REVISED Renal Anatomy and Physiology Worksheet. 1. On the diagram below label the major organs of the urinary system.

Transcription

1 Revised August 2015 Name REVISED Renal Anatomy and Physiology Worksheet 1. On the diagram below label the major organs of the urinary system. 2. List the major functions performed by the kidneys. List as many as your textbook (or professor) has given. 3. On the diagram below label the major parts of the kidney. outermost connective tissue conduit for blood vessels & nerves space space region region region rounded tip entire structure space tube

2 4. On the diagram below label the parts of the cortical and juxtamedullary nephrons and other nonnephron parts of the kidney. 2 C O R T B capillaries specialized cells capillaries E A X specialized cells O U T E R M E D U L L A I N N E R M E D U L L A duct - not part of nephron rounded tip space - not part of nephron 5. Which nephron above (A or B) is the cortical nephron and which is the juxtamedullary nephron? A is the B is the 6. a. Draw at least one arrow in each labelled part of the cortical and juxtamedullary nephrons above to indicate the direction of fluid flow. The more arrows the better.

3 3 b. Fill in the blanks below to trace the flow of fluid through a cortical nephron. The first line, glomerulus has been filled in for you. glomerulus space tubule limb limb tubule tubule duct both limbs together c. Fill in the blanks below to trace the flow of fluid through a juxtamedullary nephron. glomerulus space tubule limb limb all sections of both limbs together limb tubule tubule duct

4 d. Fill in blanks to trace urine flow from collecting duct to outside a female s body. collecting duct 4 duct through wide area tube hollow muscular organ sphincter (involuntary) tube sphincter (voluntary) opening to exterior e. Fill in blanks to trace urine flow from collecting duct to outside a male s body. collecting duct duct through wide area tube hollow muscular organ sphincter (involuntary) tube sphincter (voluntary) (omit membranous urethra) tube opening to exterior

5 7. Three nephron processes are responsible for producing urine. On the simplified diagram below label each of these 3 processes on the bold label lines. 5 afferent arteriole glomerular capillaries efferent arteriole cortical radiate artery Bowman s capsule peritubular capillaries rest of nephron (proximal convoluted tubule through collecting duct) urine 8. Each of the 6 diagrams below is similar to the one above. Based on the arrows shown in each diagram determine whether the substance shown is NORMALLY only filtered, only secreted, filtered and completely reabsorbed, filtered and partially reabsorbed, filtered and secreted, or filtered and partially reabsorbed and secreted. THEN, name a substance that the nephron handles in exactly the manner shown. a. This substance is Optional: An example of a substance handled by the nephron in this manner is urine

6 6 b. This substance is Optional: An example of a substance handled by the nephron in this manner is urine c. This substance is An example of a substance handled by the urine nephron in this manner is d. This substance is Optional: An example of a substance handled by the nephron in this manner is urine

7 e. 7 This substance is An example of a substance handled by the nephron in this manner is urine f. This substance is An example of a substance handled by the nephron in this manner is urine

8 8 9. Write the names of renal blood vessels on the blanks below to indicate the direction of blood flow through a kidney. Note that the first line, aorta has been filled in for you, as have the names of some of the arteries and veins. On the three lines labelled capillaries you are to write the names of those particular capillaries. aorta segmental artery interlobar artery arcuate artery capillaries from both cortical & juxtamedullary nephrons from juxtamedullary nephrons only capillaries capillaries cortical radiate (interlobular) veins arcuate vein interlobar vein inferior vena cava

