Kidney Dialysis Essay

The kidney has two important functions for the body because it is connected to the body’s blood flow, it can help monitor blood pressure and secrete hormones, which can raise blood pressure in the event when it does not receive enough blood flow. However the most important job is filtration of blood. The kidney works to filter out toxins, especially chemicals that are formed as a result of cells using energy. The kidneys also work to maintain the balance of electrolytes within the body which can be lost during exercise. Cells need a good balance of electrolytes such as sodium and potassium within the body. If one kidney fails the other one is enough to maintain the body however if both fail to work it is a major issue and it causes problems as the kidney cannot filter the blood. How does a renal dialysis work: A dialysis machine tries to mimic some of the functions of a normal human kidney. One of the jobs of a kidney is to remove urea and some salts from the blood so they can leave the body in the urine. In a dialysis machine, blood from the patient runs through tubes made of a semi-porous membrane. Outside the tubes is a sterile solution made up of water, sugars and other components. Red and white blood cells and other important blood components are too large to fit through the pores in the membranes this acts like the glomerlus in the bowman’s capsule where ultra filtration takes place, but urea and salt pass through membranes into the sterile solution and are removed, this is what happens in a normal functioning kidney the small molecules can pass through the glomerlus but proteins and cells cannot as they are too large. What is haemodialysis: Kidney failure, whether it is permanent or temporary, is mostly treated using renal dialysis, which kind of replaces the kidneys filtration function. One form of renal dialysis is called hemodialysis. With hemodialysis, the patient’s blood is run through a machine with a special filter that helps clean out the waste products. Once the blood has been filtered, it is allowed to return to the body. One of the difficulties of hemodialysis is that it takes place at special medical centres and we are short of machines. This means that the patient has to visit three times per week that lasts between three to five hours per session, this takes up a lot of time. What is peritoneal dialysis: Peritoneal dialysis is the other main form of renal dialysis. With peritoneal dialysis, a sterile cleansing fluid called dialysis solution is injected into the abdominal cavity. The abdominal cavity is lined by a membrane called the peritoneum, which allows the waste products and extra electrolytes to pass through it and travel to the dialysis solution. The dialysis solution also contains a sugar called dextrose, which helps speed the process up. After the solution has sat in the abdominal cavity for four to six hours, it is drained out. This process is repeated four times per day. This type of treatment can take place at home because it makes use of a catheter, which allows the patient to connect a bag of dialysis fluid to a tube that feeds directly into the peritoneal cavity. This treatment allows a person to be a bit more flexible however the patient still needs to do this treatment a few times a day which means it takes up time of a normal persons life. The benefits and risks of a kidney transplant: A kidney transplant is much better than staying on a dialysis machine. A kidney transplant means you can live a normal life, you won’t have to go to the hospital a few times a week to get treated and this wastes time as it takes 2-3 hours on a dialysis machine 3-4 times a week this means that you cannot go away. Someone who’s on a dialysis machine has to give up a lot of time and this may get in the way as they may have to cancel many things during their normal daily life. A kidney transplant gives the body a whole new kidney and works perfectly where as a dialysis machine can only mimic a few of the roles of a kidney. The risks of a kidney transplant are that the body may reject the kidney as it is foreign so a very close tissue match is required. After a person has had a kidney transplant they have to be on drugs for the rest of their life so that the body does not reject the kidney. Kidney transplants can also cause infections or bleeding which can dangerous. Donor cards: A donor card is a card that shows that a person has agreed to give away some  of the organs after they die, and this can be used for transplants. However there are issues, some people believe that it is religiously wrong to give away your organs after you die and this causes a lot of problems. A family member may have given consent to give away their organs when they die but after they die their family members may object and not allow it and this causes a lot of problems. There is a long list for transplants and it is very hard to receive a transplant, donors help quicken this service. In England it is optional to become a donor or not. Another issue may be about race some people will not wish to have an organ from someone else from another race or the donor may not wish to give their organs to someone else from another race or religion and this is another problem that causes delays and means there’s a shortage of donors. Definitions: Ultra filtration: A high pressure filtration through a semipermeable membrane in which colloidal particles are retained while the small sized solutes and the solvent are forced to move across the membrane by hydrostatic pressure forces. Ultrafiltration is a vital process that takes place in the kidneys. With ultrafiltration, large molecules (such as cells and proteins) that are essential are separated or filtered out to be reabsorbed. The ultrafiltrate, in turn, is passed through the proximal tubule, the loop of Henle, the distal convoluted tubule, and a series of collecting ducts to form urine. Osmosis: Diffusion of a solvent (usually water molecules) through a semipermeable membrane from an area of low solute concentration to an area of high solute concentration. Selective reabsorption: The act or process of absorbing again, as the selective absorption by the kidneys of substances (glucose, proteins, sodium, etc.) already secreted into the renal tubules and their return to the circ ulating blood. Microvilli: Any of the minute hairlike structures projecting from the surface of certain types of epithelial cells, especially those of the small intestine. Co-transport proteins: Facilitated diffusion: Transport of substances across a biological membrane from an area of higher concentration to an area of lower concentration by means of a carrier molecule. Since the substances move along the direction of their concentration gradients, energy is not required. Active transport: A kind of transport wherein ions or molecules move against a concentration gradient, which means movement in the direction opposite that of diffusion – or – movement from an area of lower concentration to an area of higher concentration. Hence, this process will require expenditure of energy, and the assistance of a type of protein called a carrier protein. ADH: a peptide hormone released from the posterior pituitary lobe but synthesised in the hypothalamus. There are 2 forms, differing only in the amino acid at position 8: arginine vasopressin is widespread, while lysine vasopressin is found in pigs. Has antidiuretic and vasopressor actions. Used in the treatment of diabetes insipidus. Osmoregulation: The process of regulating water potential in order to keep fluid and electrolyte balance within a cell or organism relative to the surrounding. Counter-current multipliers: Resources used: http://www.livestrong.com/article/75374-renal-dialysis-work-those-kidney/ http://health.howstuffworks.com/medicine/tests-treatment/question17.htm