THE URINARY SYSTEM Hello and welcome back to InterpreterPrep.com First of all if you're reading this and you've gotten this far it means you really like medical terminology and medical interpreting. There is certainly great potential in you and I congratulate you for staying on board with us! Today, we are going to be covering the URINARY SYSTEM. You may want to review the presentation on the Male Reproductive System after reading this as both body systems have some things in common. The urinary system is composed of: 1) KIDNEYS: which are 2 reddish-brown, bean-shaped organs located one on each side of the vertebral column, in the back part of the abdomen. The RENAL ARTERY brings blood into the kidney. If we remember, in the presentation on the cardiovascular system, we explained that arteries branch out into arterioles and then capillaries. In this case, the renal artery branches out into arterioles which branch out to form these little round capillary balls known as the GLOMERULI in the outer layer of the kidney called the CORTEX. Each glomerulus sits in what's known as Bowman's capsule. The blood that flows in through the glomerulus goes through a clean-up process that begins with: FILTRATION: things like mineral salts, glucose and waste products (like urea and creatinine) are removed from the blood and drip down into the renal tubule. Most of what's filtered can be reused so in the tubule REABSORPTION: takes place and most of the water, mineral salts and nutrients will be returned to the blood. Another thing going on in the tubule is SECRETION: of water, mineral salts, drugs and waste products coming into the tubule. By the time this pre-urine reaches the end of its journey through the tubule, only water, waste products and some remaining mineral salts and acids are left to undergo: EXCRETION: making up that lovely yellow water called URINE. Normally, the larger things like blood cells and proteins are not filtered and remain in the blood.therefore their presence in urine indicates something is not right. The sum of these elements we talked about: Bowman's capsule The glomerulus The tubule... make up the NEPHRON or urine forming unit. Each kidney has millions of microscopic nephrons. The nephrons are to the kidney what the alveoli are to the lungs. Just as the alveoli are where gas exchange takes place, the nephrons are the kidney's functional units where our blood is filtered and converted into the urine. Kidneys make about 1.5 liters of urine per day, 95% of which is water. The inner region of the kidney is called the MEDULLA and is composed of several cone shaped tissues called RENAL PYRAMIDS which contain the collecting tubules. The tip of each pyramid ends in a cup-like urine collection cavity called a CALYX. The urine from each calyx flows into a basin-like central collecting area called the RENAL PELVIS before continuing on down the:
2) URETERS: which are those 2 musculomembranous tubes that carry the urine from the renal pelvis to the bladder. They move the urine along through wavelike contractions called peristalsis thanks to that smooth muscle that's in them. Our next stop on our way down is the: 3) URINARY BLADDER: which is basically a storage tank for urine. Without it we would be constantly urinating. It's a hollow musculomembranous sac located in the pelvis. The bladder can normally hold about 2 cups (16 oz.) of urine until you can get to the nearest restroom. When it's time to void, the bladder contracts, the urinary sphincter relaxes and the urine exits via the: 4) URETHRA: We've already mentioned the urethra in the presentations on the reproductive system. The urethra is a musculomembranous tube that leads from the bladder to the exterior of the body (please do not confuse urethra with ureter!) The external opening of the urethra is called the urinary meatus. In women the urethra handles exclusively urine but in men it's a crossroads for the male reproductive system and the urinary system as the urethra not only handles urine but also carries semen during ejaculation. Because men have a penis they have a longer urethra than women. Now let's talk about: SOME SIGNS OF DISEASE: when there are urinary problems a patient can come in complaining of: 1) PAIN IN THE BACK OR SIDE: which when related to the presence of kidney stones can be very intense and is known as RENAL COLIC 2) PAINFUL URINATION (DYSURIA) 3) FREQUENCY: which is a need to urinate more often than usual. 4) URGENCY: which is a sudden compelling urge to urinate. Need to go NOW! Can't wait! A patient may also come in complaining of: 5) BLOOD IN URINE (HEMATURIA) or say that they've been noticing 6) CLOUDY URINE: this can be due to the presence of pus in urine what doctors call: PYURIA. When a patient gets up to go to the bathroom too many times that's known as: 7) EXCESSIVE NOCTURNAL URINATION (NOCTURIA) 8) There may also be CHANGES IN AMOUNT OF URINE: like too much of it: POLYURIA too little: OLIGURIA when the kidneys just totally shut down and stop making urine: ANURIA SOME DISEASES 1) GLOMERULONEPHRITIS: is the inflammation of the glomeruli and inflammation always affects the function of whatever organ it touches. In this case the glomeruli start having problems filtering the waste products from the blood and we begin seeing increasing levels of waste products in blood. The glomeruli also start letting proteins pass into the tubules and leak into urine. The presence of proteins in urine is called: proteinuria. Edema which is swelling due to an abnormal buildup of fluid in the body can also occur. When we get:
