Urinary system
Urinary system | |
---|---|
bladder where it is stored until it exits the body through the urethra (longer in males, shorter in females) during urination | |
Details | |
Identifiers | |
Latin | systema urinarium |
MeSH | D014551 |
TA98 | A08.0.00.000 |
TA2 | 3357 |
FMA | 7159 |
Anatomical terminology] |
The human urinary system, also known as the urinary tract or renal system, consists of the
Urine is formed in the kidneys through a filtration of blood. The urine is then passed through the ureters to the bladder, where it is stored. During urination, the urine is passed from the bladder through the urethra to the outside of the body.
800–2,000 milliliters (mL) of urine are normally produced every day in a healthy human. This amount varies according to fluid intake and kidney function.
Structure
This section's factual accuracy is disputed. (March 2024) |
The urinary system refers to the structures that produce and transport urine to the point of excretion. In the human urinary system there are two kidneys that are located between the dorsal body wall and parietal peritoneum on both the left and right sides.
The formation of urine begins within the functional unit of the kidney, the nephrons. Urine then flows through the nephrons, through a system of converging tubules called collecting ducts. These collecting ducts then join together to form the minor calyces, followed by the major calyces that ultimately join the renal pelvis. From here, urine continues its flow from the renal pelvis into the ureter, transporting urine into the urinary bladder. The anatomy of the human urinary system differs between males and females at the level of the urinary bladder. In males, the urethra begins at the internal urethral orifice in the trigone of the bladder, continues through the external urethral orifice, and then becomes the prostatic, membranous, bulbar, and penile urethra. Urine exits the male urethra through the urinary meatus in the glans penis. The female urethra is much shorter, beginning at the bladder neck and terminating in the vulval vestibule.
Development
Microanatomy
Under microscopy, the urinary system is covered in a unique lining called
Function
The main functions of the urinary system and its components are to:
- Regulate blood volume and composition (e.g. sodium, potassium and calcium)
- Regulate blood pressure.
- Regulate pH homeostasis of the blood.
- Contributes to the production of red blood cells by the kidney.
- Helps synthesize calcitriol (the active form of Vitamin D).
- Stores waste products (mainly urea and uric acid) before it and other products are removed from the body.
Urine formation
Average urine production in adult humans is about 1–2
The first step in urine formation is the filtration of blood in the kidneys. In a healthy human, the kidney receives between 12 and 30% of cardiac output, but it averages about 20% or about 1.25 L/min.
The basic structural and functional unit of the kidney is the
.In the first part of the nephron,
The urinary system is regulated by the
Regulation of concentration and volume
The urinary system is under influence of the circulatory system, nervous system, and endocrine system.
Urination
Urination, also sometimes referred to as micturition, is the ejection of
Clinical significance
Urologic disease can involve congenital or acquired dysfunction of the urinary system. As an example, urinary tract obstruction is a urologic disease that can cause urinary retention.
Diseases of the kidney tissue are normally treated by
Diseases of other bodily systems also have a direct effect on urogenital function. For instance, it has been shown that
Diabetes also can have a direct effect in urination due to peripheral neuropathies, which occur in some individuals with poorly controlled blood sugar levels.[7]
Some cancers also target the urinary system, including bladder cancer, kidney cancer, ureteral cancer, and urethral cancer. Due to the role and location of these organs, treatment is often complicated.[citation needed]
History
The first to examine the ureter through an internal approach, called ureteroscopy, rather than surgery was
See also
- Excretory system
- Major systems of the human body
References
- ^ "The Urinary Tract & How It Works | NIDDK". National Institute of Diabetes and Digestive and Kidney Diseases.
- ^ C. Dugdale, David (16 September 2011). "Female urinary tract". MedLine Plus Medical Encyclopedia.
- ISBN 0-13-981176-1.
- ISBN 0-387-30348-0.
- PMID 7532304.
- PMID 2256104.
- ^ "Peripheral Neuropathy". Patient UK. Retrieved 2014-03-20.
- S2CID 80659370.)
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: Cite journal requires|journal=
(help)CS1 maint: DOI inactive as of April 2024 (link - S2CID 83458685.
- ^ PMID 24348156.
- PMID 21805756.