Dialysis is a procedure that replaces some of the kidney’s normal functions and is performed when a person’s own kidneys can no longer function adequately to maintain life.

Description

Treatment with dialysis is necessary when a person experiences kidney failure, usually when more than 95 percent of normal kidney function is gone in both kidneys.

Dialysis can keep your body in balance, like healthy kidneys, by:

1)        Removing waste products, including salt, and excess fluids that build-up in the body

2)        Maintaining a safe level of blood chemicals in the body, such as potassium, sodium and chloride

3)        Controlling blood pressure

Types

There are two types of dialysis, which are:

·         Hemodialysis

·         Peritoneal dialysis

Hemodialysis

Hemodialysis means “cleaning the blood” – and that is exactly what this treatment does. Blood is circulated through a machine which contains a dialyzer (also called an artificial kidney). The dialyzer has two spaces separated by a thin membrane. Blood passes on one side of the membrane and dialysis fluid passes on the other. The wastes and excess water pass from the blood through the membrane into the dialysis fluid, which is then discarded. The cleaned blood is returned to your bloodstream.

Peritoneal Dialysis

In peritoneal dialysis, the blood is cleaned inside the body in the abdomen in the peritoneal cavity, which is lined by a thin membrane called the peritoneum that surrounds the intestines and other internal organs. This cavity is filled with dialysis fluid that enters the body through a permanently implanted catheter. Excess water and wastes pass through the peritoneum into the dialysis fluid, which is then drained from the body and discarded. The process is repeated from three to five times a day. This treatment can be performed without assistance, either at home or at work.

The wastes in your blood come from the normal breakdown of active tissues and from the food you eat. Your body uses the food for energy and self-repair. After your body has taken what it needs from the food, waste is sent to the blood. If your kidneys did not remove these wastes, the wastes would build up in the blood and damage your body.

The actual filtering occurs in tiny units inside your kidneys called nephrons. Every kidney has about a million nephrons. In the nephron, a glomerulus—which is a tiny blood vessel, or capillary—intertwines with a tiny urine-collecting tube called a tubule. A complicated chemical exchange takes place, as waste materials and water leave your blood and enter your urinary system

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In the nephron (left), tiny blood vessels intertwine with urine-collecting tubes. Each kidney contains about 1 million nephrons

The kidneys remove wastes and extra water from the blood to form urine. Urine flows from the kidneys to the bladder through the ureters.

The Excretory System is the system which expells the waste which your body doesn’t need. Organs which are involved in the excretory system include the lungs, sweat glands and the rectum, however, the kidneys are the primary excretory organ. The skin is another part of the system, containing sweat that help regulate the concentration in one’s body while also keeping him or her cool. The liver is a vital part of the excretory system, and the human body. It regulates glycogen storage, plasma protein synthesis, and drug detoxification. The liver secretes bile, a base used for breaking down fats. Therefore, it helps get rid of unneeded wastes in the body. Bile is a substance secreted by the liver and used for breaking down fats, ethanol, and acidic wastes.

We aim to help you to: -

• understand more about kidney dialysis
• describe the two main forms of dialysis (hemodialysis and peritoneal dialysis)
• discuss possible risks involved
• provide dietary information for renal failure patients
• provide you with useful links to some major charities and other organisations assisting kidney failure patients, and news about those carrying out research into kidney diseases in general.
• and include breaking news of interest to those with renal problems.

We aim to present you with useful information about dialysis in straightforward language, but with enough medical terms to help you understand what your doctor is saying. Don’t be afraid to ask your doctor to explain any medical terms used – don’t sit there confused and worried, ASK, it’s your right to be told what is involved and what the medical terms mean.

Kidney failure need not be the end of your active life. In fact dialysis can be a new beginning, making life more bearable, and extending it considerably, compared to a life without dialysis. While your work will be affected to some extent, as you have to allow for your regular treatment, you are still capable of working.