PROTEINURIA + EDEMA NEPHROTIC SYNDROME At other times, blood cells appear in urine and the patient's blood pressure starts going up and when that happens: HEMATURIA + HYPERTENSION NEPHRITIC SYNDROME Glomerulonephritis can cause both of these syndromes and is also one of the main causes of: 2) KIDNEY FAILURE: when kidney failure occurs the kidneys: can't remove the body's waste products and make little or no urine which leads to: WASTE PRODUCTS ACID ELECTROLYTE IMBALANCE also appears. And logically if you are not making much urine then fluid starts to accumulate in the tissues which is known as : EDEMA. Kidney failure can occur all of a sudden ACUTE KIDNEY FAILURE -an example of this would be a child who drinks antifreeze-or it can develop slowly and progressively CHRONIC KIDNEY FAILURE which is what may occur in diseases like diabetes or lupus. When chronic kidney failure gets to the point it requires dialysis it is known as: END STAGE RENAL DISEASE (ESRD) Because levels of urea go up in kidney failure the term UREMIA is often used to describe the signs and symptoms of kidney failure even though the urea itself does not seem to be the cause of the symptoms per se. We mentioned that in kidney failure there are: 3) ELECTROLYTE DISORDERS: the kidney manages our body's mineral salts. MINERAL SALTS (ELECTROLYTES) SODIUM POTASSIUM CHLORIDE. When the kidney fails, potassium in blood may get too high this is known as: POTASSIUM HYPERKALEMIA, or the sodium may get too low, this is known as SODIUM HYPONATREMIA and because the normal kidney activation of vitamin D does not occur, calcium levels can drop, this is known as: CALCIUM HYPOCALCEMIA The kidney also manages the body's ph level. So when it's not working well we get what's known as: 4) ACID-BASE DISORDERS like when there's too much acid in the body the blood's ph level falls ph ACIDOSIS and we get acidosis (sick kidneys can't eliminate or neutralize the body's acid). And on the contrary, when the ph level rises ph ALKALOSIS we get that's known as alkalosis. Normal ph for the human body is 7.4
5) RENAL CELL CARCINOMA: this kidney cancer originates in the cells of the renal tubules. Risk factors for this cancer include smoking and obesity. 6) NEPHROLITHIASIS: Some unfortunate individuals have a tendency to form these little stones -sometimes not so little-made from the dietary minerals in their urine known as KIDNEY STONES aka URINARY CALCULI. The problem with these stones is that they can get lodged in the kidney, the ureters or the bladder. The stones are most frequently made of calcium. If a kidney stone gets stuck in the ureter, that can give way to: 7) HYDRONEPHROSIS: refers to a large, puffy kidney that is full of fluid due to the presence of an obstruction to the flow of urine. This obstruction causes backup of urine which leads to the subsequent dilation of the calyces and the renal pelvis. If untreated it leads to kidney failure. We can also find enlarged kidneys in: 8) POLYCYSTIC KIDNEY DISEASE: which is a genetic disorder characterized by the presence of cysts in the kidney and in other organs. Polycystic kidney disease leads to kidney failure. 9) URINARY TRACT INFECTION (UTI): means that bacteria have made their way up to the bladder and infected it, in which case we get what's called: CYSTITIS = LOWER URINARY TRACT INFECTION If the bacteria are able to continue their journey up the urinary tract and reach the kidneys then we get what's called: PYELONEPHRITIS = UPPER URINARY TRACT INFECTION The infections of the lower tract can be treated with ORAL ANTIBIOTICS but the infections of the upper tract generally require hospitalization and INTRAVENOUS ANTIBIOTICS. Women are more susceptible to having UTI's because they have a shorter urethra so it's a short hike up to the bladder for bacteria like E. COLI and KLEBSIELLA Also, some patients have an abnormal backflow of urine from the bladder up into the ureters called VESICOURETERAL REFLUX- a phenomenon similar to gastroesophageal reflux. Gastric reflux causes esophagitis and ureteral reflux predisposes the patient to getting RECURRENT UTI's which can lead to scarring of the kidneys and kidney failure. 10) BLADDER CANCER: Smoking is a risk factor for bladder cancer so for those of you puffing away, here s another good reason to stop! 11) URINARY RETENTION: is the inability to urinate causing an abnormal, involuntary accumulation of urine in the bladder. This can be due to prostate problems like benign prostatic hyperplasia where the enlarged prostate puts the squeeze on the urethra obstructing the flow of urine. It can also occur without any obstruction due to lesions of the spinal cord or the nerves that go to the bladder muscles a condition known as: NEUROGENIC BLADDER. The opposite of urinary retention is:
