How does urinary system control ph

The urine pH varies in different types of acidosis and alkalosis. Control of pH is important in the management of several diseases, including bacteriuria, renal calculi, and drug therapy. The formation of renal stones is related to the urine pH. Patients being treated for renal calculi are frequently given diets or medications to change the pH of the urine so that kidney stones will not form. Calcium phosphate, calcium carbonate, and magnesium phosphate stones develop in alkaline urine; when this occurs, the urine is kept acidic.

Uric acid, cystine, and calcium oxalate stones precipitate in acidic urine; in this situation, the urine should be kept alkaline or less acidic than normal. Drugs such as streptomycin, neomycin, and kanamycin are effective in treating urinary tract infections if the urine is alkaline.

The blood exiting the capillaries has reabsorbed all of the nutrients along with most of the water and ions that the body needs to function. After urine has been produced by the kidneys, it is transported through the ureters to the urinary bladder.

The urinary bladder fills with urine and stores it until the body is ready for its excretion. When the volume of the urinary bladder reaches anywhere from to milliliters, its walls begin to stretch and stretch receptors in its walls send signals to the brain and spinal cord.

These signals result in the relaxation of the involuntary internal urethral sphincter and the sensation of needing to urinate. Urination may be delayed as long as the bladder does not exceed its maximum volume, but increasing nerve signals lead to greater discomfort and desire to urinate. Urination is the process of releasing urine from the urinary bladder through the urethra and out of the body.

The process of urination begins when the muscles of the urethral sphincters relax, allowing urine to pass through the urethra.

At the same time that the sphincters relax, the smooth muscle in the walls of the urinary bladder contract to expel urine from the bladder. The kidneys produce and interact with several hormones that are involved in the control of systems outside of the urinary system. Calcitriol is the active form of vitamin D in the human body. It is produced by the kidneys from precursor molecules produced by UV radiation striking the skin. Calcitriol works together with parathyroid hormone PTH to raise the level of calcium ions in the bloodstream.

When the level of calcium ions in the blood drops below a threshold level, the parathyroid glands release PTH, which in turn stimulates the kidneys to release calcitriol. Calcitriol promotes the small intestine to absorb calcium from food and deposit it into the bloodstream.

It also stimulates the osteoclasts of the skeletal system to break down bone matrix to release calcium ions into the blood. Erythropoietin, also known as EPO, is a hormone that is produced by the kidneys to stimulate the production of red blood cells. The kidneys monitor the condition of the blood that passes through their capillaries, including the oxygen-carrying capacity of the blood. When the blood becomes hypoxic, meaning that it is carrying deficient levels of oxygen, cells lining the capillaries begin producing EPO and release it into the bloodstream.

EPO travels through the blood to the r ed bone marrow , where it stimulates hematopoietic cells to increase their rate of red blood cell production. Renin is not a hormone itself, but an enzyme that the kidneys produce to start the renin-angiotensin system RAS. The RAS increases blood volume and blood pressure in response to low blood pressure, blood loss, or dehydration. Renin is released into the blood where it catalyzes angiotensinogen from the liver into angiotensin I.

Angiotensin I is further catalyzed by another enzyme into Angiotensin II. Angiotensin II stimulates several processes, including stimulating the adrenal cortex to produce the hormone aldosterone. Aldosterone then changes the function of the kidneys to increase the reabsorption of water and sodium ions into the blood, increasing blood volume and raising blood pressure. Nephrons are the main functional component inside the parenchyma of the kidneys, which filter blood to remove urea, a waste product formed by the oxidation of proteins, as well as ions like potassium and sodium.

The nephrons are made up of a capsule capillaries the glomerulus and a small renal tube. The renal tube of the nephron consists of a network of tubules and loops that are selectively permeable to water and ions. Many hormones involved in homeostasis will alter the permeability of these tubules to change the amount of water that is retained by the body. The bladder is flexible and is used as storage until the urine is allowed to pass through the urethra and out of the body.

The kidneys play a very large role in human osmoregulation by regulating the amount of water reabsorbed from the glomerular filtrate in kidney tubules, which is controlled by hormones such as antidiuretic hormone ADH , renin, aldosterone, and angiotensin I and II. A basic example is that a decrease in water concentration of blood is detected by osmoreceptors in the hypothalamus, which stimulates ADH release from the pituitary gland to increase the permeability of the wall of the collecting ducts and tubules in the nephrons.

Therefore, a large proportion of water is reabsorbed from fluid to prevent a fair proportion of water from being excreted. The extent of blood volume and blood pressure regulation facilitated by the kidneys is a complex process. Besides ADH secretion, the renin-angiotensin feedback system is critically important to maintain blood volume and blood pressure homeostasis. Privacy Policy. Skip to main content. Urinary System.