Somatic Pathways Flashcards
What are somatic sensations?
Tactile sensations that arise from the skin (eg. touch, pressure, vibration, temp, pain)
Proprioceptive (position sense) sensations that arise from the muscles and joints
What are special senses?
Vision, hearing, taste, smell, balance
What is visceral sensation?
Sensations that arise from the visceral organs (eg. pressure, stretch, chemical, concentrations)
What are the types of sensory receptors?
Free nerve endings - bare dendrites (eg. pain, temp)
Encapsulated nerve endings (eg. pressure, vibration)
Separate cells (eg. special senses)
What are the types of tactile sensory receptors?
Touch - merkel disc, meissner corpuscle, ruffini corpuscle
Pressure - merkel disc, ruffini corpuscle
Vibration - meissner corpuscle, pacinian corpuscle
Temperature - free nerve endings
Pain - free-nerve endings
What are the types of Proprioceptive Sensory Receptors?
Position sense (muscles) - muscle spindles, tendon organs
Position sense (joints) - ruffini corpuscles, pacinian corpuscles
What pathway do sensory (afferent) pathways travel?
Bottom -> up (CNS)
Outside -> in (PNS)
What pathway do motor (efferent) pathways travel?
Top -> down (CNS)
Inside -> out (PNS)
In somatic sensory pathways, which order-neuron crosses over to the other side of the body?
The 2nd neuron in the pathway crosses to the opposite side of the body
(consists of a 3-neuron relay system)
In somatic motor pathways, which order-neuron crosses over to the other side of the body?
The 1st neuron in the pathway crosses to the opposite side of the body (consist of a 2-neuron relay system)
Describe the anterolateral (spinothamalic) pathway.
-Carries signals related to temperature and pain
-Uses tracts in the anterior and lateral columns
Describe the posterior column pathway.
-Carries signals related to touch, pressure, vibration and proprioception
-Uses tracts in the posterior column
What are direct and indirect motor pathways?
Direct motor pathways - carry signals originating in the cerebral cortex
Indirect motor pathways - carry signals originating in the brain stem