9 9 10. Write the equation used to define and calculate net filtration pressure (NFP). You may use words or the standard symbols for the terms of the equation. 11. In 11a and 11c below you are asked to calculate a numerical value for net filtration pressure first at the afferent end of the glomerular capillaries (11a) and then at the efferent end of the glomerular capillaries (11b). In 11e you are asked to average these two pressures to determine the average net filtration pressure across all of the glomerular capillaries. Don t forget to include units with your answer. a. At the afferent end of the glomerular capillaries: glomerular capillary blood (hydrostatic or hydraulic) pressure is 60 mm Hg; hydrostatic (hydraulic) pressure in Bowman s capsule is 15 mm Hg; colloid osmotic pressure of blood in the glomerular capillaries at the afferent end is 21 mm Hg; and colloid osmotic pressure in Bowman s capsule is 0 mm Hg. Please show your work. b. Does your answer to the above question indicate that filtration or reabsorption is occurring across the glomerular capillaries at their afferent end? c. At the efferent end of the glomerular capillaries: glomerular capillary blood (hydrostatic or hydraulic) pressure is 58 mm Hg; hydrostatic (hydraulic) pressure in Bowman s capsule is 15 mm Hg; colloid osmotic pressure of blood in the glomerular capillaries at the efferent end is 33 mm Hg; and colloid osmotic pressure in Bowman s capsule is 0 mm Hg. Please show your work. d. Does your answer to the above question indicate that filtration or reabsorption is occurring across the glomerular capillaries at their efferent end? e. What is the average net filtration pressure across the glomerular capillaries in the above 2 problems? Show your work and include units. f. Write a sentence or two explaining why colloid osmotic pressure in the glomerular capillaries is greater at the efferent end than at the afferent end.

10 a. Calculate a numerical value for net filtration pressure (NFP) in the peritubular capillaries using the values given below. Peritubular capillary blood (hydrostatic or hydraulic) pressure is 20 mm Hg; hydrostatic (hydraulic) pressure in interstitial fluid outside the capillaries is 3 mm Hg; colloid osmotic pressure of blood in the peritubular capillaries is 33 mm Hg; and colloid osmotic pressure of the interstitial fluid is 6 mm Hg. Please show your work and include units with your answer. b. Does your answer to the above question indicate that filtration or reabsorption is occurring across the peritubular capillaries? 13. The following are cause and effect chains of events. In each a sideways arrow ( ) means causes. An up arrow ( ) means increases. A down arrow ( ) means decreases. Always assume that any items or variables not listed remain unchanged and so can be ignored. Fill in each blank with either an up arrow, a down arrow, or No to indicate no change in the listed variables. As an example to get you started, the blanks in the first chain of events have been filled in for you. a. afferent glomerular capillary NFP GFR arteriole blood pressure constriction renal blood flow b. afferent glomerular capillary NFP GFR arteriole blood pressure dilation renal blood flow c. efferent glomerular capillary NFP GFR arteriole blood pressure constriction renal blood flow d. efferent glomerular capillary NFP GFR arteriole blood pressure dilation renal blood flow e. both afferent glomerular capillary NFP GFR and efferent blood pressure arteriole constriction renal blood flow equally

11 a. Below is part of the wall of a generalized nephron, i.e., the cells could be from any part of the nephron - the proximal or distal convoluted tubule, thin descending or thin ascending limbs of Henle s loop, thick ascending limb of Henle s loop, connecting tubule, or the collecting duct. Label the parts shown. Words in small font beneath the lines provide additional information to guide you. Of course not all parts of the nephron are composed of the non-microvilli simple cuboidal cells shown in the diagram. So in parts b.-d. at the bottom of the page name the nephron segment(s) composed of the cell type listed. Fluid Flow Blood Flow space seal epithelial cell of nephron this particular surface or membrane this particular surface or membrane route through cell route through seal and between cells fluid or space blood vessel b. In the the simple cuboidal cells all have microvilli. 1 nephron segment c. In the 2 nephron segments the cells are simple squamous cells. d. In the 4 nephron segments the cells are mainly simple cuboidal cells (without microvilli) as shown above.

