Mental Illnesses Essay Example | Topics and Well Written Essays - 500 words

Mental Illnesses - Essay ExamplePhysiological Process The physiological process of schizophrenia is not clearly defined. However, experts tie-up chemical abnormality to be associated with the signs and symptoms of the illness. The imbalance of dopamine and glutamate affects the way a persons creative thinker reacts to the stimuli making the schizoid person overwhelmed by sensory(prenominal) stimulation in which other people without such condition may easily handle. The study of Dalya and company ( 2007) supported such claim in explaining that changes in the neural circuits as a result of neurotransmitter abnormality may cause patient to experience auditory hallucinations. Other studies have also shown that abnormalities in brain structures and death of tissues in the brain may cause changes in its cells and that relay of sensory information is altered. Symptom Manifestations Manifestation involves hallucinations in the form of hearing voices, delusions which ar persecutory in nat ure, and disorganization in speech and thinking. The individual when communicating to others may present lose of thoughts and sentences are incoherent with its meaning or it is a confederacy of loose ideas that it becomes word salad. Schizoids do not pay attention to how they childbed themselves thus they dress poorly. They do not have the motivation for themselves and have project poor judgment as well. Others may have problems of responsiveness and social cognition.

Analyzing a Major Issue Assignment Example | Topics and Well Written Essays - 1250 words

Analyzing a major(ip) Issue - Assignment Example out-of-pocket to the expansive and differently broad definition that has been given, it is possible for theWhereas other forms of violence in society are oftentimes the work of an outside or otherwise unknown force, law enforcement began to notice the prevalence of this form of violence and denoted a specific label with regards to differentiating it from the various other sorts of crime that exist within the system. As a means of seeking to lower the incidence of such violence within society, there are a number of factors that can and should be use from a perspective of social work (Gibbons, 2011). The first of these is to increase awareness and perception of the issue. Only by increasing awareness and perception can it be hoped that a higher percentage of domestic violence cases are reported to proper law enforcement authorities to investigate and prosecute as they see fit.Major changes to the way the legal system came to engage wit h domestic violence came to be exhibited not long after the feminist movement began to gain traction in the late 1960s and 1970s. However, even as domestic abuse came to be categorized as a separate type of violence with stiffer penalties as compared to the akin assault and battery charge, the history of the way in which domestic violence has been defined and understood dates back far longer than the recent past few decades. As far back as 1641, individual municipalities throughout the colonies began to adopt statutes that forbade husbands from striping their wives. This served as the first example for the way in which early regulation was placed on the books and forbade the practice at least in theory. Similarly, changes in the 1850s, at the state level of Tennessee, specifically forbade any physical violence say at a spouse for any reason something that was unique and groundbreaking at that time. By the

Approaches to Adjustment and Deviance Case Study

Approaches to Adjustment and Deviance - Case Study ExampleJason is the third child and has one older brother. Family conflicts arise when Jason attempts to emulate the activities of his 17-year-old brother. As a center child, there have never been any clear boundaries set for Jason and he has oftentimes been emotionally neglected. He has struggled for his mothers attention and has taken on a controversy with his father. His father has been stern, believing in tough love, without the emotional support or communication required to carry it out successfully. Jasons mother has made excuses for her son and has covered up and allowed his inappropriate behavior, possibly due to her own guilt. The conflict between the mother and father are at the core of the family problems and Jason reacts negatively to this conflict.It was advised that the family enter family counselling based on Cognitive Behavioral Therapy (CBT). Through questioning, it was found that the mother and father rarely eff ectively communicate the important issues surrounding Jasons behavior and often have vastly different perceptions of what is acceptable to the family. Through role playing, the family was taught to communicate more effectively.

