12+Urology

Urology Chapter 17



__**Content Summary **__ //Chapter 17 covers the physiology of the kidneys and their functions. The main points of the chapter are the structure and function of the kidney, glomerular filtration, reabsorption of salt and water, renal plasma clearance, renal control of electrolyte and acid-base balance, and finally the clinical applications of the diuretic drugs. The complexity of the kidneys stretches to a number of processes that are vital to our survival as human beings. This entire chapter interests me very much because it is a topic that I thought I knew enough about, but it turned out that what I thought I knew wasn’t even a good start. The kidneys, to me, are one of the most interesting organs in the human body. While going through this chapter 3 of my favorite topics were the glomerular filtration, reabsorption of salt and water, and the clinical application portion. //

//The glomerular filtration is the second topic covered in this chapter, right behind the basic structure and functions of the kidney. The filtration has one major objective, and that is to filter the blood so it can be re-circulated back through the body. The filtrate is produced when the blood plasma passes through the basement membrane of the glomerular capillaries. It passes through the slits in the process of the podocytes, which are the general makeup of the inner walls of the glomerular capsule. The byproduct of this is an ultrafiltrate, which is formed under the blood pressure and contains a very low rate of protein. The rate at which this happens is called the glomerular filtration rate, or the GFR. The GFR is the takes into account the output from both kidneys, and is expressed in ml/min. This ranges from 115 to 125 ml/min in a human. The GFR is greatly affected by the diameter of the afferent arterioles. The dilation or constriction of the afferent arterioles is effected by sympathetic innervations. //

[|Glomerular Filtration]



// The second topic from this chapter that I took an interest in was the process of reabsorption of salt and water. The main culprits for reabsorption of salt and water are the proximal convoluted tubules. In fact approximately 65 percent of the salt and water that are ultimately absorbed are taken in here in the proximal convoluted tubules. Active transport is responsible for the transport of sodium, which is followed by chloride passively via electrical attraction. Water then follows the sodium out of the tubules. Hormone regulation has no effect on the salt transport in the proximal tubules. The countercurrent multiplier system is the action behind the remaining water reabsorption. Throughout this process it is important to note that the collecting duct is permeable to water, but not to salt. The permeability of the collecting ducts to water is caused by the ADH, also known as the antidiuretic hormone. //

//The medicines used as diuretics serve a couple of specific purposes. The clinical applications of diuretic drugs serve to increase urine volume, and thus lowering the blood volume and ultimately the blood pressure as well. Diuretics fall into three major categories discussed here, and those three happen to be the loop diuretics, osmotic diuretics, and the potassium-sparing diuretics. Each of these three diuretics impact the bodies in their own specific way but all serve to restore some sort of homeostasis. Loop diuretics for example act early on in the distal tubule and ascending limb to inhibit the Na+ transport. Osmotic diuretics are essentially extra solutes in the filtrate that increase the osmotic pressure of the filtrate and block the reabsorption of water by osmosis. The potassium-sparing diuretics have a few commonalities with the loop diuretics in that they act on the distal tubule to inhibit the reabsorption of Na+, but they also block the secretion of K+. In addition to diuretics, during glomerulonephritis the glomeruli admit the leakage of plasma proteins into the urine. Also, when the use of diuretics is simply not enough, renal insufficiency can be treated by the process of hemodialysis. // Source (Physiology Book)

__**Application **__ //In the nursing field, I could easily see how having knowledge of the kidneys could make things much simpler for one. The basics are a good start, but knowing this process a little more in depth could benefit many. The nurse part comes in when it comes to the medications used to help people with kidney dysfunction. The specific diuretics used to treat these dysfunctions all have a little bit of a different effect, and the wrong one could mean serious health problems to anyone who engages in taking them without a proper prescription. The diuretics either block the reabsorption of a molecule, or enhance the ability of that specific molecule to be absorbed. As a nurse administering drugs, it is always a safe practice to be able, and to mindfully know, what it is that you are giving to a patient. With that comes the responsibility of knowing why they are receiving that drug, and what outcome you are looking for with it. The diuretics should be carefully monitored so that it is known that the desired response is being achieved. //

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**__Essential Questions __** //Filtration occurs to filter the unwanted and un-needed molecules and substances out of the blood. The kidneys filter the blood so fast that every 40 minutes the total blood volume is filtered and then reabsorbed. Reabsorption is defined as the transport of a substance from the lumen of the renal nephron into the peritubular cavities. Around 90 percent of the total potassium that is reabsorbed it done so in the early regions of the nephron. Renal secretion is defined as the transport of a substance from the blood through the wall of the nephron tubule into the urine. The secretion of K+ that takes place in the late distal tubule matches the amount of K+ that the body ingests in order to keep the amount in the normal range. Excretion is the action of the body to remove toxic and unwanted materials out of the body. Kidneys regulate blood pH by excreting H+ in the urine. //

//The maintenance of electrolytes is important because they are needed to perform vital operations throughout the body. These electrolytes include sodium, potassium, chloride, bicarbonate, and phosphate. For example Na+ is responsible to maintaining blood pressure and overall volume of the blood at any given time in the body. Also, the proper levels of K+ are required to accurately maintain the proper function of the cardiac and skeletal muscles. These electrolytes are maintained by a simple process that matches the amount of each individual electrolyte, which then matches the urinary excretion with the specific amount ingested. //  Source (Physiology Book)