Referring to the diagram above, give the function of each of the parts labeled on the diagram. This link may help you. |
Use this link to define the following terms: analgesia anesthesia anesthetic pain pain tolerance level pain threshold suffering neuralgia neuritis neuropathy |
The Neuroscience of Pain |
Pain is the first line of defense for an organism against environmental conditions which may threaten the existence of an organism. Pain is affected by a variety of factors which impact the quality and the quantity of pain we experience. When you investigate pain and ultimate the relief of pain, you must be able to achieve a systematic and quantitative meansurement of the phenomenon. In humans, this is done by measuring thresholds of reported pains under carefully controlled situations. As far as reliability of this type of data when collected, there is always the challenge resulting from the fact that these thresholds are not discrete but in fact are influenced by expectation, instructions and a variety of other factors. |
DO RESEARCH: What is the "flinch/jump" test? What is the "paw lick" test? What is the "tail flick" test? |
Algology: the study of the phenomenon of pain. |
Use this link to define the following terms: analgesia anesthesia anesthetic pain pain tolerance level pain threshold suffering neuralgia neuritis neuropathy |
In order to gain a true understanding of the perception of pain, one must know which parts of the body are involved in the phenomenon. In the brain, it is the cerebral cortex, brain stem and dorsal horn of the spinal cord in conjunction with the limbic system. When considering the sensation of pain, the parts of the nervous system involved are the somatosensory region of the cerebral cortex, the medulla oblongata, thalamus and hypothalamus. |
The Limbic System: This is the part of the brain where you experience emotion, fear for flight or fight, and where traits of your personality develop. Shown here in brightly colored areas. |
The Peripheral Nervous System: This system includes the receptors throughout the body which send impulses to the brain so it can interpret the body's environmental condition. It consists of neurons and ganglia, knots of nerve fibers found throughout the body. |
Initiation Of A Painful Stimulus |
Scattered over the skin and througout many organs are the receptors which bring send messages to the brain. These receptors detect changes that occur both within the internal enviroment and the external. These "signals" are passed as cold, warmth, touch, pain, etc. depending on the type of stimulus registered with the receptor. Sensory Receptor types: Mechanoreceptors: detect pressure or touch Thermoreceptors: detect sensations of heat or cold Chemoreceptors: detect a range of substances and are present in the organs for taste and smell. These also assist in the regulation of the body's chemistry. Nociceptors: respond to noxious stimuli or what we refer to as pain. Only the last two of these receptors are said to be free nerve endings. |
Referring to the diagram above, give the function of each of the parts labeled on the diagram. This link may help you. |
Impulses from nociceptors or pain receptors, carrie their impulses to the central nervous system one of two ways: Sharp, stabbing pain is carried by Myelinated A-delta nerve fibers at 20m/sec Dull, aching pain is transferred along the Non-myelinated C nerve fibers at the rate of 2m/sec. Questions: What is myelin? How do you think its presence affects transmission of a nerve impulse? Most pain sensation, however, is a combination of two types of message. |
Chemistry's Role in Pain Perception When cells are injured, they release chemicals that can also signal a pain response within the nervous system. These chemicals are called prostaglandins and leucotrienes. Some chemicals cause the sensation of pain to be triggered while others just lower the pain threshold to enhance the perception of pain. Crossing synapses, the impulse travels to the dorsal horn of the spinal cord. It is through the spinal cord that the transfer of information in made to the brain. |
Click on star to learn each part's role in detecting pain |
Raising and Lowering the Pain Threshold Raises it: .....pleasant environment ......freedom from worry ......hope ......restful sleep ......confidence that things are under control Lowers it: ......fear ......sadness ......depression ......isolation ......sleeplessness |
Did you know? There is actually some basis for sucking a finger when you prick it or biting a knuckle when you stub a toe. The pressure you ex- ert by doing that you compete with the pathway taking the pain informa- from the site of the real injury thus impeding the sensation. Opium was first extracted and used as an analgesic in the 1500's by a Swiss physician, Parcelsus. His extract, laudanum is still used today. The word "heroine" comes from the name "hero drug" because it was believed it could stop pain without addiction! Narcotics are used to treat pain because their effect is two fold. They reduce the pain and reduce the psychological trauma associated with pain. Left handed males have higher levels of autoimmune disorders as a result of testosterone inhibiting the growth the thymus gland and left hemisphere of the brain. |
Principles related to pain: 1. Opium, an extract of the poppy plant, contains both morhphine and codeine which are used to treat pain, and from that a synthetic compound heroine is made. 2. Specific receptors for opiate drugs are found in the brain. These receptors mediate the effects of endorphins, chemicals in the body that produce morphine-like effects. 3. B-lipotropin is produced in the pituitary and it is involved with the stress response to pain. 4. There are four systems of pain reduction: ......opioid from neural sources ......opioid from hormonal sources ......nonopioid from neural sources ......nonopioid from hormonal sources. 5. Placebo effects and acupuncture appear to be mediated by endorphins. 6. It is the responsibility of the immune system to recognize and defend the biological self. 7. The immune system has two major modes of responding: .....humoral response, circulating immunoglobulins .....cellular response, proliferation of T cells. 8. Mild stressors can lead to suppression of the immune systems thereby interfering with the regulation of pain. 9.Parkinson's disease and some forms of diabetes are the result of an autoimmune response to our own pain receptors. |
Click on the brain to learn more about the physiology of pain. |
Research: What is the Melzack and Wall's Gate Control Theory of Pain? |
