Osmoregulation Definition and Explanation

Osmoregulation is the active regulation of osmotic pressure to maintain the balance of water and electrolytes in an organism. Control of osmotic pressure is  needed to perform biochemical reactions and preserve homeostasis. How Osmoregulation Works Osmosis is the movement of solvent molecules through a semipermeable membrane into an area that has a higher solute concentration. Osmotic pressure is the external pressure needed to prevent the solvent from crossing the membrane. Osmotic pressure depends on the concentration of solute particles. In an organism, the solvent is water and the solute particles are mainly dissolved salts and other ions, since larger molecules (proteins and polysaccharides) and nonpolar or hydrophobic molecules (dissolved gases, lipids) dont cross a semipermeable membrane. To maintain the water and electrolyte balance, organisms excrete excess water, solute molecules, and wastes. Osmoconformers and Osmoregulators There are two strategies used for osmoregulation—conforming and regulating. Osmoconformers use active or passive processes to match their internal osmolarity to that of the environment. This is commonly seen in marine invertebrates, which have the same internal osmotic pressure inside their cells as the outside water, even though the chemical composition of the solutes may be different. Osmoregulators control internal osmotic pressure so that conditions are maintained within a tightly-regulated range. Many animals are osmoregulators, including vertebrates (like humans). Osmoregulation Strategies of Different Organisms Bacteria - When osmolarity increases around bacteria, they may use transport mechanisms to absorb electrolytes or small organic molecules. The osmotic stress activates genes in certain bacteria that lead to the synthesis of osmoprotectant molecules. Protozoa - Protists use contractile vacuoles to transport ammonia and other excretory wastes from the cytoplasm to the cell membrane, where the vacuole opens to the environment. Osmotic pressure forces water into the cytoplasm, while diffusion and active transport control the flow of water and electrolytes. Plants - Higher plants use the stomata on the underside of leaves to control water loss. Plant cells rely on vacuoles to regulate  cytoplasm osmolarity. Plants that live in hydrated soil (mesophytes) easily compensate for water lost from transpiration by absorbing more water. The leaves and stem of the plants may be protected from excessive water loss by a waxy outer coating called the cuticle. Plants that live in dry habitats (xerophytes) store water in vacuoles, have thick cuticles, and may have structural modifications (i.e., needle-shaped leaves, protected stomata) to protect against water loss. Plants that live in salty environments (halophytes) have to regulate not only water intake/loss but also the effect on osmotic pressure by salt. Some species store salts in their roots so the low water potential will draw the solvent in via osmosis. Salt may be excreted onto leaves to trap water molecules for absorption by leaf cells. Plants that live in water or damp environments (hydr ophytes) can absorb water across their entire surface. Animals - Animals utilize an excretory system to control the amount of water that is lost to the environment and maintain osmotic pressure. Protein metabolism also generates waste molecules which could disrupt osmotic pressure. The organs that are responsible for osmoregulation depend on the species. Osmoregulation in Humans In humans, the primary organ that regulates water is the kidney. Water, glucose, and amino acids may be reabsorbed from the glomerular filtrate in the kidneys or it may continue through the ureters to the bladder for excretion in urine. In this way, the kidneys maintain the electrolyte balance of the blood and also regulate blood pressure. Absorption is controlled by the hormones aldosterone, antidiuretic hormone (ADH), and angiotensin II. Humans also lose water and electrolytes via perspiration. Osmoreceptors in the hypothalamus of the brain monitor changes in water potential, controlling thirst and secreting ADH. ADH is stored in the pituitary gland. When it is released, it targets the endothelial cells in the nephrons of the kidneys. These cells are unique because they have aquaporins. Water can pass through aquaporins directly rather than having to navigate through the lipid bilayer of the cell membrane. ADH opens the water channels of the aquaporins, allowing water to flow. The kidneys continue to absorb water, returning it to the bloodstream, until the pituitary gland stops releasing ADH.