Macbeth Analysis Essay Example for Free

Macbeth Analysis EssayIn the beginning Macbeth starts out as a successful and respected warrior, who leads major power Duncans army. Then his life starts to go downhill for him when he decides to follow to a witches prophecy. His wife Lady Macbeth pressures him to kill Duncan while he is staying at the Macbeths castle. At first, Macbeths ambitions deluge his doubts and hesitations, however later both he and his wife ar driven to insanity by their guilt. Macbeth then goes on to kill suspicious Banquo, and he similarly plans to kill Macduff, who too has his own suspicions about Macbeth. Macbeth is non in the right state of mind to grieve when his wife dies from her mental anguish. Finally, Macduff kills Macbeth in battle, and Malcolm becomes the advanced king.The context of our key scene (Act 2, Scene 3) is about Duncans eat up by Macbeth. Macbeth has his own strong motivations not to kill Duncan, but is pushed and pressurised into it by the witches and Lady Macbeth. Lady Macbeth gives her married man advice to look like the innocent flower, but be the serpent chthonian it, which means he must be vicious inside but fall out innocent on the outside to the rest of the characters, which they experience to do purge after the slaughter. There is a sense of suspense, such as, how will the thanes react to the murder? Will Macbeth get away with it forever? And will his plan be successful?Act 2, Scene 3 is about the aftermath of King Duncans murder by Macbeth. It begins with a rather comic interlude, where a drunken Porter is roaming about in Macbeths castle and is speaking nonsense, with ironic mentions about hell. He opens the penetration to Macbeth and Lennox, and they go to the quarters where they find that Duncan is dead. Lennox and others are genuinely shocked, whilst finable Macbeth babbles too much about the situation, and even his wife makes it slightly look as if she is much concerned about her house than the kings death. Sly Lady Macbeth t urns the attention and suspicion away from her husband by fainting. Duncans sons Malcolm and Donaldbain fear for their lives and run away to neighbouring countries.Both our main characters develop in similar and different ways. Macbeth has constant doubts about the murder, then immediately feels shameful after he commits it. Both he and his wife repugn to talk without dropping small suspicious clues, but lady Macbeth mainly manages to keep them out of suspicion. Macbeths sense of guilt leads to panic, as he is forced to be deceptive to cover up his crime. There is hesitation in his speech, and guilty remorse is revealed through his actions. Although he was pushed by his wife to kill Duncan, he wasnt inspire by anyone to kill the guards. He is forced to take action to control the situation, and feels he has to keep killing because there is no going back. He is instaltime to experience with the consequences, like the poison chalice.Up until now, Lady Macbeth has been the prime mo ver, but is now beginning to crumble and is no longer the strong person that she was. She does show some human sensitivity in her, even if she is evil. She has a genuine wifely devotion and loyalty to her husband. Also, she knows that she cant go very far in the world of that era because she is a woman, so she is getting close to somewhere high through Macbeth. Lady Macbeth may be sad and evil partly due to losing her electric razor, compared to Lady Macduff, who has children and seems to be a nicer, calmer person.In this head for the hills, we can see the theme of appearance vs. reality, as the Macbeth couple are forced to conceal the guilty reality of their crime by putting on innocent appearances. It was Lady Macbeth who quoted the image of appearing like the innocent flower, but being the serpent under it, by which she meant to be brutal but act innocent. There are images with references to heaven and hell, such as when the drunken porter appears to be talking nonsense, but h is words actually make some sense. Some of his quotes include if a man were a porter of hell-gate and whos there in the name of Beelzebub?, which seems to concern in with the evil deed that Macbeth has just committed.Macbeths act of killing the king is called regicide, which leads to confused events. To kill a king was seen as damnable because it was removing Gods representative on earth. Macbeths image of the fountain being stopped (by him, which he doesnt make obvious) shows an interference with the Divine Right of Kings, a belief that royalty is passed down in the family. As with most tragedies, betrayal is very prominent in this play. He betrays his guest and king Duncan by killing him instead of protecting him. We see the use of iambic pentameter, and this is when a line follows a certain rhythmic pattern, such as confusion now hath made his masterpiece.We can see a tragic mental synthesis in the play of Macbeth. Firstly, as with most tragedies, he falls from an elevated posi tion to a tragic demise. At the beginning of the play he is a war hero, but after some bad influences and wrong choices, becomes disgraced, isolated, and at long last killed. Macbeths fall is seen in this scene when he kills innocent people to cover up his first murder he filiations into insanity and loses control of the situation. He has an internal conflict between the benign and vilify sides to his characters. His benign side is telling him not to do the murder, then after it happens he thinks if I could turn back time, wishing he had not done it after all. Then there is his malign ambition to be king and become powerful no matter what, and to listen to the bad advice of Lady Macbeth and the witches. There is the prominent theme of betrayal, which Arthur Miller of A View from the Bridge said is the key to many tragedies.Macbeth betrays many people such as Duncan, by not protecting him as his host, Banquo, by also killing him, Macduff, by giving orders for his family to be kil led, God, by removing his designated representative on earth, Scotland, by leaving it in a political vacuum, and even himself, for sinking so low. He lies a lot to conceal his guilt and murder. There is an overwhelming sense of wasted potential. Many characters such as Duncan, Banquo, and even Macbeth himself should all have lived peaceful, happy, contented lives, but Macbeth spoils it for all of them. There is also the chance that Macbeth could have become king honourably without the need to kill. Also, Malcolm could have become king antecedent without the chaos which leaves Scotland unsettled, and the political vacuum. In this scene we see Macbeth become an independent murderer without influence from anyone. He is visibly a deceitful liar, and there are many beginnings of chaos.The events of our key scene (Act 2, Scene 3) leave us questioning what will happen next and wanting to know more. This is how Shakespeare evokes suspense in the play of Macbeth. After Macbeth commits the t errible murder, we are left wondering what will happen to the state of Macbeths mind, as we later find out that his increasing insanity finally finishes him off. We wonder if the Macbeth couple will ever be found out of their wicked conspiracy. Although they do not get caught by country officials, they see the suspicions from Banquo and Macduff.We could even say that the Macbeths punish themselves in a way, by having to face the guilt-ridden consequences of their actions. From the beginning, Lady Macbeth has been the more prominent partner in the relationship, but her mental decline seems to affect her quicker than Macbeth, even to the point that she dies and he does not seem to care much. Going back to the murders aftermath, there is the question of who will be the new king, and what will happen to Scotland from this point. We, as the audience, are waiting to find out what happens next, and see that some of our questions are answered, and some are not, (like, what exactly happened to Lady Macbeths child that she had vaguely mentioned?).

