Urinary System I Flashcards
Although a great deal of waste material is discarded by the intestines, most was never
truly within the body. Almost all of the waste products originating from within the body itself
are removed and discarded by the _____.
kidneys
The kidneys play a major role in _____ by sorting useful and necessary molecules from
those that are toxic or unneeded.
waste removal
Urine is usually _____ but the pH can vary from ~4.5 to ~8.0 in response to changes in
metabolism or diet.
slightly acidic
Urine composition is complex, but includes ions, _____ from catabolism of amino acids,
_____ from catabolism of dietary nucleic acids and RNA, _____ from decomposition of
creatine in the muscles and the yellow _____ from heme breakdown.
urea; urate OR uric acid;
creatinine; urobilins OR
urochrome
Excessive plasma concentrations of organic molecules (such as glucose) can overwhelm
the kidney’s transport proteins and result in _____.
the presence of organic
molecules in the urine
Damage to the structures of the urinary system from injury or infection can result in the
presence of _____, _____ or _____ in the urine.
large molecules; formed
elements; cells
In a healthy individual, urine is a(n) _____ liquid until it leaves the body, at which time
bacteria present on the external genitalia may contaminate it.
sterile
Kidneys regulate blood _____ and _____ by altering the concentration of the urine (and
thus, the amount of water lost or conserved) and by releasing _____.
volume; pressure; renin
By changing the amount of each ion which is conserved or discarded, the kidneys
indirectly regulate the concentrations of solutes in the _____.
blood OR body
By alternating between direct disposal of urea and disposal of ammonia, and also by
selectively secreting hydrogen or bicarbonate ions, the kidneys have a major influence on
the body’s _____.
pH
By monitoring their own oxygen supply and responding (if low) by releasing _____, a
hormone, the kidneys regulate _____.
erythropoietin; red blood cell
synthesis
The kidneys help to control bone density by regulating the disposal of, or conservation of,
_____ in response to _____.
calcium; parathyroid hormone
The kidneys help to control calcium absorption by regulating the conversion of vitamin D
to _____, which is done in response to _____.
its active form; parathyroid
hormone
Urine is formed by each of two _____. From each, a muscular tube called the _____
propels urine to the _____ where it is stored until its release is convenient, at which time it
flows out of the body through the _____.
kidneys; ureter; bladder; urethra
The kidneys are _____ to the peritoneum. Each lies in the _____ region, anterior to the
_____, but the right is slightly lower than the left to make room for the _____.
posterior; upper lumbar; 12th
rib; liver
The kidneys are encased in a fibrous layer of connective tissue called the _____.
renal capsule
The kidneys are surrounded by an outer fibrous layer called the _____ which _____. This
layer surrounds the adrenal glands as well.
renal fascia; fastens the kidney
to surrounding structures
A dense layer of adipose tissue called the _____ lies between the renal capsule and the
renal fascia. Its function is to _____ and _____ the kidneys.
adipose capsule; support;
cushion
The medial surface is concave and has a(n) _____, where the ureters, blood vessels,
nerves, and lymphatics enter or leave the kidney.
hilus OR hilum
The hilus is continuous with the _____, a much deeper indentation filled with fat which
cushions the structures which enter and leave the kidney.
renal sinus
The outer layer of the kidney, just deep to the renal capsule, is the _____. Columns of
tissue from this region called _____ extend toward the hilus; it is within these columns that
those renal blood vessels having the largest diameter lie.
renal cortex; renal columns
The renal cortex surrounds the _____; columns of cortical tissue extend toward the hilus,
separating it into distinct regions called _____.
medulla; renal pyramids
Each renal pyramid and the cortical tissue surrounding it is called a(n) _____. The term
‘_____’ refers to these units.
renal lobe; lobar
Each renal pyramid is striated. The striations extend from the hilus toward the cortex and
are called _____. (They are actually _____.)
medullary rays; collecting ducts
Each renal pyramid projects into a tube within the renal sinus which conducts urine away
from the kidney. The projection itself is called the _____; the tube which it enters is called
a(n) _____ (the plural is ‘:_____’).
renal papilla; minor calyx; minor
calyces
Several minor calyces merge to form a(n) _____
major calyx
Each kidney contains roughly _____ minor calyces and _____ major calyces.