12 The purpose of the diagrams on this and the next three pages is to show the mechanisms by which the proximal convoluted tubule reabsorbs common substances. Part 15a shows only Na + reabsorption, but of course it is essential to keep in mind that it creates the conditions for reabsorption of most of the other substances in 15b, 15c, and 15d. Also, remember that each proximal convoluted tubule cell is carrying out all of these processes (and more) simultaneously. General directions for all 4 diagrams are as follows. To show movement through transporters or channels, draw arrows across both the luminal (apical) and basolateral (basal) membranes, and/or through the tight junctions. Use dashed arrows ( ) to represent passive transport. Use dash/dot arrows ( ) to represent active transport, either primary or secondary. In addition, make your arrows slant downward in the direction of flow to show movement of a substance down its concentration gradient or slant upward to show movement of a substance up its concentration gradient. Specific instructions for each diagram are given with that diagram. a. Specific directions: Show how Na + is reabsorbed across the proximal convoluted tubule cell below and into the blood. First, show what the Na + and K + concentrations are in every compartment (luminal filtrate, intracellular fluid, interstitial fluid, and blood) by writing either High Na + or Low Na + AND either High K + or Low K+ in each compartment. Next draw and label each of the following: Na + K + ATPase pump, Na + transporter/channel, and a K + ion channel. Lastly, draw arrows (as described above in the general directions) to show the movement of Na + through each transporter/channel, or pump as it is reabsorbed from filtrate in the lumen to blood in peritubular capillaries. Also show the pumping and leaking of K +. interstitial peritubular lumen fluid capillary fluid flow PCT cell blood flow PCT cell PCT cell

13 13 b. Specific directions: Show how H 2 O, Cl, K +, Ca 2+, and urea are reabsorbed from luminal filtrate to blood across the proximal convoluted tubule below. You may wish to start by redrawing the reabsorption of Na + from the previous page as a reminder that all of these substances follow Na +. Draw and label aquaporin channels for water. Transporters and channels for other substances do not have to be shown. Draw arrows (as described in the general directions on page 12) to show the pathway(s) for reabsorption of each of the substances above. Show which substances are reabsorbed via the transcellular route, which via the paracellular route, and which via both routes. interstitial peritubular lumen fluid capillary fluid flow PCT cell blood flow PCT cell PCT cell

14 14 c. Specific directions: Show how the proximal convoluted tubule removes bicarbonate ion, HCO 3, from the filtrate and adds it to the blood. Show that this process is not technically reabsorption because the HCO 3 removed from the filtrate is not the same one that is released into the blood. In the lumen write the complete chemical reaction of HCO 3 with H + to H 2 CO 3 and then to CO 2 and H 2 O. Show which step is catalyzed by a famous enzyme. Draw in the location of the enzyme and label it. Show which substance(s) can cross the apical (luminal) membrane and enter the cell. Use the appropriate arrows described in the general directions on page 12. Next write the complete chemical reaction that these substances undergo within the proximal convoluted tubule cell being sure to show again which step is catalyzed by the famous enzyme and labelling that enzyme. Lastly, use the appropriate arrows to show the correct movement of the products of this chemical reaction out of the cell, into the interstitial fluid and peritubular capillary blood. interstitial peritubular lumen fluid capillary fluid flow PCT cell blood flow PCT cell PCT cell

15 15 d. Specific directions: Show how glucose and amino acids are reabsorbed from luminal filtrate to blood across the proximal convoluted tubule below. Draw and label a Na + -glucose cotransporter, a Na + -amino acid cotransporter, Na + K + ATPase pump, a facilitated diffusion glucose transporter and a facilitated diffusion amino acid transporter. Next show what the Na + concentration is in every compartment (luminal filtrate, intracellular fluid, interstitial fluid, and blood) by writing either High Na + or Low Na + in each compartment. Write High glucose and High amino acids in the compartment that has the highest concentration of these substances. Write Low glucose and Low amino acids in each of the other compartments. Lastly and most importantly, draw arrows (as described in the general directions on page 12) to show the pathway for reabsorption of Na +, glucose, and amino acids. interstitial peritubular lumen fluid capillary fluid flow PCT cell blood flow PCT cell PCT cell

