The Urinary System Basics
The Urinary System Basics
Peter Loisides (Board Certified Urologist, Saint John's Health Center) gives expert video advice on: What are common causes of urinary problems?; How will my urologist make a diagnosis? and more...
What is a "urologist"?
A urologist is a surgeon who is trained first in general surgery and then for another four years in urological speciality, basically.
What is the "urinary system"?
The urinary system consists of the kidneys, which generate the urine, the ureters, which conduct the urine down from the kidneys into the bladder, and the bladder, which acts as a storage vesicle or reservoir through which the urine is held. The final part of the urinary system is the urethra, where urine passes out into the environment once passage of urine is dictated by the individual.
How does the urinary system work?
Well, of course, the kidneys, the ureters, and the bladder are exactly the same between men and women. The differences exist, actually, once you are downstream from the bladder, where you encounter a prostate in men instead of simply the urethra which conducts the urine in women.
What is "urine", and how is it made?
The urine is made by the kidneys. The purpose of the urine is to excrete acids from the body. The way that the body has been designed is that it's excreted through ammonia, which is converted to urea by your liver. Then, it's allowed to pass into your urine. Urine is a way that the metabolic acids from the body are eliminated.
What are the major functions of the kidneys?
The kidneys can actually perform multiple functions, and are integral in maintaining the right volume of water to keep the body's fluid constant. The kidneys also perform the major function of maintaining blood pressure. The kidneys also secrete hormones which can affect blood pressure. In addition, the kidneys provide a way for the body to eliminate metabolic acids in the form of urea. The final major function of the kidneys is to facilitate the breakdown of hemoglobin in the form of urobilins.
How does the bladder work?
Well the bladder of course is a reservoir, it's a storage vehicle for urine. Its primary function is to keep the urine in a place that is water tight without letting the urea and the waste products be reabsorbed into the body until the individual can find time to empty the bladder. A whole sequence of events occurs when the bladder has filled and a signal is sent to the brain that there's been filling. Basically, the urethra has a sphincter muscle within it; one in women, and two in men--the second one being within the prostrate gland. So the first step is that the brain has signalled that the bladder's full, and the urethra, or urethras, will then relax, and allow opening of the channel, then the bladder will contract, thus expelling urine from the body.
What are the most common urinary diseases?
First of all, in terms of disease processes, of course cancers can affect the entire urinary system along its tract. Stones can form and they commonly do in individuals. Finally, you can also have incontinence issues where leakage in an unexpected fashion occurs.
What tests are used to diagnose a urinary disease?
Well, the primary test in testing the urinary system for urinary disease is the urine analysis. It's done routinely; it's very simple to do. Typically it can be done with a test strip in the office setting, but more formally the urine is spun down and is analysed under the microscope. We look for various things including white blood cells (which are the equivalent of pus), the presence of bacteria through its metabolic by-products; nitrites, and we can detect the presence of blood in the urine as well. We also look at some other things including the pH and the concentration, and they're helpful to utilise as well.
What are common causes of urinary problems?
Common causes of urinary problems may include ageing, illnesses, and trauma to the urinary system. There are environmental influences on the urinary system as well, including cigarette smoking.
How will my urologist make a diagnosis?
Well, again, the urinalysis is key to starting the process. Then, finally we could use a whole host of other tests, including cystoscopic evaluations which include fibre-optic studies; placing the scope within the system to investigate the anatomy. We can use functional studies, like urodynamics which assess not only the storage of urine into the bladder, but also the emptying phase of urination. We can use radiographic studies as well, like CAT scans (or CT scans as we refer to them), as well as ultrasound.