Types of sensory receptors
Based on the location:
- 1-Exteroreceptors: (Superficial receptors; from the surface of the body, mainly the skin) detect pain, temperature and fine touch.
- 2-Proprioreceptors: detect sense of position, movement, pressure and vibration (physical state of the body), present mainly in musculo-skeletal system.
- 3- Enteroreceptors: from the internal organs; viscera.
Based on the structure:
- 1. Free nerve endings
- 2. Encapsulated endings.
Free nerve endings
↳ = naked unmyelinated
1. Pain Receptors :
A- Structure:
Naked nerve endings, penetrate basement membrane, branch in between epithelial cells.
B- Function: of the dermis
Carry pain sensation (nociceptors).
C- Site:
- 1- Epithelium: skin up to granular layer, cornea& buccal mucosa.
- 2- CT of tympanic membrane& dental pulp.
- 3- Muscle, joints, bone& viscera.
2. Thermoreceptors :
A- Structure:
Naked nerve endings, ramify in the papillary layer of the dermis at dermo-epidermal junction, parallel to the skin surface.
B- Function:
Carry temperature sensation.
C-Site:
The papillary layer of the dermis at dermo-epidermal junction.