Challenge and Response to Body Integrity System

Question: Discuss about the Challenge and Response to Body Integrity System. Answer: Introduction: The reception of pain in the peripheral nervous system to the perception of the same in the brain, and the corresponding generation of response behaviours, is achieved through several pathways. These different nociceptive pathways kick-off in a similar manner in which a pain signal coming from the skin, for instance, travels up a sensory nerve fibre made up of axons of the spinal ganglion. The axons then enter the spinal cord, upon which they immediately divide into the upward and downward segments of the spinal cord (Purves, 2012; Hughes, 2008). There are five phases that make up the pain pathway, first, it is transduction of pain at the receptors, the second phase is signal conduction at peripheral nerves, and modulation at the spinal cord level. These steps are further succeeded by descending inhibition and perception at the supra spinal sites. Transduction of pain begins when nociceptors respond to noxious stimuli which may be as a result of damage and inflammation attributes to trauma or infection (Siegel, 2006). Nociceptors are available in both visceral (skin, bones, muscles and joints) and somatic structures (visceral organs). Pain transmission occurs in three phases. The first phase is the transmission of the impulse from the transduction site to the spinal cord, followed by the transmission from the spinal cord to the brain stem, and lastly transmission through connections between the thalamus, cortex and higher brain levels. Perception of pain is where pain becomes a conscious multidimensional experience with compo nents such as emotions and behaviours. Pain modulation involves altering or obstructing transmission of the impulses through in the spinal cord. Modulation is effected by the descending modulatory pain pathways (DMPP) which play both excitatory or inhibition roles (Moffat Rae, 2011; Farquhar-smith, 2008; Hudspith, 2016). Morphine is an opioid drug that binds to opioid receptors. Molecular signalling of these receptors activates a wide range of actions. Generally, these actions are meant to make cell membranes less excitable and also initiate suppression of actions of pathways that control blood pressure, breathing and heart rate. Morphine receptors may include Mu receptors of the thalamus and the brainstem. Stimulation of mu receptors translate into pain relief and sedation. Another class of receptors is the kappa receptor of the limbic system, spinal cord, and the brain stem. Activation of this receptors also causes sedation and pain relief. The delta receptor, on the other hand, is abundant in the brain, spinal cord, and digestive tract. Stimulation of the delta receptor produces in both analgesic and antidepressant effects (McGavock, 2011). Despite morphine being relatively selective for the mu receptor, it interacts with other opioid receptors when at high concentrations. Morphine as an opioid produces analgesia by acting at several levels of the nervous system through two actions. The first action is by inhibiting the release of neurotransmitter from the primary efferent terminals in the spinal cord. The other action is by activating the descending inhibitory controls of the midbrain. Morphine inhibits neurotransmitter release by directly affecting the entry of calcium ions, and secondly, by indirectly reducing repolarisation time and the duration of the action potential (McGavock, 2011; Workman LaCharity, 2015). Through the stimulation of the different receptors, morphine provides relief from physical pain through analgesia, euphoria, and pain modulation. References Farquhar-smith, W. P. (2008). Anatomy, physiology and pharmacology of pain. Anaesthesia Intensive Care Medicine, 3-7. Hudspith, M. J. (2016). Anatomy, physiology and pharmacology of pain. Anaesthesia Intensive Care Medicine, 425-430. Hughes, J. (2008). Pain Management: From Basics to Clinical Practice. New York: Elsevier Health Sciences. McGavock, H. (2011). How drugs work : basic pharmacology for healthcare professionals. London: Radcliffe Pub. Moffat, R., Rae, C. P. (2011). Anatomy, physiology and pharmacology of pain. Anaesthesia Intensive Care Medicine, 12-15. Purves, D. (2012). Neuroscience. Massachusetts: Sinauer Associates. Siegel, G. J. (2006). Basic neurochemistry : molecular, cellular and medical aspects. New York: Elsevier. Workman, M. L., LaCharity, L. A. (2015). Understanding pharmacology : essentials for medication safety. New York: Elsevier Health Science.