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Thehuman body functions like a small natural environment that sustainsitself through the complex natural process. These processes preventit from detrimental effects of an exaggerated activity in the body(Taylor, 2012 P. 9). All the processes are taking place in the bodywork towards maintaining a constant internal environment that isoptimal for the functions of the body cells. Scholars coined the wordhomeostasis to refer to the self-sustaining internal environment inthe body through involuntary natural occurrences. The word emanatesfrom two Greek words, that is, homoios which means similar and statiswhich means still. The body has various primary organs whosefunctions maintain an optimum condition in the body. The structuresinclude the liver, kidneys, heart, skin and the brain. All of theseorgans have a mutual dependence on other body organs, and theycontrol the body’s environment t in different ways. The brain actsas the center of control since it receipts the changes in theenvironment and stimulates the release of control hormones in thevarious organs. Their characteristics and structures have uniqueadaptations to their different functions.

Homeostaticmechanisms occur in two phases. That is negative and positivefeedbacks. Whenever there is a change in the environment, thereceptor cells detect the change and transfers the information to theeffectors cells mostly located in the brain. The brain sends a signalto the respective organ of the body to take action to control thesituation. Positive feedback involves accelerates the body asfunctioning to stay at the normal rate in the changing environment.For example, people develop goose bumps on the skin during a coldday. The negative feedback lowers the functions of the body to bringdown the rate to the appropriate level in a particular environment.For example, excreting sweat during a hot day or releasing insulin bythe pancreas to lower the level of glucose.

Theheart rate is imperative in determining the amount of oxygentransferred to the cells for the breakdown of food to release energy.Whenever there is an immediate requirement for extra energy in thebody, the hearts muscles increase the intensity of systole anddiastole and blood moves at a high speed to the muscle cells. Forexample, during a splint, he body requires a lot of energy to poweran individual throughout the race. As one runs, more energy is used,and more is in requirement than when one is at rest. Increased bloodflow in ten muscles provides more oxygen for oxidation, and the cellsrelease energy at a high rate. When an individual is at rest, themuscles require less energy and the rate of systole and diastole islow (Riganello et al. 2015 P.35)

Breathingrate goes hand in hand with the heart rate. The rate of breathing isdirectly proportional to the amount of oxygen needed in the body(Janson et al., 2013 P.2624). When the body is in need of the highlevel of energy, it automatically increases the breathing rate toprovide oxygen to aid in breaking down the stored food substances toreleases energy. The example of a person in a splint is sufficient inthis phenomenon. When an individual runs, the muscles require a lotof energy. The breathing rate increases to provide the requiredamount of oxygen to hasten the breakdown (Cooke, 2013 P. 149).

Changesin temperature also instigate the body to act in different ways. Theoptimum functioning of the body cell takes place when the temperatureis around 38 or 39 degrees Celsius (Hochachka &amp Somero, 2014 P.14). Any increase or drop in the external environmental temperaturesstimulates mechanisms to retain the internal temperature within thatrange. Several organs like the skin, the liver and the hypothalamuscell in the brain take part in regulating the body temperature. Someof the mechanisms for increased temperatures include sweating andlying of the hair on the skin. They assist the body to lose excessheat to the environment. Mechanisms for a cold environment includeshivering, the erection of the hair follicles and developing goosebumps. These mechanisms protect the body from losing heat to theenvironment.

Anotherimportant element that needs a constant regulation is blood sugar orglucose. Glucose is imperative in providing energy in the body cellsafter being oxidized in the presence of oxygen. The normal level ofblood sugar for a healthy individual is between 70 and 90g/dl (Hyun,2013 P. 2351). However, it should not drop beyond or exceed therecommended level in the blood. When the blood sugar is above therate, the pancreas releases high levels of insulin that helps toconvert excess glucose into fats (Florkin, 2012 P.150). In the eventof low blood sugar levels, the pancreas releases glucagon that is thehormone responsible for stimulating the liver to release storedglucose into the bloodstream.

Danis taking a five-mile run. His heart beat, body temperature and rateof breathing increase. Since he is on the run, his muscles require alot of energy to propel his legs to finish the race. His heart rateincreases to increases the rate of blood flow into the cell toprovide enough oxygen to break down glucose to energy. The intensityof muscles generates heart during the activity, and the body controlsit by eliminating through sweating (Hall et al. 2011 P. 991). Hisbreathing rate serves his body in two ways. First, increasedbreathing rate takes in more oxygen to the lungs and then gets intothe blood stream from the heart and finally into the cells. Secondly,since his muscles are in an intensified activity, they give outexcess carbon dioxide, and it needs removal removed from the body. Hehas to breathe faster to get rid f the waste carbon dioxide toprevent from accumulating in the cells.

