PART mechanism known as the feedback regulation. This is

PART BExplain and Evaluate homeostasis inthe human body.Word Count Limit:1500 – 2000 wordsRoughly 300-400 words to each question. Importance of homeostasis within thehuman bodyHomeostasisin short, is the stable condition of an organism and its internal environment,it maintains the equilibrium and balance of functions of the human body, whichthe nervous system and hormones are responsible for. Maintaining balance iscritical in keeping the body alive and healthy.

To do that, the cells must bekept in perfect conditions to function and survive. Homeostasis is in importantin the human body. One reason is that certain chemicals such as oxygen (O2) andcarbon dioxide (CO2) and food that is digested exit and enter cells usingosmosis and diffusion. Diffusion is essentially the passive movement ofmolecules from a place of high concentration to a place of low concentration.

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Osmosis on the other hand is the movement of water from a dilute to a more of aconcentrated solution through a partially permeable membrane. Active transportalso moves chemicals such as a glucose as well. If there is excess water thatfinds its way into a cell by the process of osmosis, the cell membrane canactually rupture but if there is too much water movement out of the cells theywill not be able to function as they should. For both osmosis and diffusion towork as they should, homeostasis is needed to help keep our body (and water andsalt level) balanced. Homeostasis helps keep enzymes functioning properly bymaintaining the correct body temperature. Without the temperature beingcontrolled the enzymes would not be able function as they should and as aconsequence cells would die.To resist any change that happens in or out of an organism environment the mechanismsto attain homeostasis are stable.

Depending on the individual, the mechanismscan vary and can either be negative or positive feedback.Explanation of how the endocrinesystem is involved in homeostasisInhomeostasis hormones will control the activity of body cells which theendocrine system is responsible for. Its done via a self-regulating mechanismknown as the feedback regulation.This is when a stimulus controls the release of hormones into the blood stream.There can be either an increase of decrease by the stimulus of the number ofhormones that are being secreted. It can then become a new stimulus as theresponse to the original stimuli changed the internal environment.  The feedback part of the regulation happenswhen the response to a stimulus influences the original stimuli. Dependant onthe response type will determine what feedback is called.

There is bothPositive Feedback and Negative Feedback.Positive Feedback is when there is an increase of the original stimulus due tothe response. Negative Feedback is when the stimulus response reduces theoriginal stimulus.Out of thetwo, negative feedback is far more common. It is a system that reacts toreverse change. Due to this, the maintenance is lowed for the balance ofhomeostasis. The process of Osmoregulation isby which the body keeps homeostasis of an organism’s water level constant byregulating the osmotic pressure of any organism fluids.

In short osmoregulationis used to prevent the bodily fluid from being either too concentrated or toodiluted. To measure the ability of water to move from one solution to anothersolution via osmosis, an osmotic pressure is used. Osmotic pressure is when aliquid solution diffuses, thereby moving from a lower concentration to a higherconcentration across a membrane. For humans it is critical to have the osmoticpressure maintained. There is no loss or gain of fluids or salts into the cellsof the body as osmotic pressure gained an isotonic solution. Instead there is aconstant and steady in and out of the cell membrane of substances.

When the water level in the blood drops below normal range the hypothalamus detectsthe change and the higher concentration of solutes in the blood. When thisoccurs, two things happen. Firstly the hypothalamus creates a feeling of thirstand the pituitary gland releases more ADH to stimulate the kidney’s intoabsorbing more water when the person drinks, which helps restore the balance inthe in the body. At least 3 examplesof homeostasis within the human bodyA goodexample of this would be the regulation of carbon dioxide in the human body.Carbon Dioxide is a waste product of respiration.

It travels in the bloodstreamfrom the cells to the lungs and leaves our body when we exhale. Carbon Dioxidewhen it is dissolved in water forms an acidic solution. In order to prevent theblood from becoming too acidic or too alkaline the Carbon Dioxide levels mustbe controlled. The pH of blood can be affected if Carbon Dioxide is allowed tooverproduce.

This would then affect many blood proteins and more specificallythe enzymes. Other critical processes such as clotting of the blood could beaffected. To start with something disturbs the homeostasis, either there is toomuch or too little CO2 being produced.

As an example I will use too much CO2.When there is too much CO2 the pH of the blood will decrease and the O2 levelsin the blood will decrease too as well as in the cerebral spinal fluid. Afterthe disturbance there will be a reflex response. In this instance chemoreceptorsare stimulated which then leads to a respiratory response. In the respiratoryresponse the medulla oblongata is stimulated and the respiratory rateincreases.