16 On page 17 is a diagram of a juxtamedullary nephron, well, at least most of one. It includes Bowman s capsule, proximal convoluted tubule, descending limb of the loop of Henle, thin and thick ascending limbs of the loop of Henle, and the distal convoluted tubule. Collecting ducts for this nephron are shown on pages 19 & 20. The general instructions for page 17 are to show which substances are reabsorbed and/or secreted in each segment from the proximal convoluted tubule through the collecting duct. For each substance use the symbol drawn across the nephron s wall to represent active transport, either primary or secondary, and the symbol also drawn across the nephron s wall to represent passive transport. Of course each arrow could be coming out of the tubular fluid to represent reabsorption or going into tubular fluid to represent secretion. The line representing the nephron s wall is a composite of BOTH the luminal (apical) and basolateral (basal) membranes. If a substance is actively reabsorbed or secreted across either membrane, use the active transport symbol ( ) to show its movement. If a substance is passively reabsorbed or secreted across both membranes, use the passive transport symbol ( ) to show its movement. Specific instructions for each nephron segment follow. A curved arrow glancing off the nephron s wall shows that the nephron segment is impermeable to that substance. These curved arrows have been added for you on page 17. PROXIMAL CONVOLUTED TUBULE: In the proximal convoluted tubule segment of the nephron on page 17 use the symbols or to show the reabsorption or secretion (if applicable) for each of the following substances: Na +, H 2 O, Cl, K +, Ca 2+, HCO 3, H +, urea, glucose, and amino acids. Label each symbol with the substance being reabsorbed or secreted. As an example Na +, H +, and H 2 O have been done for you. Note: Here we simplify HCO 3 handling and say it is reabsorbed. As you showed on page 14, the HCO 3 ion that enters the blood is not the same one that was filtered. However, the net effect is that HCO 3 is removed from the filtrate and added to the blood as if it had been reabsorbed. DESCENDING LIMB OF THE LOOP OF HENLE: In the descending limb of the loop of Henle on page 17 use the appropriate symbols to show the reabsorption or secretion (if applicable) of H 2 O and urea. The curved arrow with Na + Cl at its end shows that this segment is impermeable to Na + and Cl. THIN ASCENDING LIMB OF THE LOOP OF HENLE: In the thin ascending limb of the loop of Henle on page 17 use the appropriate symbols to show the reabsorption or secretion (if applicable) of Na +, Cl, and urea. The curved arrows with H 2 O show that this segment is impermeable to water. THICK ASCENDING LIMB OF THE LOOP OF HENLE: In the thick ascending limb of the loop of Henle on page 17 use the appropriate symbols to show the reabsorption or secretion (if applicable) of Na +, Cl, and K +. The curved arrows with H 2 O and urea at their ends show that this segment is impermeable to both water and urea. DISTAL CONVOLUTED TUBULE: In the distal convoluted tubule on page 17 use the appropriate symbols to show the reabsorption or secretion (if applicable) of Na + and Cl, and then Ca 2+ when parathyroid hormone (PTH) is present. The curved arrows with H 2 O and urea at their ends show that this segment is relatively impermeable to both water and urea. (Note: Connecting tubule will be included with the collecting duct in the next section.)

17 17 Na + H 2 O H + to collecting duct H 2 O urea urea Na + Cl H 2 O Na + Cl H 2 O

18 18 GENERAL DIRECTIONS FOR COLLECTING DUCTS: For this exercise the connecting tubules may be considered to be part of the collecting duct system. Because so many substances are reabsorbed and/or secreted across the collecting duct system and because the final reabsorption or secretion depends upon various conditions and hormones in the body and because the mechanisms of reabsorption and secretion are sometimes not straightforward, the functions of the collecting duct system are complicated. The approach here is to try to simplify the functions and mechanisms to the level of an introductory, two-semester anatomy and physiology course. For example we will treat HCO 3 as being reabsorbed, when as was seen on page 14, the process is not that simple, although the net effect is reabsorption. In another attempt at simplification, the collecting duct is treated separately for each of four contrasting conditions: ADH, aldosterone, dietary K +, and acidosis/alkalosis. Separate directions for each set of contrasting conditions are given below. COLLECTING DUCT IN PRESENCE AND ABSENCE OF ANTIDIURETIC HORMONE (ADH): The purpose of this section is to show the collecting duct s reabsorption, secretion, and/or impenetrability to H 2 O and urea when ADH is present (left side) and when ADH is absent (right side). A simplifying assumption is that the collecting duct s permeability to Na + and Cl is very low and unchanging. Use the following symbols to show the movement (or lack of movement) across the collecting duct: H 2 O or H 2 O for passive transport of H 2 O down its concentration gradient H 2 O for H 2 O unable to pass through collecting duct cells (see example on p. 17) urea or urea for passive transport of urea down its concentration gradient urea for urea unable to pass through collecting duct cells (see example on p. 17) Recall that ADH does not directly affect the movement of urea. However water s movement, or lack of movement, may affect urea s concentration in the collecting duct fluid and hence affect urea s movement. The dashed line represents the boundary between the cortical collecting duct above the line and the medullary collecting duct below the line. Be sure to show any differences in the reabsorption, secretion, or impenetrability of H 2 O and urea in these two regions of the collecting duct. Lastly, at the bottom of each side of the collecting duct, circle the most appropriate water content of the urine, volume of the urine, and osmolarity (compared to plasma) of the urine that is produced in the presence and absence of ADH. COLLECTING DUCT IN PRESENCE AND ABSENCE OF ALDOSTERONE: The purpose of this section is to show the reabsorption, secretion, and/or no transport of Na +, Cl, K + and H 2 O when aldosterone is present (left side) and absent (right side). Because this section is meant to focus on aldosterone s effect on Na + Cl reabsorption, you should assume constant and normal blood K + levels. However, because aldosterone also affects K + reabsorption/secretion, you must show the results of those affects. Also, even though the collecting duct is able to separate Na + Cl reabsorption from H 2 O reabsorption, some H 2 O usually follows Na + Cl. Please show this H 2 O movement. Use the following symbols to show movement (or lack of movement) across the collecting duct: Na + Cl or Na + Cl for active transport of Na + Cl against its concentration gradient Na + Cl for Na + Cl essentially unable to pass through collecting duct (see example on p. 17) K + or K + for active transport of K + K + or K + for passive transport of K + H 2 O or H 2 O for passive transport of H 2 O

