Comparison of the physiology of CNS and other Body Parts - Essay Example

Comparison of the physiology of CNS and other Body Parts Introduction Pathology is the discipline that explores disease, its causes and effects, towards bridging the gap between basic science and clinical practice. The discipline involves the exploration of the etiology of diseases, the underlying changes (commonly referred as the pathogenesis of the disease), and the relationship between these two areas and the symptoms and the signs showing on the body of the patient. The field explores diseases by reviewing different molecular, immunologic and microbial models, so as to comprehend the structural, biochemical, and the functional changes that take place in organs, at the tissue level and at the cell level (Barry and Bleackley, 2002). During the diagnosis and the treatment of these conditions, medical pathologists will point out the microscopic as well as the gross changes in the appearance of tissues and cells; they check the biochemical changes that are evident in different areas, including body fluids like urine and blood. The Central Nervous System (CNS) is made up of the spinal cord, the brain, sensory organs, as well as the rest of the nerves that link these organs with other parts of the body (Rask, 1999). The CNS has certain characteristics that make its pathological processes different from the rest of the body. Most important, the organ is located in spinal column and a body skull, which makes it difficult to expand like many other organs in the body. In addition, the fact that the brain is contained in cerebrospinal fluid (CSF) and lacks the typical lymphatic system significantly limits its immunologic capability. This structural uniqueness, also, means that the manner in which CNS responds to healing is different from the rest of the body. Some of the keys characteristics of CNS that makes it different from the rest of the body organisms include: non-regenerative ability of the neuron which is its functional unit; complexity of function and structure; the concept of blood brain barrier; and Glial framework instead of fibroblastic (Seiffert et al., 2004). The brain is made up of millions of neurons, which are classified as either motor, sensory or autonomic (McCorry, 2007). The pathological processes in different neurons differ depending on their neuronal interconnections, differences in morphology, electrical and metabolic activities and neurotransmitter type, among many others. These differences cause selective exposure of some neurons to pathological problems such as neurodegenerative and hypoxia diseases. In other words, neurons possess a huge round nucleus with an outstanding nucleolus as well as millions of cytoplasm. When a neuron is injured, the processes that result include neuronal degeneration in cases of chronic diseases, red neurons which take place following a toxic attack, neuronal inclusions, and axonal reactions (Tansey, McKay, & Kakulas, 2012). The aim of the paper is to give an overview of the pathological processes in the CNS, highlighting its similarities and differences of this process with the rest of the body. Bacterial infections The Blood Brain Barrier (BBB) has features which make CNS unique, including ionization at physiological pH, size, the level of binding to plasma proteins, liquid solubility. Through its blood brain barrier capability, the CNS has capillary endothelia cells, which are capable of controlling solute fluxes from corner to corner of the capillary wall. This process is facilitated by differential allocation of membrane forces between antiluminal membranes and luminal of endothelia cells. In addition, the endothelial luminal plasma membranes have oligosaccharide residues, which is different from other body organs as they contain vessels. The brain, unlike other body parts, is less susceptible to many forms of bacterial infections. Therefore, the brain is hardly infected by bacteria. The few infections that affect CNS are usually very severe and their treatment is not easy either. According to Raza, Shad, and Pedler (2005), the blood-brain barrier does not allow most antibodies to pass through its wall because they are too large. Due to this barrier, only a few antibiotics can pass through and in some cases a direct administration of pharmacon to the cerebrospinal fluid is necessary. Due to the tortuous nature of the brain’s interstitial space, direct administration of drugs into CNS does not infiltrate the brain tissue (Raza, Shad, and Pedler, 2005). However, during inflammation, the BBB becomes more permeable, hence some antibiotics can effectively penetrate it. It is, therefore evident that treatment of bacterial infection that affects certain regions of the brain is harder than treating the same condition in other body parts because of the complexity in delivering therapeutic agents (Brigger et al., 2002). Consequences of inflammation When the body is attached by microbial such as bacteria, viruses, part of the immune systems whose aim is to give the body a defence against such invasion includes inflammation. Scientists have shown evidence that inflammation in the body leads to inflammation in the brain. Conditions that occur in various parts of the body, such as cancer chemotherapy, heart attack, and peripheral nerve damage, can lead to problems that originate from the CNS – including