Neuroscience 2 - Somatosensory

Front 1

Ways somatic sensory system is different from others: __[2]

Back 1

Receptors all over body, different stimuli

Front 2

The sense of body position is called __

Back 2

Proprioception

Front 3

The two major types of skin are: __[2]

Back 3

Hairy, glabrous

Front 4

Types of mechanoreceptors: ___[5]

Back 4

Pacinian corpuscle, Ruffini’s endings, Meissner’s corpuscles, Merkel’s discs, Krause end bulbs

Front 5

___ had small receptive fields, only a few millimeters wide, while ___ had large receptive fields that could cover an entire finger or half the palm

Back 5

Meissner’s corpuscles and Merkel’s disks, Pacinian corpuscles and Ruffini’s endings

Front 6

___ tend to respond quickly at first but then stop firing even though the stimulus continues; these receptors are said to be rapidly adapting. Other receptors, such as ___, are slowly adapting and generate a more sustained response during a long stimulus.

Back 6

Meissner’s and Pacinian corpuscles, Merkel’s disks and Ruffini’s endings

Front 7

You “feel” the music largely with your ___. If you stroke your fingertips across the coarse screen covering the speaker, each point of skin will hit the bumps at frequencies about optimal to activate ___. You feel this as a sensation of rough texture. Stimulation of even lower frequency can activate ___ and yields a “fluttering” feeling.

Back 7

Pacinian corpuscles, Meissner’s corpuscles, Ruffini’s endings

Front 8

The Pacinian corpuscle is shaped like ___ with ___, which makes it sensitive to ___ and unresponsive to ___

Back 8

A football-shaped capsule, layers of connective tissue, high frequency stimuli, steady pressure

Front 9

Reasons why fingertips have best two-point discrimination: ___[4]

Back 9

Higher density of mechanoreceptors, small receptive fields, more brain tissue devoted, special neural mechanisms

Front 10

In terms of decreasing size, axons from skin sensory receptors are usually designated ___; axons of similar size, but innervating the muscles and tendons, are called groups ___.

Back 10

Aα, Aβ, Aδ, C; I, II, III, IV

Front 11

Smaller touch axons are ___, and the smallest one is unique in ___

Back 11

Slower, having no myelin

Front 12

Each spinal nerve, consisting of ___, passes through a ___ between the vertebrae (the “back bones”) of the spinal column

Back 12

Dorsal root and ventral root axons, notch

Front 13

There are ___ spinal segments divided into __[4]

Back 13

30, cervica, thoracic, lumbar, sacral

Front 14

The area of skin innervated by the right and left dorsal roots of a single spinal segment is called a ___

Back 14

dermatome

Front 15

To lose all sensation in one dermatome, therefore, ___ adjacent dorsal roots must be cut. However, the skin innervated by the axons of one dorsal root is plainly revealed by a condition called ___

Back 15

Three, shingles

Front 16

The spinal cord is composed of an inner core of ___, surrounded by a thick covering of ___ that are often called columns. Each half of the spinal gray matter is divided into ___[3]

Back 16

Gray matter, white matter; dorsal horn, intermediate zone, ventral horn

Front 17

The large, myelinated Aβ axons conveying information about a touch to the skin enter the ___ and branch. One branch synapses in the deep part on ___. These connections can initiate or modify a variety of rapid and unconscious reflexes. The other branch of the A β primary afferent axon ___

Back 17

Dorsal horn, second-order sensory neurons, ascends straight to the brain

Front 18

The pathway serving touch is called the___. The ascending branch of the large sensory axons (Aβ) enters the ___

Back 18

dorsal column–medial lemniscal pathway, ipsilateral dorsal column

Front 19

Axons from cells of the dorsal column nuclei arch toward the ___ and ___. From this point onward, the somatic sensory system of one side of the brain is concerned with sensations deriving from the other side of the body

Back 19

ventral and medial medulla, decussate

Front 20

The axons of the dorsal column nuclei ascend within a conspicuous white matter tract called the ___, upon neurons of the ___ in the ___, which projects to __

Back 20

medial lemniscus, ventral posterior (VP) nucleus, thalamus, primary somatosensory cortex (S1)

Front 21

One common transformation in change in information of touch is the amplification of differences in the activity of neighboring neurons, also known as ___, one mechanism being ___, where ___

Back 21

Contrast enhancement, lateral inhibition, neighboring cells inhibit each other

Front 22

Somatic sensation of the face is supplied mostly by the large ___, which enter the brain at the ___

Back 22

trigeminal nerves(cranial nerve V), pons

Front 23

The axons from the trigeminal nucleus decussate and project into___; from here, information is relayed to the ___

Back 23

the medial part of the VP nucleus of the thalamus, somatosensory cortex

Front 24

Most of the cortex concerned with the somatic sensory system is located in the ___. ___, now regarded as the primary somatosensory cortex (S1), is easy to find in humans because it lies on the ___

