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Glucose Is Not Found In The Urine Because It Is Not Filtered Out Of The Blood True Or False

Physiology Of The Kidneys

Physiology Of The Kidneys

Urine is formed in three steps: filtration, reabsorption, and secretion. Filtration involves the transfer of soluble components, such as water and waste, from the blood into the glomerulus. Reabsorption involves the absorption of molecules, ions, and water that are necessary for the body to maintain homeostasis from the glomerular filtrate back into the blood. Secretion involves the transfer of hydrogen ions, creatinine, drugs, and urea from the blood into the collecting duct, and is primarily made of water. Blood and glucose are not normally found in urine. urine: A liquid excrement consisting of water, salts, and urea, which is made in the kidneys then released through the urethra. glomerulus: A small, intertwined group of capillaries within nephrons of the kidney that filter the blood to make urine. Urine is a waste byproduct formed from excess water and metabolic waste molecules during the process of renal system filtration. The primary function of the renal system is to regulate blood volume and plasma osmolarity, and waste removal via urine is essentially a convenient way that the body performs many functions using one process. Urine formation occurs during three processes: During filtration, blood enters the afferent arteriole and flows into the glomerulus where filterable blood components, such as water and nitrogenous waste, will move towards the inside of the glomerulus, and nonfilterable components, such as cells and serum albumins, will exit via the efferent arteriole. These filterable components accumulate in the glomerulus to form the glomerular filtrate. Normally, about 20% of the total blood pumped by the heart each minute will enter the kidneys to undergo filtration; this is called the filtration fraction. The remaining 80% of the blood flows through t Continue reading >>

Glycosuria

Glycosuria

Basic Information Negative in healthy horses Physiology Serum glucose is freely filtered by the glomerulus and subsequently reabsorbed from the ultrafiltrate by the proximal tubules. The reabsorption of glucose by the renal tubules is a saturable process, and serum glucose levels above 150 mg/dL result in more glucose in the ultrafiltrate than can be resorbed by the renal tubules. Causes of Abnormally High Levels • Hyperglycemic glucosuria (eg, pituitary pars intermedia dysfunction [PPID], Cushing's disease, and rarely diestrus) • Renal glucosuria (normoglycemic glucosuria) due to defective renal tubular resorption resulting from tubular abnormalities or damage • False increase (see later) Evaluate serum glucose concentration and renal parameters. Drug Effects on Levels • False increases (via Clinitest copper-reduction method) may occur with cephalosporins and high concentrations of ascorbic acid. • False increases may also occur with elevated progesterone levels and megestrol acetate. • False decreases (via dipstick) may be caused by ascorbic acid. Specimen and Processing Considerations Lab Artifacts that May Interfere with Readings of Levels of this Substance (and How—Artificially Elevated vs. Depressed) Sample for Collection (Type of Specimen, Color Tube) and Any Special Specimen Handling Notes Midstream urine collection in a clean container Urine should be at room temperature or warmer for enzymes in the reagent pad of the dipstick to work appropriately. AUTHOR: LAURA C. CREGAR EDITOR: CHARLES WIEDMEYER Glucosuria Glucosuria occurs in acute tubular nephrosis as a result of failure of tubular resorption, and is one of the most sensitive indices for the presence of a proximal tubule. Glucosuria is occasionally detected in severely ill ruminants, particul Continue reading >>