10-20; 2-3
The major calyces in each kidney merge to form a funnel-like chamber called the _____,
which later narrows to form the _____, which conducts urine to the urinary bladder.
renal pelvis; ureter
Blood (1/4 of the blood pumped by the heart, when one is resting) reaches the kidneys via
the _____, which branch to form _____ which branch again within the renal sinus to form
the _____.
renal arteries; segmental
arteries; lobar arteries
Most of the blood reaching the kidney flows to the _____, where it will be filtered.
renal cortex
Blood flows to the renal cortex through the _____ arteries, then arches around the renal
lobes just below the cortex via the _____ arteries. Many small arteries called the _____
arteries arise here: these supply blood to the _____ arterioles and _____.
interlobar; arcuate; interlobular;
afferent; glomerulus
Blood leaves the glomerulus via the _____, which take it to a second capillary bed, the
_____.
efferent arterioles; peritubular
capillaries
Juxtamedullary nephrons are supplied with a special type of peritubular capillary, the
_____, whose long straight vessels travel directly into and out of the renal pyramids.
vasa recta
From the peritubular capillaries, blood leaves the kidneys by flowing through veins whose
paths and names are identical to those of the _____.
arteries that delivered the blood
to the kidney
The blood flow within the kidneys is controlled by the _____, which is supplied by fibers of
the sympathetic nervous system originating in the least thoracic and first lumbar
splanchnic nerves.
renal plexus
_____ are the structures within the kidney that actually sort the substances which should
be kept or discarded.
Nephrons
Each kidney contains _____ nephrons.
over a million
Each nephron has two major parts: the _____ in the cortex and a thin _____, U-shaped at
the center, which extends from the cortex into the medulla and back.
renal corpuscle; tubule
There are two types of nephron: the glomerulus of _____ nephrons is near the medulla,
and the tubule of these nephrons _____ into a renal pyramid. These nephrons are very
important in the production of _____ urine.
juxtamedullary; travels deep;
concentrated
There are two types of nephron: most are _____ nephrons. Each of these has a
glomerulus which is near the outer surface of the cortex, and a short tubule which _____
into a renal pyramid.
cortical; does not extend far
The function of the renal corpuscle is to _____ in the first step of urine formation.
filter the blood
The renal corpuscle has two parts: the central portion is a tangled ball of capillaries called
the _____. This is surrounded by the outer portion, a double-walled, cup-like chamber
called the _____.
glomerulus; Bowman’s capsule
The _____ is the interior of the Bowman’s capsule, and is continuous with the _____.
capsular space; proximal tubule
The inner wall of the Bowman’s capsule is permeable to liquid and is called the _____
layer. Liquid cannot pass, however, through the outer wall, the _____ layer.
visceral; parietal
Glomerular capillaries contain many _____ through which liquid can pass.
fenestrations
_____ forces liquid to leave the capillaries in the glomerulus, while formed elements and
large molecules are left behind. The fluid passes through the visceral layer of the
Bowman’s capsule to enter the capsular space.
Blood pressure
The visceral layer of the Bowman’s capsule is formed by specialized cells called _____.
Fingerlike extensions of these cells wrap the capillaries of the glomerulus; between these
are gaps called _____ which allow liquid to pass into the proximal tubule.
podocytes; filtration slits
Between the capillary walls and the visceral layer of the Bowman’s capsule is a thin
basement membrane through which liquid easily passes. Together, these three structures
form the _____.
filtration membrane
Blood to the glomerulus is supplied by the _____ and leaves by the _____.
afferent arteriole; efferent
arteriole
The tubule consists of simple epithelium: the _____ or _____ surface of the epithelial cells
contacts the filtrate in the lumen, while the _____ or _____ surface contacts the interstitial
fluid surrounding the tubule.
apical; lumenal; basal;
basolateral
The tubular portion of the nephron is divided into several sections both functionally and
conceptually: the portion of the tube closest to the renal corpuscle is the _____. Its
primary function is _____.
proximal convoluted tubule
(PCT); resorption of solutes
and water
The tubular portion of the nephron is divided into several sections both functionally and
conceptually: the portion of the tube farthest from the renal corpuscle is the _____. Its
primary function is resorption of water, but this is varied depending on _____.
distal convoluted tubule (DCT);
the body’s needs
Both the proximal and distal tubules are very _____.
convoluted OR twisted
The proximal and distal tubules of the nephron are connected by a hairpin-like loop called
the _____, which extends toward or into the renal pyramids. Its primary function is _____
loop of Henle; resorption of
water and salt
The loop of Henle in _____ nephrons extends deep into the renal medulla.
juxtamedullary
The region of the loop of Henle in which fluid is traveling toward the hilus is called the
_____; the region where fluid is flowing toward the outer surface of the kidney is the
_____.
descending limb; ascending
limb
. Each limb of the loop of Henle has a(n) _____ and a(n) _____ portion.
thick; thin
The tubule of the nephron twists in such a way that the beginning of the DCT and the
afferent and efferent arterioles contact one another. Cells in this region (the _____) are
specialized to sense blood pressure, filtration rate, and oxygen availability.