Many organisations and authors produce useful booklets to help you understand more about dialysis, so we also recommend you read these for more information. The more high quality information you have to work from, the easier you will find it to handle any problems you may have during your treatment.

When it comes to dialysis, remember you have a choice of the type of treatment you receive. Hemodialysis (also called haemodialysis) works more quickly than peritoneal dialysis, so it only needs to be done in short sessions, typically three times a week. Peritoneal dialysis is a simpler process, but needs to be performed several times every day. One form of peritoneal dialysis has the advantage that trips away do not require any special planning, unlike hemodialysis.

While we strive to give you accurate kidney dialysis information, we always recommend you listen to your doctor and follow their advice. They know all your renal case details.

Some Basic Information:

The liver is the biggest internal organ in the entire body. The liver exists in all living vertebrates and in some other animals. Its main functions are Detoxification, the decomposition of red blood cells and glycogen storage. It is also used significantly in the metabolism. It is on the right habd side of the abdomen, below the diaphram. The liver is an almost triangular shape and is a brown/red colour with some pink on it. As well as it being the largest organ it is also the largest gland. The liver weighs between 1.4-1.6kg. It has a soft spongy texture and is roughly the sze of a rugby ball.

The liver produces an alkaline substance called bile which aids heavily in the digestive process.

The liver processes blood (for nutrients and bi-products of digestion) from the hepatic prortal vein. The blood has come from several organs including the spleen, pancreas, the intestines and stomach.

The liver is one of the only organs in the human body which is capable of regenerating itself. As long as 1/4 of the liver remains, it can regenerate to it full self again. And only 1/4 of the liver is actually needed to live.

Bile imn the liver is used to aid digestion. Bile is collected in the Bile Canaliculi. These then join together in order to create bile ducts. If bile is not automaticaly needed, it is collected and stored in the gal bladder.

            

How a patient is feeling and blood tests determine when it is necessary to begin dialysis. Some patients do not need to start until some time – occasionally years – after diagnosis. But even if this is the case, they need to know in advance about the different options available, because they should have a choice about which method of dialysis they use.

There are two different kinds of dialysis – haemodialysis, where the blood is cleaned outside the body via a machine, and Peritoneal dialysis, where the cleaning is done inside the body. Occasionally, there may be medical reasons to prefer one sort of dialysis to another – this is something to discuss with your doctor.

Human homeostasis is the property to regulate the internal environment of the body, as to maintain
constant condition for all the body.
Humans are regulators, they try to maintain constant conditions, e.g. temperature.
The main contributor to homeostasis are the kidneys. Kidneys can regulate homeostasis in 5 different
ways:

1. Regulation of blood water levels
2. Reabsorption of substances into the blood
3. Maintenance of salt and iron levels in the blood
4. Regulation of blood pH
5. Excretion of urea and wastes

 Thermoregulation

 Thermoregulation is an important aspect of human homeostasis. Heat is mainly produced by the liver. Humans have been able to adapt to a great diversity of climates. High temperatures pose serious stresses for the human body, placing the person in great danger of injury or even death. In order to deal with these conditions, humans have developed many modes of adaptation.

The skin assists in homeostasis. It does this by reacting differently to hot and cold conditions so that the inner body temperature remains constant. Sweating is the primary mode by which humans attempt to lose excess body heat.

A lot of diseases result from a “homeostasis imbalance”. There is a large range of diseases, for example:

• Diabetes
• Dehydration
• Hypoglycemia
• Gout
• Or any disease resulting in a toxin in the blood

The liver is the largest organ in an animal’s body but it is only present in those with a backbone .It plays a major role in metabolism and has a number of functions in the body, including glycogen storage, decomposition of red blood cells, plasma protein synthesis, and detoxification. The liver is also the largest gland in the human body. It lies below the diaphragm in the thoracic region of the abdomen. It produces bile, an alkaline compound which aids in digestion, via the emulsification of lipids. It also performs and regulates a wide variety of high-volume biochemical reactions requiring very specialized tissues. The adult human liver normally weighs between 1.4 – 1.6 kilograms and it is a soft, pinkish-brown, triangular organ. The splenic vein joins the inferior mesenteric vein, which then together join the superior mesenteric vein to form the hepatic portal vein, bringing venous blood from the spleen, pancreas, stomach, small intestine, and large intestine, so that the liver can process the nutrients and biproducts of food digestion.

