Ch. 24 Urinary System
The hormone ____________ acts in this part of the nephron and has a big impact on sodium and potassium levels in the filtrate.
Aldosterone
Match the component of urine formation with its description.
Filtration: Water and solutes passively move out of the glomerulus Tubular Reabsorption: Active transport or diffusion of substances into the blood Tubular Secretion: Active transport of solutes into the tubular fluid
Match the component of a nephron with its description.
Glomerulus: Contains podocytes, pedicels, and filtration slits Distal Convoluted Tubule: Secretes ions into the tubular fluid; reabsorption of water Nephron Loop: Contains a descending limb and an ascending limb Proximal Convoluted Tubule: Cuboidal cells with tall microvilli; active reabsorption
The net result of angiotensin II, aldosterone, and ADH cooperatively is a(n) ____________ in blood pressure resulting largely from increased blood volume.
increase
The countercurrent multiplier is a phenomenon that occurs in the ____________ .
Nephron Loop.
A person who experiences higher than normal levels of phosphate in their blood and higher than normal levels of Ca²⁺ in their urine probably suffers from a deficiency in the production of ____________ .
Parathyroid Hormone
Micturition Reflex
Production of urine by the kidneys begins to fill the urinary bladder. The fullness of the urinary bladder is detected by stretch receptors. Sensory nerve impulses travel along the pelvic nerve to the sacral spinal cord. Efferent impulses excite the detrusor muscle and relax the internal urethral sphincter. Voiding of the bladder is delayed by voluntary control of the external urethral sphincter.
The recycling of ________ out of the collecting duct and back into the nephron loop contributes significantly to the medullary osmotic gradient.
Urea
The increase in osmolarity as filtrate moves down the descending limb is due to ____________ moving out of the tubule.
Water
Which choice describes the countercurrent mechanism of the nephron loop?
Water moves out of the descending limb; sodium moves out of the ascending limb
When we consume more proteins and wheat, the pH of urine becomes more __________.
acidic
The activation of ____________ stimulates widespread vasoconstriction, release of ADH from the posterior pituitary, as well as the adrenal cortex to release aldosterone.
angiotensin II
Water is reabsorbed through specific water transporter proteins called ____________.
aquaporins
Antidiuretic hormone provides a means of controlling water ____________ .
output
The increased osmolarity of the blood stimulates the hypothalamus to stimulate the ____________ pituitary to release ADH.
posterior
Substances are ___________ when they move from the tubular fluid back into the blood.
reabsorbed
Aldosterone from the adrenal cortex causes sodium ions to be ____________________________.
reabsorbed and water to be reabsorbed
The maximum plasma concentration of a substance that can be carried in the blood without eventually appearing in the urine is called the ________________.
renal threshold
Aldosterone acts on the ____________ of the kidney tubules to reabsorb greater amounts of ____________ from the tubular fluid.
DCT; sodium
Which of the following would increase the rate of glomerular filtration?
Increased blood pressure
The majority of glucose is reabsorbed through the walls of the ______________.
proximal convoluted tubule
Low blood pressure causes the kidneys to increase the secretion of ____________ from the JG cells.
renin
The color of urine ranges from almost clear to dark yellow, depending on the concentration of pigment from _____________.
urobilin
A negative feedback system is used until the blood ____________ and osmolarity return to normal levels.
volume
What are the names of the characteristics usually associated with urine? Check all that apply.
-Volume -pH -Color -Smell
Under normal circumstances, urine does not contain which of the following?
-WBC -RBC -Glucose
The normal pH for urine ranges between _________ with an average value of ________.
4.5-8; 6
Urine volume can be several liters per day if there is a decrease in the release of ____________.
ADH
When the level of the hormone ____________ increases, a person will experience an increase in Na⁺ excretion in their urine.
Atrial Natriuretic Peptide
The decrease in osmolarity of the filtrate as it moves up the ascending limb is due to ____________ moving out of the tubule.
Solutes
Countercurrent exchange occurs as both solutes and water move freely in and out of the ______________.
Vasa Recta
ADH will work on the kidneys to ____________ water into the bloodstream.
reabsorb
The right kidney is __________ to the left kidney.
inferior
During dehydration blood volume declines and ____________ concentration rises.
sodium
A byproduct of amino acid catabolism in the liver is _______.
urea
Which type of nephron plays the more important role of establishing a salt concentration gradient?
Juxtamedullary
____________ is unlike other substances previously covered because it is both reabsorbed and secreted.
Potassium
The cell type in the distal tubule and collecting duct that is responsible for Na⁺ and water reabsorption is the ____________ .
Principal Cell
What type of cells line the PCT?
Simple Cuboidal Epithelium
True or False: If urine production drops below .40 L per day, wastes will accumulate in the blood.
