Urinary system

Your body makes pee to stay healthy.

It helps clean your blood. Two small parts called kidneys do this work. The kidneys filter your blood to make pee. This helps keep the right amount of water in you. The pee travels through small tubes. It goes into a small bag called a bladder. The bladder holds the pee for you. Then the pee leaves your body.

Most people make a lot of pee every day. How much water do you drink?

Your body has a special way to stay clean. This is the urinary system. It helps remove waste from your blood. It also helps control your blood pressure.

The system has a few main parts. First, you have two kidneys. These organs filter your blood. Inside each kidney are tiny units called nephrons. These nephrons work to clean the blood. They keep the good things like water and sodium. They let out the waste as urine.

Next, urine travels through two tubes called ureters. These tubes carry urine to the bladder. The bladder is a small bag that holds urine. When the bladder is full, you pee. Urine leaves the body through a tube called the urethra. In males, this tube is long. In females, it is much shorter.

Healthy humans make a lot of urine. People make about 800 to 2,000 milliliters every day. This amount can change. It depends on how much water you drink. It also depends on your health.

Your body has a clever way to stay clean and balanced. This is the work of the urinary system. It is a key part of the larger excretory system in vertebrates. This system does many important jobs at once. It removes waste like urea and uric acid from your body. It also helps control your blood pressure and blood volume. The system even helps keep your blood pH at the right level.

The way it works is a step-by-step process. It all starts in the kidneys. Each kidney has tiny functional units called nephrons. These nephrons filter your blood to regulate water and sodium. First, a part called Bowman's capsule filters the blood. This creates a liquid called filtrate. The kidney then reabsorbs about 99% of that liquid. The remaining 1% becomes the urine you know.

Urine follows a very specific path once it is made. It flows through collecting ducts in the kidney. These ducts join to form the minor and major calyces. These then lead to the renal pelvis. From there, the ureters carry the urine to the bladder. The bladder is a storage bag for waste. Finally, urine leaves the body through the urethra.

There are many interesting facts about this system. A healthy human makes 800 to 2,000 milliliters of urine daily. This can change based on how much you drink. Some people produce more than 2.5 liters, called polyuria. Others produce very little, which is called oliguria. The kidneys receive about 20% of your blood flow. This averages about 1.25 liters every single minute.

You can think of the system like a water filter. Just as a filter cleans water, nephrons clean your blood. The system also uses hormones to manage its work. For example, aldosterone helps regulate your blood pressure. Another hormone called antidiuretic hormone helps your body retain water. This keeps you from getting too thirsty. Even your brain helps control when you go to the bathroom.

The urinary system, also known as the renal system, is a vital part of the vertebrate excretory system. It serves several critical roles in maintaining the body's internal balance. The system eliminates waste products like urea and uric acid from the body. It also regulates blood volume and blood pressure. Furthermore, it controls the levels of electrolytes, such as sodium and potassium, and metabolites. The system even helps maintain blood pH homeostasis, which is the stable balance of acidity.

To understand how this works, we must look at the kidneys. Each kidney contains thousands of tiny functional units called nephrons. The process begins with blood filtration in the nephrons. Blood enters the kidney through the renal arteries. Inside the nephron, a structure called Bowman's capsule filters the blood. This creates a liquid called filtrate. This filtrate contains water, ions, and small molecules. However, larger items like proteins and blood cells cannot pass through the membrane. The amount of filtrate produced every minute is known as the glomerular filtration rate, or GFR. In a healthy human, the GFR is about 180 liters per day.

After filtration, the body must reclaim what it needs. About 99% of the filtrate is reabsorbed as it moves through the nephron. The remaining 1% becomes the actual urine. The urine follows a specific path through the kidney's anatomy. It flows through collecting ducts, which then join to form minor calyces. These join to form major calyces, which eventually lead to the renal pelvis. From the renal pelvis, the ureters transport the urine to the urinary bladder. The bladder stores the waste until it is time for urination.

This complex process is regulated by the endocrine system through various hormones. One important hormone is aldosterone. Aldosterone acts on the distal tubules and collecting ducts of the nephron. It increases the reabsorption of sodium from the glomerular filtrate. Because sodium retention causes water retention, this helps increase blood pressure and volume. Another key hormone is antidiuretic hormone, also called vasopressin. This hormone increases water reabsorption in the collecting ducts. It does this by inducing the translocation of aquaporin-CD water channels in the cell membranes.

The anatomy of the urinary tract differs slightly between males and females. Both sexes use the bladder and ureters. However, the urethra, which carries urine out of the body, varies in length. In males, the urethra is longer and passes through several sections. It includes the prostatic, membranous, bulbar, and penile urethra. It ends at the urinary meatus in the glans penis. In females, the urethra is much shorter. It begins at the bladder neck and ends in the vulval vestibule.

Medical professionals monitor urine production closely to assess health. Healthy humans produce between 800 and 2,000 milliliters of urine daily. This amount can vary based on hydration and health. An adult may produce up to 12 liters of urine per day depending on many factors. Some conditions involve excessive production, called polyuria, which is more than 2.5 liters per day. Other conditions involve low output. Oliguria is defined as less than 400 milliliters per day. Anuria is even lower, at less than 100 milliliters per day.

Humans have studied the urinary system for a very long time. Records show that kidney stones have been known since ancient times. In the second century AD, Galen described the ureters and their function. Modern medical technology changed how doctors see these organs. In 1929, Hampton Young first used ureteroscopy to examine the ureter internally. Later, in 1964, VF Marshall used a flexible endoscope based on fiber optics. In 1941, doctors first described nephrostomy. This is a method to insert a drainage tube directly into the renal pelvis. This was a major change from the open surgeries used for two thousand years.