Understanding Sensory Receptors and Eye Anatomy

Understanding Sensory Receptors

Quimioreceptors: Sensitive to chemicals.

Mechanoceptors: Sensitive to mechanical stimuli, such as pressure and sound.

Photoreceptors: Sensitive to light.

Thermoreceptors: Sensitive to temperature variations.

Nociceptors: Sensitive to intense pressures and are responsible for pain.

Types of Receptors

• Interoceptors: Located inside the body, particularly in the viscera, responsible for collecting information about the internal state of the organism (e.g., hunger and thirst).
• Exteroceptors: Located on the surface of the body, responsible for collecting stimuli from the outside, such as light, sound, and temperature.

Eye Anatomy

Light enters the eye through the cornea, which acts as a convex lens to diverge light rays to a single point.

The pupil is an opening that controls the amount of light entering the eye.

Crystalline lens: An elastic body that allows the focus of images. Cornea: The transparent area of the sclera. Iris: The colored disk made of muscle fibers.

Blind spot: The area where the optic nerve exits the eye.

Choroid: The intermediate layer, dark and filled with blood vessels that nourish the cells of the eye.

The eyeball consists of three layers: the sclera, choroid, and retina.

The protective organs are those that help move the eye and enable its functions.

Skin Layers

• Sclera: The outer layer, hard, opaque, and white.
• Epidermis: The outer layer formed by several layers of epithelial tissue cells. Their cells contain keratin, a protein that waterproofs the eye.
• Dermis: The layer beneath the epidermis, composed of connective tissue that gives skin elasticity.
• Hypodermis: The innermost layer, also called subcutaneous tissue, primarily composed of adipose tissue.

Common Vision Problems

Hyperopia: Images do not focus on the retina but behind it, causing blurred vision. This may be due to a small eyeball size or a weakness in the ability to focus.

Myopia: Difficulty focusing on distant objects, resulting in blurry images on the retina.

Astigmatism: Incorrect curvature of the cornea, which is hemispherical rather than flat, causing blurred vision of nearby and distant objects.

Visual Processing

The optic nerve carries visual information in the form of nerve impulses to the brain.

The retina contains cones, which are responsible for daytime vision and color, and rods, which enable the appreciation of weak stimuli in black and white.