BIOD 152 MODULE 7 - PROBLEM SET
1. What causes water and solutes to leave the glomerulus?
Answer: The afferent arteriole, which is fed by the interlobular artery, is much larger in
diameter than the efferent arteriole. The difference in diameter causes an extremely high blood
pressure in the glomerular capillaries, forcing water and solutes out of the blood,thus making
filtration possible. Water and solutes leave the glomerulus, enter theglomerular capsule, and
subsequently flow into the renal tubule.
2. Once water and solutes leave the blood and enter the glomerular capsuleit is called .
Answer: Filtrate
3. are found in the cortex region of the kidney, except for a portionof their loop
of Henle which extends into the medulla. pass deeply
intothe medulla because of their location and their longer loops of Henle.
Answer: Corticalnephrons; juxtamedullary nephrons
4. Describe the proximal convoluted tubule.
Answer: The first section of the tubule is acoiled proximal convoluted tubule which is
specialized to reabsorb water and manysolutes from the glomerular filtrate into the low-pressure
peritubular capillaries whichsurround the renal tubule as well as secrete certain unwanted
substances.
5. Describe the loop of Henle.
Answer: The second section is the hairpin loop of Henle.Initially the loop of Henle has the
descending limb followed by the ascending limb.The descending limb allows water loss and
the ascending limb allows salt (NaCl) loss.
6. Describe the distal convoluted tubule.
Answer: The last part of the tubule is the highlycoiled distal convoluted tubule which allows for
hormonally controlled reabsorption ofwater and solutes. Mostly the distal convoluted tubule is
responsible for the secretionof unwanted substances.
7. What are the three types of capillaries associated with nephrons and theirfunction?
Answer: The glomerular capillaries, the peritubular capillaries and the vasa recta.The
glomerular capillaries (glomerulus) are highly coiled capillary beds formed fromthe afferent
arteriole, leaving as the efferent arteriole. The peritubular capillaries closely follow the renal
tubules and drain into the interlobular vein. the vasa recta which follow the loops of Henle in
the juxtamedullary nephrons of the medulla.
8. Describe the process of micturition.
Answer: Micturition is the act of emptying the bladder. As urine accumulates, the rugae
flatten and the wall of the bladder thins as it stretches, allowing the bladder to store larger
amounts of urine without a significant rise in internal pressure. The urge to urinate usually
starts when about 200 ml of urine has accumulated, causing distension of the bladder walls
, which initiates a visceral reflex arc. This causes the detrusor muscle to contract and the
internal sphincter to relax forcing stored urine through the internal sphincter into the
upper part of the urethra. A person can consciously resist this initial urge to urinatebecause the
external sphincter is voluntarily controlled. As the bladder continues to fill, the desire to urinate
becomes stronger. Eventually, if the amount of urine reaches 100% of the bladder's capacity, the
voluntary sphincter opens, and micturition occursinvoluntarily.
9. What is incontinence?
Answer: Incontinence is the inability to control micturition voluntarily.
10. What is urinary retention?
Answer: The inability to expel stored urine.
11. How many times a day does the kidney filter through the blood plasma?
Answer: -The kidneys filter the entire blood plasma volume about 60 times each day.
12. About how many gallons are filtered vs. excreted as urine?
Answer: About 47 gallons of glomerular filtrate containing the water, nutrients, and essential
ions areremoved daily from the blood plasma. By the time filtrate enters the collecting ducts,it
contains about only 0.5 gallons of urine, with the other 99% being returned to theblood.
13. What are the three steps of urine formation?
Answer: For the body to filter the entireblood and then retain the important elements, three
processes must take place: filtration, reabsorption and secretion.
14. What is Blood hydrostatic pressure (HP)?
Answer: It is the amount of pressure foundinside the blood in the capillaries, driving fluids out
of the glomerular capillary.
15. What is Colloid osmotic pressure (COP)?
Answer: It is also called oncotic pressure.COP is dependent on the amount of proteins in the
plasma. COP opposes blood hydrostatic pressure by driving fluids back into the capillary
beds.
16. What is the normal range of COP?
Answer: The COP needs to remain within a normalrange between 25-32mmHg.
17. What is capsular pressure?
Answer: It also opposes blood hydrostatic pressure anddrives fluid back into the glomerular
capillaries.
18. The urinary system has kidneys, ureters, and
bladder.
