Human Anatomy and Physiology - Problem Drill 23: The Urinary System, Fluid, Electrolyte and Acid-Base Balance Question No. 1 of 10 Which of the following statements about the functions of the urinary system is not correct? Question #01 A. The urinary system is involved in the regulation of blood ph. B. The urinary system is involved in the formation and regulation of vitamin C absorption. C. The urinary system is involved in regulating ion concentration. D. The urinary system is involved in the removal of toxic substances from the bloodstream. E. None of the answers is correct. The urinary system is involved in the regulation of blood ph. B. Correct! The urinary system is involved in the synthesis of vitamin D. The urinary system is involved in the regulation of ions. The primary role of the kidneys is to filter the blood and remove toxic substances from the blood. There is one correct answer above. The primary function of the kidneys is to eliminate wastes from the body, but there are a number of other functions performed by this system: (1) regulation of blood ph, (2) regulation of blood volume, (3) regulation of ion concentration, (4) assistance in vitamin D synthesis, and (5) removal of toxic substances from the body, for example, during extreme dieting and starvation.
Question No. 2 of 10 A 45-year-old male is injured in a car accident. The injuries include damage to the renal artery on the right side of his body. Based on this information, which of the following statements is correct? Question #02 A. The renal artery branches off the inferior vena cava, just inferior to the diaphragm. B. The renal artery delivers between 1-5% of the total cardiac output to the kidneys for filtering. C. Inside the kidney, the renal artery divides into the segmental arteries and then into interlobar arteries. D. The glomeruli are directly connected to the renal artery at the hilum of the kidney. E. The vasa recta are a group of veins that deliver venous blood to the kidneys. The renal arteries arise along the posterolateral surface of the abdominal aorta. B. Incorrect! Between 20-25% of the total cardiac output is delivered to the kidneys for filtering. C. Correct! Inside the kidney, the renal artery divides into the segmental arteries and then into interlobar arteries. The glomeruli are connected to the afferent and efferent arterioles. The efferent arteriole divides into a meshwork of capillaries called the vasa recta. Blood is continually filtered within Bowman s capsule. Wastes and other solutes are passed into the tubule for inclusion in the urine, while large items like cells or large proteins are retained in the blood. Blood flows into the kidney at the renal artery. The renal artery branches into several afferent arterioles. Each afferent arteriole subdivides into a network of capillaries, called a glomerulus. The capillaries merge into an efferent arteriole. The efferent arteriole divides into a meshwork of capillaries, called the vasa recta. The vasa recta converge at the renal vein, and blood flows out of the kidney.
Question No. 3 of 10 The nephrons perform many key functions collectively to filter the incoming blood. Which of the following statements about filtration is correct? Question #03 A. Filtration in the nephron is the movement of fluid from Bowman s capsule into the glomerulus. B. Normally, proteins do not cross into the nephron during filtration. C. The movement of solutes and fluid across the glomerulus into the nephron is driven by negatively charged proteins in Bowman s capsule. D. The filtration process only occurs to a fraction of the blood entering the kidneys. E. None of the answers is correct. During filtration at the glomerulus, fluid moves from the glomerulus into the nephron. B. Correct! Proteins and cells are too large to filter through the pores of the glomerulus, whereas glucose, water, and sodium are filtered through the pores into the nephrons. The movement of fluid and dissolved components through the glomerulus is due to the pressure exerted by the blood entering Bowman s Capsule. All the blood that enters the glomerulus is filtered, and then 99% of the filtrate is reabsorbed. There is one correct answer above. Filtration in the kidney refers to the movement of substances from the glomerular capillary into the nephron. This is due to the pressure exerted by the blood entering Bowman s Capsule, which forces water and dissolved components through the glomerulus to form filtrate. Proteins and cells are too large to filter through the pores, whereas glucose, water, and sodium are filtered through the pores into the nephrons.
Question No. 4 of 10 Which segment of the nephron is labelled in the image below? Question #04 A. Thick descending limb. B. Proximal convoluted tubule. C. Collecting duct. D. Thin ascending limb. E. Renal corpuscle. The proximal convoluted tubule is labelled in the image; the thin descending limb is further downstream. B. Correct! The label in the image is pointing at the proximal convoluted terminal. The collecting duct is the most distal segment of the nephron; the proximal convoluted tubule is labelled in the image. The ascending limb is part of the nephron loop or loop of Henle. The renal corpuscle is adjacent to the glomerulus.
