Urinary System - Essay Example

November 15, Urinary System The urinary system is a key component in the bodies of humans and other animals. It is responsible for purifying blood of wastes and also for maintaining “homeostasis of water, ions, pH, blood pressure, calcium and red blood cells” (Taylor). It comprises of kidneys, ureters, urethra and the urinary bladder which work in cooperation to perform the above mentioned functions. Though all these organs are necessary, the most important one around which the whole urinary system is built is the kidney. A study of the system with the kidney in focus has been done to establish in detail the functions of the parts and the overall working of the system. The diagram below illustrates the parts of a urinary system. Fig. 1. Components of urinary system. IvyRose Holistic. http://www.ivy-rose.co.uk/HumanBody/Urinary/Urinary_System.php Parts of the urinary system Kidneys The urinary system has a pair of kidneys which are bean shaped and approximately the size of a clenched fist located in the middle of the spine just below the ribcage (Lynch and Wein). Kidneys are responsible for filtering the blood to remove excess ions, chemicals, water and other metabolic wastes so as to form urine. They work without stopping all day and lack of them causes death in an individual after a few days due to accumulation of wastes though research has reliably established that one can live on a single kidney. Inside the kidneys are numerous tiny structures referred to as nephrons that perform the actual filtering of blood. (Mangusan). Ureters Ureters are tubes of about 8 to 10 inches long that drain from the kidneys into the urinary bladder. They have smooth muscles that contract and relax to guide urine down into the bladder together with the action of gravity. Its ends are sealed by ureterovesical valves that prevent urine from flowing back once it lands into the bladder (Taylor). Urinary Bladder The bladder is an expandable muscular sac that holds urine filled in by ureters before it is excreted. It is strategically located in the lower abdominal area near the pelvic bones. When full, the bladder can hold between 600 and 800 milliliters of urine. Its triangular shape together with the internal sphincter muscles prevent urine from flowing back into the ureters or urethra (Krucik). Urethra It is the tube that guides urine outside the body from the bladder. In females, the urethra is about 2 inches ending somewhere between the clitoris and vagina while in males it is 8 to 10 inches long ending at the tip of the penis. Internal sphincter muscles made of smooth muscles control the opening from the bladder and open involuntarily when the bladder thus generating the sensation to urinate. The external sphincter muscles made of skeletal muscles are stronger and therefore control the end of the urethra allowing or stopping urine from coming out (Taylor). Urinary System Physiology Maintenance of Homeostasis Homeostasis is achieved through a number of ways. When ions are in excess in the blood, the kidney increases their excretion into urine and conversely permits their reabsorption when their level recedes in the blood. In the same way, hydrogen ions that dictate the PH of the blood are controlled to maintain a safe PH. Osmoregulation aims at maintaining a healthy blood pressure by either absorbing or excreting water into urine. By so doing, a constant range of osmotic pressure and blood sugar concentration are controlled. Antidiuretic hormone (ADH) which is produced in the hypothalamus and released by the posterior pituitary gland is responsible for the retention of water in the body (Taylor) Storage and excretion of wastes As discussed in the previous section, the key function of the urinal system is to filter wastes from the blood, store them and finally release them out of the body. The kidney filters through the help of the nephrons, the ureters transport, the urinary bladder stores and the urethra completes the cycle to deposit the wastes outside the body. Production of hormones and enzymes The kidney is responsible for production of a number of hormones and enzymes that help with various functionality in the body. Calcitriol is a hormone produced due to the action of UV radiation on the skin and together with parathyroid hormone help raise the level of calcium ions in the body. Their action is by increasing absorption of calcium in the small intestines and decomposition of bone marrow to create calcium. (Taylor). Erythropoietin is another hormone produced by the kidney capillaries that informs the red bone marrow to produce more red blood cells in cases where the oxygen level in the blood flowing through the kidney is low. Renin is an enzyme produced by the kidney 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” (Taylor). Filtration Fig. 2. Structure of a nephron. Available from http://www.ivy-rose.co.uk/HumanBody/Urinary/Urinary_System_Nephron_Diagram.php Filtration is done by the above structure. Arterioles deliver unfiltered blood to the glomerulus which is basically a bundle of capillaries surrounded by a capsule. Plasma is forced out of the blood into the capsule and flows into the proximal convoluted tubule. Here, capillaries that wrap around the large surface area of the tubules reabsorb water and mineral ions into the blood. This occurs along the length of the tubule until the blood attains the right concentration of water and ions. The remaining fluid in the tubule is entirely urine containing water, wastes and excess ions that are then channeled into the collecting duct and into the ureters (Taylor). Common Urinary Disorders Urology is the branch of medicine that studies the urinary tract (Baptist Health). Reports at Baptist Health indicate that more than 31 million people are affected by chronic kidney disorders with 85 000 adults in the US dying yearly from kidney failure. Based on this, it becomes important to understand some of these disorders associated with the urinary system. The urogenital is associated with so many disorders among them being cystitis or bladder infection that is caused by bacteria, enlarged prostate in men that causes difficulty in discharging urine, kidney stones caused by high levels of calcium in the blood and incontinence, a condition where urine leaks from the urethra (Better Health). Diabetes insipidus is a urinary condition characterized by frequent urination. The condition is caused by deficiency in antidiuretic hormone. Individuals develop a lot of thirst due to the excessive loss of water and dehydration is common in victims that do not take enough water (Mangusan). From the discussion in this paper, it is apparent that the urinary system is of crucial significance to someone’s health and therefore life. People should therefore take precautionary measures to avoid complications of this nature. Works Cited “Kidney and urinary disorders”. Baptist Health. n.p, n.d. Web. 15 Nov 2014. Krucik, George. Bladder. Healthline, 24 Apr. 2013. Web. 15 Nov 2014. Lync, John, and Wein Alan. Urinary tract and how it works. National Kidney and Urologic Diseases Information Clearinghouse (NKUDIC), n.d. Web. 15 Nov 2014. Mangusan, David. Structure and function of nephron. Kidney Health Care, n.d. Web. 15 Nov 2014. Taylor, Tim. Urinary system. Inner Body, n.d. Web. 15 Nov 2014. < http://www.innerbody.com/anatomy/urinary-male#full-description > “Urinary system”. Better health. n.p, March. 2012. Web. 15 Nov 2014. Read More