The Urinary system, also known as the renal system, is a group of organs in the body involved in eliminating wastes from the body through the process of filtration.

FUNCTIONS OF THE URINARY SYSTEM:

• Formation of urine.
• Elimination of urine.
• Removal of waste product from the body (urea and uric acid)
• Regulation of electrolyte balance (sodium, potassium and calcium)
• Maintain a steady acid – base homeostasis. Helps in the regulation of pH of the blood. Blood pH is controlled by maintaining the concentration of Carbonic acid (controlled by the Respiratory System) and Sodium Bicarbonate (controlled by kidneys). Carbonic acid and Sodium Bicarbonate form the most important buffer systems that maintain a relatively constant plasma pH.
• Helps in production of Red Blood Cells (RBC). The kidneys produce erythropoietin that helps produce red blood cells).
• Helps in maintaining blood pressure. The kidneys produce renin (a hormone important in regulating blood pressure).

 

PARTS OF URINARY SYSTEM AND THEIR FUNCTIONS:

1). KIDNEYS (enclosed in a renal capsule)

• Nephron (consists of Glomerulus and Tubules) – is the functional unit of the kidney.
•  Medulla, Cortex, and Papillary Ducts – are the non-functional parts of the kidney.
• Glomerulus (enclosed in Bowman’s Capsule) – helps in filtering of fluids out of blood.
• Bowman’s Capsule – collects the fluids or waste products from Glomerulus.
• Tubules – are the Proximal Convulated Tubule, Henle’s loop, Distal Convulated Tubule and Collecting Duct. The fluid or waste filtered from the blood is converted into urine in the tubules.

      Functions of Kidneys:

• Kidneys filter the blood.
• The kidneys excrete wastes.
•  Kidneys regulate the balance of electrolytes.
•  Kidneys control the body’s fluid balance.

2). URETER   

• The ureters are narrow tubes measuring up to 18 inches long, that extend from the kidneys to the urinary bladder. There are two ureters, one attached to each kidney.
• The function of the ureters is to transport urine from the renal pelvis of the kidneys to the urinary bladder for storage before disposal by urination.
  

 3). BLADDER

• The urinary bladder is pear shaped, muscular organ that is located in the lower abdominal region, above and behind the pubic bone.
• It is the organ that collects and stores urine excreted by the kidneys before it is expelled by urination.
• Total capacity of the urinary bladder is 700 ml to 1 liter.

4). URETHRA 

• The urethra is the tube that connects the urinary bladder to the genita through which urine is eliminated from the body.
• Male Urethra – is 8 inches long, from the bladder to the tip of the penis. It is longer than the female Urethra. The male urethra serves as an exit for urine and for releasing semen during ejaculation.
• Female Urethra – is 2 inches long. Because female urethra is shorter than the male urethra, it is more prone to get infections from bacteria in the vagina.  It serves solely for urinary elimination.

FILTRATION takes place in the kidneys, this happens, at the “Bowman’s Capsule” or “Glomerulus“. This is where the waste is filtered out from the blood. The large pressure of blood flowing in the glomerulus forces the waste products out.

FILTRATION PROCESS

BLOOD ——>Kidneys —–> Nephron —–> Glomerulus (filters fluid out  from the blood)—-> Filtrates moves and collected by Bowman’s Capsule——> fluid and waste products converted in the form of  URINE  at the tubules—–> Proximal Convulated Tubule—–> Descending Loop of Henle—–> Ascending Loop of Henle—> Distal Convoluted Tubule—> Collecting Duct—-> papillary duct——> minor calyce—-> major calyce—-> urine moves to the —–>  Renal pelvis—–> urine passes thru the—–> Ureters—–> empties into—-> Urinary bladder for storage ( total capacity of the bladder is 700 ml to 1 liter)—–> expelled via—–> Urethra —–> External Urethral Orifice —–> URINATION (peeing)

URINARY SYSTEM DISORDER:
An injury or damage to any organs or parts of the urinary system can impair the entire process of elimination, thus leading to a number of health problems. .

Anuria – Defined as a urine output of less than <100 ml of urine in a 24 hour period. Anuria is often caused by failure in the function of kidneys, or obstruction due to presence of kidney stones or lumps.

Cystitis – Inflammation of the bladder, most of the time caused by bacterial infection, and it is commonly called UTI.

Cystolithiasis – Urinary stones in the bladder.

Dysuria (painful urination) – Pain or discomfort during urination that maybe caused by an infection that includes UTIs.

Interstitial cystitis (IC) – Characterized by a feeling or need to urinate with urgency or frequency, and most of the time accompanied with pelvic pain. It is a chronic bladder condition of unknown cause which can make the bladder less elastic, thus  causing the bladder to be unable to hold as much urine.

