General sensory systems Flashcards
What are exteroreceptors?
Located on body surfaces
Exteroreceptors are involved in sensing external stimuli.
What do GSA neurons detect?
Touch, temperature, pressure, noxious stimuli
GSA stands for general somatic afferent.
Where are general proprioceptors located?
In muscles, tendons, joints
General proprioceptors help in sensing body position and movement.
What do interoreceptors monitor?
Internal body temperature, blood pressure, gas concentration, pressure and movement of viscera
Interoreceptors are involved in sensing internal bodily conditions.
What are nociceptors sensitive to?
Potentially destructive stimuli
Nociceptors have a high stimulus threshold.
What is the role of 1a afferent receptors?
Located in neuromuscular spindles, involved in proprioception
They help relay information about muscle stretch.
What does the dorsal spinocerebellar tract convey?
Information about limb, trunk, and neck position to the cerebellum
It predominantly transmits information ipsilaterally.
What happens when there is a unilateral cervical spinal cord lesion?
Causes GP ataxia on the same side as the lesion
GP stands for general proprioception.
What is the function of the cuneocerebellar tract?
Transmits proprioceptive information from thoracic limbs and cervical regions
It plays a role in unconscious proprioception.
What is the conscious proprioceptive pathway?
Involves the medial lemniscus and thalamic projections to the somesthetic cortex
This pathway is crucial for proprioceptive awareness.
What is the function of the lateral cervical nucleus?
Major role in conscious projection of tactile sensation
It is part of the spinocervicothalamic pathway.
What is a dermatome?
Area for an individual dorsal root to supply
Dermatomes have up to three areas of overlap.
What is the role of the withdrawal reflex?
Involves activation of GSE motor neurons in adjacent spinal cord segments
It is a protective mechanism against harmful stimuli.
What does nociception involve?
Release of serotonin, bradykinin, prostaglandins
These substances lower the threshold of nociceptors.
What is the lateral spinothalamic tract?
Multisynaptic pathway for nociceptive signals
It continues rostrally to the brainstem and thalamus.
What happens to GSA axons in the cranial nerve system?
Course from receptors on the surface of the head through trigeminal branches
They are involved in sensation from facial structures.
What is the function of the mesencephalic tract of the trigeminal nerve?
Transmits proprioceptive information from muscles of mastication
It synapses on alpha motor neurons for reflex actions.
What is the significance of the thalamic projections to the somesthetic cortex?
Conveys sensory information for conscious perception
This includes touch, pain, and temperature sensations.
What is an autonomous zone?
Portion of body surface innervated by only one named nerve
This zone has no overlap with other nerves.
What is the role of serotonin in nociception?
Acts as an inhibitory neurotransmitter in projection pathways
It helps modulate pain perception.
