7.2.1 The Mechanical Senses 2 Flashcards

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1
Q

The thicker and faster axons convey ____ pain. The thinner ones convey duller pain, such as postsurgical pain.

A

sharp

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2
Q

Although pain messages reach the brain more slowly than other sensations, the brain processes pain information ____. Motor responses to pain are faster than motor responses to touch stimuli.

A

rapidly

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3
Q

Pain axons release two neurotransmitters in the spinal-cord. Mild pain releases the neurotransmitter glutamate, whereas stronger pain releases both glutamate and _____.

A

substance P

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4
Q

The pain-sensitive cells in the spinal-cord relay information to several sites in the brain. One path extends to the ventral posterior nucleus of the ____ and from there to the somatosensory cortex, which responds to painful stimuli, memories of pain, and signals that warn of impending pain.

A

thalamus

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5
Q

The pain pathway crosses immediately from receptors on the one side of the body to a tract ascending the ____ side of the spinal-cord.

A

contralateral

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6
Q

Painful stimuli also activate the path that goes through the reticular formation of the medulla and then to several of the central nuclei of the thalamus, the amygdala, hippocampus, prefrontal cortex, and cingulate cortex. These areas react not to the sensation but to its ____ associations.

A

emotional

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7
Q

A hypnotic suggestion to feel no pain decreases the responses in the cingulate cortex without much effect on the somatosensory cortex. That is, someone responding to a hypnotic sensation still feels the painful sensation but reacts with ____ ____.

A

emotional indifference

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8
Q

Relieving pain. The brain puts the brakes on prolonged pain by ____ mechanisms – systems that respond to opiate drugs and similar chemicals.

A

opioid

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9
Q

Opiates bind to receptors found mostly in the spinal-cord and the ____ ____ area of the midbrain.

A

preaqueductal grey

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10
Q

Later researchers found that opiate receptors act by blocking the release of ____.

A

substance P

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11
Q

The discovery of opiate receptors was exciting because it was the first evidence that opiates act on the ____ ____ rather than on the injured tissue.

A

nervous system

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12
Q

Furthermore, it implied that the nervous system must have its own opiate-type chemicals. The transmitters that attach to the same receptors as morphine are known as endorphins – a contraction of ____ ____.

A

endogenous morphines

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13
Q

The gate theory was an attempt to explain why some people ____ pain better than others and why the same injuries hurt worse at some times than others.

A

withstand

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14
Q

According to the gate theory, spinal-cord neurons that receive messages from pain receptors also received input from touch receptors and from axons descending from the brain. These other inputs can close the “gates” for the ____ ____– and we now see that they do so at least partly by releasing endorphins.

A

pain messages

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15
Q

Nonpain stimuli modify the ____ of pain. When you have an injury, you can decrease the pain by gently rubbing the skin around it or by concentrating on something else.

A

intensity

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16
Q

People also experience pain relief from ____. A ____ is a drug or other procedure with no pharmacological effects.

A

placebos

17
Q

People who receive placebos do not just say the pain decreased; scans of the brain and spinal-cord also show a ____ response to pain.

A

decreased

18
Q

However, a placebos affects are mainly on the emotional response to pain, not the sensation itself. That is, a placebo decreases the response in the ____ ____ but not the somatosensory cortex.

A

cingulate cortex

19
Q

Placebos relieve pain partly by increasing the release of opiates and partly by increasing the release of dopamine. In contrast, antiplacebos or ____ (suggestions that the pain will increase) worsen pain by increasing anxiety.

A

nocebos

20
Q

Damaged or inflamed tissue, such as sunburned skin, releases histamine, nerve growth factor, and other chemicals that help repair the damage but also magnify the responses of nearby ____ and ____ receptors.

A

heat and pain

21
Q

Social pain. Hurt feelings do ____ physical pain in important regards.

A

resemble

22
Q

Experimenters monitored peoples brain activity during this task and found significantly increased activity in the cingulate cortex when someone ____ ___ ___. Recall the cingulate cortex responds to emotional aspects of pain.

A

felt left out

23
Q

Hurt feelings like real pain in another way, you can relieve hurt feelings with the pain-relieving drug ____ (Tylenol).

A

acetaminophen

24
Q

Researchers have identified special receptors for ____ and special spinal-cord pathways conveying ____.

A

itch

25
Q

You have at least two kinds of itch. They feel about the same, but the ____ are different.

A

causes

26
Q

The first type of itch, when you have mild ____ ____ – such as when your skin is healing after a cut – your skin releases histamines that dilate blood vessels and produce an itching sensation.

A

tissue damage

27
Q

The second type of itch, contact with certain ____ also produces itch. Antihistamines block the itch that histamines cause but not the itch that some plants cause.

A

plants

28
Q

A particular spinal-cord ____ conveys itch sensation. Some of its axons respond to histamine itch and some to plant itch.

A

path

29
Q

Itch axons activate certain neurons in the spinal-cord to produce a chemical called ____ ____. Blocking that peptide has been shown to decrease scratching in mice without affecting their responses to pain.

A

gastrin-releasing peptide

30
Q

Itch is useful because it directs you to scratch the itchy area and remove whatever is irritating your skin. Vigorous scratching produces ____ ____, and mild pain inhabits itch.

A

mild pain

31
Q

Opiates, which ____ pain, ____ itch. This inhibitory relationship between pain and itch is the strongest evidence that itch is not the type of pain.

A

decrease : increase