19 19 H 2 O for H 2 O essentially unable to pass through collecting duct (see example on p. 17) Lastly, at the bottom of each side of the collecting duct, circle the most appropriate Na +, Cl, K +, and H 2 O contents of the urine produced. COLLECTING DUCT UNDER HIGH AND LOW K + CONDITIONS: The purpose of this section is to show the net reabsorption and/or net secretion of K + under conditions of high K + (left side) and low K + (right side). In this section ignore the effects of acidosis/alkalosis. They will be covered in the next section. Also, because the collecting duct is constantly reabsorbing some K + and can only change K + secretion, show only the net K + reabsorption or net K + secretion. Use the symbol K + or K + to show net active transport of K +, and K + or K + to show net passive transport of K +. Lastly, at the bottom of each side of the collecting duct, circle the most appropriate K + content of the urine produced. COLLECTING DUCT DURING ANIMAL PROTEIN DIET/ACIDOSIS OR VEGETARIAN DIET/ALKALOSIS: The purpose of this section is to show how the collecting duct is involved in acid-base regulation by reabsorbing or secreting H + and HCO 3 and how this process affects K + reabsorption/secretion. At the top of each collecting duct, write the type of intercalated cell carrying out the transport processes you will show below. Use the following symbols to show the movement across the collecting duct: H + or H + for active transport of H + H + H + or for the active transport exchange of H + for K + K + K + HCO 3 or HCO 3 for passive transport of HCO 3 Lastly, at the bottom of each side of the collecting duct, circle the most appropriate H +, HCO 3, and K + contents of the urine produced.

20 20 + ADH ADH + aldosterone aldosterone interstitial fluid and blood interstitial fluid and blood more Na + in urine more Na + in urine more H 2 O in urine more H 2 O in urine less Na + in urine less Na + in urine less H 2 O in urine less H 2 O in urine more Cl in urine more Cl in urine large urine volume large urine volume less Cl in urine less Cl in urine small urine volume small urine volume more K + in urine more K + in urine iso-osmotic urine iso-osmotic urine less K + in urine less K + in urine hyperosmotic urine hyperosmotic urine more H 2 O in urine more H 2 O in urine hypo-osmotic urine hypo-osmotic urine less H 2 O in urine less H 2 O in urine

21 21 normal or high K + diet, low K + diet, hyperkalemia, or hypokalemia, or animal protein in diet, vegetarian diet, or + aldosterone aldosterone or body in acidosis body in alkalosis interstitial interstitial fluid fluid type of CD cell type of CD cell and and blood blood more H + in urine more H + in urine less H + in urine less H + in urine more K + in urine more K + in urine more HCO 3 in urine more HCO 3 in urine less K + in urine less K + in urine less HCO 3 in urine less HCO 3 in urine more K + in urine more K + in urine less K + in urine less K + in urine

