blind spot.

Aqueous humor

A clear fluid produced by the ciliary body that fills the space between the cornea and the lens.

Color blindness

A visual deficiency due to the absence or deficiency of one or more types of cone cells.

Cation channels

Channels in the cell membrane that allow positively charged ions to enter the cell.

Ganglion cells

The type of neuron in the retina whose axons form the optic nerve.

Optic nerve

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

Optic chiasm

The point where the optic nerves from both eyes cross each other.

Bipolar cells

Cells in the retina that transmit signals from photoreceptors to ganglion cells.

Neural pathways of vision

The route that visual information takes from the retina to the brain.

Depth perception

The ability to perceive the world in three dimensions and judge distances.

Cilium

A hair-like structure that helps in various functions, but not typically found in photoreceptor cells.

Electromagnetic spectrum

The range of all types of electromagnetic radiation, including visible light.

Visual pigments

Light-sensitive molecules in photoreceptor cells that absorb light.

Bleaching of rhodopsin

The process that occurs when rhodopsin is exposed to light, causing it to become inactive.

Visual acuity

The clarity or sharpness of vision, often related to the ability to resolve fine details.

Ciliary muscles

Muscles that adjust the shape of the lens for focusing.

Retinal

A derivative of vitamin A that is part of the visual pigments in photoreceptors.

Signal transduction pathway

The process by which a chemical or physical signal is transmitted through a cell.

Action potential (AP)

A rapid rise and subsequent fall in the membrane potential of a cell.

Lateral inhibition

A process where an excited neuron reduces the activity of its neighbors, enhancing contrast in sensory input.

Phototransduction

The conversion of light into electrical signals in the retina.

Conjunctiva

A mucous membrane that protects the front of the eye and keeps it moist.

Fovea

The central region of the retina responsible for sharp central vision.