Question No. 5 of 10 Nephrons perform the key functions of the kidneys. Which of the following statements about the nephron is not correct? Question #05 A. There are over 1 million in each kidney. B. All the nephrons drain towards the center of the kidney into the collecting duct system. C. The vasa recta converge at the renal vein, and blood flows out of the kidney. D. The two functional processes of the nephrons are filtration and reabsorption. E. Filtration in the kidney refers to the movement of substances from the glomerular capillary into the nephron. There are over 1 million in each kidney. B. Incorrect! All the nephrons drain towards the center of the kidney into the collecting duct system. The vasa recta converge at the renal vein, and blood flows out of the kidney. D. Correct! The functional processes of the kidneys are: (1) filtration and reabsorption, (2) secretion, and (3) excretion. Filtration in the kidney refers to the movement of substances from the glomerular capillary into the nephron. The nephrons of the kidneys perform a number of functional processes that facilitate the overall function of the kidneys in the body. These functional processes are: (1) filtration and reabsorption, (2) secretion, and (3) excretion. Filtration in the kidney refers to the movement of substances from the glomerular capillary into the nephron. This is due to the pressure exerted by the blood entering Bowman s Capsule, which forces water and dissolved components through the glomerulus to form filtrate. Proteins and cells are too large to filter through the pores, whereas glucose, water, and sodium are filtered through the pores into the nephrons.
Question No. 6 of 10 The nephrons in the kidneys are responsible for fluid and solute balance, and respond to hormonal activation in these processes. Which of the following statements about tubular reabsorption is correct? Question #06 A. Tubular reabsorption is the process by where the body gets rid of excess fluids and sodium. B. The reabsorption that takes place in the renal tubule has a limit to the maximum reabsorption of glucose. C. During times of low water intake, you would expect the kidneys to decrease the amount of fluid that is reabsorbed in the nephrons. D. Tubular maximum refers to the maximum rate of only fluid reabsorption. E. Reabsorption that takes place in the nephrons remains constant and cannot change. Reabsorption is the process whereby the filtrate produced in the glomerulus is reabsorbed through the renal tubule to recover needed fluid and solutes. B. Correct! Tubular maximum, with respect to glucose, is limited and excess glucose (diabetes) in the bloodstream will lead to a loss of glucose out of the body in the urine. During times of low water intake, you would expect the kidneys to increase the amount of fluid that is reabsorbed in the nephrons to maintain normal fluid levels in the body. Tubular maximum refers to the maximum rate of reabsorption, and this impacts both fluid and solutes. The reabsorption that takes place in the kidneys can be modulated based on the needs of the body. Reabsorption is the process whereby the filtrate produced in the glomerulus is reabsorbed through the renal tubule. Approximately 99% of all the filtrate is reabsorbed and this includes: water, sodium, glucose, magnesium, etc. The reabsorption process is specific to the changing needs of the body. In uncontrolled diabetes, higher than normal blood glucose levels occur. This leads to greater than normal glucose being filtered in the glomerulus. Therefore, glucose levels in the nephron exceed tubular maximum and this causes glucose to be excreted in the urine. The excreted glucose can be easily detected on urine test strips.
Question No. 7 of 10 Which of the following statements is not correct about the nephron loop? Question #07 A. The nephron loop can be divided into 2 functional regions: descending limb and the ascending limb. B. Another name for the nephron loop is the loop of Henle. C. Normally, water moves in to the descending limb of the nephron loop. D. Na + and Cl - are actively transported out of the ascending limb. E. The nephron loop enters the medulla region of the kidney. The nephron loop, or loop of Henle, can be divided into 2 functional regions: descending limb and the ascending limb. B. Incorrect! Another name for the nephron loop is the loop of Henle. C. Correct! Normally, water moves out of the descending limb of the nephron loop, into the medulla. In the ascending limb, fluid travels towards the cortex. In this region of the nephron, Na+ and Cl- are actively transported out of the limb. Cortical nephrons do extend into the medulla of the kidney. The nephrons are tubular structures, which are the functional unit of the kidneys. There are over 1 million in each kidney. All the nephrons drain towards the center of the kidney into the collecting duct system. The nephron performs almost all of the kidneys functions, including reabsorption and secretion of certain solutes and ions. Nephrons are classified into two groups: (1) The Juxtamedullary apparatus extends into the medulla, and (2) Cortical, which do not extend into medulla.