Urinalysis - Clinical Methods - Ncbi Bookshelf

Urinalysis - Clinical Methods - Ncbi Bookshelf

Urinalysis is the examination of urine for certain physical properties, solutes, cells, casts, crystals, organisms, or particulate matter. Because urinalysis is easy, cheap, and productive, it is recommended as part of the initial examination of all patients and should be repeated as clinically warranted. This chapter focuses on what the physician may do in a few minutes with a urine sample, reagent strips, a microscope, and an inquiring mind. Such analysis may lead to more sophisticated chemical, immunologic, or bacteriologic studies. The rationale and technique of urinalysis are straightforward. Nevertheless, various circumstances may alter the information obtained. For example, one should not be surprised if the urine analyzed did not come from the patient named, or that the protein and red cells were added to the urine after it reached the collection bottle. Such illicit treatment of the sample is not frequent, but may be used in an attempt to justify disability, military discharge, or need for hospitalization. Interestingly, if the temperature of fresh urine is checked, it may help to diagnose factitious oral or rectal fevers. A sample should be obtained that is free of skin epithelium or bacteria, glandular secretions, skin salves, hair, lint, talcum, or other debris. In rare circumstances, it may be necessary to have the sample passed under observation to assure its source and freedom from exogenously introduced materials. Ordinarily, a suitable sample may be obtained from a male simply by asking that the foreskin, if present, be pulled back, that the initial part of the stream be allowed to pass into the toilet, that the next ounce or two be collected, and that the last part of the stream be discarded with the first. In females, care must be taken to separate t Continue reading >>

Bbc - Gcse Bitesize Science - The Urinary System : Revision, Page 3

Bbc - Gcse Bitesize Science - The Urinary System : Revision, Page 3

Urine is produced in microscopic structures in the kidney called nephrons. There are approximately 1 million nephrons in each kidney. The glomerulus filters blood and produces glomerular filtrate. This filtrate contains water, glucose [glucose: A simple sugar made by the body from food, which is used by cells to make energy in respiration.], salts and urea [urea: A nitrogenous waste product resulting from the breakdown of proteins. It is excreted in urine.]. Large molecules such as protein [protein: Organic compound made up of amino acid molecules. One of the three main food groups, proteins are needed by the body for cell growth and repair.] are too large to fit through the blood capillary [capillaries: Extremely narrow tubes, which carry blood around a body's tissues.] walls. The Bowman's capsule collects the filtrate and it enters the tubules. All glucose is reabsorbed immediately into the blood capillaries. As the rest of the filtrate travels through the tubules, water and salts needed by the body are reabsorbed into the blood capillaries. The loop of Henl helps maintain the correct water balance in the body by filtering out salts. The waste, consisting of excess water, excess salts and urea, is urine. The collecting duct collects the urine, which is then transported in the ureter to the bladder. The bladder stores urine until the body is ready to expel it through the urethra. This process can be summarised in three important steps: Filtration - where lots of water, ions [ion: The charged particle formed when an atom, or a group of atoms, lose or gain electrons. Ion charge helps determine a substance's acidity or alkalinity.], urea [urea: A nitrogenous waste product resulting from the breakdown of proteins. It is excreted in urine.] and sugar are squeezed from the Continue reading >>

Human Physiology/the Urinary System

Human Physiology/the Urinary System

This is the latest reviewed version , checked on 13 April 2017. (+) The Urinary System is a group of organs in the body concerned with filtering out excess fluid and other substances from the bloodstream. The substances are filtered out from the body in the form of urine. Urine is a liquid produced by the kidneys, collected in the bladder and excreted through the urethra. Urine is used to extract excess minerals or vitamins as well as blood corpuscles from the body. The Urinary organs include the kidneys, ureters, bladder, and urethra. The Urinary system works with the other systems of the body to help maintain homeostasis. The kidneys are the main organs of homeostasis because they maintain the acid base balance and the water salt balance of the blood. One of the major functions of the Urinary system is the process of excretion. Excretion is the process of eliminating, from an organism, waste products of metabolism and other materials that are of no use. The urinary system maintains an appropriate fluid volume by regulating the amount of water that is excreted in the urine. Other aspects of its function include regulating the concentrations of various electrolytes in the body fluids and maintaining normal pH of the blood. Several body organs carry out excretion, but the kidneys are the most important excretory organ. The primary function of the kidneys is to maintain a stable internal environment (homeostasis) for optimal cell and tissue metabolism. They do this by separating urea, mineral salts, toxins, and other waste products from the blood. They also do the job of conserving water, salts, and electrolytes. At least one kidney must function properly for life to be maintained. Six important roles of the kidneys are: Regulation of plasma ionic composition. Ions such Continue reading >>

