Urinary System II Flashcards
When the sodium and chloride concentrations in the DCT are too high, cells in the
juxtaglomerular apparatus called _____ cells secrete a chemical signal which causes the
_____, allowing more time for ion resorption.
macula densa; afferent
arteriole to constrict
When the filtrate flow in the DCT is too low or the filtrate is too dilute, cells in the
juxtaglomerular apparatus called _____ cells STOP secreting a chemical signal which
causes the _____. As a result, GFR increases.
macula densa; afferent
arteriole to constrict
When the filtrate flow in the DCT is too low or the filtrate is too dilute, cells in the
juxtaglomerular apparatus called _____ cells secrete renin, which indirectly causes a(n)
_____ in systemic blood pressure.
juxtaglomerular (JG); increase
When blood pressure in the afferent and efferent arterioles is insufficient, cells in the
juxtaglomerular apparatus called _____ cells secrete renin, which indirectly causes a(n)
_____ in systemic blood pressure and indirectly _____.
juxtaglomerular (JG); increase;
increases sodium retention
Renin hydrolyses angiotensinogen to angiotensin I which is converted to _____ by ACE.
This in turn stimulates _____ and also production of _____.
angiotensin II; vasoconstriction;
aldosterone
Aldosterone, released by the cortex of the _____, _____ blood pressure by causing
_____ and thus (by osmosis) _____.
adrenal glands; increases;
sodium retention; water
retention
Angiotensin II increases systemic blood pressure by causing generalized vasoconstriction:
however, in the kidney, it affects the _____ arterioles more than the _____ ones, and so
GFP _____.
efferent; afferent; does not decrease
During periods of intense stress, sympathetic signals to the afferent arterioles override the
kidney’s autoregulation and _____; thus, filtration is _____.
decrease blood flow to the
glomerulus; decreased
Renal clearance tests measure the _____ per minute, and are used to diagnose
glomerular damage or monitor kidney disease.
volume of plasma from which a
solute is removed
If a renal clearance test is done using a solute that enters the filtrate but which is neither
resorbed nor secreted by the nephron, then the renal clearance rate equals the _____.
(_____ is often administered and used for this purpose.)
glomerular filtration rate (GFR);
Inulin
. Most solutes and water are resorbed in the _____.
PCT
Most or all of the organic nutrients such as glucose which are present in the filtrate are
_____.
resorbed in the PCT
Resorption of sodium and potassium is controlled by _____.
aldosterone
Resorption of calcium is controlled by _____; it is not unusual, in that the resorption of
most minerals is _____.
PTH; hormonally controlled
Water resorption is regulated by two hormones, _____ and _____: both of these act only
on the _____ and _____.
aldosterone; ADH; DCT;
collecting duct
Most resorption involves the movement of molecules _____ the tubule cells. This, in turn,
almost always requires the presence of _____ in the cell membrane.
through; carrier proteins
Under certain conditions, so much of a particular solute may be present in the filtrate that
the _____ responsible for its resorption aren’t sufficient for the task. In such cases, the
concentration in the plasma is said to be above the _____.
carrier proteins; renal threshold
_____ join tubule cells to one another and prevent the passage of most substances
between cells; however, it is thought that water and a few ions are able to be resorbed by
this _____ route.
Tight junctions; paracellular
A large volume of water is resorbed in the PCT, simply because the _____ creates
enough osmotic pressure to cause the water to follow. (Sodium in particular contributes to
this effect.)
transfer of solutes to the
interstitial fluid
As water is resorbed in the PCT, the concentration of the solutes left behind _____. This
in turn makes it easier for them to be resorbed.
increases
Water movements out of the proximal tubule and loop of Henle is driven by osmotic
pressure and sodium concentrations, and is referred to as _____ because it is not
regulated directly.
obligatory water resorption
Water resorption in the DCT and collecting duct is hormonally controlled, and is referred
to as _____.
facultative water resorption
Resorption of most substances in the PCT depends on a large _____ gradient between
the filtrate and the tubule cells. This gradient is created by _____ at the basal membrane.
sodium; sodium-potassium
ATPases
Most substances in the PCT are resorbed using _____: that is, _____ enters the cell
along with the substance being resorbed, and in fact provides the driving force.
sodium cotransport; sodium
_____ during solute resorption in the PCT directly involves ATP hydrolysis, and is the step
performed by the _____. _____ occurs when energy stored in a gradient is used to
transport a solute.