Question No. 8 of 10 The kidneys are dynamic in their function and can respond to the changing needs of the entire body. One of the abilities of the kidneys is to produce urine of different concentration of solutes. Which of the following statements about the processes to concentrate urine is correct? Question #08 A. The osmolarity in the medulla is higher than the cortex. B. When there is concentrated fluid in the nephron after the ascending limb, a large volume of urine will be expelled from the body. C. The maximum osmolarity in the loop of Henle is 600 mosm. D. In order to conserve water, the kidneys decrease the amount reabsorbed. E. None of the answers are correct. A. Correct! The countercurrent mechanism establishes an osmolarity gradient in which the osmolarity increases from the cortex towards the medulla. B. Incorrect! When there are no hormones released for reabsorption, a large volume of dilute urine is produced. This occurs by the nephron containing dilute fluid, after the ascending limb, which then proceeds out of the kidney for excretion. The maximum osmolarity of 1200 mosm occurs in the loop of Henle. During times of low water intake, the kidneys can conserve water by increasing the volume of reabsorbed fluid. There is one correct answer above. When there are no hormones released for reabsorption, a large volume of dilute urine is produced. This occurs by the nephron containing dilute fluid, after the ascending limb, which then proceeds out of the kidney for excretion. During times of low water intake, the kidneys can conserve water by increasing the volume of reabsorbed fluid. This is accomplished by the countercurrent mechanism. The countercurrent mechanism establishes an osmolarity gradient in which the osmolarity increases from the cortex towards the medulla. The maximum osmolarity of 1200 mosm occurs in the loop of Henle and, as the flitrate passes through the collecting tubule, water moves out into the interstitial fluid space and eventually returns to the rest of the body.
Question No. 9 of 10 A number of processes take place during the act of urination. Which of the following statements about the steps of urination is not correct? Question #09 A. 4-5 minor calyces deliver urine into a major calyx and eventually to the renal pelvis. B. The two sphincters in the urethra are only under involuntary control. C. As the bladder fills, stretch receptors send impulses to the spinal cord. D. The contraction of the abdominal muscles leads to an increase in abdominal pressure, which assists in contracting the urinary bladder. E. None of the answers are correct. 4-5 minor calyces deliver urine into a major calyx and eventually to the renal pelvis. B. Correct! Once the voluntary action of urinating has been initiated, the external urethral sphincter relaxes. This leads to the stimulation that relaxes the internal urethral sphincter. As the bladder fills, stretch receptors send impulses to the spinal cord. The contraction of the abdominal muscles leads to an increase in abdominal pressure, which assists in contracting the urinary bladder. There is one correct answer above. Inside the kidneys, the urine is collected in the collecting tubules and then delivered to the minor calyx. Next, the filtrate in 4-5 minor calyces delivers the urine into a major calyx. The major calyces form the renal pelvis, through which the urine leaves the kidneys and enters the ureter. The urine is transported from each kidney, through the ureter into the urinary bladder. Bladder Stretch: as the bladder fills, stretch receptors send impulses to the spinal cord and eventually to the cortex for processing. Once the voluntary action of urinating has been initiated, the external urethral sphincter relaxes. This leads to the stimulation that relaxes the internal urethral sphincter. The contraction of the abdominal muscles leads to an increase in abdominal pressure, which assists in contracting the urinary bladder and with expelling urine out of the body.
Question No. 10 of 10 Which of the following statement about acid-base balance is correct? Question #10 A. Plasma bicarbonate is not represented on the Davenport diagram. B. Respiratory acidosis occurs from abnormally low levels of carbon dioxide in the blood. C. Respiratory Alkalosis results from too low a level of carbon dioxide, due to hyperventilation. D. The adjustment of renal acid secretion is not a mechanism used by the body to control a change in acid-balance of body fluids. E. None of the answers are correct. Plasma bicarbonate is on the Y axis of the Davenport diagram. B. Incorrect! Respiratory Acidosis results from a build-up of carbon dioxide, due to hypoventilation. C. Correct! Respiratory Alkalosis results from too low a level of carbon dioxide, due to hyperventilation. The human body has 3 main mechanisms to control a change in the acid-base balance of body fluids: (A) Extracellular and intracellular buffering, (B) changing the respiration rate of the lungs and (C) adjustments to renal acid secretion. There is one correct answer above. Acidosis is a state of increased acidity in the body, characterized by a ph < 7.35. Acidosis can be caused by two mechanisms: (A) Respiratory Acidosis results from a build-up of carbon dioxide, due to hypoventilation. It is usually caused by respiratory problems such as anesthetics, and severe pneumonia. As the build-up of carbon dioxide takes place, this leads to increased formation of carbonic acid via carbonic anhydrase. The increased dissociation of carbonic acid into hydrogen protons, causes a decrease in ph (increase in acidity). Alkalosis is a state of decreased acidity (increased ph) in the body, characterized by a ph > 7.45. Alkalosis can be caused by two mechanisms: (A) Respiratory Alkalosis and (B) Metabolic Alkalosis.