Kidney Disorders

Diabetes Mellitus (Type 1 & 2) Excess sugar in the nephron because inadequate secretion of insulin. Excess sugar provides osmotic pressure which leads to more water secreted and excreted in the urine. As a result, these individuals (if untreated) release large volume of urine As a consequence they are often thirsty and need to replenish lost water

Diabetes Insipidus Destruction of ADH producing cells (regulate water reabsorption) As a result, H2O is not reabsorbed and too much water is lost through urination. As much as 20 L of dilute urine can be produced each day, creating a strong thirst response. Individuals must consume large quantities of water to replenish lost water.

Diabetes Insipidus

Bright’s Disease (Nephritis) Refers to many diseases characterized by the inflammation of the nephrons. Can be caused by toxins (from invading microbes) which destroy blood vessels in the glomerulus This affects the permeability and allows larger molecules such as proteins to pass into the nephron. Since proteins do not usually enter the nephron, there is no mechanism in place reabsorb them As the result, water remains in the nephron and volume of urine output increases.

Kidney Stones Caused by the precipitation of mineral solutes from the blood. Consist mainly of calcium oxalate or calcium phosphate. Stones become lodged in the renal pelvis or may move into the ureter. The formation of kidney stones can be extremely painful. If the stones block fluid flow into the ureter, urine will build up in the kidney causing pain.

Kidney Stones As stones move through the very narrow ureter, the jagged edges can tear the delicate tissues, leading to blood in the urine (however it is not always present) and pain Stones can be removed by surgery or by shock-wave lithotripsy or can be passed with the help of medication to widen the urinary tract. Lithotripsy involves using shock waves to break apart the stones into small fragments that can be passed through urination over the next few days.

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“I passed a kidney stone”

Dehydration Dehydration: when more water leaves the body than enters. Can be the result of exercise, insufficient water intake, diarrhoea, water loss during overheating. A sign of dehydration is darker, more concentrated urine, with a stronger odor due to increased solute concentration Dehydration leads to tiredness, lethargy, increased tissue exposure to metabolic wastes, low blood pressure Body temperature may be affected because inability to sweat.

Overhydration Overhydration: when there is an over-consumption of water, diluting blood solutes. May result from excessive water consumption after exercise without replacing lost electrolytes. Results in the swelling of body cells resulting in headaches and disruption of nerve function.

Treating Kidney Failure If the kidneys are no longer capable of filtering the blood properly and maintaining homeostasis, medical intervention such as dialysis or a transplant is required.

Dialysis Technology DIALYSIS: exchange of substances across a semipermeable membrane. Used to restore proper solute balance to those whose kidneys cannot effectively process bodily wastes. Dialysis machines use principles of diffusion and blood pressure – but unlike a kidney, they cannot perform active transport.

Hemodialysis Dialysis machine is connected to a patient’s circulatory system via a vein. Blood is pumped through a series of dialysis tubes that are submerged in a bath of various solutes with specific concentration gradients. Ex: If the blood is too acidic, HCO3- will move from the bath and into the blood. Urea and other waste solutes are continuously removed. Hormones (that the kidney makes) are also added to the blood.

Peritoneal Dialysis Done through the peritoneal membranes – the lining of the abdominal cavity. A catheter is inserted (permanently) 2L of dialysis fluids are pumped into the abdominal cavity. The cavity membrane will selectively filter wastes from the blood. Urea and other wastes diffuse from the plasma into the peritoneum, and into the dialysis fluid. Waste accumulates in the fluid and can be drained off and replaced several times a day.

Kidney Transplants In cases of kidney failure, if a suitable kidney donor is available, a kidney transplant may be done. The donated kidney can come from a living relative (but most often from a deceased donor) The transplanted kidney is placed in your lower abdomen The new (donated) kidney’s renal artery and renal vein are connected to the iliac artery and vein (the blood vessels in your pelvis)

Kidney Transplants The new kidney’s ureter is connected to the bladder of the patient. The original kidneys are left in place unless they are causing high blood pressure, infections, or are too large for your body. The patient will stay on immunosuppressive drugs for the rest of his/her life to prevent reject organ rejection