CHAPTER 26: The Urinary System
At a volume of ________ mL, there may be sufficient pressure in the bladder to force the opening of the internal urinary sphincter and, consequently, the external urinary sphincter.
500
The average pH for normal urine is about
6.0
As the filtrate passes through the renal tubules, approximately what percentage is reabsorbed and returned to the circulation?
99
increases the permeability of the collecting ducts to water.
Antidiuretic hormone
Osmotic pressure resulting from suspended proteins, drawing water out of the filtrate
Blood colloid osmotic pressure
The thick ascending limb of the nephron loop (loop of Henle) is almost impermeable to water, but reabsorbs sodium, potassium, and chloride ions from the filtrate.
Both are true and relate to production of a dilute urine.
Force of the fluid in the glomerular capsule on the blood
Capsular hydrostatic pressure
Layer of collagen fibers covering and protecting the kidney
Fibrous capsule
Difference between the hydrostatic pressure and the colloid pressure across the glomerular capillaries
Filtration pressure
Amount of filtrate produced by the kidneys each minute
Glomerular filtration rate
Blood pressure in the glomerular capillaries
Glomerular hydrostatic pressure
The sympathetic division of the nervous system has which of the following effects on the kidney?
It causes a decrease in the GFR because of the constriction of the afferent arteriole.
Difference between the pressure pushing water and solutes out of the blood stream and the pressure pushing water and solutes into the blood stream
Net hydrostatic pressure
Which portion of the nephron contains cuboidal cells covered with microvilli?
PCT
Dilation of the afferent arteriole and glomerular capillaries and constriction of the efferent arteriole when blood flow and glomerular pressure decline cause
elevation of glomerular blood pressure to normal levels
Countercurrent refers to the
exchange occurring between fluids moving in opposite directions
Bundles of tissue that extend between pyramids from the cortex
Renal columns
Which mechanism is important in the reabsorption of glucose and amino acids when their concentrations in the filtrate are relatively high?
facilitated transport
Sympathetic innervation of the afferent arterioles causes
a decrease in GFR and slowing of filtrate production
The fibrous capsule is
a layer of collagen fibers that covers the outer surface of each kidney
Aldosterone stimulates ion pumps along the distal convoluted tubule (DCT), the collecting tubule, and the collecting duct, causing
a reduction in the number of sodium ions lost in the urine
The filtration process within the renal corpuscle involves passage across the filtration membrane, which consists of
fenestrated capillary endothelium, dense layer, and filtration slits
Cortical radiate arteries branch to form __________, which enter __________.
afferent arterioles; glomeruli
Substances larger than ________ are normally not allowed to pass through the filtration membrane.
albumin
During reabsorption of water in the proximal convoluted tubule, what causes water to osmose from the lumen into the interstitial space?
an increase in the osmolarity of the interstitium
A muscular sac for temporary storage of urine
bladder
The process of filtration is driven by
blood hydrostatic pressure
ADH stimulates the reabsorption of water in
both the distal convoluted tubule and the collecting system
The pressure that represents the resistance to flow along the nephron and conducting system is the
capsular hydrostatic pressure (CHP)
What are the opposing forces of the filtration pressure at the glomerulus?
capsular hydrostatic pressure and blood osmotic pressure
The thick segments in the nephron loop
contain transport mechanisms that pump materials out of the filtrate
In which region of the kidney would you find the renal corpuscles?
cortex
The majority of glomeruli are located in the ________ of the kidney.
cortex
To which vessels does blood flow immediately after it passes through the arcuate arteries?
cortical radiate arteries
Reabsorption of filtered glucose from the lumen in the PCT is largely by means of
cotransport
What is the term for the type of transport where two substrates cross the membrane while bound to a carrier protein, with at least one following its concentration gradient?
