Sensory Systems Flashcards
What is Somatosensory?
Bodily sensations of touch, pain, temperature, vibrations and proprioception
-received from sensory receptors in skin and muscle
What are the 5 cutaneous mechanorecptors
Free Nerve endings Messiner Corpuscles Merkel Cells Ruffini Endings Pacinian Corpuscles
What do the free nerve endings do and what is their receptor field?
Temperature, pain and crude touch
-most superficial
Small or large receptors fields
What do the Meissner corpuscles and what are their receptor fields
Light touch
Small receptor fields
What do the Merkel Cells and what are their receptor fields
Light touch
Small receptor fields
What do the Ruffini Endings and what are their receptor fields
Vibration, pressure
Stretching of skin - help provide secondary info re: proprioception
Large receptor fields
What do the Pacinian Corpuscles and what are their receptor fields
Vibration, Pressure
Large Receptor fields
Most Deep
What is proprioception
Sense of joint/limb position in space
What are the 3 proprioceptors?
Muscle Spindles
Golgi Tendon Organs
Joint Receptors
What do Muscle spindles of the proprioceptors do and where are they located?
Rate and degree of stretch
Intrafusal fibers: run parallel to muscle fibers
What do Golgi Tendon Organs of the proprioceptors do and where are they located?
Monitor tension within tendons
Near muscle-tendon junction
What do Joint Receptors of the proprioceptors do and where are they located?
Monitor stretch in synovial joints
Sends info to cerebellum and spinal reflex arcs
What are the 3 joint receptors and do they help with?
Pacinian: AROM
Ruffini: indicate end range and PROM
Free Nerve Endings: pain from joint inflammation
What are the 4 Sensory nerve fibers (in order from biggest to smallest)
A alpha
A beta
A delta
C
What 2 qualities distinguish between the sensory nerve fibers?
Which nerve fiber has the least and the most
Primarily surrounding their diameter size and presence of myelin
C and A alpha
What are dermatomes?
Area of skin with sensory innervation by the single dorsal spinal root
What do the cutaneous peripheral nerves supply?
Area of the skin that related to a peripheral nerve
What are the 3 segments of the Psuedounipolar neuron?
Distal Axon (PNS) Dorsal Root Ganglion Proximal Axon (CNS)
What is in the Distal Axon?
Mechanoreceptors and proprioceptors
Dorsal (back) and Ventral (ventral trunk & limbs) Rami
Spinal Nerve
What is in the Proximal Axon
Dorsal Root
What does the dorsal column help with in regards to somatosensory
Light touch, proprioception, vibration
What does the anterolateral column do in regards to somatosensory system?
Pain, temperature, pressure & crude touch
What does the Medial Lemniscal Pathway convey?
Conveys proprioception, vibration and discriminative touch
What do the Anterolateral pathways convey?
Pain, temperature, crude touch and pressure
What are the 3 tracts of the anterolateral pathways and what are their general functions?
Spinothalamic: discrimination (location and intensity) of pain, temperature and crude touch
Spinoreticular: Emotional and arousal aspects of pain
Spinomesencephalic: Pain modulation
What is the function of the Thalamus
Crucial relay station for all pathways traveling to the cortex (afferent)
What are the 3 relay nuclei in the Thalamus
Medial Nuclear Group
Lateral Nucleus Group
Anterior Nuclear Group
What is unique about thalami reticular nucleus
Do NOT project to cortex, instead receives info from the Reticular Formation
Helps with thalamic regulation
Ventral Posterior Lateral (VPL) Nucelus of the Relay Nuclei of Lateral Nuclear Group
(Modality it receives and where is it going)
Somatosensory (Spinal cord) to primary sensory cortex
Ventral posteromedial nucleus (VPM) of the Relay Nuclei of Lateral Nuclear Group
(Modality it receives and where is it going)
Somatosensory (CNs) to primary sensory cortex
Lateral geniculate nucleus (LGN) of the Relay Nuclei of Lateral Nuclear Group
(Modality it receives and where is it going)
Vision to primary visual cortex
Medial geniculate nucleus (MGN) of the Relay Nuclei of Lateral Nuclear Group
(Modality it receives and where is it going)
Auditory to primary auditory cortex
Ventral Lateral (VL) Nucelus of the Relay Nuclei of Lateral Nuclear Group (Modality it receives and where is it going)
Cerebelllum and basal ganglia to primary motor cortex, premotor and supplementary motor cortex
Ventral Anterior (VA) nucleus of the Relay Nuclei of Lateral Nuclear Group (Modality it receives and where is it going)
Cerebellum and basal ganglia to primary motor cortex, premotor and supplementary motor cortex, frontal lobe
Mediodorsal (MD) Nucleus of the Relay Nuclei in the Medial Nuclear group
(Modality it receives and where is it going)
Limbic, basal ganglia to frontal cortex
Anterior Nucleus of the Relay Nuclei in the Anterior Nuclear group
(Modality it receives and where is it going)
Mammillary body, hippocampus to cingulate gyrus
