What causes pain the anatomy of pain information myvmc electricity 2pm mp3


Every tissue in your body is supplied by special nerve receptors called ‘ nociceptors‘. These are nerves which are specially designed to detect painful (or ‘noxious’) stimuli, for example extreme heat, mechanical damage like a pinch, or irritating chemicals. When the nociceptors detect a painful stimulus, the nerve will fire off an impulse which travels back along the nerve fibre to your spinal cord. From there, the pain message is conveyed up to the brain via a spinal neuron (nerve), travelling up through a part of the brain called the thalamus before ending in many different areas of the brain’s cortex.

The parts of the brain that the pain signals are sent to are important because they affect the way we perceive pain. For example, some of the nerve fibres end in parts of the frontal lobe of the brain, which normally handles behaviour and decision-making. The pain fibres that end in the frontal lobe cause us to feel pain as an unpleasant emotional sensation, sometimes even producing fear. In contrast, the pain fibres that end in an area called the somatosensory cortex provide what we would think of as the purely ‘sensory’ aspects of pain, like its location and quality.

You may hear people talking about ‘ referred pain‘. This means pain that originally comes from one organ or part of the body, but is felt in a different place. The commonest example is the pain of a heart attack, which may be felt in the left shoulder and down the left arm.

Referred pain occurs because of the way nerves meet up and interlink in your spinal cord. Deep structures such as the heart are supplied by different nerves from your skin. In the spinal cord, though, both of the deep and cutaneous (skin) nerves might meet up with just a single spinal nerve. This means that if the heart sends a pain signal up to the brain via that one spinal nerve, the brain can’t tell whether the pain comes from the heart or from the area of skin. Because most pain signals come from the skin, and we only rarely feel pain from deep organs, the brain will interpret the signal as having come from the skin – and that is where the pain will be felt.

Sensitisation refers to a situation where part of the pain pathway becomes over-sensitive. Sensitisation may occur after intense, repeated or prolonged stimulation of damaged tissues. When sensitisation does occur, pain fibres are more likely to be triggered in response to stimuli which would not normally be painful. This may contribute to the development of chronic pain (see below).

‘ Gating‘ is a normal regulatory mechanism which affects the way we perceive pain. The first gating mechanism is found in the spinal cord. Here, normal (non-pain) sensory fibres are linked to pain fibres in such a way that one can suppress the other. For example, after stubbing your toe (a painful stimulus), gently rubbing the skin over the toe (non-pain sensation) can reduce the feeling of pain. The non-pain sensation takes over and inhibits the transmission of the pain sensation. This mechanism is the basis of some types of pain treatment, including spinal cord stimulation.

Nociceptive pain can be further divided into somatic pain and visceral pain, depending on the type of tissue that is damaged. The viscera are the organs of the body, so visceral pain means pain originating in an organ or hollow structure, such as the stomach or the gall bladder. Compared to the skin, these organs have a very low density of nociceptive fibres, meaning that pain from the viscera is very hard to localise, or may even be felt as referred pain. Visceral pain may be described as gnawing or aching, and may be associated with feelings of nausea.

Neuropathic pain is a special type of pain produced by damage to part of the pain pathway. It is not associated with true tissue damage; instead, the pain pathway is ‘misfiring’, causing the experience of pain without actual injury. Neuropathic pain may occur after a disease such as herpes zoster infection (shingles), where damaged nociceptive nerve fibres in the skin send pain signals up to the brain even when no tissue damage is actually occurring.

Neuropathic pain is often severe, and is classically described as tingling, burning or having an electric-shock type quality. It may be associated with allodynia (severe pain on very light touch). Neuropathic pain can be highly resistant to standard pain treatments such as opiates, and antidepressant and anticonvulsant medications may be needed to help control pain.

Acute pain is a short-term feeling of pain felt in response to an easily identifiable cause. It might be caused by surgery, some kind of trauma, or an acute illness. The feeling of pain is acting like a sort of warning system to let you know that an injury has occurred. Acute pain lasts for less than three months.

Chronic pain may begin as acute pain, but lasts longer than would normally be expected for the sort of injury that has occurred. Chronic pain may also occur when pain comes back for an unknown reason. In chronic pain syndromes, the pain may feel a lot worse than seems to fit with the injury or damage that can be seen. The link between the tissue damage and the pain is lost. Chronic pain may develop from acute pain for a number of reasons. Factors which may contribute to the development of a chronic pain syndrome include:

Chronic pain can be very difficult to treat, and is often frustrating for both the patient and medical professional. The optimal treatment approach should involve looking not only for the source of the pain and other physical factors, but also consideration of environmental and psychological factors which may be contributing to the pain syndrome.

The biomedical model of pain is an older model which considers the mind and body as separate entities. This model aims to treat a single cause of pain, with little focus on emotional, psychological and other factors. It is unlikely to result in good outcomes if used to manage chronic pain.