Branches of Philosophy Essay Example for Free

Branches of ism EssayIn order to narrow the aims of discussion philosophic system was broken into branches. Traditionally philosophy has been broken into four briny branches however we would like to add a fifth branch in our text -Epistemology Epistemology, from the Greek words episteme ( noesis) and logos (word/speech) is the branch of philosophy that deals with the nature, origin, and scope of knowledge and love. -Metaphysics Metaphysics (derived from the Greek words ta meta ta physika biblia) meaning the hold back that follows the physics book. It was the way students referred to a specific book in the works of Aristotle, and it was a book on First Philosophy. (The assumption that the word means beyond physics is misleading) Metaphysics is the branch of philosophy concerned with the study of first principles and being (ontology). In other(a) words, Metaphysics is the study of the to the highest degree general aspects of reality, such as substance, identity, the nature of the mind, and free will. In other way is a study of nature and the nature of the cosmea in which man lives -Logic Logic (from Classical Greek (logos), originally meaning the word, or what is spoken, but coming to mean thought or reason) is most lots said to be the study of arguments, although the exact definition of logic is a matter of controversy amongst philosophers (see below). However the subject is grounded, the task of the logician is the same to come along an account of valid and fallacious inference to allow one to distinguish good from bad arguments. -Ethics Ethics is a general term for what is often set forth as the erudition (study) of morality. In philosophy, ethical behavior is that which is good or right. The Western tradition of ethics is sometimes called moral philosophy. Other Branches Philosophy of information fairly self-explanatory. A minor branch, mainly concerned with what is the correct way to educate a person. Classic works include Platos Republic, Lockes Thoughts Concerning Education, and Rousseaus Emile. Philosophy of HistoryFairly minor branch (not as minor as education), although highly important to Hegel and those who followed him, most notably Marx. It is the philosophical study of invoice, particularly concerned with the question whether history (i. e.the universe and/or humankind) is progressing towards a specific end? Hegel argued that it was, as did Marx.Classic works include Vicos New Science, and Hegel and Marxs works. Philosophy of Language Ancient branch of philosophy which gained prominence in the last century under Wittgenstein. Basically concerned with how our languages affect our thought. Wittgenstein famously asserted that the limits of our languages mark the limits of our thought. Classic works include Platos Cratylus, Lockes Essay, and Wittgensteins Tractatus Logico-Philosophicus. Philosophy of Law Also called Jurisprudence.Study of law attempting to discern what the best laws might be, how laws came int o being in the first place, attempting to delimit human laws from natural laws, whether we should always follow the law, and so on. Law isnt often directly dealt with by philosophers, but much of political philosophy obviously has a bearing on it. Philosophy of mathematics Concerned with issues such as, the nature of the axioms and symbols (numbers, triangle, operands) of mathematics that we use to understand the world, do perfect mathematical forms exist in the real world, and so on.Principia Mathematica is almost for sure the most important work in this field. Philosophy of Mind Study of the mind, attempting to ascertain exactly what the mind is, how it interacts with our body, do other minds exist, how does it work, and so on. Probably the most popular branch of philosophy right now, it has expanded to include issues of AI. Classic works include Platos Republic and Wittgensteins Philosophical Investigations, although every major philosopher has had some sound judgement at least on what the mind is and how it works. Philosophy of Politics Closely related to ethics, this is a study of government and nations, particularlyhow they came about, what makes good governments, what obligations citizens have towards their government, and so on. Classic works include Platos Republic, Hobbes Leviathan, Lockes Two Treatises, and J. S. Mills On Liberty. Philosophy of Religion Theology is concerned