cotransport
Chloride ion is reabsorbed in the thick ascending limb by
cotransport with Na and K ions
Inadequate ADH secretion results in the inability to reclaim the water entering the filtrate, causing
dehydration
What is the triple-layered muscle responsible for urinary bladder contractions?
detrusor
Which of the following disorders describes the production of very dilute urine as a result of a lack of ADH production?
diabetes insipidus
What is the primary site for secretion of potassium and hydrogen ions into the filtrate?
distal convoluted tubule
Which portion of the renal segment is under ADH and aldosterone stimulation?
distal convoluted tubule
In which of the following parts of the nephron does aldosterone control the reabsorption of sodium ions?
distal convoluted tubule and collecting duct
What are the three concentric layers of connective tissue that protect and anchor the kidneys?
fibrous capsule, perinephric fat capsule, and renal fascia
When plasma glucose concentrations are higher than the renal threshold, glucose concentrations in the filtrate exceed the transport maximum (Tm), and
glucose appears in the urine
What results from the effect of aldosterone along the DCT, the collecting tubule, and the collecting duct?
increased conservation of sodium ions and water
The collecting system in the kidney is responsible for
making final adjustments to the sodium ion concentration and volume of urine
The inner layer of the kidney is the
medulla
After passage through the nephron loop, the filtrate is
more concentrated
When antidiuretic hormone levels rise, the distal convoluted tubule becomes
more permeable to water; water reabsorption increases
Because of the small diameter of the glomerular capillaries, the blood pressure in the efferent arteriole is ___________ that of the pressure in the afferent arteriole.
much higher than
In which of the following areas of the nephron would countercurrent multiplication occur?
nephron loop
Which of the following parts of the nephron has two limbs with thick segments and thin segments?
nephron loop
What is the primary site in the nephron where the loss of water, sodium, and potassium ions is regulated?
nephron loop and collecting duct
Urine production begins in the
nephrons
The difference between the net hydrostatic pressure and the net colloid osmotic pressure is the
net filtration pressure
What is the limiting factor for the reabsorption of most actively transported solutes in the proximal tubule?
number of transport carriers in the luminal membrane
During the micturition reflex, increased afferent fiber activity in the pelvic nerves facilitates
parasympathetic motor neurons in the sacral spinal cord
Blood supply to the proximal and distal convoluted tubules of the nephron is provided by the _
peritubular capillaries
Capillaries that surround the proximal convoluted tubules are
peritubular capillaries
Juxtaglomerular nephrons
produce concentrated urine
The renal papilla
projects into the renal sinus
In a nephron, the long tubular passageway through which the filtrate passes includes the
proximal and distal convoluted tubules and the nephron loop
In which of the following areas of the nephron are most nutrients reabsorbed?
proximal convoluted tubule
Sixty to 70 percent of the water is reabsorbed in the
proximal convoluted tubule
What is the primary site of nutrient reabsorption in the nephron?
proximal convoluted tubule
Which portion of the nephron reabsorbs most of the important nutrients, such as glucose and amino acids as well as any plasma proteins?
proximal convoluted tubule (PCT)
Triangular or conical structures located in the renal medulla are called
pyramids
Aldosterone __________ in the proximal convoluted tubule.
regulates potassium and sodium exchange
Which of the following brings oxygenated blood into the kidney?
renal artery
In which region would you find interlobar arteries?
renal column
The filtration of plasma that generates approximately 80 liters/day of filtrate occurs in the
renal corpuscle
The glomerulus and the glomerular capsule form the
renal corpuscle
An inability of the kidneys to excrete adequately to maintain homeostasis is
renal failure
Which of the following is a dense fibrous layer that anchors the kidney to surrounding structures?
renal fascia
In what part of the kidney are the renal pyramids located?
renal medulla
The region of the kidney containing the renal pyramids, renal columns, and interlobar arteries is called the
renal medulla
What is the expanded, funnel-shaped structure in the kidney leading to the ureter?
renal pelvis
The active transport of which ion out of proximal convoluted tubule cells causes the reabsorption of both water and solutes?
