ANP 1106 Lecture Notes - Lecture 22: Inhibitory Postsynaptic Potential, Lamellar Corpuscle, Metabotropic Receptor
29 Apr 2018
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ANP1106 – Sensory Receptors
Neuron: Neurotransmitter Action
- Action depends on the receptor which can either be:
o 1) Ionotrophic – receptor is part of ion channel
▪ Ex. glycine
o 2) Metabotropic – receptor is separate from ion channel
▪ Ex. dopamine, norepinephrine
- Graded postsynaptic potentials result from successive potentials:
o 1) Temporal summation – increased frequency of stimuli
o 2) Spatial summation – stimuli from multiple sources
- 2 options of ligand-gated channel selectivity on postsynaptic
o Excitatory postsynaptic potential (EPSP) – selective to sodium,
depolarize/excite
o Inhibitory postsynaptic potential (IPSP) – selective to potassium,
hyperpolarizes/inhibits
- Action potential occurs when membrane potential crosses threshold or else
it restores to -70mV
- 4 types of neuronal circuits:
o 1) Diverging
o 2) Converging
o 3) Reverberating
o 4) Parallel after-discharge
Sensory Receptors: Classification
- 3 methods to classify sensory receptors:
o 1) Anatomical location of stimulus
▪ Exteroceptors – located close to surface of body, receive info
from external environment for hearing/vision/smell/touch
▪ Visceroceptors – located in blood vessels/internal organs,
provide info for automatic control of internal milieu
▪ Proprioceptors – located in muscles, provide info on posture
o 2) Type of stimulus
▪ Mechanoreceptors – detect mechanical stimuli
▪ Thermoreceptors – detect thermal stimuli, temperature
changes the energy of channel
▪ Photoreceptors – detect visual stimuli
▪ Chemoreceptors – detect molecules
▪ Nociceptors – detect stimuli that causes damage to organism
o 3) Complexity of structure
▪ Complex receptors – from sensory organs of senses
▪ Simple receptors – from somatic/autonomic systems (all other
besides senses)
- Example Pacinian corpuscle is: exteroceptor, mechanoreceptor and simple
receptor
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