Primary active transport;
sodium-potassium ATPase;
Secondary active transport
Solutes that have been resorbed leave the tubule cells via _____ or _____ diffusion.
simple; facilitated
Water and solutes that have been resorbed enter the _____ and are carried from the
kidney.
peritubular capillaries
The concentration of a solution can be increased in either of two ways: _____ can be
added or _____ can be removed.
solutes; solvent
The major difference between the permeabilities of the descending and ascending loops
of Henle is that the descending loop is permeable to _____ but not to _____, while the
reverse is true in the ascending loop.
water; NaCl
In the descending loop of Henle, the filtrate becomes _____ concentrated
due to the removal of _____; in the ascending loop, it becomes _____
concentrated due to the removal of _____.
more; water; less; NaCl
Removal of NaCl from the filtrate in the ascending loop of Henle requires _____.
active transport OR ATP
_____ is able to diffuse from the collecting duct into the deep medullary tissue,
contributing to the increasing osmotic gradient encountered by filtrate as it moves through
the loop.
Urea
In the medulla, the interstitial fluid is 4 times more concentrated near the _____ than near
the _____. This allows juxtamedullary nephrons to produce urine that is _____.
renal papillae; cortex; very
concentrated
By transporting the filtrate through a region of _____, the kidney maximizes the movement
of water out of the filtrate due to osmosis.
high osmolarity
Systems such as the vasa recta which rely on exchange between currents flowing in
opposite directions in order to maintain a gradient are called _____.
countercurrent systems
Blood enters the renal medulla in the descending branch of the _____, and loses _____
and gains _____ in the process. However, the gradient is not disturbed, because blood is
carried out along the same route and these processes _____.
vasa recta; water; salt; reverse
Although independent, secretion and resorption are not separated _____ (that is, they
occur _____).
chronologically; together
The sodium gradient used by the PCT to cotransport solutes during resorption can also be
used for _____. In this process, a molecule or ion is secreted. The membrane protein
performing the task is referred to as a(n) _____
countertransport; antiporter
Some organic acids and bases (including some drugs) are secreted in the _____ and
_____. These pathways are not specific, and so secretion of one generally competes with
_____.
PCT; DCT; secretion of the
others
The concentration of nitrogen-containing wastes (ammonium ions, urea and uric acid) in
urine is increased by secretion in the _____, _____ and _____.
PCT; DCT; collecting duct
In addition to their obvious function (collecting urine), collecting ducts in the kidney also
control the concentration of the urine by changing their _____ in response to ADH.
permeability to water
When the hypothalamus detects that the osmolarity of the blood is too high, _____ is
released from the neurohypophysis to conserve water.
antidiuretic hormone
ADH acts on the _____ to increase water permeability: this increases _____ water
reabsorption.
DCT and collecting ducts;
facultative
The heart produces _____, which reduces blood pressure, blood volume, and blood
sodium concentration by inhibiting _____ release; it also dilates the afferent arteriole to
increase _____ and inhibits sodium resorption in the DCT and collecting duct.
atrial natriuretic peptide or
hormone (ANP or ANH); renin;
GFR
Solutes which exceed the _____ of their carriers (or in the case of some drugs, which are
not recognized by any carriers) act as _____.
transport maximum; osmotic
diuretics
Chemicals (drugs) which increase GFR, decrease water resorption, or increase the
osmolarity of the filtrate reaching the collecting duct act as _____.
diuretics
Calcium resorption is controlled by _____ hormone; in response to this hormone, calcium
resorption in the _____ is increased.
parathyroid; DCT
Aldosterone acts on the DCT and collecting duct to increase _____.
sodium resorption
Excess potassium is toxic, and so secretion is sometimes necessary: this occurs in the
_____ and _____ and is controlled by the hormone _____.
DCT; collecting duct;
aldosterone
K+ and H+ ion secretion in the DCT and collecting ducts uses Na+ antiporters, and so an increase in Na+ transport out of the filtrate results in an increase in K+ or H+ ion transport \_\_\_\_\_.
into the filtrate
An increase in plasma potassium levels results in the secretion of _____, which indirectly
leads to secretion of potassium by the DCT and collecting duct.
aldosterone
Hydrogen ions are secreted or resorbed (depending on the _____) in the _____, _____
and _____.
pH of the blood; PCT; DCT;
collecting duct
Bicarbonate ions are secreted or resorbed (depending on the _____) in the _____.
pH of the blood; collecting duct
Amino acids can be catabolized in the liver; but the nitrogen must be eliminated from the
body. If blood pH is normal, the liver makes _____ (which contains two nitrogen atoms) to
dispose of nitrogen.
urea
Amino acids can be catabolized in the liver; but the nitrogen must be eliminated from the
body. If blood pH is acidic, the liver transfers some of the nitrogen to glutamate to make
_____.
glutamine
If blood pH is acidic, the kidney uses nitrogen from _____ to form _____, which combines
with a hydrogen ion and allows it to be disposed of in the urine
glutamine; ammonia
The kidneys can secrete hydrogen ions in several ways: directly by _____ dependent
primary active transport, by countertransport with _____, or in combination with _____
(whose secretion also depends on countertransport).
