Exteroception Flashcards
What is columnar organization?
the vertical arrangement of functionally related cells (barrels) of the cortex
What info does the antero-lateral system convey?
- pain
- temperature
- crude touch
What are slowly adapting receptors?
those that will keep firing when stimulated by steady touch throughout the time the skin is pressed
The lemniscal system for the head involes the ______.
trigeminal nerve
Name the receptor:
- fast adapting
- large receptive field
- vibration sensation
Pacinian corpuscles
Afferent information about touch, proprioception, pain, and temperature on the face and head flow through the _____.
trigeminal nerve
What are the key features of Pacinian corpuscles?
- fast adapting
- large receptive field
- vibration sensation
Name the receptor:
- slow adapting
- large receptive field
- stretch sensation/grip
Ruffini’s endings
Name the receptor:
- rapidly-adapting
- small receptive fields
- fine tactile sensation
Meissner’s Corpuscles
What are the 3 branches of the trigeminal nerve?
- opthalamic
- maxillary
- mandibular
Name the receptor:
- slow adapting
- small receptive fields
- fine tactile sensation
Merkel’s discs
The cell bodies of mechanoreceptors from skin and proprioceptors are found where?
in the dorsal root ganglia
What info does the dorsal column/lemniscal system (posterior column) convey?
- fine, discriminative touch
- limb proprioception
What are the key features of Meissner’s Corpuscles?
- rapidly-adapting
- small receptive fields
- fine tactile sensation
What are the key features of Ruffini’s endings?
- slow adapting
- large receptive field
- stretch sensation/grip
What is the significance of the horizontal layers of organization in the cortex?
to project to and receive projections from different areas of the brain for proper distribution
What system transmits info about pain, temperature, and crude touch?
the antero-lateral system
What system transmits info about fine, discriminative touch and limb proprioception?
the dorsal column/lemniscal system (posterior column)
Mechanoreceptors of the skin and joint receptors have _____ fibers.
Aβ
What is a receptive field?
the area of the skin in which a mechanical stimulus elicits a response from the cell
Name the 2 broad somatosensory receptors based on size of receptive field.
- small fields (2-8mm with sharp borders) = Meissner’s corpuscles and Merkel’s discs
- large fields (entire finger or greater area, poorly defined)= Pacinian corpuscles and Raffini endings
What is the somatosensory system?
the collection of receptors that transduce info about the body surface and deeper tissues
What is the significance of the columnar organization in the cortex?
they vertically separate cells by response modality
Proprioceptors of skeletal muscle have ____ fibers.
Aα
What are the key features of Merkel’s discs?
- slow adapting
- small receptive fields
- fine tactile sensation
What are rapidly adapting receptors?
those that, when stimulated, fire a few APs and then stop firing even though the stimulus is still there
What are the 2 major subdivisions of the somatosensory system?
- dorsal column/lemniscal system (posterior column)
- antero-lateral system
What is somatotopy?
the precise and orderly mapping of the body surface onto the cortex
