Pain + analgesics Flashcards
Where do pain signals travel to + how can they be used to reduce pain?
From damaged tissues into spinal cord and up towards the brain.
Pain can be reduced by:
Interfering with nerve signals carrying pain.
Reducing inflammatory response therefore reducing intensity of pain signals.
What are the 3 types of pain?
Visceral (stretch receptors)
Neurogenic pain/Neuropathic
Somatic pain (A-delta= milenated, acute pain. C-fibres= non-milenated, acute pain.)
What are the characteristics of visceral pain?
Comes from internal body organs (tumours, fluid collection, heart problems)
It is throbbing pain that is hard to pinpoint the source of.
What are the characteristics of somatic pain?
Pain from bones, tendons and tissues.
It is sharp, cutting pain with an easily identifiable source.
What is nociceptive pain?
A type of physical pain, caused by potentially harmful stimuli being detected by nociceptors around the body.
What is neurogenic/neuropathic pain?
Pain that develops when the nervous system is damaged or not working properly.
Can be caused by disease or illness.
It does not develop in response to any specific circumstance or stimulus.
How does the brain process pain?
Fore-brain, hypothalamus
Brain makes judgements as to whether pain is important, contextualises it.
Fore-brain controls emotional response to pain.
Hypothalamus controls autonomic/physical responses to pain (HR, sweating, dilated pupils)
What are the sensory (afferent) pathways in pain?
1st order neurone (primary afferent) is first in chain, carries pain from injury to spinal cord.
Pain arrived in dorsal horn and synapses with 2nd order neurone - crosses from one side of dorsal horn to other + up spinal cord.
Pain travels up spinal cord along 2nd order neurone up into brain and synapses in thalamus with 3rd order neurone.
What does the vecticular formation + the limbic system do in response to pain?
Recticular formation - increases alertness and triggers increase in HR + BP.
Limbic system - emotional response
What does the cortex + the hypothalamus do in response to pain?
Cortex - determines location, intensity and discriminates pain and determines the meaning of incoming pain signals.
Hypothalamus - autonomic and endocrine response to pain.
What is descending inhibition?
Certain areas of the brain (periaqueductal grey matter) can activate descending pathways, sending signals back down the spinal cord to block transmission of the incoming psi signal between 1st + 2nd order neurone.
This has the capacity to block incoming pain signals.
What is the process of descending inhibition?
- Pain signals travel along 1st order nerves to spinal cord.
- In spinal cord the 1st order neurone synapses with 2nd order neurone.
- Signals travel up brain and are transmitted and processed.
- Regions of brain (PAG) respond by sending inhibitory signals down to 1st + 2nd order neurone synapse, inhibiting it and blocking pain signals.
What are the 4 phases of nociception?
Transduction
Transmission
Modulation
Perception
What is transduction?
The process of stimuli activating nerve endings.
What is transmission?
Transmission is the functions by which pain is carried to the brain.