The Role Of Women During Medieval Culture - 1272 Words

The Role of Women in Medieval Culture Women were very important in medieval culture. They ran households, gave birth to and raised children, took care of business when their husbands were away and much more. Women had high standards that were placed upon them and that they set for themselves, much like the women and girls of today. Women worked for much less than men did, even though they worked as much if not more than men did. Noblewomen were occasionally educated. In all women were amazing and talented and worked very hard. Life in Medieval times was rough. There were plagues, famine and food poising, death in the military and even execution, but women made it through. For many peasant women life in the fields was tough. They didn’t even get paid half of what men did. But Noble women didn’t have it really easy either. They still had to take care of children and oversee the servants. Peasant women had to weave cloth and make clothes for the family. They tended to the family gardens, where many of the fruits and vegetables were grown. They made food and cleaned the house, looked after livestock and also helped in the fields. Noble women ran the castle, keeping the servants in line. They also arranged feasts and parties, made sure that the servants were paid on time and defended the castle if the lord was away. Life in a castle was easier than life out in the countryside but noble and peasant women alike had many responsibilities that started early in their life.Show MoreRelatedComparing and Contrasting the Role of Women during the Roman Empire and the Middle Ages1564 Words   |  7 PagesPart A: Plan of Investigation This investigation strives to compare and contrast of the role of women during the Roman Empire and the Middle Ages. The inquiry is significant because in order to understand the culture and ethics of the Roman Empire and the Middle Ages it is crucial to understand the importance of women. 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In the book Women and Spiritual Equality in Christian Tradition, by Patricia Ranft, a new and innovative look at the role of women in the sphere of Christianity is examined. In a total of twelve chapters, the Central Michigan University professor discusses the role that women played in the first fifteen hundred years of Christianity and she disputes the contentionRead MoreThe Middle Ages Was A Great Era For Artists And They Produced Great Artistic Works That?1576 Words   |  7 Pagesend of the Fifth Century through 1485. After the collapse of the Roman Empire, the economy was in shambles and many towns were abandoned. After several centuries of Germanic invasion, new cultures and people emerged, developing into predatory kingdoms that competed for power. After a while, a great artistic culture flourished under the Anglo-Saxons, producers, epic poems, Beowulf and sophisticated metalwork. 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Eating Disorders Essay Conclusion Example For Students

Eating Disorders Essay Conclusion Did you know that 90% of women dislike the way they look? And its all because of the media and their emphasis on the ideal figure of a woman. Supermodels like Kate Moss and other Barbie-doll-figure-inspired women grace the cover of magazines all over the world promoting a perfect shape. Girls of all ages think that this is what people want to see. They think that this is what they should look like and try to set impossible goals for themselves to look like covergirls. As a result, many women in North America suffer from psychological illnesses. Among the most common are eating disorders such as Anorexia and Bulimia Nervosa. Anorexia and Bulimia generally arise in young women, but may also occur in older females and occasionally in men. People suffering from any of these sicknesses usually suffer from low self esteem. Victims may think things such as, my life would be better if I lost weight, or they may think that people would like them better if they were thinner. They may feel incapable and tell themselves, I never do anything right, or feel that nothing I ever do is enough. When they look in the mirror, victims see fat staring at them, no matter how thin and bony they may look to others. When shown pictures of themselves, Anorexia and Bulimia patients realize how thin they are but still are dissatisfied with their shape when they go to look in the mirror. Sufferers may lie about how much, how little, or when and where they have eaten so as not to admit to themselves or to others that they have a problem. They may also lie about vomiting and the use of laxatives. Depression or mood swings may also be symptoms of eating disorders. Lack of motivation, feeling isolated and alone, and having the feeling of no self-worth can lead to suicide. Eating disorders are commonly caused by a chemical imbalance in the victims brain. Everyone has a chemical in their brain called Seratonin. This is what controls your appetite. In Bulimia patients, this chemical is deficient and so they keep eating and eating. At that point they feel guilty and have the urge to dispose of the consumed food either by vomiting or having a bowel movement promptly after eating. Subsequently, their Vasopressin level increases and eventually takes over, making the disposal of food