Answer: 2;2; 1
1. What causes water and solutes to leave the glomerulus?
Answer: The afferent arteriole, which is fed by the interlobular artery, is much larger in
diameter than the efferent arteriole. The difference in diameter causes an extremely high blood
pressure in the glomerular capillaries, forcing water and solutes out of the blood,thus making
filtration possible. Water and solutes leave the glomerulus, enter theglomerular capsule, and
subsequently flow into the renal tubule.
2. Once water and solutes leave the blood and enter the glomerular capsuleit is called .
Answer: Filtrate
3. are found in the cortex region of the kidney, except for a portionof their loop
of Henle which extends into the medulla. pass deeply
intothe medulla because of their location and their longer loops of Henle.
Answer: Corticalnephrons; juxtamedullary nephrons
4. Describe the proximal convoluted tubule.
Answer: The first section of the tubule is acoiled proximal convoluted tubule which is
specialized to reabsorb water and manysolutes from the glomerular filtrate into the low-pressure
peritubular capillaries whichsurround the renal tubule as well as secrete certain unwanted
substances.
5. Describe the loop of Henle.
Answer: The second section is the hairpin loop of Henle.Initially the loop of Henle has the
descending limb followed by the ascending limb.The descending limb allows water loss and
the ascending limb allows salt (NaCl) loss.
6. Describe the distal convoluted tubule.
Answer: The last part of the tubule is the highlycoiled distal convoluted tubule which allows for
hormonally controlled reabsorption ofwater and solutes. Mostly the distal convoluted tubule is
responsible for the secretionof unwanted substances.
7. What are the three types of capillaries associated with nephrons and theirfunction?
Answer: The glomerular capillaries, the peritubular capillaries and the vasa recta.The
glomerular capillaries (glomerulus) are highly coiled capillary beds formed fromthe afferent
arteriole, leaving as the efferent arteriole. The peritubular capillaries closely follow the renal
tubules and drain into the interlobular vein. the vasa recta which follow the loops of Henle in
the juxtamedullary nephrons of the medulla.
8. Describe the process of micturition.
Answer: Micturition is the act of emptying the bladder. As urine accumulates, the rugae
flatten and the wall of the bladder thins as it stretches, allowing the bladder to store larger
amounts of urine without a significant rise in internal pressure. The urge to urinate usually
starts when about 200 ml of urine has accumulated, causing distension of the bladder walls
, which initiates a visceral reflex arc. This causes the detrusor muscle to contract and the
internal sphincter to relax forcing stored urine through the internal sphincter into the
upper part of the urethra. A person can consciously resist this initial urge to urinatebecause the
external sphincter is voluntarily controlled. As the bladder continues to fill, the desire to urinate
becomes stronger. Eventually, if the amount of urine reaches 100% of the bladder's capacity, the
voluntary sphincter opens, and micturition occursinvoluntarily.
9. What is incontinence?
Answer: Incontinence is the inability to control micturition voluntarily.
10. What is urinary retention?
Answer: The inability to expel stored urine.
11. How many times a day does the kidney filter through the blood plasma?
Answer: -The kidneys filter the entire blood plasma volume about 60 times each day.
12. About how many gallons are filtered vs. excreted as urine?
Answer: About 47 gallons of glomerular filtrate containing the water, nutrients, and essential
ions areremoved daily from the blood plasma. By the time filtrate enters the collecting ducts,it
contains about only 0.5 gallons of urine, with the other 99% being returned to theblood.
13. What are the three steps of urine formation?
Answer: For the body to filter the entireblood and then retain the important elements, three
processes must take place: filtration, reabsorption and secretion.
14. What is Blood hydrostatic pressure (HP)?
Answer: It is the amount of pressure foundinside the blood in the capillaries, driving fluids out
of the glomerular capillary.
15. What is Colloid osmotic pressure (COP)?
Answer: It is also called oncotic pressure.COP is dependent on the amount of proteins in the
plasma. COP opposes blood hydrostatic pressure by driving fluids back into the capillary
beds.
16. What is the normal range of COP?
Answer: The COP needs to remain within a normalrange between 25-32mmHg.
17. What is capsular pressure?
Answer: It also opposes blood hydrostatic pressure anddrives fluid back into the glomerular
capillaries.
18. The urinary system has kidneys, ureters, and
bladder.
Answer: 2;2; 1
