Human Excretion and Kidney Physiology

Inulin is an indicator of GFR because, it is neither reabsorbed into the blood after filtration nor secreted through peritubular capillaries, amount of inulin cleared through the urine is indicative of the amount of plasma filtered by body's glomeruli.

Mine sites are often described as being hotter than hell. The hot ambient temperatures, long days and extended work cycles often experienced by mining workers are sweltering and this causes a gradual increase in the accumulation of dehydration in workers. Dehydration along with the loss of water also cause loss of electrolytes (salts). Electrolytes play a vital role in muscle contraction, nerve reactions and regulating fluid levels. Imbalance of these electrolytes can cause fatigue and muscle weakness, dizziness, nausea and sometimes fainting. Some of the common symptoms for mild to moderate dehydration are thirst, dry mouth, fatigue, tiredness, decreased urination and urination dark in colour, dry skin, headache, dizziness, and lack of concentration. If the symptoms of dehydration are ignored it can escalate to heat exhaustion and heat stroke which can be life threatening. So, it is important for workers to be proactive in preventing dehydration when working in high risk environment like mining.

Artificial kidney (Dialysing unit ) is a machine that is used for filtration of blood in the people whose kidneys are failed or damaged by the process called Dialysis.

Dialysis of kidneys is a process in which the blood is purified with the help of machine. It is done when the Kidneys fail to perform their function of filtering blood and balancing electrolytes and fluid concentration. Due to this,  Dialysis is also referred as Artificial Kidneys. Transplantation is a process in which a damaged organ is replaced by the healthy one. And filteration and diffusion are process that occurs in kidneys as well as other cells of the body. 

The process of filtering the blood by the artificial kidney is known as hemodialysis. It is a method of removing excess water, nitrogenous wastes (urea), toxins from the blood in the patient who is rapidly developing loss of kidney function. It is also called renal replacement therapy. Uraemia is the presence of excess urea in the blood. It may occur due to chronic kidney disease or kidney failure. Hence In uraemia, the artificial kidney is used for removing accumulated waste products like urea by the process called hemodialysis.

The process of filtering the blood by the artificial kidney is known as hemodialysis. It is a method of removing excess water, nitrogenous wastes (urea), toxins from the blood in the patient who is rapidly developing loss of kidney function. It is also called renal replacement therapy. Hence haemodialysis is also called as artificial Kidney.

• Haemodialysis is a process of purifying the blood of a person whose kidneys are not working normally. This type of dialysis achieves the extracorporeal removal of waste products such as creatinine and urea and free water from the blood when the kidneys are in a state of kidney failure. 
• Haemodialysis is one of three renal replacement therapies (the other two being kidney transplant and peritoneal dialysis). An alternative method for extracorporeal separation of blood components such as plasma or cells is apheresis.

Answer is option B i.e. "The dialysis unit has a coiled cellophane tube"
Dialysis is an ‘artificial kidney’ consists of a long coiled cellophane tube immersed in a water bath. The cellophane tube is semi-permeable and allows body waste to diffuse out of the blood into the water bath, while retaining the plasma proteins and blood cells, only the excess amounts of ions and glucose diffuse into the bath from the blood.

Malfunctioning of kidneys can lead to accumulation of urea in blood, a condition called uremia, which is highly harmful and may lead to kidney failure. In such patients, urea can be removed by a process called hemodialysis (artificial kidney). In this procedure, blood drained from a convenient artery is pumped into a dialysing unit after adding an anticoagulant like heparin. The unit contains a coiled cellophane tube surrounded by a fluid (dialysing fluid) having the same composition as that of plasma except for the nitrogenous wastes. The porous cellophane membrane of the tube allows the passage of molecules based on concentration gradient. As nitrogenous wastes are absent in the dialysing fluid, these substances freely move out, thereby clearing the blood. The cleared blood is pumped back to the body through a vein after adding anti-heparin to it. This method is a boon for thousands of uremic patients all over the world.

The process of purifying blood artificially of a person whose kidney is not working is called hemodialysis. In this process, the impure blood is taken to a dialyzer and returned pure to the body. While filtering, the blood flows through tubes made up of a membrane (cellophane) that allows the waste products smaller than the blood cells to pass through it. Passing through the membrane the waste products goes into a dialysis solution called dialysate then out of the machine. The clean and pure blood is carried on through and returned safely to the body.  

Haemodialysis is a method for removing waste products such as creatinine and urea, as well as free water from the blood when the kidneys can not work properly. The mechanical device used to clean the patient's blood is called a dialyzer, also known as an artificial kidney. 

Blood urea nitrogen (BUN) measures the amount of urea nitrogen, a waste product of protein metabolism, in the blood. Urea is formed by the liver and carried by the blood to the kidneys for excretion. Because urea is cleared from the bloodstream by the kidneys, a test measuring how much urea nitrogen remains in the blood can be used as a test of renal function. Diseased or damaged kidneys cause an elevated BUN because the kidneys are less able to clear urea from the bloodstream. In conditions in which renal perfusion is decreased, such as hypovolemic shock or congestive heart failure, BUN levels rise. A patient who is severely dehydrated may also have a high BUN due to the lack of fluid volume to excrete waste products.

Kidney dialysis is a life-support treatment that uses a special machine to filter harmful wastes, salt, and excess fluid from your blood. This restores the blood to a normal, healthy balance. Dialysis replaces many of the kidney's important functions. There are different types of kidney dialysis, including hemodialysis- blood is filtered using a dialyzer and dialysis machine and peritoneal dialysis- blood is filtered inside the body after the abdomen is filled with a special cleaning solution.