A & P Chapter 17 Urinary

A & P Chapter 17 Urinary

A series of small elevations that project into the renal sinus of the kidney are called The blood is supplied to the nephrons of the kidney directly by the Which of the following structures is not a part of the renal tubule? Which of the following renal structures is found in the medulla of the kidney? Blood leaving the glomerulus directly enters theWhich of the following structures is not a part of the renal tubule? High pressure is maintained in the glomerulus because the diameter of the efferent arteriole is less than that of the afferent arteriole Which of the following is not one of the three main processes involved in urine formation? Substances that are secreted into the kidney tubules include all but Feedback: H+, certain drugs such as penicillin, histamine, and creatinine are secreted into the urine. Which of the following factors will increase the glomerular filtration rate (GFR)? Feedback: Constriction of the afferent arteriole reduces glomerular pressure and filtration rate. All of the following will cause the juxtaglomerular cells of the kidney to secrete renin except Feedback: Renin is released in response to low blood pressure or volume, low sodium, and sympathetic stimulation. How much fluid filters through the glomerulus in a 24-hour period? Feedback: Typically at least 45 gallons (180 liters) of blood pass through the glomerulus each day. Which of the following substances is normally present in glomerular filtrate but not in urine? Feedback: Glucose will normally not pass into the urine unless the blood sugar level exceeds 160-180 mg/dl; urea diffuses freely. Most of tubular reabsorption takes place in the Feedback: Most reabsorption back into the blood occurs at the level of the proximal convoluted tubule. Water reabsorption from the kidney tubule is Continue reading >>

Physiology: Renal

Physiology: Renal

STRUCTURE: Layers of the glomerular filter, from blood-space to bowman's space. ENDOTHELIAL CELLS: Capillary endothelial cells are fenestrated. They extend interdigitating Foot Processes onto the capillary wall, which can separate from each other when mesangial cells contract. Tight Junctions between foot processes serve as an additional barrier to filtration (in addition to the GBM). FILTRATION SLITS: The spaces between the foot processes, through whichblood and blood solutes pass. The width of the slits can vary from 240 angstroms to 3000-5000 angstroms,under the influence of the mesangial cells. MESANGIAL CELLS: They are interstitial cells in the glomerulus. FNXN: They can phagocytose debris from the interstitium. GLOMERULAR BASEMENT MEMBRANE (GBM): The GBM is the primary barrier to filtration. Lamina Rara Externa: Facing the capillary space. Lamina Rara Interna: Facing the tubular space. NEGATIVE CHARGE: The basement membrane has an overall negativecharge due to presence of Sialic Acid in the Glomerular membrane. This negative charge makes the glomerulus repel large negativeproteins in the blood so they don't filter. BOWMAN'S SPACE: Contains the glomerular filtrate. GLOMERULAR FILTRATE: It is identical in composition to blood except it doesn'tcontain large anionic blood proteins (such as Albumin and other protein-transporters). Dextran: Neutral dextran has a fractional clearance of 0.19, while DextranSulfate (negatively charged) has 1/10th that value: 0.015. Albumin: Not a chance, under normal circumstances. GLOMERULONEPHRITIS: Immune reactions in kidneys ------> proteolyticenzymes destroy the glomerular barrier, such that large blood proteins can getthrough. Experimental evidence says that Glomerulonephritis causes the GlomerularBM to lose its negative charge, so Continue reading >>

