Somatic Nervous System

Classified based on: cell type, position, or function

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Cell Type: 

1. Free nerve endings

2. Encapsulated endings

3. Specialized (i.e. photoreceptors)

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Position

1. Exteroceptors: located near the stimulus in external environment

E.g. somatosensory receptors in cutaneous epithelium

2. Interoceptors: interprets stimuli from internal organs and tissues

E.g. receptors that sense the increase in blood pressure in the aorta or carotid sinus

3. Proprioceptors: located bear a moving part of the body that interprets positions of tissues as they move

E.g. Muscle

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Function

Based on stimuli the cell transduces: electrical/ionic, physical, electromagnetic radiation (visible light)

Chemoreceptors: detects chemicals, such as taste or smell

Osmoreceptor: detects concentrations of bodily fluids

Nociceptors: detects the presence of chemicals from tissue damage/pain

Mechanoreceptors: detects pressure and vibration

Thermoreceptors: detects temperature