The urinary or renal system includes the kidneys, ureter, urinary bladder and urethra. This organ system filters excess fluid out of blood as well as other substances, such as excess ions and metabolic wastes, which mainly consist of urea and uric acid. These products are filtered out of the blood and combined with water before exiting the body in the form of urine. The main function of kidneys, the most complex organs of the urinary system, is to sustain homeostasis for optimal cell and tissue metabolism.
As further studies are conducted to assess the safety and effectiveness of stem cell therapy, we will move closer to a day when kidney injury is rare, and curative treatments are routine.
The effects of failure of parts of the urinary system may range from inconvenient incontinence to fatal loss of filtration and many others. The kidney hormone EPO stimulates erythrocyte development and promotes adequate O 2 transport. The kidneys work with the adrenal cortex, lungs, and liver in the renin—angiotensin—aldosterone system to regulate blood pressure.
They regulate osmolarity of the blood by regulating both solutes and water. The kidneys share pH regulation with the lungs and plasma buffers, so that proteins can preserve their three-dimensional conformation and thus their function. Stem cells and their role in renal ischaemia reperfusion injury.
Am J Nephrol [Internet]. Review Questions. Which step in vitamin D production does the kidney perform? Which hormone does the kidney produce that stimulates red blood cell production?
Click here to view solutions. How does lack of protein in the blood cause edema? Which three electrolytes are most closely regulated by the kidney? It looks like you're using Internet Explorer 11 or older. This website works best with modern browsers such as the latest versions of Chrome, Firefox, Safari, and Edge. If you continue with this browser, you may see unexpected results. To print this page: Click on the printer icon at the bottom of the screen Is your printout incomplete?
OpenStax CNX. Blood pressure and osmolarity are regulated in a similar fashion. Severe hypo-osmolarity can cause problems like lysis rupture of blood cells or widespread edema, which is due to a solute imbalance. Inadequate solute concentration such as protein in the plasma results in water moving toward an area of greater solute concentration, in this case, the interstitial space and cell cytoplasm. If the kidney glomeruli are damaged by an autoimmune illness, large quantities of protein may be lost in the urine.
The resultant drop in serum osmolarity leads to widespread edema that, if severe, may lead to damaging or fatal brain swelling. Severe hypertonic conditions may arise with severe dehydration from lack of water intake, severe vomiting, or uncontrolled diarrhea. When the kidney is unable to recover sufficient water from the forming urine, the consequences may be severe lethargy, confusion, muscle cramps, and finally, death.
Sodium, calcium, and potassium must be closely regulated. Recall that enzymes lose their three-dimensional conformation and, therefore, their function if the pH is too acidic or basic. This loss of conformation may be a consequence of the breaking of hydrogen bonds. Move the pH away from the optimum for a specific enzyme and you may severely hamper its function throughout the body, including hormone binding, central nervous system signaling, or myocardial contraction.
Proper kidney function is essential for pH homeostasis. Stem cells are unspecialized cells that can reproduce themselves via cell division, sometimes after years of inactivity.
Under certain conditions, they may differentiate into tissue-specific or organ-specific cells with special functions. In some cases, stem cells may continually divide to produce a mature cell and to replace themselves. Stem cell therapy has an enormous potential to improve the quality of life or save the lives of people suffering from debilitating or life-threatening diseases. There have been several studies in animals, but since stem cell therapy is still in its infancy, there have been limited experiments in humans.
For example, water follows ions via an osmotic gradient, so mechanisms that alter sodium levels or sodium retention in the renal system will alter water retention levels as well. Kidneys are the most complex and critical part of the urinary system. The primary function of the kidneys is to maintain a stable internal environment homeostasis for optimal cell and tissue metabolism. The kidneys have an extensive blood supply from the renal arteries that leave the kidneys via the renal vein.
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.
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