Kidney stones can develop from minerals or other substances that are found in urine. These can be things like uric acid or calcium salts that settle out of urine to form these kidney stones. Kidney stones can range in size from being pretty small to fairly large.
If a kidney stone is small enough, it'll end up just passing out of the body with the urine. If they're large enough, they can become very painful as they move through the urinary system and can clog up different parts of the urinary system. They may get clogged in a ureter, which connects a kidney to the urinary bladder. At that point, the person would have to go to the doctor and get some sort of treatment to break this kidney stone down into a size small enough to pass. This can be a very painful process and may also cause damage to the lining of ureters.
Urinary tract infections are caused when bacteria from outside the body make their way into the bladder and cause inflammation. They are actually more common in women because they have a much shorter urethra than men, so it's much easier for bacteria to travel up a short urethra and into the bladder than up a very long urethra and into the bladder.
Nephritis is the inflammation of the kidneys, which can be caused by bacterial infections, among other factors, and result in pressure build up around capillaries. Filtration of blood then becomes ineffective. Because of its hard outer covering, the kidney has a hard time swelling if fluid accumulates within it.
Remember that the renal arterioles are very narrow, so blood pressure is relatively high when it enters the glomerulus (just like when you put your thumb over the water stream of a hose, making the spray shoot harder and further). It's this pressure that forces the water and solutes of the blood plasma into the Bowman's capsule for filtration. If there's back-pressure (if there's inflammation of the kidneys pushing back on the pressure from the renal arterioles), the total pressure of the blood plasma on the capillaries of the glomerulus is less. The result is less fluid being forced from the blood into the Bowman's capsule, so filtration is far less effective.
Kidney cancer is a cancer of the kidney, as the name implies. This type of cancer can actually spread very easily through the bloodstream because kidneys filter the blood. If the kidneys have cancer, it can be fairly easy for some of those cancerous cells to basically flow with the blood and implant themselves in another part of the body. Kidney cancer can spread easily throughout the body due to its access to the bloodstream.
Bladder cancer is another cancer that is closely related to the kidneys. Both bladder cancer and kidney cancer are more common in men than they are in women.
Dialysis is a process in which a machine will clean the blood if the kidneys are unable to. If a person has some sort of kidney disorder, where kidneys are not properly functioning, they can't properly filter the blood. Dialysis is the process in which a machine will filter blood for them. A dialysis machine cleans the blood and helps maintain the volume and composition of extracellular fluids.
Consumption of alcohol is another factor that can have an effect on kidney health. Consumption of alcohol will inhibit ADH, which stands for anti-diuretic hormone. This causes the body to lose more water, and as the body loses more water, the concentration of ions will be upset, and balance will be altered. Alcohol causes the kidneys to increase urinary output, which will then lead to dehydration. If a person heavily drinks over a long period of time throughout their life, it can actually lead to much more serious kidney disorders in the future.
Source: THIS WORK IS ADAPTED FROM SOPHIA AUTHOR AMANDA SODERLIND