Whenthe heart rate has a problem and the rate fails to change to meet thedemand of the external environment, the individual cannot respond toemergency situations efficiently. For example, during a splint, theindividual will not have enough oxygen for oxidization and the resultwill be insufficient energy for the activity (Fleming et al., 2011 P.1014). When the breathing rate falls, the rate of oxygen intake andremoval of carbon dioxide fails to meet the demands of the body.Fewer oxygen results is a reduced rate of oxidation and failure toremove carbon dioxide from the cell may lead to cell poisoning. Thefailure of the mechanisms that control body temperature may havedetrimental effects on the body cells. Excess temperature beyond 38degree Celsius may destroy the cell and denature the enzymes. Verylow temperature with failed body mechanisms will make the cellsinactive, and they may not function optimally. The result will be ageneral reduction of body activities. The pancreas may fail toproduce enough insulin or glucagon into the blood stream.Insufficient insulin results in excess glucose in the blood and verylittle of the amount gets converted o energy. Insufficient level ofglucagon in the body hinders the release of the stored glucose fromthe liver to the body. The body can, therefore, become weak due tolack of stored energy.

Theurinary system

Theurinary system is one of the complex units in the body, and it has acrucial role in maintaining a constant environment in the bodythrough excretion. In the body, the urinary system lies in the pelvicarea, and it anatomically links to the reproductive system (Sherwood,2015 P. 52). The major role of the urinary system is to remove excesssalts and water in the body. The phenomenon helps to maintain anoptimal osmotic potential in the body. Its major structures are thekidneys, ureter, bladder and the urethra. The various structures haveunique adaptations that enable them to function purposively.

Thekidneys lie in the abdominal cavity, and they occur in a pair. Theyare bean-shaped and dark red in color. The kidneys act as the filterto remove unwanted water and salts in the body. Blood finds its wayinto the kidney through the renal artery and finds its way into thenephrons (Moore, et al., 2013 P. 67). Each kidney contains millionsof nephrons that help in filtering blood. Each nephron has a crucialstructure known as the glomerulus that changes its permeability toallow the contents to flow through it. The nephron has an extensiveloop known as the loop of Henle that is in coils to increase thesurface area for the absorption of water and salts. When there is anincreased water requirement in the body, the kidney absorbs water inlarge amounts. A hormone known as Antidiuretic hormone controls theamount of water absorbed in the loop of Henle (Pocock, et al., 2013P. 63). Aldosterone controls some salts reabsorbed into the bodythrough the loop of Henle. The remaining mixture of water and saltspasses into the collecting duct ready from removal from the body(Morel, 2013 P 271). The kidney, therefore, is the blood cleaningagent in the body.

Ahuman being has two ureters with each coming from each kidney andproceeding to the bladder. In a human adult, the ureter is about 10inches long with a fibrous coat capable of expanding and contracting(McLafferty et al., 2013 P 45). Its cells receive nutrients from theblood supply by the iliac arteries and the renal arteries. The majorfunction of the ureter is to carry urine from the kidney to thebladder.

Thebladder is a bag-shaped structure found in the pelvic area of thehuman body. The excess mixture of water and salts filtered from theblood in the kidney accumulates in the bladder. The human bladdertakes the form of a pear when empty. When full the walls expand toallow the storage of urine, and this makes it possible only torelease urine voluntarily. Te normal capacity of a human bladder isbetween 400ml to 600ml. When full or when one intends to urinate itsmuscles contract to expel the urine. It passes through the urethrato outside the body through urination (Jones et al., 2013 P 18).

Theurethra is a passage that allows urine to get out of the body. Inmales, the urethra serves the reproductive and the excretion purposewhile females have a separate urethra for excretion and a vaginalcavity for reproduction. It muscles relax and contract to allow urineto pass. It is the final structure of the urinary system, and itsopening extends to the external body.

Excretionis the removal of waste product from metabolism activities. It is achemical process that takes place in the cells as they give out thebyproducts of their activities. The human body excretes three mainproducts. That is, water, urea, and carbon dioxide. Excretion is animportant process because, without it, the substances can accumulateto toxic levels and kill the cells. It also helps to main theappropriate composition of body fluids (Sawyer &amp Pang, 2014 P.296).

