Urinary: Features

Urinary
We will discuss:
The kidneys
The formation of urine
Urination
Body fluids


The kidneys

The most important excretory organ is the kidney, whose main functions are: elimination of foreign substances to the body, regulation of water balance, regulation of mineral balance, maintenance of osmotic pressure and maintaining blood pH within normal limits. In the kidneys can highlight the capsules of Bowman, who together form the nephron renal tubule. There are millions of these capsules in each kidney. These lead to the so-called minor calyx wing and from there to the ureter and renal pelvis. The ureters empty into the bladder. Bladder out the urethra.

The formation of urine

It is performed by filtration of blood plasma level of the Malpighian corpuscles. After the filtrate passes tubules and undergoes modification as a result of complex phenomena of filtration and reabsorption due to hydrostatic pressure and plasma protein osmotic pressure. Glucose, amino acids, proteins and most of the electrolytes are reabsorbed. Substances such as urea, uric acid, etc., Do not undergo resorption. In the regulation of renal function mainly involved the endocrine system. For example, the antidiuretic hormone influences the reabsorption of water.

Urination

When the contents of the bladder reaches 400-500 ml., Sensitive receptors in the bladder wall are excited and transmit nerve impulses that reach the medulla, through which the autonomic nerves and contract the bladder relaxes the internal sphincter. Higher centers of the nervous system produce a conscious desire to urinate. Now is the external sphincter, subordinate to the will, which decides whether the time is right.

Body fluids

In an adult male water represents a 65 percent by weight. On the one hand this intracellular fluid (29 liters), interstitial fluid (14 liters) and plasma (3 liters). The main difference between the first two is the amount of potassium that is in the intracellular. The main difference between the interstitial and plasma concentration is the major protein in plasma.

*Automatic Translation