Pain and analgesics second half of 1 2.0

Question 1

Where does the AP go after it has gone through the first synapse in the spinal cord?

Answer 1

Crosses over to the other side of the body and goes up into the brain, into the thalamus

Question 2

What type of input can the somatosensory part of the cortex receive?

Answer 2

Touch and nociception

Question 3

What does the somatosensory cortex do with the touch and nociception?

Answer 3

Tells the brain where it has come from

Question 4

Role of insular and anterior cingulate cortex in nociception?

Answer 4

Tells the brain that it is pain that is being experienced, affect your mood

Question 5

How is the body mapped regarding pain perception and location?

Answer 5

As you go round the outside of the somatosensory cortex, different parts of it receive input form different body areas

Question 6

What is the pain pathway to the brain?

Answer 6

Spinothalamic pathway/tract

Question 7

Why is pain referred?

Answer 7

Not enough space in somatosensory cortex to have an acute sensation to map every part of the bodys pain

Question 8

Which body parts have a good pain mapping (know where the pain is coming from)?

Answer 8

Skin

Question 9

Which body parts have a poor pain mapping (don’t know where the pain is coming from)?

Answer 9

Internal organs

Question 10

Where does pain sourced in the oesophagus feel like its coming from?

Answer 10

Heart

Question 11

What can hurt when having a heart attack?

Answer 11

Left arm

Question 12

Which neurons are shared in referred pain?

Answer 12

Second order

Question 13

What is the second order neuron?

Answer 13

The one after the first synapse in the spinal cord

Question 14

What is hyperalgesia?

Answer 14

Increased response to a noxious stimulus

Question 15

What is allodynia?

Answer 15

Painful responses to a non-noxious stimulus

Question 16

Why is hyperalgesia a thing?

Answer 16

To protect already injured/damaged areas of the body

Question 17

How does nociceptor sensitisation work?

Answer 17

Cut skin–> skin cells break–> intracellular components of skin cells is released into extracellular space–> some of these components are H+, ATP, K+ which are nociceptor agonists

Question 18

Why does an elevated conc of extracellular K+ increase the amount of APs fired from a neuron?

Answer 18

Conc grad is disrupted meaning it is harder for the neurons to repolarise, makes them more excitable

Question 19

What is unusual about nociceptive neurons?

Answer 19

They can release NTs from their dendritic end

Question 20

Which NT is released from the dendritic end of nociceptive neurons?

Answer 20

Substance P

Question 21

What does substance P do to blood vessels?

Answer 21

Activate receptors on blood vessels that makes them leaky

Question 22

Outcome of substance P’s action on blood vessels?

Answer 22

More nociceptor agonists are released, generating more nociceptive APs

Question 23

Which cells does substance P recruit?

Answer 23

Mast cells

Question 24

Action of mast cells?

Answer 24

Release histamine which makes blood vessels leaky

Question 25

Which three molecules are used for healing the part of the body that has been damaged?

Answer 25

Bradykinin, prostagladin, neural growth factor

Question 26

What does nerve growth factor do?

Answer 26

Activates TrkA receptor–> this sensitises nociceptors by lowering their opening threshold

Question 27

What is peripheral sensitization?

Answer 27

Increased sensitivity of peripheral nociceptors

Question 28

What is central sensitization?

Answer 28

Increased transmission in spinal cord

Question 29

Which fibres do itch sensations travel down?

Answer 29

Adelta and C

Question 30

Difference between pain and itch?

Answer 30

Analgesics don’t inhibit itch, can imagine an itchy sensation but not a painful one

Question 31

What kind of input cures an itch?

Answer 31

Nociceptive (scratching it hard)