Lecture 28: Somatic Sensory Nervous System Flashcards
What are the special senses?
Vision, hearing, taste, smell and vestibular (balance).
What is transduction?
Conversion of physical stimulus to action potential.
Sensory receptor -> Afferent neurons -> ____ -_____
Integration centre.
What are the 4 types of info that describe a sensory stimulus?
Modality (type of sensor), Intensity (frequency of AP), Duration, Location.
What are the two sensors for proprioception?
(body position/posture)
Length receptors and tension receptors.
With a larger stimulus, frequency of APs in axon ______.
Increases.
Touch receptors are ______ adapting, which means APs are no longer generated after a while.
Rapidly adapting.
Stretch receptors are ______ adapting, which means APs are still generated after a while, even if at a lower frequency.
Slowly adapting.
What is a receptive field, and what gives good discrimination?
a region of space in which a stimulus can lead to activity in a particular afferent neuron. Small fields and dense innervation gives good discrimination. Fields can overlap.
What is the medial lemniscal pathway, how many neurons does it contain in relay and which column is it part of?
Afferent touch and posture pathway, 3 neurons in relay and part of the dorsal column.
What 2 major roles does the somatosensory cortex play?
Sensation; identification of ‘what and where’.
Perception; interpretation and association.
What two types of pain can be felt? How do their receptive fields and axons differ?
Fast Acute pain (somatic pain); small receptive fields and large myelinated axons.
Slow Chronic Pain (visceral pain); large receptive fields, small, unmyelinated axons.
What is the lateral spinothalamic pathway and how many neurons does it contain in relay?
Specific afferent pathway for pain, minimum of 3 neurons in relay.