ATP; sodium; ammonia
When peritubular cells in the kidney become hypoxic, they secrete _____ to stimulate the
formation of more oxygen-carrying red blood cells.
erythropoietin
Like the liver, the renal cortex can produce glucose from non-carbohydrate precursors.
The kidney uses _____ as the starting material for this purpose. The process is called
_____.
glutamine; gluconeogenesis
Once the urine is formed, it leaves the kidneys and travels to the bladder through the
_____, which are muscular tubes with three tissue layers: the lumenal _____, the _____,
and the outer _____.
ureters; mucosa; muscularis;
adventitia
The ureters enter the bladder at the base and at an angle. Because of this, increases in
bladder pressure cause _____ which prevents _____.
the ureters to close; urine from
being pushed back into the
kidney
The muscularis of the ureters contracts in _____.
peristaltic waves
The bladder is a hollow, distensible ball of muscle lined with _____ and surrounded by a
fibrous _____. (On its superior surface, the outer layer is actually the _____.) It stores
urine until its disposal is convenient.
mucosa; adventitia; peritoneum
The mucosa of the bladder consists of _____ epithelium, which allows it to stretch easily
and far, supported by a(n) _____.
transitional; lamina propria
The muscular layer which comprises the bulk of the bladder is the _____ muscle, and
consists of _____ muscle whose fibers are arranged in three layers.
detrusor; smooth
At the base of the bladder, the two ureteric openings and the urethral opening for a
triangle: the region of the bladder encompassed by this triangle is called the _____
trigone
Bladder distension is sensed by stretch receptors in the _____. Ordinarily, the urge to
urinate is felt after _____ ml are present; this can be inhibited voluntarily,
but it returns periodically as more urine enters the bladder.
detrusor muscle; ~200
The maximum bladder capacity is 3/4 to 1 liter; if circumstances force urine retention to (or
above) this level, urination _____ or (much more serious) _____.
may occur involuntarily; the
bladder may burst (especially if
an abdominal impact occurs)
Urine leaves the bladder through the _____. This tube is _____ times longer in males
than in females.
urethra; five
Urine is prevented from leaving the bladder prematurely by two rings of muscle: one is the
voluntarily controlled _____, which can be assisted by contraction of the _____.
external urethral sphincter;
levator ani
Urine is prevented from leaving the bladder prematurely by two rings of muscle: the
involuntary _____ is formed continuous with the detrusor muscle.
internal urethral sphincter
In females, the outer urethral opening is immediately _____ to the vaginal opening
anterior
In males, the urethra has three regions: the _____ urethra just under the bladder, the
_____ urethra within the penis, and the _____ urethra which connects them.
prostatic; spongy OR penile;
membranous
_____ is another word for urination.
Micturition
The lowest level of bladder control, and first to develop, is the _____: filling of the bladder
sends a signal to the sacral spinal cord, and an efferent signal is sent in response which
triggers _____.
sacral micturition reflex;
micturition
As development progresses, the sacral micturition reflex comes under the control of the
_____, which is located in the pons.
pontine micturition center
The micturition center in the _____ inhibits the pontine micturition center in the _____ to
prevent socially inappropriate urination, but this control does not develop until 2-4 years of
age.
frontal lobe; pons
Bladder filling is an active process which depends on sympathetic fibers which leave the
spinal cord in the _____. These inhibit the detrusor muscle and excite the internal urethral
sphincter, allowing _____.
lumbar region; the bladder to
stretch
_____ control the contraction and relaxation of the external sphincter in response to
signals from the _____ and from the stretching of the _____.
Sacral nerves; pons OR
pontine micturition center;
detrusor muscles
Contraction of the detrusor muscle (which is necessary to fully empty the bladder) is
controlled by _____.
sacral nerves
_____ carry most of the afferent signals of detrusor stretch; if the spinal cord is intact,
these signals are relayed to the pons and from there to higher brain regions.
Sacral nerves
Involuntary urination is called urinary incontinence. If it occurs only in small volumes when
the bladder is placed under pressure, it is _____. If it is due to involuntary contractions of
the detrusor muscle, it is _____.
stress incontinence; urge
incontinence
Normally, urine is sterile. If bacteria invade the urinary system, the infection is called a(n)
_____.
urinary tract infection (UTI)
Inflammation of components of the urinary system is common in response to bacterial or
fungal infections: _____ is inflammation of the bladder.
cystitis
Inflammation of components of the urinary system is common in response to bacterial or
fungal infections: _____ is inflammation of the urethra.
urethritis
_____ is inflammation that results when an infection reaches the pyelum (pelvis) of the
kidney.
Pyelonephritis
Various health and dietary factors may lead to the formation of _____, which if small may
pass on their own (with much pain!) or if large may require medical intervention.
kidney stones OR renal calculi
_____ refers to an abnormally low rate of urine formation caused by low _____ or kidney
_____.
Anuria; glomerular hydrostatic
pressure (HPg); disease
