Sensory Systems Flashcards
Define somatosensory
Bodily sensations of touch, pain, temp, vibration, and proprioception
Identify the components of somatosensory system
signals received from sensory receptors in the skin, joints, fascia, ligaments, and muscle–detection of changes INTERNALLY or externally
What types of sensations do free nerve ending cells detect? What size are their receptor fields?
temperature, pain, crude touch
small or large receptor fields
Alpha-delta (3)- pain, cool, itch
C (4)-pain, warm,itch
What types of sensations do Merkel cells detect? What size are their receptor fields?
light touch (shape and texture) small receptive fields
What types of sensations do Meissner corpuscles detect? What size are their receptor fields?
light touch and low-frequency vibration (just enough to detect movement)
small receptor fields >4x more sensitive than Merkel
What types of sensations do Ruffini cells detect? What size are their receptor fields?
deep vibration (like a power tool), pressure, and stretching of the skin (FLEX/EXT, friction,healing, weight gain)
large receptor fields
What types of sensations do Pacinian cells detect? What size are their receptor fields?
deep vibrations (like a death grip), pressure large receptor fields
what is proprioception?
the sense of joint limb position in space
Where are intrafusal fibers located and what do they detect?
Inside muscle spindle
they detect the rate and degree of stretch in a noncontractile muscle force.
What do intrafusal fibers trigger?
muscle contraction and antagonist inhibition (control myotactic reflex)
where are GTOs located and what do they detect?
golgi tendon organs are located in the tendon, especially dense where the muscle connects.
they detect contractile force via tension
Alpha-alpha/type 1 fiber
What do GTOs trigger?
muscle relaxation (autogenic inhibition) and inhibit muscle spindles
What is autogenic inhibition?
when our muscles give out in a contraction (as opposed to reaching ultimate failure)
How do synovial joint receptors monitor stretch?
via spinal reflex arcs and the cerebellum
What types of mechanoreceptors are used by our joint receptors? What do they detect?
Pacinian (AROM and compression)
Ruffini (end range and PROM)
Free nerve endings (pain and non-noxious stimuli)
what sensations does the medial lemniscal pathway detect?
discriminative touch, proprioception, and vibration
what are the 3 anterolateral pathways?
spinothalamic, spinoreticular, spinomesencephalic
what sensations do the spinothalamic pathway detect?
discrimination of intensity and location of pain, temperature and crude touch
what types of sensations do the spinoreticular pathway detect?
emotion and arousal related to pain
what type of sensation does the spinomesencephalic pathway detect?
pain modulation
what are the 3 groups that make up the relay nuclei?
medial, lateral, and anterior nuclear groups
What are the 6 components of the lateral nuclear group?
ventral posterolateral nucleus ventral posteromedial nucleus ventral lateral nucleus Ventral anterior nucleus lateral geniculate nucleus medial geniculate nucleus
What is the function of the ventral posterolateral nucleus?
To relay info from the somatosensory spinal cord to the primary sensory cortex
What is the function of the ventral posteromedial nucleus?
to relay information from the somatosensory cranial nerves to the primary sensory cortex
