5.4 Somatosensation Flashcards
somatosensory perception
the perception of all mechanical stimuli that affect the body, including the interpretation of signals that indicate the position of our limbs and the position of our head, as well as our senses of temperature, pressure, touch and pain
nociceptors
the least differentiated of the skin’s sensory receptors
Thermal receptors (nociceptors)
respond to heat or cold
Mechanical receptors (nociceptors)
respond to heavy mechanical stimulation
Multimodal receptors (nociceptors)
respond to a wide range of noxious stimuli, such as heat, mechanical insults, and chemicals
myelinated vs unmyelinated pain neurons
The myelinated fibers quickly conduct information about pain, the activation of these cells usually produces immediate action
vs
The unmyelinated fibers are responsible for duller, longer-lasting pain
proprioception
Specialized nerve cells provide information about the body’s position. This enables the sensory and motor systems to represent information about the state of the muscles and limbs.
somatosensory receptors
have their cell bodies in the dorsal-root ganglia. They enter the spinal cord via the dorsal root
primary somatosensory cortex S1
The initial cortical receiving area is called the primary somatosensory cortex, or S1. It contains a somatotopic representation of the body, called the sensory homunculus. The relative amount of cortical representation in the sensory homunculus corresponds to the relative importance of somatosensory information for that part of the body
secondary somatosensory cortex S2
Builds more complex representations. Regarding to touch, the S2 neurons may code information about object texture and size