with the study of God, recommending the best religious practises, how our religion should hammer our life, and so on. Philosophy of religion is concerned with much the same issues, but where Theology uses religious works, like the Bible, as its authority, philosophy likes to use reason as the ultimate authority.Philosophy of Science Study of science concerned with whether scientific knowledge can be said to be certain, how we obtain it, can science really explain everything, does causation really exist, can every event in the universe be described in terms of physics and so o n. Also popular in recent times, classic works include Humes Treatise on Human Nature, Kripkes Naming and Necessity, Kuhns Structure of Scientific Revolutions. Empiricism is a philosophical idea based on the idea that all reliable knowledge about the world is gained in the process of experience.Famous empiricists were Hume, Locke and Berkley, basing themselves on ideas already postulated by Aristotle, that we are born with the Tabula Rasa which receives throughout our lives information on which it can base all thinking and knowing. The movement of empiricism was in part a countermovement to what Descartes and de Spinoza had proposed as rationalism. Knowledge derived from experience is called a posteriori. - Doing Philosophy Many fields can be studied and learned without ever actually working with the tools in the field.For instance, chemistry can be learned in depth without ever picking up a test tube or mixing garret compounds. Philosophy, however, is more about the methodology beh ind deriving answers than it is about the answers themselves. As such, students studying philosophy must use the methodology of philosophy on the philosophy they are learning as they are learning it. Doing philosophy involves asking the right questions, critically examining the work of previous philosophers, truly understanding the works and the ratiocination behind the works, and possibly building on the works of previous philosophers by expanding or testing this methodology.

Astromnomy Lab Questions Essay Example for Free

Astromnomy Lab Questions Essay1. Why do some scientists believe that there might have been vivification on Mars? Some scientists believe there was life on Mars due to a number of factors. For one we know there was at one point a substantial amount of liquid peeing when the planet was much younger. We also know Marss electromagnetic field of study has dampened, making it more susceptible to interstellar heat and radiation, thus eliminating the life that could have existed. There are also other several factors including volcanic activeness and evidence of salt oceans. 2. Why are scientists interested in whether weewee was or is on Mars? What do their tests and observations suggest about the possibility of water on Mars? Scientists are interested in whether water was or is on mars because this is the most direct clue to the signature of life. Scientists tests prefigure most if not all water is frozen on Mars, but it was not in the distant past during which life could have exis ted. 3. Why do some scientists believe that life may not have ever existed on Mars? Some scientists believe this because they say it is too far on back in the goldilocks zone. Others note the mineral composition and lack of a strong atmosphere containing proper gas elements. 4. What may have happened to the water on Mars?The atmosphere may have been blown away over time due to the damping of its magnetic fields and thus creating frigid advance conditions freezing all liquid water. 5. What do scientists believe may have happened to leave Mars vulnerable to the solar winds? Scientists hypothesize that the degradation of Marss inter core which produces its electromagnetic field that protects the planet from interstellar winds and storms. 6. Do you think life existed or exists on Mars? Why or wherefore not? Use information from the video and unit to provide support for your reasoning.Mars Up Close - your second lab link1. Why did the scientists accept this particular location for the Spirit rover? Spirit Opportunity couldve landed almost anywhere. From orbital photos, there had been an initial list of 134 landing sites, each of which were debated on the pros and cons of landing there. Spirit was targeted to a landing site that appeared to have been affected by flowing water at some point in the Martian past.

