Pain Flashcards
What is the difference between pain and nociception
How many nerve endings
PAIN = subjective experience = a perception and feeling that is subjective
NOCICEPTION = sensory detection of noxious stimuli (harmful or potentially harmful stimuli eg tearing tissue
Has 3 nerve ending - mechano - mechanothermal - polymodal
What are the 2 types of nociceptive neurons
A delta fibres = myelinated short, sharp, fast first pain
C fibres = un-myelinated slow, dull, long pain
Describe the pathway of pain
The nociceptive neurons sense a harmful noxious stimulus positively stimulating and releasing substance P to the secondary neuron that’s across the other side of the spinal cord.
This signal travels up the spinal cord via the spinal thalamic tract and to the thalamus which can send to brain regions like the primary somatosensory cortex which identifies the type of stimuli, intensity and location.
Also sent to limbic system and prefrontal cortex.
Limbic runs the emotional response to pain whereas prefrontal makes us rationalise and understand the pain.
What is cutaneous pain?
Cutaneous pain is where the nociceptors have been triggered in skin
What is somatic pain?
Pain experiences associated with triggering of nociceptors found within musculoskeletal structures and associated CT
What is visceral pain?
Visceral pain is the triggering of nociceptors found in the viscera of the body like kidneys. It merges and synapses with the same neurons as somatic nociceptive neurons = this is referred pain.
Referred pain is where pain is felt somewhere other than the actual source of pain.
We can’t feel or identify where the pain is coming from in the viscera. The perceptions of pain in the body location is different to the location of noxious stimuli.
Eg kidney pain – lower back pain
What is pain perception?
What is the difference between pain threshold and pain tolerance?
Pain perception = Occurs once signals reach cerebral cortex.
There are 2 concepts of pain perception
Pain threshold is the level of intensity or amount of stimulation required for a person to start feeling pain. Its determined by the strength of a stimulus that causes nerve cells to generate AP and send signals to brain. Relatively uniform factor between individuals
Pain tolerance = Subjective eg how much it hurts. Influenced by many factors (from previous experience or mood etc) and is variable among individuals.
What is the main mechanism of pain modulation
What’s the patho?
Gate control
Modulates pain by regulating the ascending pain signals
There are other neurons other than nociceptors neurons called NON nociceptors neurons (touch/pressure.thermal).
The NON nociceptive neuron positively stimulates the inter neuron then the inter neuron will negatively stimulate the secondary neuron inhibiting the pain signals coming from the nociceptive neuron hence why we rub when we get hurt.
Another type of pain modulation?
Descending
Interneuron is stimulated from brain positively allowing the inter neuron to stimulate the secondary negatively reducing pain
What is Endorphins/endogenous opioids in regards to pain modulation
Body’s own pain relief system
Involved in both mechanisms of pain modulation (GATE + DESCENDING)
Body produces chemicals which binds to opioid receptors in brain stem and dorsal horn of spinal cord inhibiting the AP frequency
What is neuropathic pain
Neuropathic pain is a classification and its caused by abnormal functioning or damage to the sensory nerves. Basically abnormal signalling in the nerves themselves. Meaning it manifests as pain sensations without nociception.
