1. Conveying Information
Department of Biology, WCU

2. Receptors Classification 1. Type of stimuli Mechanical (touch, BP)
Thermal (internal & external)
Photo (light detection)
Chemical (blood pH)

3. Receptors 2. Body region Exteroceptors (touch, temp)
Interoceptors (blood pH, BP, temp)

4. Receptors 3. Structural complexity Simple: monitor sensory information
A. free dendritic endings (skin, mucosal membrane)
B. encapsulated endings (mechanoreceptors)

5. Receptors
Complex : sense organs

6. Graded Potentials
Receptor potentials

7. Graded Potentials
Generator potential

8. Graded potentials Characteristics greater stimulus = greater response
maintained provided stimulus maintained
Adaptation over time
Receptor types
A. phasic (touch)
B. tonic (pain)

9. Graded potentials
Phasic: adapt quickly
Tonic: adapt slowly

10. Graded Potentials Every potential other than an AP EPSP/IPSP’s GP’s
AP’s
AP’s

11. Transmission inhibition
Diseases, toxins, drugs
1. Myasthenia gravis
shortage of Ach receptors
swallowing, talking, muscle weakness
2. Paralysis
binding to Ach receptors (curare)
3. Tetradotoxin
decreases Na+ conduction