12) URINARY INCONTINENCE: here there's a loss of bladder control. The severity of this problem can range from losing a few drops when sneezing (STRESS INCONTINENCE) to just plain wetting oneself when a sudden urge to void appears (URGE INCONTINENCE). More common in females and in the elderly. 13) URETHRITIS: is the inflammation of the urethra commonly caused by germs like gonococcus or chlamydia. Causes a burning sensation when urinating and there may also be purulent discharge from the urinary meatus. SOME DIAGNOSTIC PROCEDURES: the most common one being a: 1) URINALYSIS: which is the physical, chemical or microscopic examination of a sample of urine. The lab tech observes the color and aspect of the urine and takes a look under the microscope to see if there are any blood cells, crystals, mucus or bacteria. The presence of bacteria in urine is known as BACTERIURIA. A dipstick dipped into the urine provides information on its chemical composition indicating the presence of: Glucose (GLYCOSURIA) for example Normally urine does not contain glucose or proteins (just traces), etc. 2) BASIC METABOLIC PANEL (BMP): is a blood test which measures: ELECTROLYTES GLUCOSE and also includes: KIDNEY FUNCTION TESTS: - BLOOD UREA NITROGEN (BUN) - BLOOD CREATININE LEVEL The kidney is in charge of removing nitrogenous waste products-like urea and creatininefrom the blood. Urea is the end product of protein catabolism. Creatinine is a product of muscle catabolism. When the kidney's not working well the levels of BUN and creatinine increase in blood. KIDNEY FAILURE BUN and CREATININE 3) URINE CULTURE: Cultures are done to determine which bacteria or yeast is causing an infection (culture was already explained in detail in second part of the presentation on the respiratory system). 4) 24-HOUR URINE SPECIMEN: sometimes the doctor will request that the patient collect their urine during 24 hours. Used to know daily volume of urine or measure amount of protein lost in urine in 24 hours for example. 5) KUB: a plain X-ray of the abdomen used to assess the Kidneys, Ureters and Bladder (KUB). 6) RENAL ULTRASOUND: is a non-invasive procedure in which sound waves bounce off the kidneys creating a pattern of echoes which are transformed into images by a computer. Ultrasound is silent to the human ear. It is useful to evaluate the size of the kidneys (like in hydronephrosis) or to view kidney cysts or stones.
7) INTRAVENOUS PYELOGRAM (IVP): this is like a KUB but a contrast is injected into the patient's vein. The contrast reaches the kidneys and is excreted in the urine making the urinary tract visible on x-rays. Another way of doing this study is by placing a small catheter in the ureter and then shooting the contrast up into the ureter and renal pelvis instead of waiting for it to drip down with the urine, reason why it's called a RETROGRADE PYELOGRAM 8) CT UROGRAM: is a contrasted CT scan of the urinary tract. 9) RENAL SCAN: the renal scan is a diagnostic test that uses a radioactive tracer. The tracer is injected into a vein and reaches the kidneys which are then scanned by gamma camera which detects the radioactivity coming from the kidneys. A computer then transforms that into 2-D images and provides detailed information about kidney function making it useful to study patients with kidney failure or who have been transplanted The advantage of this study is that it does not carry the risk of toxicity found with contrast. I want to take this opportunity to explain that these tests that involve the injection of a radioactive tracer to then be scanned by gamma camera and produce 2D images have many different names: RADIOISOTOPE SCAN NUCLEAR SCAN RADIONUCLIDE SCAN SCINTIGRAPHY All these terms refer to the same kind of test! 10) RENAL ANGIOGRAPHY: an angiography is a contrasted study of the blood vessels. You can't really see blood vessels without the contrast. Angiography can be used to study the arteries of the legs, heart and brain to name a few. In this case a catheter is passed into the femoral artery in the groin and is guided under fluoroscopic control to the renal artery. Contrast is then injected into the renal artery to make the kidney's blood vessels visible on x-rays. SOME TREATMENTS 1) EXPECTANT THERAPY: this is the decision to wait, it may be what a doctor decides to do in the case of a kidney stone, recommending that the patient drink plenty of water and wait and see if the patient can pass the stone on their own, without any further medical intervention. 2) DIETARY CHANGES: patients with kidney stones are advised to drink plenty of liquid and may be put on a diet, restricting their calcium intake (less milk, cheeses for example) and also restricting their salt intake. These are measures done for the: 3) PREVENTION OF KIDNEY STONES: certain medications can also help reduce the chances of kidney stones forming like:
SODIUM BICARBONATE used to alkalinize urine (because stones have less of a chance of forming in less acidic urine). Diuretics like: CHLORTHALIDONE reduce the excretion of calcium in urine and when there's less calcium in urine there's less of a chance of calcium stones developing. And if the stones can't be prevented and are too large to pass then 4) EXTRACORPOREAL SHOCK WAVE LITHOTRIPSY (ESWL) a medical procedure that uses shock waves to break up kidney stones into small pieces can be used to make it possible to pass them out in the urine. 5) CORTICOSTEROIDS: like prednisone are useful to treat glomerulonephritis for example. 6) QUINOLONES are a group of antibiotics widely used to treat urinary tract infections. CIPROFLOXACIN and LEVOFLOXACIN belong to this group. 7) DIURETICS: FUROSEMIDE (Lasix) may be given to combat edema in patients with nephrotic syndrome. 8) IV THERAPY: is the infusion of liquid substances directly into a vein through an IV LINE to: - correct electrolyte imbalances - replace lost fluids or - as a fast way of administering medications Different fluids are used in IV therapy like: SALINE SOLUTION: which has sodium, chloride and water, things our cells love. I want to clarify that when we add the word NORMAL in front of the term saline solution NORMAL SALINE SOLUTION this means that the concentration of sodium chloride in it is similar to the concentration of sodium chloride found in the body. Then we have DEXTROSE: which is sweeter because it's a glucose solution LACTATED RINGER'S SOLUTION: contains lactate which acts as a ph buffer helping correct metabolic acidosis. These are all transparent solutions that you'll observe in bags, hanging from POLES next to the patient's bed and are commonly referred to as a DRIP. Other times you may see an INFUSION PUMP which is programmable and permits a more precise delivery of fluids with medicines into the patient's vein. 9) FOLEY CATHETER: is a urinary catheter that comes with a balloon on its tip. It is a soft catheter that is passed through the urethra up into the bladder, as we see here, and then the balloon on its tip is inflated so it can't slip back out. Because it is left in place, they call it an indwelling catheter. It goes connected to a DRAINAGE BAG that catches the urine. This way the doctors know exactly how much urine a patient's is making.
10) HEMODIALYSIS: Dialysis removes waste products from the blood and prevents the buildup of potassium, acid and toxic metabolites. It is indicated in patients with ESRD. For hemodialysis to be possible, the blood must exit the body through an artery, pass through the dialysis machine and come back to the body through a vein. And to do that a vascular access must be created which can be done using a graft- a U-shaped tube-that is connected on one end to an artery and to a vein on the other. When it's time for dialysis, lines are placed onto the graft to get the arterial blood out to the dialysis machine, get it cleaned up and then flow back into the vein. At other times another method of dialysis called: 11) PERITONEAL DIALYSIS is used. The advantage here is that it can be done at home avoiding having to schedule dialysis sessions or travel. Here a permanent catheter is placed into the abdomen. A bag of dialysis solution, called dialysate, is passed into the abdominal cavity. The dialysate is designed to attract the waste products in the blood and pull them out through the peritoneum. The dialysate is left in the abdomen for 4-6 hours, after which it must be drained. To do this 2 bags are connected to the patient's catheter. First the waste fluid is removed from the abdomen and drains down to the empty bag below and then fresh dialysate is passed into the abdomen. It's sort of like peeing through a catheter in your belly. The process of filling and draining the abdomen with the dialysate is called exchange and it must be done like 4 times each day. 12) SURGERY: here are the names of a few of the urinary surgical procedures. CYSTOSCOPY: is a diagnostic and surgical endoscopic procedure done to visualize and operate the bladder and also the prostate. URETEROSCOPIC STONE REMOVAL: this is an endoscopic procedure done using a thin scope called a ureteroscope which is used to reach and remove a stone lodged in the ureter. The scope may also be used to break the stone into smaller bits by the use of a laser in the scope. CYSTECTOMY: is the surgical removal of the bladder. NEPHROLITHOTOMY: is a surgical procedure done to remove a stone from a kidney by making a small incision in the flank. Although a scope is used it is different from ureteroscopy in that it is necessary to make an incision in the skin to reach and remove the kidney stones. SIMPLE NEPHRECTOMY: surgical removal of a kidney. RADICAL NEPHRECTOMY: here apart from removing the kidney they also take out the adrenal gland and the regional lymph nodes. The doctors who specialize in diseases of the male reproductive system and the urinary system and do surgery are called UROLOGISTS. They are specialists in the field of UROLOGY. The doctors who treat kidney disease are known as NEPHROLOGISTS. NEPHROLOGY is a branch of INTERNAL MEDICINE therefore nephrologists do not operate. In this lesson we have gone over many terms related to UROLOGY and NEPHROLOGY while we discussed topics like the anatomy and physiology of the URINARY SYSTEM. Signs and symptoms of sickness, diseases, diagnostic procedures and some treatments were also discussed. I hope you've enjoyed this lesson and come away with a better understanding of the fields of UROLOGY and NEPHROLOGY and the terms related to these fields of medicine. Thank you for choosing InterpreterPrep.com