This system is concerned with removing waste products produced by the body tissues. These wastes are dissolved in blood and passed out as urine. The structures that make up the urinary system are:
The kidneys are dark-reddish, bean-shaped organs located in the loin areas on both sides of the back. Adult kidneys are about 12 cm in length. The right one is usually a few centimetres lower than the left because the liver lies above it. Both kidneys move up and down during expiration and inspiration respectively.
Each kidney contains about 1 million functional units (nephrons). These nephrons do the job of filtering blood and reabsorbing necessary substances from the product of filtration (this is the function taken over by the dialysis machine when the kidney is damaged).
The kidneys are largely responsible for regulating the volume and composition of body fluids. They are primarily concerned with the excretion of many breakdown products, drugs and toxins. In addition, the kidney produces a number of hormones like erythropoietin (for red blood cell production) and renin. It also takes part in vitamin D production.
The ureters, bladder and urethra
Each ureter is 25 cm long. Urine flows through them from the kidneys down into the bladder.
The bladder is an elastic muscular sac, the shape of a 3-sided pyramid when empty and that of a globe when full. It is used for the storage of produced urine for controlled urination.
The urethra is a tube about 10 cm in males and 4 cm in females. It is continuous from the bladder such that urine flows through it to the outside of the body.
Symptoms of Urological Disease
- Pain in the flank, loin or genitals
- Blood in urine
- Little or no urine production
- Excessive urine production
- Increased frequency of urination
- Interrupting night sleep more than once to urinate
- Painful urination
- Urgency of urination
- Involuntary passage of urine
- Difficulty in initiating urination
- Weak urine stream
- Dribbling of urine after urination
- Discharge from the tip of the penis
Pain arising from the urinary tract is a common symptom that is often due to obstruction, infection or cancer. Kidney pain is usually felt in the flank or the loin. When pain arises from obstruction of the ureter (e.g. a stone), discomfort may additionally spread to the testicle or the vulva.
Sudden bladder outflow obstruction presents with severe pain above the pubic bone. However, pain above the pubic bone and genital area most commonly arises from an infection in the lower urinary tract (bladder and urethra). Such pain is frequently accompanied by painful urination or increased frequency of urination.
Kidney tumours (cancers) may cause a dull persistent flank pain.
Blood in urine
Blood in the urine is called Haematuria in medical terminology. It can be present with or without pain and may be occur all the time or intermittently. If visible to the naked eye, it is termed macroscopic or gross haematuria. If detected only by lab tests or using a microscope, it is called microscopic haematuria.
Haematuria may be caused by a disease of the kidney substance itself. It can arise from tumours in the kidney or bladder.
Reduced urine production
Reduced urine production is called oliguria. It is the passage of less than 500 ml of urine per day. Anuria is the complete absence of urine flow.
A reduction in urinary flow rate may be found in healthy people whose fluid intake is low. It may also imply the presence of intrinsic renal disease. Oliguria may result from mechanical obstruction at any level in the urinary system. Anuria and oliguria may be signs of renal failure.
Excessive urine production
High urinary flow rate is called polyuria. There will always be an associated increase in the frequency of urination, and often waking up at night more than once to urinate. Polyuria most commonly results from excessive water intake (beer drinking, for example). Conditions like diabetes and chronic kidney disease or use of some antihypertensive drugs (diuretics) may also cause polyuria.
Increased frequency of urination
Increased frequency of micturition results from polyuria, a reduction in effective bladder capacity, or irritation of the bladder or urethra. The commonest cause of polyuria is excessive fluid intake, whereas reduced functional bladder capacity is seen most frequently in patients with prostate enlargement and obstruction of the bladder outlet. Lower urinary tract infection (cystitis) causes bladder irritation and an increase in urinary frequency. Some patients with neurological diseases, also have frequency of micturition.
Interrupting night sleep more than once to urinate
This is called nocturia. It may be caused by polyuria, or may be due to conditions like kidney damage and sickle cell disease. Taking some antihypertensive drugs (diuretics) in the evening or at night may also cause it.
This is called dysuria. It is a specific form of discomfort arising from the urinary tract in which there is pain immediately before, during or after urination. The urine is often described as ‘burning’ or ‘scalding’, and there is usually associated increased frequency of urination and decreased functional bladder capacity. Infection and cancer of the bladder or urethra are the most important causes.
Urgency of urination, incontinence and bedwetting
Urgency is the loss of the normal ability to postpone urination beyond the time when the desire to pass urine is initially felt. Incontinence is the involuntary passage of urine. In extreme cases, urgency may lead to urge incontinence, in which the desire to urinate cannot be voluntarily suppressed. Stress incontinence, on the other hand, is leakage of urine associated with straining or coughing.
Hesitancy, Slow stream, and terminal dribbling
These symptoms are most frequently seen in elderly men with prostate enlargement. Here the bladder outlet is partially blocked by the enlarging prostate gland, with the result that there is often difficulty in initiating urination (hesitancy), and the maximum achievable urinary flow rate during urination is reduced. Even after urination, some urine still drops and stains the underpants (terminal dribbling). The symptoms are nearly always associated with frequency of urination and nocturia.
This is usually only noticed by men and always requires further investigation. There may be associated symptoms of urethral irritation and the underlying disease is likely to be an inflammation of the urethra, which is often infective and sexually transmitted.