Origins of Tissues Macrophages

Origins of create from raw stuffs MacrophagesRyan Lewis Discuss current ideas about the origins of tissue macrophages and whether these origins work the subsequent functions of macrophage graphical AbstractFigure Legend This figure highlights achievable tissue macrophage origins and their development pathways. The essay discusses contradicting findings in the literature, involving three different publications Sheng et al, 2015 (blue pathway), Hoeffel et al, 2015 (red pathway) and Perdiguero et al, 2015 (green pathway) which be shown in the figure. Cell positions hit to the time point they be established during embryonic development. Positions of egg yolk sac and fetal liver-colored are too related to the times they are developed. demonstrationIn the late 19th century Ilya Metchnikoff detect macrophages (Tauber, 2003) and since and so our understanding of the immune system and its complexity has progressed to a stage where the macrophage is no longer as simple as was origin eachy depicted by Metchnikoff. Although much more is known about tissue specific macrophages and their functions, the origins of these macrophages are less well silent including how their origins relate to the functions they have within specific tissues. This essay aims to address the current ideas about the origins of tissue macrophages and whether these origins influence the subsequent functions of macrophages.Macrophage Disco very and HistoryAs antecedently mentioned Metchnikoff discovered the macrophage late in the 19th century (Tauber, 2003). Metchnikoff published a paper talking about phagocytic cells he had observed in frogs, he described the phagocytic cells as being involved in host defence entirely also the clearing of dead and dying cells (Gordon, 2007). Mechnikoff then discovered the presence macrophages in starfish, which dont have a vascular system, which led him to the discovery of tissue-resident macrophages (Gordon, 2007). Metchnikoff received the Nobel prize for his studies on cellular immunity to infection in vertebrates which he shared with Paul Ehrlich who discovered humoral immunity (Gordon, 2007). It took roughly 80 years subsequently Metchnikoffs discovery before the origin of the tissue macrophage was uncovered. It was proposed that tissue macrophages originated from go around monocytes in the blood (van Furth and Cohn, 1968), this theory has persisted for the last 40 years however from recent studies we know that this is not the primary origin of the tissue macrophage. Shortly after the theory that tissue macrophages originated from circulating monocytes was proposed, it was discovered that tissue macrophages and monocytes are heterogenous and their heterogeneity is conserved in humans and mice (Gordon and Taylor, 2005). The discovery of monocyte subsets followed shortly after in 1983, which supported the theory that tissue macrophages originated from circulating monocytes (Yona and Jung, 2009). The theory that tissue macrophages are derived from circulating monocytes has been the prevailing view until very recently partly due to the stretch of advanced techniques including fate mapping and ionizing shaft. In the last 5-6 years, galore(postnominal) definitive publications have redefined our understanding of the origins of tissue macrophages (Epelman et al, 2014). Recent studies have shown that many tissue macrophages are established during embryonic development and continually self-replenish into liberalhood independently of any input from circulating monocytes in the blood (Epelman et al, 2014 Ginhoux et al, 2010 Hashimoto et al, 2013 Yona et al, 2013).Tissue Macrophage Heterogeneity and FunctionTissue macrophage have a huge degree of heterogeneity which reflects upon the specialization of their functions in different tissues and locations (Gordon and Taylor, 2005). Macrophage heterogeneity is required to ensure the tissue macrophage has the just about effective phenotype to take its specific microenv ironment, this is particularly important in the gut. Tissue macrophages in the gut isolated from the lamina propria have a unique phenotype characte rotated by high phagocytic and bactericidal activity but very poor production of pro-inflammatory cytokines which makes them perfectly suited to their microenvironment (Gordon and Taylor, 2005). There are many specialised tissue macrophages that have very distinct functions including osteoclasts in the bone which breakdown bone deposits for bone remodelling, alveolar consonant macrophages (dust cells) in the lung that break down foreign material and pathogens, and microglia in the brain which bet a role in neuronal development homeostasis and the recovery from pathology (Boyce et al, 2008 Rubins, 2003 Prinz et al, 2014). The theory that tissue macrophage populations are replenished from circulating monocytes in the blood is somewhat true but the almost diverse tissue macrophages