22 Control of renin secretion. The three ways in which renin secretion is controlled are listed below in a, b, & c. The steps in each cause and effect chain of events leading to renin secretion have been scrambled. Your job is two-fold. First, put the steps in the correct order leading to renin secretion. Second, in front of each step place either an up arrow ( ) to indicate increased, or a down arrow ( ) to indicate decreased, or No to indicate no change in that variable. For the purpose of this example, each of the three methods of altering renin secretion will begin with a decrease in mean arterial blood pressure indicated by MAP. As an example to get you started, the first one has been done for you. a. Scrambled steps: MAP, CNS vasomotor center activity, stimulation of granular cells of afferent arteriole, renin, sympathetic nerve impulses to kidney, carotid sinus and aortic arch baroreceptor activity correct answer: MAP carotid sinus and aortic arch baroreceptor activity CNS vasomotor center activity sympathetic nerve impulses to kidney stimulation of granular cells of afferent arterioles renin secretion b. Now it s your turn. The scrambled steps are: MAP, renin secretion, stimulation of granular cells of afferent arterioles, blood pressure in afferent arterioles MAP c. Scrambled steps: MAP, glomerular filtration rate, net filtration pressure, stimulation of granular cells of afferent arteriole, blood pressure in glomerular capillaries, blood pressure in afferent arterioles, Na + delivery to macula densa cells, renin secretion, amount of filtered Na + MAP

23 Write several sentences to describe in the correct order the sequence of events leading from increased secretion of renin to increased formation of angiotensin II. Include all of the following in your description: renin, angiotensin II, angiotensin I, angiotensinogen, the source of angiotensinogen, angiotensin converting enzyme, and the primary location of angiotensin converting enzyme in the body. 19. To summarize the effects of factors in #17 & #18 above, put either an up or down arrow on each of the blank lines below. MAP renin angiotensin II MAP renin angiotensin II 20. The questions below ask you to summarize the effects of the renin-angiotensin system on blood pressure homeostasis, particularly how the renin-angiotensin system causes an increase in MAP back toward the set point after an unexpected drop in MAP. The steps in several cause and effect chains of events involved in blood pressure regulation are scrambled below. As you did in #17 on the previous page, put the steps in the correct order and then put an up or down arrow in front of each step to indicate whether it is increased or decreased in the attempt to return blood pressure to normal. A review of basic cardiovascular physiology may be helpful if you have difficulty. Note that every chain of events will begin with a decrease in MAP and end with either an increase or decrease in MAP. a. Scrambled steps: MAP, angiotensin II, total peripheral resistance (TPR), renin, vasoconstriction of arterioles throughout body, MAP. MAP

24 24 b. Scrambled steps: MAP, end diastolic volume (EDV), stroke volume (SV), blood volume, renin, aldosterone, angiotensin II, stretch of ventricles, venous return to heart, cardiac output (CO), Na + (& H 2 O) reabsorption in collecting duct, ventricular filling, force of contraction via preload (Frank-Starling law of heart), MAP MAP c. Scrambled steps: MAP, end diastolic volume (EDV), stroke volume (SV), blood volume, renin, antidiuretic hormone (ADH), angiotensin II, stretch of ventricles, venous return to heart, cardiac output (CO), H 2 O reabsorption in collecting duct, ventricular filling, force of contraction via preload (Frank-Starling law of heart), MAP MAP

25 25 d. Scrambled steps: MAP, end diastolic volume (EDV), stroke volume (SV), blood volume, renin, activation of hypothalamic thirst center, angiotensin II, stretch of ventricles, venous return to heart, cardiac output (CO), fluid intake, ventricular filling, force of contraction via preload (Frank-Starling law of heart), MAP MAP e. Do your answers to 20a-d make sense? Each of the above cause and effect chains of events is a homeostatic mechanism designed to correct for deviations in blood pressure and to bring blood pressure back toward the set point. 1) Does each of your chains of events end with MAP moving in a direction opposite to the initial change? yes or no 2) Questions 20b-d each involved 14 steps. Does each of your answers have 14 steps? yes or no End of 2015 revised anatomy and physiology worksheet.