BioPsy: Finals L2.1 - Vision

Light

• A type of electromagnetic wave that is one of the stimulus for the sense of sight.

• Somewhere in between the electromagnetic spectrum.

Electromagnetic Spectrum

The full range of electromagnetic radiation, organized by frequency or wavelength.

Blue/Violet

• 400 nanometers

• Short wavelength

Green/Yellow

• 520 nanometers

• Medium Wavelength

Red/Orange

• 700 nanometers

• Long Wavelength

Periphery

Where the rods are located.

Photoreceptors

Specialized type of cells that transforms stimulus into a neural impulse.

Photoreceptor: Rods

• Very sensitive to light

• Responsible for our night vision

• Responsible for grayscale sight (Black and White)

• Found in our periphery

• Responsible for seeing at the sides

• 120 million

• Very slow recovery rate

Photoreceptor: Cones

• Color vision

• Red, Green, and Blue

• Found in the small region that is called Fovea.

• 6 million

• Fast Recovery Rate

Fovea

The region that is responsible for us to see in details. Where the cones are located.

Optic Plate

The structure inside a rod.

Rhodopsin

The protein of rods.

Photopsin

The protein of cones.

Sunlight

The most basic type of light that our eyes perceive.

Pupils

Dilates in low light to receive more and shrinks in high light to filter the vision.

Retina

The back of our eyes, where light hits once entering the eyes.

Optic Nerves

Anything that is perceived by the eyes is relayed through our _____.

Phototransduction Cascade

When there is/are no stimulus, the rod is turned on. But, when light suddenly hits the rod, it will suddenly turn off. This process is called _______.

Bipolar Cell

When the rod is turned off, the rhodopsin in our rods will send a signal and therefore will turn on ________.

Retinal Ganglion Cell

Once the bipolar cell is turned on, this will activate an action potential that will communicate with the ___________.

Optic Nerve

Once the Retinal Ganglion Cell has been activated by the action potential of the Bipolar Cell, the Retinal Ganglion cell will fire its own action potential and then those signals will now be transmitted to the ____________.

Brain

Signals are sent here after going through the Optic Nerve. Things we see are now interpreted.

Primary Visual Cortex

Found in the Occipital Lobe, the exact location of where the signals of the Optic Nerves are sent to interpret things that we see or the light that we have perceived through our eyes.

The most attractive colors to the eyes

• Red/Orange

• Long Wavelength colors in general are attractive to the eyes.

• This is the reason why it is used as a marketing strategy (e.g., Jollibee uses mostly red colors)

Color Blindness (Color Deficiency)

• The inability to see certain shades of color.

• Since male Chromosomes are XY, no compensations are made to the X chromosome; Hence, more common in male.

• Carried by the X Chromosome.

Agnosia

Impairment in sensations due to brain damage.

Visual Agnosia

Impairment in recognizing visually presented objects, despite otherwise normal visual field, acuity, color vision, brightness discrimination, language, and memory.

Prosopagnosia

• Inability to recognize faces.

• A person has a problem in their visual cortex and temporal lobe.

• Knows the relationship with a person, but cannot recognize their faces—even their own face.

Object Agnosia

• Inability to recognize objects.

• A person has a problem in their visual cortex.