PSB Exam 3 Questions & Answers 2024/2025
5 (3) main functions of the somatosensory system - ANSWERS- Touch, temperature, pain, position in space, and movement of joints
- Allows us to distinguish what the world does to us and what we do in the world
- Has a closer relationship with movement ...
5 (3) main functions of the somatosensory system - ANSWERS- Touch, temperature, pain, position in
space, and movement of joints
- Allows us to distinguish what the world does to us and what we do in the world
- Has a closer relationship with movement than the other senses do
How is somatosensory information from the face and head conveyed to the CNS? - ANSWERSThrough
the trigeminal nerve #5
Perception (nociception) - ANSWERSPerception of pain, itch, and temperature
Perception (hapsis) - ANSWERSPerceive fine touch and pressure and identify objects that we touch and
grasp
Perception (proprioception) - ANSWERSPerception of location and movement of the body, general crude
awareness of the body part being contacted
What is meant by "adaptation" in regards to somatosensory receptors? - ANSWERSDiminished sensitivity
to stimulus after constant exposure to that stimulus
Ex: Constant loud sound of air condition
How is the peripheral axon of a posterior root (dorsal root) ganglion neuron similar to a dendrite? -
ANSWERSThe peripheral end of the sensory neuron is the receptor ending, which is responsive to
sensory stimulation
Are spinal interneurons involved in monosynaptic reflexes? How about polysynaptic reflexes? -
ANSWERSMonosynaptic- reflex requiring one synapse between sensory input and muscle contraction
,Polysynaptic- requires several synapses between sensory input and muscle contractions
Immediately before somatosensory signals are delivered to the primary somatosensory cortex, they are
delivered to the _____________. - ANSWERSThe ventrolateral area (thalamus)
Bright light and loud noises can be painful, does this mean visual and auditory systems include
nociceptors, and that pain is conveyed to primary visual and auditory sensory cortex? - ANSWERS-
Painful stimuli are exclusively detected by somatosensory nociceptors
-Perception of pain is unpleasant but also protective
What is the "gate theory" of pain suppression? - ANSWERSWhen you stub your toe, you feel pain
because the pain pathway to your brain is open
What is the role of interneurons and "endogenous opioids" after stubbing a toe? - ANSWERS- Rubbing
the toe activates the haptic-proprioceptive pathway and reduces the flow of information in the pain
pathway because the pain gate partly
-Done through massage, acupuncture, warm water
Where is primary and secondary somatosensory cortex located? - ANSWERS- Primary: parietal lobe, in a
ridge of the postcentral gyrus
- Secondary somatosensory cortex- Located behind the primary somatosensory cortex
What are the sensory and motor homunculi? - ANSWERS-Sensory homunculus represents a map of brain
areas dedicated to sensory processing for different anatomical divisions of the body.
-Motor homunculus represents a map of brain areas dedicated to motor processing for different
anatomical divisions of the body
How are body parts represented in these homunculi, and what does this representation correspond to? -
ANSWERSSensory: the hands and mouth are huge, these feel sensations the most sensory wise
Motor: the lips, tongue, toes and hands are huge, these feel the most motor wise
Why does an inflamed or damaged lung create a painful sensation in the neck? - ANSWERS- Referred
pain- sensory signals from visceral organs
, - Relay this pain from the bodys surface and from internal organs
- These messages converge in the somatosensory cortex to generate only one perception
How is the vestibular system related to the somatosensory perception of proprioception? -
ANSWERSHumans sense position and motion in three -dimensional space through the interaction of a
variety of body proprioceptors, including muscles, tendons, joints, pressure, hearing, and the vestibular
system
How are hair cells in the vestibular system different from hair cells in the auditory system? How are they
similar? - ANSWERS- Hair cells respond to body position and to the movement of the head
- When the head moves, fluid within the semicircular canals bends the cilia on the hair cells
- Bending of cilia leads to receptor potentials in the hair cells and action potentials in the cells forming
the vestibular nerve
Why can heavy drinking (alcohol intoxication) produce loss of balance and vertigo? - ANSWERSAlcohol is
absorbed in to the fluid of the inner ear and stays there even after it is no longer present in the blood
and brain
How is the secondary somatosensory cortex related to the dorsal and ventral visual streams? -
ANSWERS- The dorsal ventral stream projects to the secondary somatosensory cortex then to the frontal
cortex (specifying movement used for grasping a target)
- Visual information is integrated with somatosensory information to produce unconscious movements
-The ventral stream provides conscious haptic information about the identity of objects and completed
movements (objects, size, shape, and texture)
What are the three major hierarchical levels of motor control? What is the main general function of each
level? - ANSWERS- Cerebrum (voluntary movements)
- Basal ganglia and cerebellum (refine sequence and movement patterns)
- Brainstem and spinal cord(execute movement patterns)
What is the role of somatosensory feedback to each of these three motor control levels? - ANSWERS-
Afferent somatosensory information travels from the sensory organs inward to the CNS
- Efferent motor movement signals travel out of the CNS to muscles
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