25.6 Tubular Reabsorption Anatomy And Physiology

25.6 Tubular Reabsorption Anatomy And Physiology

85 percent reabsorbed, inhibited by parathyroid hormone, diffusion Mechanisms by which substances move across membranes for reabsorption or secretion include active transport, diffusion, facilitated diffusion, secondary active transport, and osmosis. These were discussed in an earlier chapter, and you may wish to review them. Active transport utilizes energy, usually the energy found in a phosphate bond of ATP, to move a substance across a membrane from a low to a high concentration. It is very specific and must have an appropriately shaped receptor for the substance to be transported. An example would be the active transport of Na+ out of a cell and K+ into a cell by the Na+/K+ pump. Both ions are moved in opposite directions from a lower to a higher concentration. Simple diffusion moves a substance from a higher to a lower concentration down its concentration gradient. It requires no energy and only needs to be soluble. Facilitated diffusion is similar to diffusion in that it moves a substance down its concentration gradient. The difference is that it requires specific membrane receptors or channel proteins for movement. The movement of glucose and, in certain situations, Na+ ions, is an example of facilitated diffusion. In some cases of facilitated diffusion, two different substances share the same channel protein port; these mechanisms are described by the terms symport and antiport. Symport mechanisms move two or more substances in the same direction at the same time, whereas antiport mechanisms move two or more substances in opposite directions across the cell membrane. Both mechanisms may utilize concentration gradients maintained by ATP pumps. This is a mechanism described by the term secondary active transport. For example, a Na+ ATPase pump on the basilar mem Continue reading >>

Proteinuria

Proteinuria

Summary Protein in urine can sometimes be a sign of kidney disease, as well as other health problems. It is worth asking at your GP surgery for a urine test. What is it? Along with fats and sugars, proteins form the major building blocks for our bodies. The right amount of protein is important in our diets, for growth and repair. Protein is present in the blood; healthy kidneys should only filter tiny (trace) amounts into the urine as most protein molecules are too large for the filters (glomeruli) It is not usual to lose protein to the urine. When this does happen it is known as ‘Proteinuria’ Several proteins can be found in the urine, but the most relevant to kidney disease is albumin Protein in the urine is not usually obvious, but can be detected by a simple dip- stick test, or sometimes by more sensitive lab tests The presence of protein in the urine can act as a warning signal that not all is well with the kidneys Symptoms Usually there are no symptoms If the protein loss is heavy, the urine has a frothy appearance, and would most likely be associated with other symptoms e.g. oedema, where there is an excess of water in the body tissues Possible causes of proteinuria Diseases of the glomeruli (the kidney’s filtering units), for example glomerulonephritis or diabetes Urine infection can cause proteinuria, but usually there are other signs of this – see cystitis/urinary tract infections Proteinuria can also be a symptom of some other conditions and diseases: for example: congestive heart failure, a first warning of eclampsia in pregnancy Sometimes a positive dipstick for protein isn’t abnormal, for example concentrated samples first thing in the morning, or if you have become dehydrated or haven’t drunk much. Lab tests can sort this out (protein/creatini Continue reading >>

Renal Glycosuria

Renal Glycosuria

Causes Renal glycosuria is considered an inherited defect of membrane transport (i.e., an abnormal renal transport syndrome). Membrane transport disorders are characterized by abnormalities in the movement (i.e., transport) of one or more compounds across cell membranes. They are thought to result from genetic changes (mutations) causing alterations in specific membrane proteins. As noted above, due to impaired renal tubular functioning, renal glycosuria is characterized by a reduction in the blood glucose concentration at which glucose begins to be excreted in urine (reduced renal threshold for glucose) and, in some instances, a reduction in the maximum rate at which glucose may be reabsorbed into the bloodstream (reduced transport maximum [tubular maximum for glucose or “TmG”]). Researchers have classified renal glycosuria into two major subtypes based upon the presence of such defects: type A (low threshold, reduced TmG) and type B (low threshold, normal TmG). In addition, investigators have described a form of renal glycosuria termed type 0, in which there is complete absence of renal tubular glucose reabsorption. Isolated renal glycosuria with otherwise normal kidney function is thought to be transmitted as an “incompletely” recessive trait (see below). Human traits, including the classic genetic diseases, are the product of the interaction of two genes for that condition, one received from the father and one from the mother. In autosomal recessive disorders, the condition may not appear unless a person inherits a defective (mutated) gene for the same trait from each parent. If an individual receives one normal gene and one gene for the disease, the person will be a carrier for the disease but usually will not show symptoms. The risk of transmitting the dis Continue reading >>