such as microglia, alveolar macrophages and osteoclasts are replenished through self-renewal and proliferation (Yona and Jung, 2009). There is a substantial number of studies discussing whether macrophages originating from monocytes in the blood ordure differentiate into resident tissue macrophages. In most cases the monocyte subset that the macrophage originated from determines its ability to differentiate into a specialized resident tissue macrophage, this is particularly true in the lung as studies have shown only Ly6Clo, not Ly6Chi, monocytes have the ability to differentiate into enchymal lung macrophages (Landsman et al, 2007). In regards to the more complex and specialised alveolar macrophages in the lung, studies have shown that these macrophages require a parenchymal lung macrophage intermediate (Landsman and Jung, 2007). Circulating monocytes in the blood were long believed to be the origin of specialised tissue macrophages but recent evidence has shown that this is incorrect and proven that many of these tissue macrophage po pulations are developed long before birth (Epelman et al, 2014).Origins of Tissue MacrophagesMacrophages are first observed during embryonic day 6.5 and are alleged in the yolk sac during what is termed as earthy haematopoiesis (Epelman et al, 2014). During this early stage in development macrophages are the only immune cell produced due to restricted progenitors in the yolk sac. During embryonic days 8.5 10.5 hematopoietic stem cells (HSCs) emerge from the aorta-gonad meso-nephros (AGM) and give rise to all immune lineages (Epelman et al, 2014). At embryonic day 10.5 HSCs migrate from the AGM to the foetal liver, the foetal liver then becomes the major(ip) hematopoietic organ until birth. Only after birth do bone internality HSCs become the primary progenitors and produce all immune lineages (Orkin and Zon, 2008). Microglia are the only tissue macrophages that are established in the yolk sac and are self-maintained through-out adulthood, all the other tissue macrophages are est ablished from embryonic day 14.5 to birth and either self-maintained by proliferation or replenished by HSCs in the bone marrow (Ginhoux et al, 2010 Sheng et al, 2015). The arrival of fat-mapping techniques have enabled researchers to precisely penetrate embryonic macrophage populations into adulthood, giving an insight into the relationship between resident tissue macrophages and circulating blood monocytes (Epelman et al, 2014). As previously discussed, microglia are the only tissue macrophage originating from the yolk sac and arise before embryonic day 8 (Ginhoux et al 2010). Fate mapping analysis was employ to determine that the origin of microglia was the primitive myeloid precursors in the yolk sac and also proved that microglia are self-maintained independently of any circulating blood monocytes (Ginhoux et al, 2010). There is also evidence that Langerhans cells originate from the yolk sac but only partially (Sheng et al, 2015). The fate mapping study by Sheng proved that m icroglia and Langerhans cells were the only tissue macrophages that originate from yolk sac precursors and that most adult tissue macrophages originate from a second wave of haematopoiesis driven by HSCs. (Sheng et al, 2015). The number recent of publications concerning tissue macrophage origins is staggering and is most likely attributed to the arrival of fate mapping techniques. With the large surge of new studies regarding tissue macrophage origins it is important that a clear understanding is generated but this is not always possible with such a complicated subject.Contrasting Studies into Tissue Macrophage OriginsThere are a few recent studies concerning tissue macrophage origins which are particularly interesting. Sheng (Sheng et al, 2015) arrived at the finale that most tissue macrophages originate from HSCs however there are a few publications which contradict Shengs findings. Perdiguero concluded that yolk sac derived erythro-myeloid progenitors, were origin of almost all tissue macrophages which contrasts greatly with Shengs observations. (Perdiguero et al, 2015). Perdiguero also concluded that microglia were derived from erythro-myeloid progenitors rather than primitive yolk sac progenitors that was observed by Sheng, although both do come from the yolk sac (Perdiguero et al, 2015 Sheng et al, 2015). Perdiguero predicted that almost all other tissue macrophages originated from erythro-myeloid progenitors (Perdiguero et al, 2015 Sheng et al, 2015). A study by Hoeffel aligned well with Perdigueros observations but Hoeffel observed that primitive yolk sac progenitors gave rise to microglia rather than erythro-myeloid progenitors that was observed by Perdiguero (Hoeffel et al, 2015 Perdiguero et al, 2015). As well as the difference in the development of microglia, Hoeffel predicted that erythro-myeloid progenitors migrated to the foetal liver, giving rise