Three touch and pressure sense receptors:

- Free Nerve Endings: Responsible for the sensation of itching and are common in the epithelial tissue.

- Tactile Corpuscles: Small masses that are responsible for the sensation of light touch.

Two types of temperature receptors:

- Warm Receptors: Creates a burning sensation. Becomes unresponsive at temperatures above 45 celsius.

- Cold Receptors: Creates a freezing sensation. Is very sensitive to temperatures between 10- 20 celsius.

Acute Pain Fiber: Associates with the sharp pain sensation, impulses are rapid.

Chronic Pain Fiber: Associates with dull, aching sensations, impulses are more slower.

- Chemoreceptors

- Pain Receptors

- Thermoreceptors

- Mechanoreceptors

- Photoreceptors

Two types of photoreceptors:

-Rods: Allows for night vision and is very sensitive to dim light.

-Cones: Detects color and visual acuity, is sensitive to bright light.

Iris: a thin diaphragm made of connective tissue and smooth muscle fibers that is seen as the colored part of the eye. It also expands when there is less light and contracts when the light is bright. The iris does this because it helps decrease the amount of intensity of the light entering the eye.

Conjunctiva: Lines the inner surface of the eyelid with mucous membrane.

Eyelid: Helps protect the eye.

Lacrimal Gland: Secretes tears and transports tears to the nasal cavity.