Back 24

Parietal lobe, Brodmann’s area 3b, postcentral gyrus

Front 25

S1 is flanked by other cortical areas that also process somatic sensory information. These include areas ___ on the postcentral gyrus, and areas ___ on the adjacent posterior parietal cortex

Back 25

3a, 1, 2; 5, 7

Front 26

Ways somatosensory cortex is like other cortexes: ___[2]

Back 26

Thalamus projects to IV, stacked vertically into columns

Front 27

Observations about homunculus: ___[2]

Back 27

Broken up, not scaled like human body

Front 28

Somatopy in the large ___ of rodents is evident in the ___ of S1 neurons

Back 28

Vibrissae, barrels

Front 29

Phantom limb sensations are due to ___

Back 29

Stimulation of skin regions that border the lost appendage

Front 30

___ is a condition in which people see numbers as having a specific color

Back 30

Synesthesia

Front 31

Neurons ___ are not sensitive to the direction of stimulus movement across the skin, but cells in ___ are

Back 31

below the cortex and in cortical areas 3a and 3b, areas 1 and 2

Front 32

In ___, the inability to recognize objects even though simple sensory skills seem to be normal. People with ___ cannot recognize common objects by feeling them

Back 32

Agnosia, astereognosia

Front 33

Parietal cortical lesions may also cause ___, in which a part of the body or a part of the world is suppressed

Back 33

a neglect syndrome

Front 34

Somatic sensation depends strongly on ___, the free, branching, unmyelinated nerve endings that signal that body tissue is being damaged

Back 34

nociceptors

Front 35

Regarding nociceptors, proteases can break down an abundant extracellular peptide called ___ to form ___, another peptide called that binds to specific receptor molecules that activate ionic conductances in some nociceptors.

Back 35

Kininogen, bradykinin

Front 36

Your skin and connective tissue contain___, a component of your immune system. Mast cells can be activated by exposure to foreign substances (e.g., bee venom), causing them to release ___

Back 36

mast cells, histamine

Front 37

Uses of capsaicin: ___[3]

Back 37

Culinary, protecting birdseed, analgesia

Front 38

Examples of hyperalgesia-causing chemicals: ___[3]

Back 38

Bradykinin, prostaglandins, Substance P

Front 39

First pain is caused by the activation of ___; second pain is caused by the activation of ___

Back 39

Aδ, C

Front 40

Nociceptor small-diameter fibers enter the ___. The fibers branch immediately, travel a short distance up and down the spinal cord in a region called the ___, and then synapse on cells in the outer part of the dorsal horn in a region known as the ___

Back 40

Dorsal horn of the spinal cord, zone of Lissauer, substantia gelatinosa

Front 41

Recent experiments have shown that synaptic transmission mediated by ___ is required to experience moderate to intense pain

Back 41

Substance P

Front 42

Nocireceptor cross-talk gives rise to the phenomenon of ___, like in ___

Back 42

Referred pain; appendicitis, heart attacks

Front 43

Differences between touch and pain pathways: ___[3]

Back 43

Touch has specialized nerve structures, touch is fast myelinated, touch terminates in deep dorsal horn, while pain is in substantia gelatinosa

Front 44

Information about pain (as well as temperature) in the body is conveyed from the spinal cord to the brain via the___. Unlike the dorsal column–medial lemniscal pathway, the axons of the second-order neurons immediately ___

Back 44

spinothalamic pathway, decussate and ascend through the spinothalamic tract

Front 45

Information about touch ascends ___, while information about pain (and temperature) ascends ___

Back 45

Ipsilaterally, contralaterally

Front 46

The constellation of sensory and motor signs following damage to one side of the spinal cord is called ___

Back 46

Brown-Séquard syndrome

Front 47

The trigeminal nerve synapses first on second-order sensory neurons in the ___ of the brain stem. The axons of these cells cross and ascend to the thalamus in the ___

Back 47

spinal trigeminal nucleus, trigeminal lemniscus

Front 48

Some of the nocireceptor axons terminate in the ___ and others in the ___

Back 48

VP nucleus, small intralaminar nuclei

Front 49

The ___ proposes that certain neurons of the dorsal horns, which project an axon up the spinothalamic tract, are excited by both large-diameter sensory axons and unmyelinated pain axons.

Back 49

gate theory of pain

Front 50

Several brain regions have been implicated in pain suppression. One is a zone of neurons in the midbrain called the ___, which sends descending axons to the ___, which goes to the ___

Back 50

periventricular and periaqueductal gray matter(PAG), raphe nuclei, dorsal horn

Front 51

Opioids act by binding tightly and specifically to several types of ___ in the brain and that the brain itself manufactures endogenous morphine-like substances, collectively called ___

Back 51

opioid receptors, endorphins

Front 52

Hot receptor protein is ___, while cold is ___

Back 52

Trpv1, Trpm8