Receptors

Sensory receptors

• All sensory organs contain sensory receptors - dendrites that react to a certain external or internal stimulus. There are 5 major types of sensory receptors:

  1. mechanoreceptors - touch

  2. thermoreceptors - temperature variations

  3. pain receptors - nociceptors

  4. chemoreceptors - chemicals

  5. photoreceptors - light

• Each sensory organ has one or more of these receptors.

• The impulses produced in the skin are called cutaneous sensations. These sensations include touch, heat, cold, pressure, and pain. These receptors are not equally distributed throughout the body. Some body parts are more sensitive than others.

Types of touch receptors:

1. free nerve endings- sense pain, temp, touch, and pressure

2. Meissner corpuscles- encapsulated nerve endings found in hairless skin that detect light touch

3. merkel’s disks- detect light, touch, and pressure within the epidermis

4. hair follicle receptors- detect movement of hair

5. Ruffini’s corpuscles- detect deep pressure and stretchings of skin (static pressure)

6. Pacinian corpuscles- encapsulated nerve endings that detect deep pressure and vibration (dynamic pressure)

Summary:

• Sensory receptors are located throughout the body to respond to stimuli such as touch, temperature, pain, chemicals, and light. The skin receives cutaneous sensations through a variety of receptors spread through the dermis and epidermis.