What are the 3 main components of urine in a healthy person?

Your urinary system, also called the renal system or urinary tract, removes waste from your blood in the form of urine. It also helps regulate your blood volume and pressure, and controls the level of chemicals and salts (electrolytes) in your body's cells and blood. 

What is the urinary system?

Your urinary system prevents waste and toxins from building up in your blood. It also:

• helps regulate your blood pressure
• maintains your body's water balance
• helps keep bones strong and healthy
• controls the levels of chemicals and salts in your blood
• helps make your body's red blood cells

Your urinary system is made up of: 

• 2 kidneys – organs that filter blood to make urine
• the bladder – an organ for storing urine
• 2 ureters – tubes connecting your kidneys to your bladder
• the urethra – a tube connecting your bladder to your body's surface

How does the urinary system work?

Your kidneys work non-stop, with all of your blood passing through them every 5 minutes. 

The urine that collects is a mix of waste and excess fluid. It is carried to your bladder to be stored. Muscles in the bladder wall stay relaxed, so it can expand as it fills. Other muscles work like a dam to keep urine in your bladder until you are ready to go to the toilet. Your brain controls your bladder, signalling it when to hold urine and when to empty. Urinary incontinence is when there is accidental or involuntary loss of urine from the bladder.

To urinate normally, all parts of your urinary tract must work together in proper order. When you are ready to go to the toilet, your bladder outlet muscles (urethral sphincter and pelvic floor) relax and your bladder wall muscles contract. Urine empties from your bladder through your urethra and exits your body. 

What are the common conditions related to the urinary tract?

Urinary tract infection

Urinary tract infections (UTIs) occur when an infection, usually caused by bacteria, enters the urinary tract. The most common types of UTI include:

• cystitis, an infection of the bladder lining, and the most common lower urinary tract infection
• urethritis, an infection of the urethra
• pyelonephritis, an infection of the upper urinary tract, which is very serious because it affects the kidneys

You should see your doctor if you have symptoms of a UTI. 

Kidney stones

Kidney stones develop when waste chemicals in your urine form crystals that clump together. The can cause tremendous pain. It is important to see your doctor if you think you might have a kidney stone.

Urinary retention

Urinary retention, being unable to empty your bladder, can be acute or chronic.

If you can’t pass urine even though you feel the need to, and your bladder is full, this is acute urinary retention. If you feel you might be in retention, go to your nearest emergency department.

People with chronic urinary retention can urinate, but do not completely empty the urine from their bladders. This can be a slow-developing and long-lasting medical condition.

Prostate problems

Because a man's urethra passes through his prostate, swelling or enlargement of this gland can affect his ability to pass urine. This is one of the most common signs of possible prostate problems.

Urethra. This tube allows urine to pass outside the body. The brain signals the bladder muscles to tighten. This squeezes urine out of the bladder. At the same time, the brain signals the sphincter muscles to relax to let urine exit the bladder through the urethra. When all the signals happen in the correct order, normal urination happens.

Urethra. This tube allows urine to pass outside the body. The brain signals the bladder muscles to tighten, which squeezes urine out of the bladder. At the same time, the brain signals the sphincter muscles to relax to let urine exit the bladder through the urethra. When all the signals occur in the correct order, normal urination occurs.

Urine is a liquid produced by the kidneys to remove waste products from the bloodstream. Human urine is yellowish in color and variable in chemical composition, but here is a list of its primary components.

Primary Components

Human urine consists primarily of water (91% to 96%), with organic solutes including urea, creatinine, uric acid, and trace amounts of enzymes, carbohydrates, hormones, fatty acids, pigments, and mucins, and inorganic ions such as sodium (Na+), potassium (K+), chloride (Cl-), magnesium (Mg2+), calcium (Ca2+), ammonium (NH4+), sulfates (SO42-), and phosphates (e.g., PO43-).

