Sensory Systems

Question 1

Define somatosensory

Answer 1

Bodily sensations of touch, pain, temp, vibration, and proprioception

Question 2

Identify the components of somatosensory system

Answer 2

signals received from sensory receptors in the skin, joints, fascia, ligaments, and muscle–detection of changes INTERNALLY or externally

Question 3

What types of sensations do free nerve ending cells detect? What size are their receptor fields?

Answer 3

temperature, pain, crude touch
small or large receptor fields

Alpha-delta (3)- pain, cool, itch
C (4)-pain, warm,itch

Question 4

What types of sensations do Merkel cells detect? What size are their receptor fields?

Answer 4

light touch (shape and texture) 
small receptive fields

Question 5

What types of sensations do Meissner corpuscles detect? What size are their receptor fields?

Answer 5

light touch and low-frequency vibration (just enough to detect movement)
small receptor fields >4x more sensitive than Merkel

Question 6

What types of sensations do Ruffini cells detect? What size are their receptor fields?

Answer 6

deep vibration (like a power tool), pressure, and stretching of the skin (FLEX/EXT, friction,healing, weight gain)

large receptor fields

Question 7

What types of sensations do Pacinian cells detect? What size are their receptor fields?

Answer 7

deep vibrations (like a death grip), pressure 
large receptor fields

Question 8

what is proprioception?

Answer 8

the sense of joint limb position in space

Question 9

Where are intrafusal fibers located and what do they detect?

Answer 9

Inside muscle spindle

they detect the rate and degree of stretch in a noncontractile muscle force.

Question 10

What do intrafusal fibers trigger?

Answer 10

muscle contraction and antagonist inhibition (control myotactic reflex)

Question 11

where are GTOs located and what do they detect?

Answer 11

golgi tendon organs are located in the tendon, especially dense where the muscle connects.

they detect contractile force via tension

Alpha-alpha/type 1 fiber

Question 12

What do GTOs trigger?

Answer 12

muscle relaxation (autogenic inhibition) and inhibit muscle spindles

Question 13

What is autogenic inhibition?

Answer 13

when our muscles give out in a contraction (as opposed to reaching ultimate failure)

Question 14

How do synovial joint receptors monitor stretch?

Answer 14

via spinal reflex arcs and the cerebellum

Question 15

What types of mechanoreceptors are used by our joint receptors? What do they detect?

Answer 15

Pacinian (AROM and compression)
Ruffini (end range and PROM)
Free nerve endings (pain and non-noxious stimuli)

Question 16

what sensations does the medial lemniscal pathway detect?

Answer 16

discriminative touch, proprioception, and vibration

Question 17

what are the 3 anterolateral pathways?

Answer 17

spinothalamic, spinoreticular, spinomesencephalic

Question 18

what sensations do the spinothalamic pathway detect?

Answer 18

discrimination of intensity and location of pain, temperature and crude touch

Question 19

what types of sensations do the spinoreticular pathway detect?

Answer 19

emotion and arousal related to pain

Question 20

what type of sensation does the spinomesencephalic pathway detect?

Answer 20

pain modulation

Question 21

what are the 3 groups that make up the relay nuclei?

Answer 21

medial, lateral, and anterior nuclear groups

Question 22

What are the 6 components of the lateral nuclear group?

Answer 22

ventral posterolateral nucleus
ventral posteromedial nucleus
ventral lateral nucleus
Ventral anterior nucleus 
lateral geniculate nucleus
medial geniculate nucleus

Question 23

What is the function of the ventral posterolateral nucleus?

Answer 23

To relay info from the somatosensory spinal cord to the primary sensory cortex

Question 24

What is the function of the ventral posteromedial nucleus?

Answer 24

to relay information from the somatosensory cranial nerves to the primary sensory cortex

Question 25

What is the function of the lateral nucleus?

Answer 25

to relay information from the cerebellum and basal ganglia to the primary motor cortex and association motor cortices.

Question 26

What is the function of the ventral anterior nucleus

Answer 26

cerebellum and basal ganglia to the primary motor cortex and association motor cortices along with other frontal lobe structures

Question 27

What is the function of the lateral geniculate nucleus?

Answer 27

to relay visual input to the primary visual cortex

Question 28

What is the function of the medial geniculate nucleus?

Answer 28

to relay information to the primary auditory cortex.

Question 29

The mediodorsal nucleus makes up the medial nuclear group. What is its function ?

Answer 29

to relay info from the limbic system and basal ganglia to the frontal cortex

Question 30

The anterior nucleus makes up the anterior nuclear group. What is its function?

Answer 30

relaying info from the mamillary body and hippocampus to the cingulate gyrus

Question 31

What is the function of the primary somatosensory cortex

Answer 31

starts process of touch recognition

Question 32

what is the function of the somatosensory association cortex

Answer 32

unimodal assn cortex w/ 1-way line of communication

Question 33

what is the function of the heteromodal cortex?

Answer 33

higher-order processing in frontal and parietal lobes> sight, motor, hearing, etc.