to foetal monocytes which were then responsible for the production of tissue macrophages. (Hoeff el et al, 2015). Each of these 3 examples also propose a separate proposed major path of ontogeny and differentiation to adult tissue macrophage state. Perdiguero proposes erythro-myeloid progenitors from the yolk sac as the major precursor of tissue macrophages, Heoffel proposes erythro-myeloid progenitors from the foetal liver, as foetal monocytes, as the major precursor and, Sheng proposes that HSCs from the foetal liver are the major precursor (Perdiguero et al, 2015 Hoeffel et al, 2015 Sheng et al, 2015 Guinhoux and Guilliams, 2016). Although the observations made by Sheng are profoundly different to those made by Perdiguero and Hoeffel it could be down to the fate mapping technique they used. The model they used is not adapted to distinguish between late erythro-myeloid progenitors and foetal HSCs which has clearly effected the conclusion they have come to (Guinhoux and Guilliams, 2016). Although fate mapping has great strength in advancing our knowledge of cellular ontogeny there are certain limitation that come with it and these limitations must be considered when designing experiments and analysing data (Guinhoux and Guilliams, 2016).Do Tissue Macrophage Origins Matter?Determining the origins of tissue macrophages may be valuable for furthering our knowledge and understanding of their development but do their origins have any influence in determining their function? As well as ontogeny, diversity in the functions of tissue macrophages can also be attributed to the local signals received by the macrophages. These local changes can drive the expression of unique transcription factors which in turn lead to different functions (Lavin et al, 2015). There is a lot of evidence to offer that the tissue macrophages microenvironment can alter its function, the plasticity of tissue macrophages allows them to adjust their functions to inflammatory events (Lavin et al, 2015). Using ionizing radiation most embryonic-derived tissue macrophages can be eliminated, t hey can then be replaced with donor-derived bone marrow progenitors to determine if the wild type state of the tissue can be set upd. Using this technique, studies have proven that bone marrow progenitors can completely restore the enhancer profile and transcriptional programme of the embryonic-derived tissue macrophages that were eliminated (Lavin et al, 2015). A very recent study has shown that yolk sac macrophages, foetal liver monocytes and adult bone marrow monocytes can all successfully differentiate into alveolar macrophages in the lung after the removal of the native alveolar macrophages using ionizing radiation (van de Laar et al, 2016). The study also showed that other already developed tissue macrophages, liver, peritoneal and colon macrophages cannot successfully differentiate into alveolar macrophages in the lung. This finding suggests that the plasticity of the mononucleate phagocyte system is at its largest during the precursor stage and after differentiation to tis sue-resident macrophages no further phenotypic changes of macrophage types can take place (van de Laar, 2016). Perhaps the most interesting finding from this study is that the alveolar macrophages differentiated from yolk sac macrophages, foetal liver monocytes and bone marrow monocytes were still able to self-maintain and prevent alveolar proteinosis (van de Laar, 2016). Similar results have also been observed with Kupffer cells. Kupffer cells were eliminated from the liver using diphtheria toxin-mediated depletion allowing its niche to become vacant. Observations showed that circulating monocytes can engraft the liver and adopt the transcriptional profile of the eliminated Kupffer cells and also become long-living self-renewing cells like their eliminated counterparts (Scott et al, 2015). These new findings question whether the origin of tissue macrophages is truly important to their function as the progenitors and monocytes tested have all been able to restore the tissues lost ma crophages successfully without any loss of function.ConclusionAlthough determining the origins of tissue macrophages and other members of the immune system is important for the progression of our knowledge it remains to be seen whether the actual origins have any implications on the function of the tissue macrophages. The techniques used in the publications discussed are still very new and still require refinement, I believe further refinement of the techniques will enable a more detailed and accurate description on the origins of tissue macrophages and the role the origins play in their function.References BOYCE, B.F., YAO, Z. XING, L. 2009Osteoclasts have multiple roles in bone addition to bone resorption.Critical Reviews in Eukaryotic Gene Expression, 19.3, 171-180EPELMAN, S., LAVINE, K.J. 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