sodium
The high osmotic concentrations found in the kidney medulla are primarily caused by the presence of
sodium ions, chloride ions, and urea
Net filtration pressure can be measured as
the difference between the net hydrostatic pressure and the blood colloid osmotic pressure
The renal corpuscle consists of
the glomerular capsule and the glomerulus
The ability to form concentrated urine depends on the functions of
the loop of Henle and the collecting duct
Which of the following causes urinary incontinence?
the loss of muscle tone in the urinary sphincter muscles
When the level of ADH (antidiuretic hormone) decreases,
the osmolarity of the urine decreases
The decreased intracellular concentration of sodium in tubular cells during active transport is caused by which of the following mechanisms?
the sodium-potassium ATPase pump in the basolateral membrane
The capillaries surrounding the nephron loop are called
the vasa recta
Which of the following descriptions best matches the term renal papilla?
tip of the medullary pyramid
Most solutes that are reabsorbed in the proximal convoluted tubule use which of the following pathways?
transcellular
The ureters and urinary bladder are lined by ________ epithelium.
transitional
The ureters are lined by what kind of epithelium, which allows them to be stretched when undergoing peristalsis and moving urine?
transitional
The mucosa of the urinary bladder consists of what type of epithelia?
transitional epithelium
The collecting system
transports fluid to the renal pelvis and adjusts the concentration and composition of urine
The area in the urinary bladder that is bounded by the openings of the ureters and the entrance to the urethra is the
trigone
The openings of the urethra and the two ureters mark an area on the internal surface of the urinary bladder called the
trigone
Which of the following organic wastes is generated from the catabolism of amino acids?
urea
Passageway carrying urine to storage area
ureter
What is the urinary structure that carries urine from the kidney to the urinary bladder?
ureter
Conduction pathway to the exterior
urethra
Contraction of the muscular bladder forces the urine out of the body through the
urethra
Which organ in the urinary system temporarily stores urine?
urinary bladder
Renal blood flow is about
1 liter/min
Which of the following transporters in the luminal membrane results in secretion?
Na+-H+ countertransport
Produces steroid hormones essential for life
Suprarenal gland
compresses the urinary bladder and expels urine through the urethra
The detrusor muscle
In which of the basic processes involved in urine formation does blood pressure force water and solutes across the wall of the glomerular capillaries?
filtration
What is the initial factor that determines whether urine will be produced?
filtration
Which of the following descriptions best matches the term calyx?
final urine enters here
In countercurrent multiplication, the countercurrent refers to the fact that an exchange occurs between
fluids moving in opposite directions
The thin segments in the nephron loop are
freely permeable to water and relatively impermeable to ions and other solutes
The process of filtration occurs at the
glomerular (Bowman's) capsule
The amount of filtrate the kidneys produce each minute is the
glomerular filtration rate
The main force that causes filtration in a nephron is
glomerular hydrostatic pressure
What is the outward pressure forcing water and solute molecules across the glomerulus wall?
glomerular hydrostatic pressure
Which of the following is the term for the blood pressure in the capillaries of the renal corpuscle?
glomerular hydrostatic pressure
The renal corpuscle consists of the
glomerulus and glomerular capsule
Which of the following substances undergo tubular secretion:
hydrogen ions
A histological examination of the nephron would reveal simple squamous tissue
in the nephron loop
The fluid in the ascending limb of the nephron loop moves __________ the fluid in the descending limb.
in the opposite direction of
During periods of strenuous exercise, sympathetic activation causes the blood flow to
increase to the skin and skeletal muscles and decrease to the kidneys
To regulate pH, all of the following are secreted into the fluid in the collecting system EXCEPT
iron
The cells of the macula densa and the juxtaglomerular cells form the
juxtaglomerular complex
Organ that filters blood and maintains fluid homeostasis
kidney
Which organ in the urinary system produces urine?
kidney