True
The __________ __________ is an expandable, muscular sac that can store as much as
urinary bladder
What are the pressures that oppose glomerular hydrostatic pressure to help determine net filtration pressure? Check all that apply.
-Blood colloid osmotic pressure -Capsular hydrostatic pressure
Some substances are not normal components of urine because they are completely reabsorbed. Choose which of the following satisfy this requirement under healthy conditions.
-Filtered Plasma Proteins -Amino Acids -Glucose -Lactate
Which of the following will increase due to an increased net filtration pressure in the kidney?
-GFR -substances in urine
The kidneys aid in acid-base balance by altering the rate of reabsorption of which of the following?
-Hydrogen -Bicarbonate
Most proteins are not freely filtered in the glomerulus. Select the proteins that ARE freely filtered there.
-Insulin -Angiotensin
Which of the following are primary organs of the urinary system? Check all that apply.
-Kidney -Ureters -Urinary bladder -Urethra
Check all that occur when there is an increase in aldosterone secretion in response to an increase in renin by the juxtaglomerular apparatus.
-Potassium secretion increases -Sodium reabsorption increases
Which of the following are major nitrogenous wastes of the human body? Check all that apply.
-Uric acid -Urea -Creatinine
Which substances escape into the filtrate?
-Vitamins B and C -Amino Acids -Glucose -Water -Ions
Which of the following substances have regulated reabsorption?
-Water -HCO3- -Na+ -K+ -Ca2+
In most of us, urine is produced by which of the following?
-Water -Ions -Waste Products
What are the chronic problems that account for the majority of progressive renal failure?
-autoimmune conditions -high blood pressure -diabetes
Besides removing waste products from the bloodstream, the urinary system performs many other functions, including which of the following?
-blood volume regulation -erythropoietin production -urine storage -acid-base balance
Pathway of Blood Through Kidney
1) Renal Artery 2) Interlobar Artery 3) Arcuate Artery 4) Cortical Radiate Artery 5) Afferent Arteriole 6) Glomerular Capillaries 7) Efferent Arteriole 8) Peritubular Capillaries 9) Cortical Radiate Vein 10) Arcuate Vein 11) Interlobar Vein 12) Renal Vein
Place the following in order of the micturition reflex staring with the first event that occurs.
1) baroreceptors in the urinary bladder are activated. 2) visceral sensory neurons stimulate the micturition reflex center within the pons. 3) parasympathetic impulses travel to the internal urethral sphincter and the detrusor muscle. 4) the detrusor muscle contracts and the internal urethral sphincter relaxes.
Conditions of extreme dehydration result in subsequent high concentration of _________ in the blood.
ADH
The release of ____________ directly stimulates the ____________ of the kidney to increase water reabsorption from the tubular filtrate.
ADH; collecting ducts
Overconsumption of alcohol can cause the hypothalamus to sense that the blood is too dilute, resulting in a decrease in the production of ____________ thus reducing the reabsorption of water leading to dehydration.
Antidiuretic Hormone
The osmolarity of the filtrate is approximately 100 mOsm/L at the end of the ____________ and around 1200 mOsm/L at the end of the ____________ .
Ascending Limb; Descending Limb.
In the thick segment of the nephron ascending limb, approx. 10% to 20% of the ___________ in the tubular fluid is reabsorbed.
K+
Aldosterone stimulates secretion of ______, while ______ & ______ are reabsorbed.
K+, Na+, H2O
Match the organ of the urinary system with its function.
Kidney: Filters blood and processes filtrate into tubular fluid, then urine Ureters: Transports urine from kidney to urinary bladder via peristalsis Urinary bladder: Reservoir for urine until micturition (urination) occurs Urethra: Transports urine from urinary bladder to outside the body
Reabsorption vs. Secretion: Indicate whether each of the following substances is reabsorbed from the filtrate or secreted into the filtrate.
Secreted: -Drugs -H+ -NH4+ Reabsorbed: -Water -Glucose -Vitamins -Amino Acids -Mg2+ -HCO3-
Renal Tubule Flow
The glomerular capsule leads into the proximal convoluted tubule, the longest and most coiled of the four regions of the renal tubule. From there, the filtrate flows into the descending limb of the nephron loop, the first part of the U-shaped portion of the tubule found mostly in the medulla. Next, the flitrate makes a 180 degree turn into the ascending limb, returning to the renal cortex. The filtrate is funnelled into the distal convoluted tubule, the end of the nephron. The collecting duct receives the filtrate from the DCTs of several nephrons and funnels it toward the medullary pyramid.
Basic Steps in the Formation of Urine
There are four major stages in the formation of urine. The first stage involves creating a filtrate in the glomerulus. Second, the filtrate flows through the tubules and useful substances are reabsorbed. Waste products will then be secreted by the tubules. The last stage is water conservation occurring in the renal tubule.
