What is pain excately? We all have suffered pain to various degrees, but what is it and how does it work. Unfortunately, it is a bit complicated to explain to a lay person. Ok, basically pain is an unpleasant feeling that is conveyed to the brain by sensory neurons. This discomfort signals actual or potential injury to the body. However, pain is really not that simple. It is not just a matter of sensation or the physical awreness of pain. Pain is something that is very subjective and can be interpretated in different ways. Perception plays a major role in the degree of pain felt, it gives us the location, intensity and can give us something about its nature. Pain can further be defined by emotional response and unconscious responses to both sensationa and perception. Look at it this way: if you think it is going to hurt it probably will, you have already subconsciously told the your body that what is going to happen is going to hurt and your body will respond to that.
There are many reasons for pain, injury, illness and may accompany a psychological condition, such as depression. It can even occur in the absence of any known trigger (insidious).
The neurology of pain:
Nerve cells, or neurons, perform many functions in the body. Certain types of neurons are capable of transmitting a pain signal to the brain. These are called nociceptors and pretty much every surface and organ in the body has them. There are several types of nociceptors:
- thermoreceptive - stimulated by temperatures that are potentially dangerous
- mechanoreceptive - respond to a pressure stimulus that may cause injury
- polymodal - most sensitive and can respond to temperature and pressure
- also respond to chemicals released by the cells in the area from which the pain originates
The receptors, are at the front end of pain sensation. When stimulated the nociceptor sends a cascade of neurotransmitters (chemicals that transmit information within the nervous system) in the spine. Each of these neurotransmitters has a specific purpose. Neurotransmitters may also stimulate nerves leading back to the site of the injury. This response prompts cells in the injured area to release chemicals that can trigger an immune response (swelling, heat and/or redness),but also influence the intensity and duration of the pain.
Types of pain: Accute and Chronic/Abnormal
Accute Pain:
- pain that goes away when the cause is removed,timeframe is within 3 months
- caused by tissue damage eg: a burn or broken bone, can also be associated with headaches or muscle cramps
Chronic/Abnormal Pain:
- pain that persists after an injury heals - timeline more than 3-6 months
- examples include cancer pain, pain related to a persistent or degenerative
disease (eg. severe arthitis), and long-term pain from an unidentifiable cause(eg. Fibromyalgia)
- may be caused by a body's inappropiate response to acute pain
- continued stimulation of nociceptors changes occur within the nervous system
- at the molecular level these changes can be very dramatic
- including alterations in genetic transcription of neurotransmitters and receptors -- changes may also occur in the absence of an identifiable cause
- one of the most frustrating things about chronic pain is that the stimulus may be
unknown - which makes getting a diagnosis very difficult, and also it can be very
very difficult getting Doctors and others to believe that you are suffering and to
understand what you are going through
Abnormal Pain:
- include allodynia, hyperalgesia, and phantom limb pain.
- often arise due to damage to the nervous system (neuropathic)
- Allodynia: a feeling of pain in response to a normally harmless stimulus
will experience unbearable pain from just the light weight of clothing etc.
- Hyperalgesia: a response to a painful stimulus is extreme
a mild pain stimulus, such as a pin prick, causes a maximum pain response
- Phantom limb pain: occurs after a limb is amputated and the nervous system continues to perceive pain originating from the area
Ok.... enough for now... we will continue with Pain Gate Theory and its relationship with Massage next time.