Homeostasis is then restored and the oxygen and pH return to normallevels.Anotherexample is thermoregulation. This is where homeostasis assists in adjusting andregulating body temperature and responding to changes in the surrounds. If thebody temperature falls, homeostasis will trigger a response in the body.Firstly the blood vessels will constrict so heat can be retained for longer. Atthis time, your body will not allow sweat glands to secrete any fluid butinstead your body will start to shiver; an involuntary response that createsheat and in turn raises the body temperature.

A finalexample would be the regulation of glucose in the human body. It is important forour body to regulate our glucose/sugar. If we have too little it can trigger hypoglycaemia(causes dizziness, sickness and extreme cases cause a coma) and likewise ifthere is too much it can cause hyperglycaemia, and if too often can be a signof Diabetes.

In homeostasis, if blood sugar becomes over a safe level insulin willbe secreted from the pancreas to correct this and bring blood sugar level backdown. Again, if blood sugar level becomes too low homeostasis will trigger aresponse form the pancreas again, releasing glucagon to up the sugar levels toa safe level.     An explanation of howeach of the key organ systems work together and contribute to overallfunctioning of the human body.Our body works together in order to keep us healthy andfunctioning.

The cardiovascular system works with our respiratory system tospread oxygen throughout the body and rid itself of waste carbon dioxide (CO2).The cardiovascular system uses its system of arteries and veins and heart topump oxygen-filled blood from the lungs to rest of the body, giving oxygen tothe organs and tissues. Once the organs and other body cells have taken theiroxygen (O2) they release carbon dioxide (CO2) back into the blood which willflow through the veins back to the heart via its right-side chambers. Oncethrough the right chambers it flows back to the lungs to exchange the wastecarbon dioxide (CO2) for oxygen (O2).

The now inhaled oxygen flows through thenasal pathways down towards the throat and onto the lungs. It then goes toalveoli where gas exchange happens. The oxygen travels through the blood fromthe lungs to hearts left chambers and is pumped with great force via thearteries to deliver oxygen to the organs and body cells that need oxygen. Thisis a cycle that continues throughout a person’s lifetime. To link further toother body systems, both the nervous system and endocrine system both regulatethe cardiovascular system.Its not just the cardiovascular system and respiratory systemthat work together; the digestive system and excretory systems also worktogether. The digestive system’s role is to break down food into molecules thatare small enough for our body tissues and cells to use.

The stomach breaks thefood apart and down by churning but also by releasing enzymes. Once through thestomach the food moves onto the small intestine where pancreatic juices andenzymes are received which are designed to dissolve and digest fats,carbohydrates and fibres. Fats are dissolved by the bile which is produced bythe liver. The small intestines’ main function is absorption.  Nutrients which are digestible are passedthrough the small intestine and the microvilli to the capillaries and finallyarriving at the liver for detoxing and final processing before being releasedto the rest of the body. Not everything is digested however, and some materialsuch as fibres, bile and bacteria journey through the large intestine and outthe colon and rectum.

Urine is formed from the kidneys that filter out wastefrom the blood. The urine flows through the ureters and then enters the bladder.When full the bladder releases urine and its exits the body via the urethra. Again,much like the cardiovascular and respiratory system, the digestive andexcretory systems are both regulated by the nervous and endocrine system. To link it all together, the cardiovascular system suppliesoxygen rich blood to the rest of the organ systems, sustaining them.

Withoutthe cardiovascular system providing the oxygen the other systems would not beable to function properly. They would die. The cardiovascular system not onlyprovides oxygen, it also removed waste products such as carbon dioxide (CO2) andbrings it back through the blood and expels it out of the lungs.   Compare and Contrasthow the endocrine system and nervous system help control our body functions.Nervous system uses electrical impulses (action potentials)as signals whereas the Endocrine System uses chemical impulses (hormones) tocommunicate with the body. Nervous system pathways is transmission by neuronswhereas the endocrine system transports the hormones through the blood.

Theendocrine is rather slow in the speed of information, but the nervous system isfast. Nervous system duration is short lived, but endocrine can either be longor short lived. Endocrine is always an involuntary action/response, but thenervous system can either be voluntary or involuntary action/response. Thetarget of the nervous system is localized which is cells that are connected toneuron. Endocrine system targets are often distant and many cells can beeffected.The nervous system is made up of neurones and they useelectrical impulses as a form of transmission. The nervous system uses nervefibres such as the axons and dendrons as a transmission pathway to communicatewith the human body.

Although the speed of the transmission is fast theduration of effect is short term and the response is localised and notwidespread.The endocrine system is made up of secretory cells and useshormones (chemicals) as a form of transmission. The endocrine system transportsthe hormones via the blood stream. Unlike the nervous system the speed oftransmission is slow but the duration of effect is long-term and widespread,but it can target a specific organ.