sensory and motor systems Flashcards
What is somatosensation?
Sensory information from all over the body about touch, temperature, pain, position, and joint movement.
How is somatosensation different from other senses?
It is closely linked to movement and helps distinguish between external forces and self-movement.
Where are somatosensory receptors located?
Skin, muscles, tendons, and joints.
how does receptor density affect sensitivity?
More receptors = higher sensitivity (e.g., hands, lips).
What are the two types of human skin?
Hairy skin (lower sensitivity) and glabrous skin (higher sensitivity, no hair, e.g., palms).
What does the two-point discrimination test show?
Differences in skin sensitivity; fingertips are most sensitive.
What is nociception?
Perception of pain and temperature.
what is hapsis?
perception of fine touch and pressure
what is proprioception?
perception of body position and movement
What are nociceptors?
Free nerve endings that detect sharp/dull pain and temperature changes.
what are haptic receptors?
receptors that detect fine touch, pull, vibration and pressure
what are proprioceptors?
receptors that detect body movement and position through stretch
What does a rapidly adapting receptor do?
Responds briefly at the beginning and end of a stimulus (e.g., vibration).
what does a slowly adapting receptor do?
responds continuously as long as a stimulus is present (e.g. sustained pain)
What do dorsal-root ganglion neurons do?
Carry sensory information from the skin to the CNS.
How are proprioceptive and haptic neurons different from nociceptive neurons?
Proprioceptive and haptic neurons are large and well-myelinated (fast), nociceptive neurons are small and less myelinated (slow).
What is deafferentation?
Loss of incoming sensory input due to nerve damage.
What happens in deafferentation (e.g., Patient G.O.)?
Loss of fine motor control without sensory feedback.
What is the dorsal spinothalamic tract?
Carries haptic and proprioceptive information ipsilaterally to the brain.
What is the ventral (anterior) spinothalamic tract?
Carries nociceptive information contralaterally to the brain.
What happens if one side of the spinal cord is damaged?
Loss of different types of sensory information on both sides of the body below the injury.
What are the two main somatosensory areas in the brain?
Primary somatosensory cortex and secondary somatosensory cortex.
What does the primary somatosensory cortex do?
Receives thalamic input and begins constructing sensory perceptions.
