Chapter 49-Somatic sensations II

Question 1

Explain the difference between fast and slow pain.

Answer 1

fast pain is felt within 0.1 sec and is sharp vs. slow pain which is felt after 1 sec and is throbbing, aching pain`

Question 2

What are other names for the fast pain?

Answer 2

Sharp pain, pricking pain, acute pain, electric pain.

Question 3

What are other names for the slow pain?

Answer 3

Aching pain, throbbing pain, nauseous pain, chronic pain.

Question 4

Wher is the fast pain felt?

Answer 4

Fast pain is mostly felt on the skin.

Question 5

Where is the slow pain felt?

Answer 5

Occurs in both skin and almost any deep tissue organ.

Question 6

What are pain receptors?

Answer 6

Free nerve endings

Question 7

Where are the free nerve ending pain receptors widespread?

Answer 7

Superficial layers of the skin and in certain internal tissues, such as the periosteum, arterial walls, joint surfaces, and falx and tentorium in the cranial vault

Question 8

Which stimuli can elicit pain?

Answer 8

Mechanical, thermal, chemical

Question 9

Which stimuli can elicit fast pain?

Answer 9

Mechanical and thermal

Question 10

Which stimuli can elicit slow pain?

Answer 10

Mechanical, thermal, and chemical

Question 11

Which chemicals excite pain receptors?

Answer 11

Bradykinin, serotonin, histamine, potassium ions, acids, acetylcholine, and proteolytic enzymes

Question 12

Which chemicals enhance the sensitivity of pain receptors?

Answer 12

Prostaglandins and substance P

Question 13

True or false: pain receptor can readily adapt to stimuli

Answer 13

False, in fact sometimes the sensitivity can actually increase as the pain progresses (hyperalgesia)

Question 14

Hyperalgesia

Answer 14

Increased sensitivity of the pain receptors.

Question 15

True or false: the tissue damage that has already occurred is the primary influencer of pain.

Answer 15

False, the rate of tissue damage is the most important determining factor of pain felt.

Question 16

What is the temperature at which an average human starts to feel pain?

Answer 16

Above 45°C.

Question 17

This chemical causes the most pain and may be the single most responsible for causing the tissue damage type of pain.

Answer 17

Bradykinin (also local increase in potassium ions and action of enzymes can contribute to pain.

Question 18

Can ischemia be a cause of pain?

Answer 18

Yes, it can be; the time that is needed for the pain to be felt depends on the metabolism of the tissue; the main chemical is thought to be lactic acid (anaerobic respiration).

Question 19

Which factors contribute to pain caused by muscle spasms?

Answer 19

Direct effect of the spasms in the pain felt by mechanosensitive receptors; indirectly the contraction of muscles causes compression of blood vessels, thus ischemia; spasms also increase the metabolic rate, worsening ischemia.

Question 20

What is the fiber transmission for fast, sharp pain?

Answer 20

Elicited by mechanical or thermal pain stimuli; transmitted in the peripheral nerves to the spinal cord by small type A-delta fibers at velocities between 6-30 m/sec

Question 21

What is the fiber transmission for slow, chronic type pain?

Answer 21

Elicited mostly by chemical (can be mechanical or thermal stimuli); transmitted to the spinal cord by type C fibers at velocities between 0.5-2 m/sec

Question 22

What is a “double-pain” sensation?

Answer 22

Sharp pain is transmitted to the brain via A-delta fibers, followed by a second later by a slow pain, conducted via type C fivers.