The Urinary System Flashcards | Quizlet

The Urinary System Flashcards | Quizlet

Glomerular filtration is an ATP-driven process. The urethra contains an internal sphincter of smooth muscle. The collecting duct is impermeable to water in the presence of ADH. In the absence of hormones, the distal tubule and collecting ducts are relatively impermeable to water. Aldosterone is a hormone that causes the renal tubules to reclaim sodium ions from the filtrate. The macula densa cells are chemoreceptors that respond to changes in the urea content of the filtrate. The proximal convoluted tubule is the portion of the nephron that attaches to the collecting duct. Incontinence is the inability to control voluntary micturition. The ureters open through pores in the roof of the urinary bladder. The kidneys secrete antidiuretic hormone to promote water retention and prevent dehydration. The kidney has more distal convoluted tubules than collecting ducts. Tight junctions prevent material from leaking between the epithelial cells of the renal tubule. Many collecting ducts empty into each minor calyx. The glomerulus is a complex of blood capillaries located in the capsular space of the glomerular capsule. Each interlobular artery serves multiple nephrons. Blood-borne solutes can become incorporated into the urine by either glomerular filtration or tubular secretion. The kidneys are normally located in the pelvic cavity. There is a transport maximum for nearly every substance that is reabsorbed using a transport protein in the membrane. Which of the following is not associated with the renal corpuscle? The kidneys are stimulated to produce renin ________. b. when the peritubular capillaries are dilated d. when the specific gravity of urine rises above 1.10 Which of the choices below is not a function of the urinary system? a. helps maintain homeostasis by controlling Continue reading >>

Human Physiology|feedback Multiple Choice Quiz

Human Physiology|feedback Multiple Choice Quiz

Which of the following activities is not regulated by the kidneys? (p. 526) regulating the volume of blood plasma and thus blood pressure in the body regulating the concentrations of certain electrolytes and waste products in the blood regulating the absorption of substances from the gastrointestinal tract regulating the acid-base balance (pH) of the blood plasma Examining the structure of the kidney reveals that the (p. 526) medulla is in contact with the outer capsule medulla is divided into eight to fifteen conical renal pyramids urethra transports urine to the urinary bladder Kidney stones are primarily composed of (p. 526) cholesterol and esters of other steroid compounds crystals and proteins that grow in the renal medulla heavy metals that precipitate in the urinary filtrate salts of weak acids that serve as buffers in the nephron Which statement about the process of micturition is false? (p. 528) It is controlled by a reflex center located in the sacral levels of the spinal cord. Stretch receptors in the bladder initiate this reflex when stretched by filling with urine. Firing of the reflex centers, results in simultaneous contraction of the detrusor muscle and relaxation of the external urethral sphincter, pressuring urine into the urethra. The urge to urinate is a reflex involving the stimulation of specific autonomic nerves The name of the blood vessel delivering blood directly to the glomerulus is the (p. 528) The net filtration pressure at the glomerulus that results in the formation of ultrafiltrate is (p. 532) about equal to arterial blood pressure at 100 mmHg partially due to the very low colloid osmotic pressure of plasma opposed by the high osmotic pressure of ultrafiltrate Which statement about the glomerular filtration rate (GFR) is false? (p. 532) Continue reading >>