The hepatic veins of the blood can be from other branches such as the superior mesenteric artery.

The portal venules & the hepatic arterioles enter approximately one million identical lobules acini, likened to and changes in the size of chylomicrons lipoproteins of dietary origin brought about by the quantity & types of food fats.

Approximately 60.5% to 80% of the blood flow to the liver is from the portal venous system, and 1/4 is from the hepatic artery.

The bile produced in the liver is collected in bile canaliculi, which merge to form bile ducts.

These eventually drain into the right and left hepatic ducts, which in turn merge to form the common hepatic duct. The cystic duct (from the gallbladder) joins with the common hepatic duct to form the common bile duct.

Bile can either drain directly into the duodenum via the common bile duct or be temporarily stored in the gallbladder via the cystic duct. The common bile duct and the pancreatic duct enter the duodenum together at the ampulla of Vater.

The branchings of the bile ducts resemble those of a tree, and indeed the term “biliary tree” is commonly used in this setting

The liver is among the few internal human organs capable of natural regeneration of lost tissue; as little as 25% of remaining liver can regenerate into a whole liver again.

This is predominantly due to the hepatocytes acting as unipotential stem cells (i.e. a single hepatocyte can divide into two hepatocyte daughter cells). There is also some evidence of bipotential stem cells, called ovalocyte, which exist in the Canals of Hering. These cells can differentiate into either hepatocytes or cholangiocytes (cells that line the bile ducts). The various functions of the liver are carried out by the liver cells or hepatocytes.

• The liver produces and excretes bile (a greenish liquid) required for emulsifying fats. Some of the bile drains directly into the duodenum, and some is stored in the gallbladder.
• The liver performs several roles in carbohydrate metabolism:
  • Gluconeogenesis (the synthesis of glucose from certain amino acids, lactate or glycerol)
  • Glycogenolysis (the breakdown of glycogen into glucose) (muscle tissues can also do this)
  • Glycogenesis (the formation of glycogen from glucose)
  • The breakdown of insulin and other hormones
• The liver is responsible for the mainstay of protein metabolism. For instance, the liver can convert lactic acid to alanine.
• The liver also performs several roles in lipid metabolism:
  • Cholesterol synthesis
  • The production of triglycerides (fats).
• The liver produces coagulation factors I (fibrinogen), II (prothrombin), V, VII, IX, X and XI, as well as protein C, protein S and antithrombin.
• The liver breaks down haemoglobin, creating metabolites that are added to bile as pigment (bilirubin and biliverdin).
• The liver breaks down toxic substances and most medicinal products in a process called drug metabolism. This sometimes results in toxication, when the metabolite is more toxic than its precursor.
• The liver converts ammonia to urea.
• The liver stores a multitude of substances, including glucose (in the form of glycogen), vitamin B12, iron, and copper.
• In the first trimester foetus, the liver is the main site of red blood cell production. By the 32nd week of gestation, the bone marrow has almost completely taken over that task.
• The liver is responsible for immunological effects- the reticuloendothelial system of the liver contains many immunologically active cells, acting as a ‘sieve’ for antigens carried to it via the portal system.
• The liver produces albumin, the major osmolar component of blood serum.

Currently, there is no artificial organ or device capable of emulating all the functions of the liver. Some functions can be emulated by liver dialysis, an experimental treatment for liver failure.

This is going to be your blog page about the Excretory System. You are going to research and post blogs about one of these 4 topics:

1. The Excretory System in general – structure and function of its components

2. The Liver – structure and function

3. Homeostasis – what is it and how is it achieved

4. Dialysis and Kidney Transplants – what are they and their advantages and disadvantages

 Good luck!!

Mr Thompson