Anotherimportant process related to excretion is osmoregulation. It is aprocess of balances solutes and water across a semi-permeablemembrane. Osmoregulation occurs through diffusion whereby cells withhigh osmotic pressure absorb more water to return them to neutralconditions. The cells that have a very low osmotic pressure loosewater to the neighboring cell and their raise their concentration tothe normal level (Sawyer &amp Pang, 2014 P. 293).Osmoregulation isimportant because it helps in maintaining an optimum concentration ofsolutes in the cells, and this makes the functions of the bodyefficient.

Acuteglomerulonephritis is the onset of proteinuria, hematuria and redblood cells in the excreted products from the urinary system. Thecondition leads to reduced glomerular filtration rate, and it becomesmore permeable than it is supposed to be normal. It hence allows thefiltration of required elements in the blood (Vance et al., 2012 P.11).The disease affects osmoregulation in the body. When theglomerulus becomes excessively permeable, it allows excess water andsalts to pass through the loop of Henle, and the re-absorption ratedoes not match the body requirement. The cells, therefore, maydevelop high osmotic pressure and it will likely maim theirfunctioning.

TheHuman Skin

Theskin is the largest organ in the body, and it covers the entiresurface of the body. The skin protects the internal organs fromphysical injuries and also takes part in excretion andthermoregulation. It has three layers that form on top of each other.Their position on the surface depends on their delicacy (Montagna,2012 P. 5).The first layer is the epidermis. It is the outermostlayer and visible to the naked eye. The epidermis offers protectionto the inner parts of the skin. It also provides a waterproofbarrier. It is one of its protective functions. It also gives theskin its color due to the presence of melanin and it helps to absorbradioactive rays and consequently to prevent them from reaching thedelicate inner organs.

Thesecond layer is the dermis. It is the layer that harbors the hairfollicles and the sweat glands. The sweat glands handle excretingexcess water and salts inform of sweat. The hair follicles play acrucial role in thermoregulation. The dermis gives rise to theepidermis (Chambers, 2014 P. 2238).

Thethird layer is the subcutaneous layer. Its main function is to storefat in the body. The excess glucose that turns into fact accumulatesin this layer and it breakdown when in need in the body. It acts asan insulator tp protect the body against heat loss.

Thereseveral incidents that may have detrimental effects on thefunctioning of the skin. One such incident is a burn that extends todestroy both the epidermis and the dermis. Medical professional referto it as third-degree burns (Museux et al., 2012 P.659). Sources ofsuch burns include scalding liquids, flames, and chemical elements. The homeostatic functioning of the skin comes to an end if thepatient does not get immediate medical attention (Kenshalo, 2012 P.21). The sweat glands found in the dermis becomes non-existent, andit becomes impossible for the body to lose excess water through thepores. The hair follicles that control the position of the hair onthe skin also get destroyed, and the thermoregulation function of thehair strands comes to an end. In extreme cases, the nerve endingsalso die in the incident and the skin fails to its function ofprotecting the inner organs through sensitivity (Blais et al., 2013P. 549).

Asmentioned earlier, one of the functions of the skin is temperatureregulation. When the temperature in the body rises beyond the optimumamount, the sweat glands found in the dermis absorbs water andexcretes it through the sweat pore (Scanlon &amp Sanders, 2014 P.18). As it gets on to the epidermis, it evaporates into theenvironment. In doing so, it draws the latent heat of vaporizationthat has a cooling effect on the skin. On a cold day or when anindividual gets into a cold environment, the sweat glands absorb verylittle water to reduce evaporation. The skin develops goose bumps toseal the sweat ducts and, therefore, to prevent any water from cominginto the outer layer (Sanford et al., 2013 P 372).

Thehair follicles also play a part in controlling the temperature. In acold environment, the follicles contract and consequently, the hairstrands stand erect on the skin. They trap air between the skin andthe environment and create a vacuum that does not allow any heat topass through. The reverse happens in a hot environment whereby thefollicles relax, and the hair strands lie flat on the skin. They trapless air and increase heat loss into the environment (Gagge &ampNishi, P. 2011 P. 16).

Whenthe body overheats, there is an immediate need for reducing theexcess heat and return the body to normal. Various activities takeplace in the body like sweating that helps to lose heat throughevaporation. There is also a reduced speed of cellular activities toavoid generating more heat. When the body gets cold, the cellularactivities intensify to generate heat from within the body. The skinseals the pores that can excrete water leading to heat loss throughevaporation. Involuntary shivering may happen, and the intensecontraction, and relaxing of body muscles generate some heat. Allthese take place to maintain the body temperature to normal foroptimal functioning.


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