Filtration Membrane

Filtration Membrane

The first step in renal processing involves the filtration of plasma in the glomerulus. Glomerular filtration is a process of bulk flow: water and low molecular weight substances move from the lumen of the capillary, across the filtration membrane, and into Bowmans space. What is filtered? Any low-molecular weight substance that is freely dissolved in plasma is filtered. This includes various polar organic molecules such as glucose or amino acids, ions, peptides, drugs, and waste products of organic metabolism such as creatinine and urea. Because filtration involves bulk flow, the concentration of a substance in Bowmans space will be the same as its concentration in the plasma. What is not filtered? Cells, of course, are too large to be filtered. Importantly, proteins are NOT filtered, but are retained in the plasma. Also, small molecular weight substances that are bound to proteins will not be filtered. It is the structure of the filtration membrane that prevents proteins from being filtered. Therearethreelayers that make up the filtration membrane: two epithelia and the basement membrane that lies between them. Figure 1 is a three-dimensional illustration of part of a capillary loop in the glomerulus and depicts the layers making up the filtration membrane. The innermost epithelium is the endothelium that lines the glomerular capillaries. This is a fenestrated endothelium, meaning that there are pores (fenestrae or fenestrations) that penetrate through the endothelial cells. The next layer is the glomerular basement membrane, a shared basement membrane between the two epithelia (endothelium and podocytes). The outer epithelium consists of the podocytes, cells with elaborate interdigitating processes known as foot processes. Figure 2 depicts a cross-section of the fil Continue reading >>

Ketones In Urine: All You Need To Know

Ketones In Urine: All You Need To Know

Authored by Robert Iafelice , Dr. Brianna Stubbs and Nate Martins For a biohacker practicing intermittent fasting, urine ketones are a useful metric to track a state of ketosis . It's a quick and cost-effective way to indicate elevated ketone levels, which provide numerous health benefits. But for someone with uncontrolled type 1 diabetes or type 2 diabetes? Extremely high ketone levels in urine may be a sign of ketoacidosis a serious complication of diabetes which, if left untreated, can lead to coma and death. More on this outlier below. Normally, elevated ketones in urine are a good thing. In this piece, well cover what ketones in urine mean, how they get there and ways to test for ketones. But lets start with a refresher: The two predominant ketone bodies in human metabolism acetoacetate (ACAC) and beta-hydroxybutyric acid (BHB) are made in the liver from fatty acids. When glucose is not available, theyre transported by blood to other body tissues to be used as an energy source. Acetone, the third and least abundant ketone, is spontaneously formed from the breakdown of acetoacetate. Its found mostly in breath, and its contribution as an energy source is insignificant. There are always some ketones present in the blood, but levels naturally increase in response to fasting, prolonged or strenuous exercise, and a low-carbohydrate ketogenic diet . 1 This is called ketosis . Like glucose, ketones are important metabolic fuels reabsorbed through the kidneys as the blood is filtered. When blood passes through the kidneys, small molecules like glucose and ketones end up in the urine, and so must be taken back up. Reabsorption of ketones prevents energy wastage and is especially important during extended fasts. The body doesnt want to flush good energy down the drain, so ke Continue reading >>

Extra Questions For Test 3

Extra Questions For Test 3

The filtration membrane is made up of the glomerular capillary pores, the basement membrane, and the foot processes of the podocytes. The capillary pores and slit pores (created by the podocytes) filter substances based on size. The basement membrane and podocyte foot processes carry a slight negative charge which repels negatively charged molecules. Most proteins carry a negative charge, so small proteins that could fit through the pores would be repelled by the negative charge. Glomerulotubular balance is ________________________. a. the ability of the tubules to increase their reabsorption rate in response to an increased tubular flow. b. the ability of the macula densa to sense sodium concentrations in the tubule and affect afferent arteriole resistance. c. the ability of the tubules to increase resistances of the afferent and efferent arterioles in response to changes in renal blood flow. d. the ability of the afferent and efferent arterioles to constrict or dilate in response to changes in renal blood flow. a. the ability of the tubules to increase their reabsorption rate in response to an increased tubular flow Glomerulotubular balance is the ability of the tubules to increase their reabsorption rate in response to increases in GFR (i.e., increases in the flow of filtrate through the tubule). The overall rate of reabsorption increases in proportion to the increase of the flow rate. Tubuloglomerular feedback involves the macula densa which senses sodium concentrations in the tubule (specifically, the thick ascending limb). The macula densa can cause an increase or decrease in renin secretion from JG cells and can also cause constriction or relaxation of the afferent arteriole. Inhibiting activity of the basolateral Na+/K+ ATPase pump would likely have what effect Continue reading >>

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