Pain is such a subjective topic ,and cannot be really seen and measured. People describe pain as a different type of pain. The pain has quite a few kinds such as acute, chronic, dull, achy, sharp, burning and throbbing.
I have written about difference between acute and chronic previous post.
Why do people feel pain differently? This has been a big question to me.
I have always thought our brain feels pain or emotions as when you are doing something different from pain or doing something happy, you feel less pain or don’t feel pain at all.
Some words you will come across when it comes to pain
- Nociceptor (Called pain receptor): Sensory receptors for pain locate nerve ending, muscle, joint, organs, skin, tendons and bone but not in the brain
- Chemoreceptor: nerve ending that finds chemical stimuli which locates in tongue, nose and blood vessels
- Mechanoreceptor: Tension and distortion in the skin and soft tissue
- Thermoreceptor: feels temperature
- Pain: type of pain such as sharp, dull, achy, throbbing and burning
- Dorsal horn: locates in spinal cord and works as a gate-like mechanism
- C fibre: nociceptive fibre also which sends pain information to the brain slowest fibre
- A-bete fibre: activated by touch
- A-delta fibre: another pain fibre but sends information faster that C fibre
- Ascending: consists of A-delta and C fibres send messages to the brain from the body
- Descending: nerve tracts send information to motor function from the brain to the rest of the body
- Gate-control theory: Related to ascending inhibition pain information stops at the spinal cord level (does not reach up to the brain)
- Cortisol: known as a stress hormone released by fear or stress
- Serotonin: This is known as a depression hormone and found in digestive system
- Enkephalin: Occurs naturally by adrenal medulla and works like a painkiller
- Endorphins: Works as a painkiller or pain reliever and is made by pituitary glands
Enkephalin and endorphins work like a drug called opioids.
*Serotonin, Enkephalin and endorphins are prone to be produced by exercise, laughing, meditation, dark chocolate and bathing the sun.
Gate control theory (Ascending and descending pathway)
Pain signals are sent to the spinal cord then up to the brain (ascending pathway). This is how people usually feel where the pain is and unpleasant feeling. However, this pain information does not reach the brain or even get diminished. Gate control theory occurs in relay point along the ascending pathway. Basically, when the gate is open, pain information is sent up to the brain but when the gate is closed, pain information somehow gets inhibited.
Ascending pathway is in charge of transmitting pain information to the brain while descending pathway is responsible for controlling and inhibiting.
This video explains well what the ascending and descending pathways are.
(PAIN!) Physiology- The ascending pathway, descending Pain Pathway and the Substantia Geletinosa
Different fibre type (Table 1)
|Type of nerve fibre||Information that they carry||Myelin sheath||Diameter||Speed (m/s)|
|A-alpha||Proprioception||Myelinated*||13-20||80-120 (sports and racing car)|
|A-delta||Pain (mechanical and thermal)||Myelinated||1-5||5-40 (bicycle)|
|C fibre||Pain (mechanical, thermal and chemical)||Non- Myelinated||0.2-1.5||0.5-2 (walking)|
*Myelinated: this locates around nerves that consist of protein and fatty substance to send information faster and more efficient.
Chronic pain and signals
A-beta and A-delta fibre
As it is shown on the table 1 above, A-beta and A-delta fibre send information faster than C fibre which causes chronic pain. These fibres travel faster than C fibre so that body and the brain react to danger or harm. For instance, when you touch something hot, your body reacts quickly to take hands away without even thinking. That is what these fibres do.
Also, if we could activate these fibres, chronic pain would be alleviated to some extent as these fibres carry information to the brain faster than C fibre.
C fibres (chronic pain)
When the pain lasts more than 2-3weeks, the pain is categorised as a chronic pain in general. Chronic pain is naughty, distractive and annoying. People who have lived with some chronic pain for a long time ignore the pain or are used to being with it as it is not a life-threatening pain. C fibres carry pain information as fast as walking speed and it causes dull, achy, cramping or nagging pain.
*A-delta fibre sends a sharp and shooting pain while C fibre does dull and achy pain information.
What makes the gate open and close?
This gate is not actual gate but the gate that is spinal cord works as a gate-like role which means that it allows some information to pass through to the brain and prioritises the information to pass through. This happens when people touch something hot or bump a little finger in foot into the wardrobe, you will rub the area. When you rub that area, A-beta fire passes faster than A-delta or C fibre which cause pain (see the table above). The brain picks up A-beta fibre which is touch sensation faster than pain information which is A-delta and C fibre. This is considered that the gate is closed. When pain information which is A-delta and C fibre pass the spinal cord and go up to the brain, it is thought that the gate is open. Basically, when the gate is open, people tend to feel more pain while the gate is closed, people tend to feel less pain.
Treatment to lower the pain level
- Treatment such as acupuncture, cupping and taping
- TEMS machine
- Heat pack or Ice
- Modify the habit which causes pain
- Bask in the sun and exercise to increase the serotonin level
What pain tells you
Pain generally is the warning sign from the body. When you get tight neck or tight upper shoulder from using a laptop or studying, that means you have been in a wrong posture or loading too much stress on your body. Some people who have lived with the chronic pain said they ignore the pain sometimes even if it gets bad as the pain is normal to them. However, that is a natural sign from your body. Take some moments to listen to your body and look after your body before it gets severe.
- Pain-health Understanding chronic pain: The gate control theory
- The brain from top to bottom Ascending pain pathways https://thebrain.mcgill.ca/flash/d/d_03/d_03_cl/d_03_cl_dou/d_03_cl_dou.html
- What is the Gate control theory of pain-How pain perception works https://www.youtube.com/watch?v=u-fUfIFduxI
- Pain 6, Gate theory and ascending inhibition https://www.youtube.com/watch?v=g9qbXKIAeNo