the norm. The opposite occurs in Anorexia patients. The Norepinephrine chemical in their brain is deficient. Norepinephrine is the appetite stimulant. In their case, they have no desire to swallow anything for fear of becoming obese. Compulsive Overeating is another eating disorder although not as common as Anorexia or Bulimia Nervosa. Patients eat uncontrollably and gain a considerable amount of weight. And unlike Anorexia and Bulimia patients, Compulsive Overeaters are mostly male. Compulsive Overeaters eat mainly to cope with stress and anything that may be disturbing them. They, like Bulimics, understand that they have a problem. Most overeaters are people who were not taught how to deal with stressful situations. As Compulsive Overeating is not yet taken as seriously as other eating disorders, patients are directed to diet centers and health spas, but in the end, Compulsive Overeating can have the same consequences as Anorexia and Bulimia Nervosa. The most serious consequence being death. Nevertheless, it can be conquered with therapy and counseling. If they knew what eating disorders do to their bodies, patients would seek help much sooner. In Anorexia patients, fatigue, lack of energy, and Amenorrhea are very common physical problems, as are hair loss, infertility, osteoporosis (caused by lack of calcium) and depression. The same goes for those who suffer from Bulimia. Also, Bulimia patients may have rotted teeth (caused by excessive vomiting), cathartic colon (caused by laxative abuse), and inflammation of the pancreas. There are many more physical consequences that victims may encounter upon suffering from these afflictions. .u0caa76832ba9107527f1d0e101f4104a , .u0caa76832ba9107527f1d0e101f4104a .postImageUrl , .u0caa76832ba9107527f1d0e101f4104a .centered-text-area { min-height: 80px; position: relative; } .u0caa76832ba9107527f1d0e101f4104a , .u0caa76832ba9107527f1d0e101f4104a:hover , .u0caa76832ba9107527f1d0e101f4104a:visited , .u0caa76832ba9107527f1d0e101f4104a:active { border:0!important; } .u0caa76832ba9107527f1d0e101f4104a .clearfix:after { content: ""; display: table; clear: both; } .u0caa76832ba9107527f1d0e101f4104a { display: block; transition: background-color 250ms; webkit-transition: background-color 250ms; width: 100%; opacity: 1; transition: opacity 250ms; webkit-transition: opacity 250ms; background-color: #95A5A6; } .u0caa76832ba9107527f1d0e101f4104a:active , .u0caa76832ba9107527f1d0e101f4104a:hover { opacity: 1; transition: opacity 250ms; webkit-transition: opacity 250ms; background-color: #2C3E50; } .u0caa76832ba9107527f1d0e101f4104a .centered-text-area { width: 100%; position: relative ; } .u0caa76832ba9107527f1d0e101f4104a .ctaText { border-bottom: 0 solid #fff; color: #2980B9; font-size: 16px; font-weight: bold; margin: 0; padding: 0; text-decoration: underline; } .u0caa76832ba9107527f1d0e101f4104a .postTitle { color: #FFFFFF; font-size: 16px; font-weight: 600; margin: 0; padding: 0; width: 100%; } .u0caa76832ba9107527f1d0e101f4104a .ctaButton { background-color: #7F8C8D!important; color: #2980B9; border: none; border-radius: 3px; box-shadow: none; font-size: 14px; font-weight: bold; line-height: 26px; moz-border-radius: 3px; text-align: center; text-decoration: none; text-shadow: none; width: 80px; min-height: 80px; background: url(https://artscolumbia.org/wp-content/plugins/intelly-related-posts/assets/images/simple-arrow.png)no-repeat; position: absolute; right: 0; top: 0; } .u0caa76832ba9107527f1d0e101f4104a:hover .ctaButton { background-color: #34495E!important; } .u0caa76832ba9107527f1d0e101f4104a .centered-text { display: table; height: 80px; padding-left : 18px; top: 0; } .u0caa76832ba9107527f1d0e101f4104a .u0caa76832ba9107527f1d0e101f4104a-content { display: table-cell; margin: 0; padding: 0; padding-right: 108px; position: relative; vertical-align: middle; width: 100%; } .u0caa76832ba9107527f1d0e101f4104a:after { content: ""; display: block; clear: both; } READ: What Leads to Intervention?: A Case Study of Inter EssayPeople who suffer from Anorexia and Bulimia are silently killing themselves. These sufferers are mostly women, but a growing percentage of men are beginning to catch on to this terrible disorder. They try to convince themselves that there is nothing wrong, but deep down they know that what they are doing is hurting their bodies. Some people eventually realize that they need help and ask for it. These people usually end up in hospital beds if not until they die, for months and even years. Unfortunately, many people dont report their illness and dont get help. Eventually, they die. To give you a better view on how uninformed BCs ministry of health is regarding this subject, here are three things that it does not know:1. The number of eating disorder patients there are in the province2. How much money they spend on eating disorder patients. 