CH. 4 Flashcards
How many nephrons are found in the average
kidney?
1.3 million
Ultrafiltration of plasma occurs in glomeruli located
in the renal
cortex
Which component of the nephron is located exclu-
sively in the renal medulla?
loop of henle
true or false: The afferent arteriole has a narrower lumen than the efferent arteriole.
false
true or false: The arteries are primarily end arteries, supplying specific areas of tissue, and they do not interconnect.
true
true or false: The arterioles subdivide into a capillary network, rejoin as an arteriole, and subdivide into a second capillary bed.
true
true or false: The vasa recta vessels deep in the renal medulla form the beginning of the venous renal circulation.
true
Formation of the ultrafiltrate in the glomerulus is
driven by the
hydrostatic blood pressure
Which of the following is a characteristic of renin, an enzyme secreted by specialized cells of the juxtaglomerular apparatus?
causes the formation of angiotensin and
the secretion of aldosterone.
The glomerular filtration barrier is composed of the
capillary endothelium
basement mmb
podocytes
the ability of a solute to cross the glomerular filtra-
tion barrier is determined by its
molecular size.
molecular radius.
electrical charge.
The epithelium characterized by a brush border
owing to numerous microvilli is found in the
proximal tubules
The kidneys play an important role in the
excretion of waste products.
regulation of water and electrolytes.
maintenance of acid-base equilibrium.
control of blood pressure and fluid balance.
What percent of the original ultrafiltrate formed in
the urinary space actually is excreted as urine?
1%
What differentiates tubular reabsorption from
tubular secretion in the nephron?
The direction of movement of the substance
being absorbed or secreted is different.
During tubular transport, the movement of a solute
against a gradient
involves specific cell membrane–binding sites.
Substances bound to plasma proteins in the blood
can be eliminated in the urine by
tubular reabsorption
The renal system has a ____ response with complete correction of the ___ to normal.
slow
pH
The kidneys excrete excess alkali (base) in the urine
as
sodium bicarbonate
Which of the following substances is secreted into
the tubular lumen to eliminate hydrogen ions?
ammonia
Urine titratable acids can form when the ultrafiltrate
contains
phosphate
The renal threshold level for glucose is 160 to
180 mg/dL. This corresponds to the
plasma concentration above which glucose is
excreted in the urine.
When too much protein is presented to the renal
tubules for reabsorption, it is excreted in the urine
because
the max tubular reabsorptive capacity for
protein has been exceeded.
More than 66% of filtered water, sodium, and chlo-
ride and 100% of filtered glucose, amino acids, and proteins are reabsorbed in the
proximal tubules
Water reabsorption occurs throughout the nephron
except in the
ascending limb of the loops of Henle.
The process solely responsible for water reabsorp-
tion throughout the nephron is
osmosis
Hypertonicity of the renal medulla is maintained by
urea cycle
Which of the following is not a feature of the renal
countercurrent multiplier mechanism?
The descending limb of the loop of Henle actively
reabsorbs sodium and urea.
The purpose of the renal countercurrent multiplier
mechanism is to
preserve the gradient hypertonicity in the
medulla.
Which vascular component is involved in the renal
countercurrent exchange mechanism?
vasa recta
Antidiuretic hormone regulates the reabsorption of
water in the collecting tubules.
Which of the following describes the tubular lumen
fluid that enters the collecting tubule compared with
the tubular lumen fluid in the proximal tubule?
isosmotic
Which of the following describes the tubular lumen
fluid that enters the collecting tubule compared with
the tubular lumen fluid in the proximal tubule?
collecting ducts.
what makes up urine
water and waste products
where does urine go after the renal pelvis
ureter
where does urine go after the ureter
bladder
where does filtrate become urine
kidneys
how much urine can the bladder hold before it feels like you have to go to the bathroom
150 mL
how does urine get pushed into the urethra
contraction of bladder and relaxation of urinary sphincter
what is the glomerulus made up of
capillary beds
what is the liquid called in the bowman’s capsule
filtrate
function of the nephron
filters blood
where are glomeruli located
outer cortex
what kind of tissue is in the medulla
pyramid-shaped
where does urine go after the pyramid
minor calyx
where does urine go after the calyces
renal pelvis
what is the area called between the medullas
renal column
where does filtration occur
bowman’s capsule
where are there a lot of microvilli
proximal convoluted tubule
where does filtrate enter the glomerulus
afferent arteriole
where does filtrate exit the glomerulus
efferent arteriole
what kind of cell lines the afferent arteriole
juxtaglomerular cell
what is the space called around the glomerulus
bowman’s space
what kind of cells are in the center of the afferent arteriole
mesangial cells
where is pressure greater in the afferent or efferent arteriole
efferent
what are the 3 cells that make up the juxtaglomerular apparatus
juxtaglomerular cell
distal convoluted tubule
mesangial cells
what enzyme is present in the juxtaglomerular apparatus
renin
why would renin be released
low arterial blood pressure
decreased sodium or increased potassium levels
low blood volume
renin causes ____ formation and _____ secretion
angiotensin
aldosterone
what does aldosterone do to the kidneys
retain sodium and water follows the sodium
what does an increase in aldosterone do to blood pressure
increase blood pressure
what turns angiotensinogen to angiotensin I
renin
what turns angiotensin I to angiotensin II
ACE
180000 mL of plasma is filtered everyday but how much urine is produced
600 - 1800 mL
what is blood’s pH
7.35-7.45
what kind of charge does the endothelium have
neg
can albumin go through glomerular filtration barrier and why
no because it has a negative charge
what kind of transport moves against gradient
active
what kind of transport moves from higher conc to lower conc
passive
what waste product does not get reabsorbed
creatinine
how much water does the proximal tubule reabsorb
65%
what are the 3 systems that maintain blood’s pH
blood buffer system
pulmonary system
renal system
what enzyme combines carbon dioxide and water
carbonic anhydrase
what enzyme breaks carbonic acid
carbonic anhydrase
what makes ADH
hypothalamus
what releases ADH
posterior pituitary gland
what is another name for ADH
vasopressin
what controls water reabsorption in collecting tubules
ADH
aquaporin
allows water to go through
what is the problem with people with diabetes insipidus
receptor do not respond to ADH
describe the urine of a person with diabetes insipidus
lots of urine
urine is dilute
