What is pee made out of

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. 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. This triangle-shaped, hollow organ is located in the lower abdomen. Now that you're older, you can understand much more about the amazing yellow stuff called pee.

You drink, you pee. But urine is more than just that drink you had a few hours ago. The body produces pee as a way to get rid of waste and extra water that it doesn't need. Before leaving your body, urine travels through the urinary tract.

The kidneys are key players in the urinary tract. They do two important jobs — filter waste from the blood and produce pee to get rid of it.

If they didn't do this, toxins bad stuff would quickly build up in your body and make you sick. That's why you hear about people getting kidney transplants sometimes. You need at least one working kidney to be healthy. You might wonder how your body ends up with waste it needs to get rid of. The increased plasma osmolarity is sensed by osmoreceptors in the hypothalamus, which will stimulate the posterior pituitary gland to release ADH. ADH will then act on the nephrons of the kidneys to cause a decrease in plasma osmolarity and an increase in urine osmolarity.

ADH increases the permeability to water of the distal convoluted tubule and collecting duct, which are normally impermeable to water. This effect causes increased water reabsorption and retention and decreases the volume of urine produced relative to its ion content. After ADH acts on the nephron to decrease plasma osmolarity and leads to increased blood volume and increase urine osmolarity, the osmoreceptors in the hypothalamus will inactivate, and ADH secretion will end. Due to this response, ADH secretion is considered to be a form of negative feedback.

A diuretic is any substance that has the opposite effect of ADH— they increase urine volume, decrease urine osmolarity, lead to an increased plasma osmolarity, and often reduced blood volume. Many substances can act as diuretics, albeit with different mechanisms. A common example is alcohol and water ingestion, which directly inhibit ADH secretion in the pituitary gland.

Alternatively caffeine is a diuretic because it interferes with sodium reabsorption reducing the amount of water reabsorbed by sodium cotransport and increases the glomerular filtration rate by temporarily increasing blood pressure. Many medications are diuretics because they inhibit the ATPase pumps, thus slowing water reabsorption further.

Summary of the process of urine formation : As the fluid flows along the proximal convoluted tubule useful substances like glucose, water, salts, potassium ions, calcium ions, and amino acids are reabsorbed into the blood capillaries that form a network around the tubules. Many of these substances are transported by active transport and energy is required. Urinalysis means the analysis of urine, and it is used to diagnose several diseases. The target parameters that are measured or quantified in urinalysis include many substances and cells, as well as other properties, such as specific gravity.

Another method is light microscopy of urine samples. Test strip urinalysis exposes urine to strips that react if the urine contains certain cells or molecules. Test strip urinalysis is the most common technique used in routine urinalysis.

A urine test strip can identify:. A urinary cast is any tiny structure found in urine that consists of multiple molecules or cells bound together. Casts form within the nephron when abnormal cells and molecules are filtered from blood, and are excreted as the bound structures in urine.

Microscopy can identify casts in urine and use them to diagnose kidney diseases, by characterizing symptoms such as:. Urinalysis : White blood cells seen under a microscope from a urine sample. In renal physiology, clearance is a measurement of the renal excretion ability, which measures the amount of plasma from which a substance is removed from the body over an interval of time.

Each substance has its own specific clearance that depends on its unique filtration characteristics. Clearance is a function of glomerular filtration, secretion from the peritubular capillaries to the nephron, and reabsorption from the nephron back to the peritubular capillaries. Clearance can be either a constant or variable component over time, depending on the type of substance.

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