Eye Anatomy and Photoreception

These flashcards cover key anatomical structures and functions of the eye, as well as the processes of photoreception and neural signaling involved in vision.

Iris

The colored part of the eye that regulates the amount of light entering the eye by contracting and dilating.

Pupil

The opening in the center of the iris that allows light to enter the eye.

Lens

A transparent structure in the eye that refracts light to focus images on the retina.

Retina

A layer of cells at the back of the eye that contains photoreceptors and processes visual information.

Vitreous humor

The clear gel that fills the space between the lens and the retina in the eyeball.

Aqueous humor

The clear fluid in the front part of the eye that provides nourishment and maintains intraocular pressure.

Optic nerve

A collection of nerve fibers that transmit visual information from the retina to the brain.

Blind spot

The area in the retina where the optic nerve exits the eye, lacking photoreceptors and therefore not sensitive to light.

Fovea

A small pit in the retina that provides the clearest vision due to the high concentration of cones.

Ganglion cells

Neurons in the retina that receive input from photoreceptors and transmit visual information to the brain.

Photoreceptor cells

Cells in the retina that detect light; includes rods and cones.

Rods

Photoreceptor cells that are sensitive to low light levels and do not detect color.

Cones

Photoreceptor cells in the retina that detect color and are active in bright light conditions.

Phototransduction

The process by which photoreceptor cells convert light into electrical signals.

Rhodopsin

A photopigment found in rod cells that is involved in the detection of light.

G proteins

Molecules that relay signals from activated receptors to target molecules inside the cell.

Cyclic GMP

A second messenger that is involved in the signaling pathways of photoreception.

Dark current

The constant depolarizing current present in photoreceptors in the absence of light.

Horizontal cells

Neurons in the retina that interact with multiple photoreceptors and help integrate visual signals.

Bipolar cells

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

Lateral inhibition

A process in the retina where activated cells inhibit their neighbors, enhancing the contrast in visual signals.

Receptive field

The specific area of the visual field that a neuron responds to; in ganglion cells, it can exhibit on-center or off-center responses.