depression, poor memory, exaggerated response to pain, and fatigue (Rask, 1999). This shows that the pathological processes that take place in the CNS are interlinked and possible very similar. Regardless of whether these conditions originate from the CNS or the body, the end result is the inducement of inflammatory responses in the body. However, one of the most striking differences is that the resultant emotional and cognitive effects are originated from the CNS. As such, pain, activity, and mood are produced by the CNS rather than the peripheral system. Sometimes back, the peripheral immune system and the CNS were function independently. That is the reason why it is hard to find the terms “brain” and “CNS” in the indexes of immunology text books or the term “immune system” in the indexes in neuroscience’s current text books. Even so, scientists have had a breakthrough in manner in which CNS processes are influenced by the immune-related events – which lead to changes in mood, cognition, and behaviour (Ryzhova et al., 2010). These new findings show that inflammation may cause long-term impacts in the brain. In essence, the defensive response (inflammation) extends beyond bodily site of infections to the CNS. Some of the most visible result of the inflammation in the CNS is where a sick person becomes to susceptible to behaviours such as reduction in activity, moods sags, poor memory, sleeplessness, and an increased sensitivity to paid. Most importantly, all the changes that occur when a person gets sick are accomplished through the CNS, although they have impact in other body parts. For example, fever takes place because the cells in the hypothalamus, which are sensitive to temperature, are increasingly aroused. Following impaired functionality of the neurons of the brain, which may result from inflammation, the CNS interprets the malfunction as the lack of signal transmission between the different neurons and regions in the brain (He and Crews, 2008). The results of the non-functionality or the impairment of functionality of the brain infects many other body tissues, for example leading to the paralysis of the eyes, amnesia, memory loss, impairment of muscle coordination and confusion (Bechara, 2005, pp. 1459).   Figure 1: Immune-to-Brain Communication (Source): http://www.dana.org/uploadedImages/Images/rop_braincomm_0812_larg.jpg The communication process, which takes place in the CNS is initiated by cytokines, which also initiated the inflammatory response in the body (see Figure 1). This explains how the CNS becomes aware about the activities of the peripheral immune system. Due to the fact that the human central nervous system is highly structured, the detective mechanisms of the CNS provide a wide collection of information about the distribution and extent of the process within the subject tissue (Chau et al., 2000). When the cytokines accumulate in the bloodstream, hence passing through the brain, active transport helps them to travel across the blood barrier into the brain’s regions where the barrier is not strong. While there, they usually attach to receptors from the inside of the cerebral vascular vessels, hence arousing the production of soluble mediators from the inside of epithelial cells, which can pass through into the brain. This shows that the whole process is coordinated between the CNS and the body, only that the brain barrier in the brain makes CNS pretty unique (Kollmann et al., 2011). Conclusion In conclusion, it is pretty evident that the CNS is pathologically different from other body parts due to its unique characteristics, which makes its pathological processes to appear unique s well. Some of its unique features that occasion such differences include its location in an inflexible skull, its lack of lymphatic system and its blood brain barrier, among many others (Löscher and Potschka, 2005). These striking structural differences, for example, make the brain very susceptible to bacterial infections. On the other hand, although the pathological processes in the CNS seem to strikingly differ from other body parts, their similarities cannot be underemphasised, mainly because attack, malfunctioning or inflammation in the body cells sends signals to the brain, which leads to sickness behaviours such as depression, poor memory, exaggerated response to pain, and fatigue among many others (Chinnaiyan, 1999). There is also the similarity in that the communication of signals over the CNS triggers the initiation of further pathological activity, which leads to the change in the functionality of body parts. References Barry, M. and Bleackley, R. C., 2002. Cytotoxic T lymphocytes: all roads lead to death. Nat Rev Immunol, 2, pp. 401–9. Bechara, A., 2005. Decision making, impulse control and loss of willpower to resist drugs: A neurocognitive perspective. Nature Neuroscience, 8(11), pp. 1458–1463. Brigger, I.; Morizet, J; Aubert, G; Chacun, H; Terrier-Lacombe, MJ; Couvreur, P; Vassal, G (December 2002). Poly(ethylene glycol)-coated hexadecylcyanoacrylate nanospheres display a combined effect for brain tumor targeting. J. Pharmacol. Exp. Ther. 303 (3), 928–36. Chau, B. N., Cheng, E. H., Kerr, D. A. and Hardwick, J. M., 2000. Aven, a novel inhibitor of caspase activation, binds Bcl-xL and Apaf-1. Mol Cell, 6, pp. 31–40. Chinnaiyan, A. M., 1999. 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