Rods

Definition

Rods are photoreceptor cells in the retina of the eye responsible for vision at low light levels. They do not mediate color vision and have a low spatial acuity.

5 Must Know Facts For Your Next Test

1. Rods are highly sensitive to dim light, making them essential for night vision.
2. There are approximately 120 million rods in the human retina.
3. Rods contain the photopigment rhodopsin, which is crucial for their light-sensing capabilities.
4. Rods are more numerous than cones and are primarily located around the periphery of the retina.
5. Rod function can be affected by certain drugs, leading to side effects such as night blindness.

Review Questions

• What type of vision are rods responsible for?
• How many rods are typically found in the human retina?
• What photopigment do rods contain that is essential for their function?

Related terms

Cones:

Photoreceptor cells responsible for color vision and high spatial acuity.

Rhodopsin: A photopigment found in rods that is essential for detecting light.

Retina:

The light-sensitive layer at the back of the eye containing rods and cones.