Retina and Photoreceptors

what are the two layers of decline tissues

1. Sensory Layer:

   • Bipolar Neurons, Glial Cells

   • leads to optic nerve

2. Photoreceptor Layer:

• Rods & Cones

What can a long-term vitamin A deficiency cause?

A long-term vitamin A deficiency can cause night blindness, which is reversible with proper vitamin A intake.

What protein do rod cells use to absorb light?

Rods use rhodopsin, a protein made from vitamin A, to absorb light.

What kind of images do rod cells produce?

Rod cells produce fuzzy images because they are more sensitive to light but do not detect color or sharp details.

Where are rod cells concentrated in the retina?

Rod cells are concentrated on the periphery of the retina, helping with peripheral vision.

What are rod photoreceptors?

Rods are highly sensitive photoreceptors in the retina that detect dim light and are important for night vision and peripheral vision.

What are cone photoreceptors?

Cones are photoreceptors in the retina that detect bright light and allow for color vision and high visual acuity.

Where are cone cells concentrated?

Cone cells are concentrated in the macula of the retina, especially in the fovea, which is the ultimate focal point for sharp vision.

What are the three types of cone cells?

• Red cones – absorb long wavelengths

• Green cones – absorb medium wavelengths

• Blue cones – absorb short wavelengths

What causes colorblindness?

Colorblindness occurs when one or more types of cone cells have reduced or no function due to genetic factors.

How does the brain process color?

The brain mixes signals from red, green, and blue cones to create the perception of different colors.

What causes afterimages?

Afterimages occur when cone cells become overstimulated and temporarily lose sensitivity due to ATP depletion. While they rest and regenerate ATP, the unstimulated cones remain active, causing the brain to perceive the opposite color.