The urinary system's function is to filter blood and create urine as a waste by-product. The organs of the urinary system include the kidneys, renal pelvis, ureters, bladder and urethra. The body takes nutrients from food and converts them to energy.
How does the urinary system work? The urinary system's function is to filter blood and create urine as a waste by-product. The organs of the urinary system include the kidneys, renal pelvis, ureters, bladder and urethra. The body takes nutrients from food and converts them to energy. After the body has taken the food components that it needs, ...
Kidneys - paired organs that filter the blood and produce urine; reabsorb useful substances (electrolytes, amino acids), eliminates waste into urine (from food, medications, toxins) Ureters - tubes that transport urine from the kidneys to the urinary bladder.
Urine is stored in the bladder until the urinary nervous system releases the contents through the urethra and out of the body. The passing of urine is known as micturition or urination. The urinary system is split into the upper and lower urinary tract. The former consists of the kidneys and ureters, the latter of the bladder and urethra.
The urinary system's function is to filter blood and create urine as a waste by-product. The organs of the urinary system include the kidneys, renal pelvis, ureters, bladder and urethra.
The kidney and urinary systems help the body to eliminate liquid waste called urea, and to keep chemicals, such as potassium and sodium, and water in balance. Urea is produced when foods containing protein, such as meat, poultry, and certain vegetables, are broken down in the body. Urea is carried in the bloodstream to the kidneys, where it is removed along with water and other wastes in the form of urine.
Two sphincter muscles. These circular muscles help keep urine from leaking by closing tightly like a rubber band around the opening of the bladder. Nerves in the bladder. The nerves alert a person when it is time to urinate, or empty the bladder. Urethra.
Two ureters. These narrow tubes carry urine from the kidneys to the bladder. Muscles in the ureter walls continually tighten and relax forcing urine downward, away from the kidneys. If urine backs up, or is allowed to stand still, a kidney infection can develop. About every 10 to 15 seconds, small amounts of urine are emptied into the bladder from the ureters.
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.
Release hormones to regulate blood pressure. Control production of red blood cells. The kidneys remove urea from the blood through tiny filtering units called nephrons.
Each nephron consists of a ball formed of small blood capillaries, called a glomerulus, and a small tube called a renal tubule. Urea, together with water and other waste substances, forms the urine as it passes through the nephrons and down the renal tubules of the kidney. Two ureters.
From the urinary bladder, the urine is released into the urethra with the initial portion being in the peritoneal cavity. The male urethra is longer than the female urethra and sub-divided into the pelvic urethra, prostatic urethra, and penile (spongy) urethra. To unlock this lesson you must be a Study.com Member.
The left and right kidneys are reddish-brown in color and bean-shaped. They are located in the retroperitoneal cavity with the left kidney being more cranial than the right kidney. Each is approximately 4.5 inches in length. Each kidney connects to its own ureter, which is a small tubular organ with a layer of muscle surrounding it that helps propel the urine into the urinary bladder. The ureters, urinary bladder, and a small portion of the urethra (where it connects to the urinary bladder) are located in the peritoneal cavity.
The kidneys reabsorb several ions, amino acids, and glucose that filter through these organs. For this reason, detection of glucose and/or protein in the urine may indicate potential disease (s), such as diabetes or kidney disease/failure.
The kidneys are stimulated to produce renin in response to low blood pressure and decreased sodium ion concentration. Renin is an enzyme produced by juxtaglomerular (JG) cells in the kidneys that converts angiotensinogen from the liver to angiotensin I (Ang I). Angiotensin converting enzyme (ACE), produced by the lungs, then converts Angiotensin I to Angiotensin II (Ang II). Ang II increases blood pressure and stimulates the release of aldosterone from the adrenal cortex. Aldosterone increases sodium ion reabsorption by the distal convoluted tubules in the kidney, which further increases blood pressure.
The main urinary system function is to filter the blood of excess water, salts, and waste products, temporarily store these within a reservoir, and intermittently expel these products from the body.
How the urinary system works is relatively simple, although the supplementary roles of the kidneys can be complex .
The image below shows the stages of micturition and the muscles involved, namely the detrusor muscle of the urinary bladder, the internal urethral sphincter, and the pelvic floor muscle which surrounds the external sphincter.
These only relax during micturition and otherwise prevent urine from constantly leaking out. The internal sphincter is an involuntary muscle; the external sphincter is voluntary. The urinary bladder is lined by a thick mucosa which forms folds when the bladder is empty but opens out as the bladder fills and expands.
The triangular shaped bladder is a large muscle into the top of which the two ureters empty the urine. Under the bladder, close to where it connects to a single urethra, lie two circular sphincters – internal and external. These only relax during micturition and otherwise prevent urine from constantly leaking out. The internal sphincter is an involuntary muscle; the external sphincter is voluntary. The urinary bladder is lined by a thick mucosa which forms folds when the bladder is empty but opens out as the bladder fills and expands.
Because the hollow areas are narrow, ureters can become blocked by debris such as salt crystals which have stuck together to create urinary stones. Complete blockage in one tube causes high pressures and urine buildup in its attached kidney and requires emergency surgery before permanent damage is done.
Ureters are two narrow but relatively long tubes (approximately 25 – 30 cm) which leave the kidneys and enter the urinary bladder.