Kidney Failure – Also called renal failure – is a condition in which the kidneys are unable to sufficiently remove waste products from the blood.

• Acute Kidney Failure (AKF) or Acute Renal Failure (ARF) – sudden loss of kidneys’ ability to remove waste and help balance fluids and electrolytes in your body. Symptoms of acute kidney injury may include: 1). little or absence of urine when you try to urinate. 2). Swelling, in your legs and feet. 3). Loss of appetite. 4). Nausea and vomiting. 5). Disorientation, anxiousness and restlessness.  6). Presence of flank pain
• Chronic Kidney Failure (CKD) or Chronic Renal Failure (CRF) – is a condition in which there is a progressive loss of kidney function. It slowly gets worse over time. It may progress so slowly that no symptoms appear until the kidney function loses almost 90% of its capacity. The final stage of chronic kidney failure is referred to as end-stage renal disease (ESRD) in which the kidneys are no longer capable of filtering wastes and excess fluids from the body, thus requiring the patient to go on dialysis or a kidney transplant.

Kidney Stone – Clumps of hard deposits made of mineral and acid salts that can be found in the urinary tract. Kidney stones can cause flank pain, as well as blood in the urine. A small stone may pass on its own during urination, causing little or no pain. A bigger kidney stone can cause blockage along the urinary tract, obstructing the flow of urine, thus leading to severe pain or bleeding.

Nephrolithiasis – Urinary stones in the kidney.

Nocturia – Excessive urination at night.

Oliguria or hypouresis – The decreased output of urine (< 400 ml of urine in 24 hours).

Polycystic kidney disease (PKD) – Cluster of cysts formed in your kidneys. Cysts are round sacs containing water-like fluid that may lead to cystic rupture, infection, formation of scar tissue and damaged nephrons. Common complications of PKD are High Blood Pressure and Kidney failure.

Polyuria – A condition defined as excessive or abnormally large volume of urine over 24 hours.  Sometimes referred to as frequent urination.

Prostatitis – Swelling and irritation of the prostate gland. Symptoms include urinary urgency and frequency, pelvic pain and painful urination. The condition may be: 1) bacterial prostatitis when the infection is caused by a bacteria or 2) non bacterial prostatitis when the ongoing infection is not caused by a bacteria.

Proteinuria also referred as albuminuria – Presence of abnormal amount of protein in the urine. Proteinuria is a sign of chronic kidney disease (CKD).

Pyuria – is a condition where there is a presence of white blood cells (WBC) or pus cells in the urine which may be due to an infection that includes UTIs.

Urinary Tract Infection (UTI) – Occurs when bacteria enter the urinary tract and can affect the urethra, bladder or even the kidneys.  UTIs are more common in women, for the following reasons 1) Women’s urethra is much shorter than a man’s, making it easier for bacteria to get into the bladder. 2) Women’s urethra is closer to her anus than a man’s is, thus making it easier for bacteria to get into her urethra and cause an infection. But UTIs can also occur in men. UTIs are typically treated with antibiotics. If the infection is not treated promptly, the infection can spread further as the bacteria move up from the bladder, the ureters up to the kidneys, thus causing kidney infection which becomes a serious condition.

Urinary Retention – Also referred as ischuria– is the inability to urinate or  inability to empty the bladder. This condition occurs when urine does not leave the bladder normally due to obstructive cause (like kidney stones) or non-obstructive causes (weak bladder muscle and nerve problems).

Urinary Incontinence – Involuntary or unintentional urination which happens when urine leaks out before you can get to a bathroom. Urinary incontinence can be caused by pregnancy, childbirth, menopause, stroke, diabetes, brain injury, infection, nerve damage, prostate condition, caffeine and alcohol. Incontinence occurs when the bladder muscles suddenly contract or the sphincter muscles are too weak to contract to hold back urine.

Urolithiasis – Condition where urinary stones or calculi are formed or present  in the urinary tract  system.

Ureterolithiasis – Urinary stones in the ureter.

 

DIAGNOSTIC TEST FOR RENAL SYSTEM DISORDER:

1. Renal Ultrasound  or Ultrasound of the Kidney.
2. Duplex Doppler Study or Renal Angiogram.
3. Kidney Biopsy.
4. Blood Creatinine Test.
5. Blood Urea Nitrogen (BUN) Test.
6. Urinalysis.
7. Computed Tomography (CT) and Magnetic Resonance Imaging (MRI).
8. KUB – Kidneys, Ureters and Bladder radiograph.

 

*** Many types of Urinary System Disorders can be prevented by following a healthy lifestyle.