Somatosensory System (Mixed) Flashcards
Broadmann’s Area: Sensory Association Area
39 and 40
Pathway: Critical for adjusting movesments and posture
Spinocerebellar
Cortical Area: Classification of sounds
Secondary Auditory (B 42)
Describe how small efferent fibers adjust spindle fiber length
Small efferents/gamma motor neurons adjust spindle fiber length via specialized intrafusal spindles. There spindles are then responsive through the physiologic range of muscle length
Describe the function of the divergent pathway
It’s the medial pain system that carries slow aching diffuse pain
Cortical Area: Stereognosis and memory of the tactile and spatial environment
Secondary Somatosensory (B 5&7)
Receptor: Alpha Delta
Free nerve ending: conscious pain, temperature, coarse touch
Divergent Pathway: Synapses in medial and intralaminar nuclei of thalamus and projects to limbic system
Spinolimbic
Divergent Pathway: Synpases in superior colliculus and periaqueductal gray
Spinomesencephalic
Divergent Pathway: Synapses in brainstem reticular formation, functions for arousal, attention, sleep/wake cycles
Spinoreticular
Receptor: Alpha Beta - Pressure
Merkel’s disc and hair follicles
Cortical Area: Distinguishes intensity of light, shape, size, and location of objects
Primary visual (B 17)
Cortical Area: Discriminates shape, texture, or size of objects
Primary Somatosensory (B 312)
Receptor: Ia
Proprioception, muscle spindles, phasic
Term: Integration of tactile and proprioceptive information from manipulating an object
Sterognosis
Receptor: Alpha Beta - Touch and vibration
Meissner’s (s) and Pacinian (d)
Receptor: C
Free nerve ending, unconscious pain, tempterature, itch, tickle
Receptor: Alpha Beta - Skin stretch
Ruffini’s Endings (d)
Receptor: Type of LMN
Ia afferents and Gamma efferents
Term: area of skin innervated by a single afferent neuron
Receptive field
Cortex: Patterns of activity and anticipation
Secondary (somato)sensory cortex
Cortical Area: Conscious discrimination of loudness and pitch of sound
Primary Auditory (B 41)
Receptor: Ib
Proprioceptive, GTO, phasic/tonic
Receptor: II
Propriocetive, muscle spindles, tonic
Cortical Area: Analysis of motion, color, and control of visual fixation
Secondary visual (B 18&19)
Receptors: Primary superficial fine toch
Meissner’s corpuscles and Merkel’s discs
Structure: Sensory organ embedded in skeletal/extrafusal muscles
Muscle Spindle
Stimuli Muscle Spindles Respond to
Muscle stretch
- Quick and tonic stretch registered by Ia
- Tonic stretch registered by II
Pathway: Unconscious proprioception
Spinocerebellar