3. The number of patients hospitalized in one year. Patients should be treated in hospitals where they can be monitored but, unfortunately, not many patients have medical insurance and without it, a hospital bed is expensive. It costs the BC government $775 a day for only one bed. If the patient hasnt any insurance, financial problems for the family could emerge. Even if they were able to afford to be treated in a hospital, there are long waiting lists. At St. Pauls hospital in Vancouver, eating disorder patients must wait 3 years to be assessed. Unfortunately, this is too late. In 1992, four young women died within a 4 month period on Vancouver Island alone. This may have been because the waiting lists were too long and they didnt receive adequate help in time. Fortunately, provincial funding for eating disorder patients has increased, but not nearly enough. Consequently, groups have set up support homes such as Safehouse in Vancouver. Safehouse is a temporary home for patients to turn to. There, patients receive a bed and therapy, are convinced to eat and most importantly are given love all at half the cost of a day in the hospital. At Safehouse, most of the volunteers have experience dealing with eating disorder patients and know how to help them recover. Therefore, many Anorexia and Bulimia sufferers turn to Safehouse for help. Sadly, many doctors, when turned to for help, are not very understanding. Some tell their patients that they will have to live with the conditions and that there is nothing they can do. Some tell their patients that they will die and some doctors even have the nerve to tell their patient that they should feel responsible because it is their fault. On the other hand, some doctors give all the help they can but still just give up hope in the end. All of this is unacceptable and it only happens because not enough people are adequately informed about the consequences that the patient and their family members have to suffer. Dealing with a sick family member can be awfully stressful. In that case, the family needs support. They have to find out all there is to know about eating disorders and related psychological illnesses. If possible, family members should gather information on what they can do to help. But most importantly, they can never give up hope. Their sick family member needs all the help and motivation possible to get well again. Someday, scientists hope to develop a pill or medication for Anorexia and Bulimia victims. This would control the Vasopressin levels of the patients brain but until then, psychological help is all they can be given.

MGMT free essay sample

Named to be one of the best indie bands of all time, MGMT was formed by two college students named Ben Goldwasser and Andrew VanWyndgarden while freshman at Wesleyan University. While getting adjusted to the new environment there, the two often got together and recorded music on their computers, experimenting with different types of rock and electronic genres. After about a year of creating music together, they decided to get serious about their musical career. We will write a custom essay sample on MGMT or any similar topic specifically for you Do Not WasteYour Time HIRE WRITER Only 13.90 / page Around 2002, they played some music for Cantora records, and were signed within a few months. Once Goldwasser and VanWyngarden graduated, they had the time to tour and endorse their first EP, Time To Pretend, playing at many gigs including the opening for the indie rock band entitled Of Montreal. MGMT’s association with Cantora records didn’t last for long, because around 2006 they were signed to another major record label, Columbia Records. This was definitely the right move for the band at the time because their next album, known as Oracular Spectacular, was a huge success and step forward in their musical career. MGMT opened for Of Montreal once again, and even performed in London, England later that year. The band entered 2008 with a bang performing on a headline tour of the UK, opening for M.I.A., and later playing several shows with Beck,, marking another year of great successes. One of MGMT’s most popular songs to this day known as Kids, gained much of it’s popularity when it premiered on the hit series Gossip Girl. Originally an underground band, MGMT was now looked at as somewhat mainstream, and many children who only looked at the top songs were now beginning to purchase their upcoming EP’s and albums. Presently, MGMT not only opens for bands, but plays at concerts of their own and tours all the time. They recently released an album on April 13th, 2010, entitled Congratulations, and was a huge hit in both the UK and the USA. Both have stated that although fame and fortune is not what they wanted out of they business, they know it is impossible to avoid and they will continue to make music in the future. Out of all of MGMTs songs and EPs, Kids is definitely my favorite. The way it combines electronic, pop, rock, and many other genres is brilliant and to do it well is an extremely hard skill to master. Not only that, but it is extremely catchy and after listening to it once Im sure youll be hooked. Another one of my favorites is Time To Pretend, for most of the same reasons as Kids, but additionally because it was their first song and its incredible how its been around for so long and is still a hit among most. Personally, I believe that MGMT is one of the best Indie bands of all time. Through their innovative electronic rock style, they are able to communicate to a fan base that ranges from the most alternative to the most mainstream supporters. Many indie rock bands attempt to get out of the spotlight after becoming famous, but I think its great that MGMT instead embraces the spotlight, and continues to make great music for everyone to enjoy.