Juxtaglomerular Apparatus
JGA
The Juxtaglomerular Apparatus (JGA) is a group of specialized cells which sense _____,
_____, and _____.
blood pressure; filtration rate;
oxygen availability
The distal tubules of each nephron merge with _____; each of these carries urine from
several nephrons to a(n) _____, where it drains via the _____ into a(n) _____ on its way
out of the kidney.
collecting ducts; renal papilla;
papillary ducts; minor calyx
A(n) _____ is a region within a renal lobe which contains a group of nephrons connected
to a common collecting duct.
renal lobule
There are three processes involved in urine formation: _____, _____ and _____.
filtration; resorption OR
reabsorption; secretion
In _____, the liquid components of the blood (including small molecules that are dissolved
therein) are separated from the formed elements and large molecules.
filtration
In resorption, molecules which are _____ are allowed to remain in the filtrate, while
glucose, amino acids, ions, and so on are reclaimed.
toxic, unneeded or
unrecognized
In the _____ and _____, several substances may be specifically secreted: these include
ammonia, hydrogen ions, and some drugs.
proximal convoluted tubule
(PCT); distal convoluted tubule
(DCT)
Blood pressure in the glomerulus is controlled by _____ in the afferent and efferent
arterioles so that it is maintained at levels that permit filtration.
smooth muscles
Glomerular blood pressure is higher than in other capillaries because the _____ arterioles
have a larger diameter than the _____ arterioles.
afferent; efferent
The blood pressure in the glomerulus is often referred to as the _____.
glomerular hydrostatic pressure
HPg
The _____ is the sum of all of the forces which influence glomerular filtration rate.
net filtration pressure
Fluid leaves the glomerulus due to glomerular hydrostatic pressure (HPg). This is inhibited
by two factors: _____ or _____ osmotic pressure, abbreviated _____, and back-pressure
due to fluid already in the capsular space (_____, abbreviated _____).
blood colloidal; glomerular;
OPg; capsular hydrostatic
pressure; HPc
The _____ is the sum of all of the various forces influencing movement of fluid in the renal
corpuscle during filtration. It is given by the formula: _____. (Note: be able to use the
formula if given values!)
net filtration pressure (NFP);
HPg – (HPc + OPg)
A bit over one liter of blood passes through the kidneys and is filtered each minute: this is
the _____.
renal blood flow rate
Since not all of the blood’s volume is due to plasma, it is useful to calculate the _____,
which is the amount of plasma filtered by the kidneys per minute.
plasma flow rate
The amount of filtrate formed by the kidneys per minute is the _____, and is usually about
a fifth of the plasma flow rate.
glomerular filtration rate (GFR)
In a healthy kidney, two factors that affect GFR normally do not change: _____ and
_____. (In disease states, these factors may change, however.)
the number of glomeruli; the
permeability of the filtration
membrane
To change the filtration rate, both local and systemic mechanisms are able to change the
_____.
glomerular hydrostatic pressure
HPg
A ‘_____’ is one in which the smooth muscles in a blood vessel respond to stretching by
contracting, or to a decrease in resistance by relaxing.
myogenic response
In response to changes in systemic blood pressure, the afferent and efferent arterioles in
the kidney dilate or contract to maintain _____; this is an example of a(n) _____. Note that
this only works if the changes in systemic pressure are _____.
glomerular hydrostatic pressure
(HPg); myogenic response;
small
Both flow rate and filtrate concentration (osmolarity) are sensed by cells in the DCT, and
signals are sent to the glomerulus in response. This is called _____.
tubuloglomerular feedback
When the filtrate flow in the DCT is too high, cells in the juxtaglomerular apparatus called
_____ cells secrete a chemical signal which causes the _____, decreasing the GFR.
macula densa; afferent
arteriole to constrict