A Representative Chemical Composition of Urine

• Water (H2O): 95%
• Urea (H2NCONH2): 9.3 g/l to 23.3 g/l
• Chloride (Cl-): 1.87 g/l to 8.4 g/l
• Sodium (Na+): 1.17 g/l to 4.39 g/l
• Potassium (K+): 0.750 g/l to 2.61 g/l
• Creatinine (C4H7N3O): 0.670 g/l to 2.15 g/l
• Inorganic sulfur (S): 0.163 to 1.80 g/l

Lesser amounts of other ions and compounds are present, including hippuric acid, phosphorus, citric acid, glucuronic acid, ammonia, uric acid, and many others. Total solids in urine add up to around 59 grams per person. Note compounds you ordinarily do not find in human urine in appreciable amounts, at least compared with blood plasma, include protein and glucose (typical normal range 0.03 g/l to 0.20 g/l). The presence of significant levels of protein or sugar in urine indicates potential health concerns.

The pH of human urine ranges from 5.5 to 7, averaging around 6.2. The specific gravity ranges from 1.003 to 1.035. Significant deviations in pH or specific gravity may be due to diet, drugs, or urinary disorders.

Table of Urine Chemical Composition

Another table of urine composition in human men lists slightly different values, as well as some additional compounds:

ChemicalConcentration in g/100 ml urineWater95Urea2Sodium0.6Chloride0.6Sulfate0.18Potassium0.15Phosphate0.12Creatinine0.1Ammonia0.05Uric acid0.03Calcium0.015Magnesium0.01Protein--Glucose--

Chemical Elements in Human Urine

The element abundance depends on diet, health, and hydration level, but human urine consists of approximately:

• Oxygen (O): 8.25 g/l
• Nitrogen (N): 8/12 g/l
• Carbon (C): 6.87 g/l
• Hydrogen (H): 1.51 g/l

Chemicals That Affect Urine Color

Human urine ranges in color from nearly clear to dark amber, depending largely on the amount of water that is present. A variety of drugs, natural chemicals from foods, and diseases can alter the color. For example, eating beets can turn urine red or pink (harmlessly). Blood in the urine may also turn it red. Green urine may result from drinking highly colored beverages or from a urinary tract infection. Colors of urine definitely indicate chemical differences relative to normal urine but aren't always an indication of illness.

Additional Sources

• Putnam, DF. NASA Contractor Report No. NASA CR-1802. July 1971.

View Article Sources

1. Rose, C., A. Parker, B. Jefferson, and E. Cartmell. "The Characterization of Feces and Urine: A Review of the Literature to Inform Advanced Treatment Technology." Critical Reviews in Environmental Science and Technology, vol 45, no. 17, 2015, pp. 1827-1879, doi:10.1080/10643389.2014.1000761

2. Bökenkamp, Arend. "Proteinuria—take a closer look!" Pediatric Nephrology, 10 Jan. 2020, doi:10.1007/s00467-019-04454-w

3. Wonhee So, Jared L. Crandon and David P. Nicolau. "Effects of Urine Matrix and pH on the Potency of Delafloxacin and Ciprofloxacin against Urogenic Escherichia coli and Klebsiella pneumoniae." Journal of Urology, vol. 194, no. 2, pp. 563-570, Aug. 2015, doi:10.1016/j.juro.2015.01.094

4. Perrier, E., Bottin, J., Vecchio, M. et al. "Criterion values for urine-specific gravity and urine color representing adequate water intake in healthy adults." European Journal of Clinical Nutrition, vol. 71, pp. 561–563, 1 Feb. 2017, doi:10.1038/ejcn.2016.269

5. "Red, brown, green: urine colors and what they might mean. Departures from the familiar yellow are often harmless but should be discussed with a doctor." Harvard Health Letter, 23 Oct. 2018. 

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Helmenstine, Anne Marie, Ph.D. "What Is the Chemical Composition of Urine?" ThoughtCo. https://www.thoughtco.com/the-chemical-composition-of-urine-603883 (accessed December 22, 2022).

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