Sensory Receptors and
Afferents 1
Objectives
sensory receptors
classification of receptors
mechanism of generation of AP in sense organ
explain why receptors respond to specific stimuli and how
the organization of a receptor affects its sensitivity
identify major sensory pathways
explain how we distinguish among sensations that originate
in different areas of the body
functions of laminae
dermatomes
Sensory receptors
these are structures which have the ability to convert one
energy form into an electrical form. i.e. action potential
🧠 action potential moves while electrical potential does
not move
Functions:
transduction - conversion of stimulus energy into membrane
potential
amplification - receives the stimulus and amplifies it so
that the CNS can detect it
Sensory Receptors and Afferents 1 1
, transmission - conducting impulses to CNS
integration - processing the information via the summation
of graded potentials
Different sensory modalities perceived by the human brain
special senses: vision, smell, hearing, rotational and
linear acceleration and taste
general senses: touch, pressure, cold, warmth, pain, joint
position and movement
senses that does not reach to consciousness: muscle length
and tension, arterial blood pressure, inflation of lungs
Classification of receptors
By location
exteroceptors
interoceptors
proprioceptors (muscle spindles, golgi tendon organs, joint
capsules)
By modality
mechanoreceptors
thermoreceptors
chemoreceptors
photoreceptors
nociceptors
By structure
unencapsulated: free nerve endings, merkel discs, hair
follicle receptors
Sensory Receptors and Afferents 1 2
Afferents 1
Objectives
sensory receptors
classification of receptors
mechanism of generation of AP in sense organ
explain why receptors respond to specific stimuli and how
the organization of a receptor affects its sensitivity
identify major sensory pathways
explain how we distinguish among sensations that originate
in different areas of the body
functions of laminae
dermatomes
Sensory receptors
these are structures which have the ability to convert one
energy form into an electrical form. i.e. action potential
🧠 action potential moves while electrical potential does
not move
Functions:
transduction - conversion of stimulus energy into membrane
potential
amplification - receives the stimulus and amplifies it so
that the CNS can detect it
Sensory Receptors and Afferents 1 1
, transmission - conducting impulses to CNS
integration - processing the information via the summation
of graded potentials
Different sensory modalities perceived by the human brain
special senses: vision, smell, hearing, rotational and
linear acceleration and taste
general senses: touch, pressure, cold, warmth, pain, joint
position and movement
senses that does not reach to consciousness: muscle length
and tension, arterial blood pressure, inflation of lungs
Classification of receptors
By location
exteroceptors
interoceptors
proprioceptors (muscle spindles, golgi tendon organs, joint
capsules)
By modality
mechanoreceptors
thermoreceptors
chemoreceptors
photoreceptors
nociceptors
By structure
unencapsulated: free nerve endings, merkel discs, hair
follicle receptors
Sensory Receptors and Afferents 1 2
