Chapter 25 (Lecture) Flashcards
what is the deepest layer of supportive tissue that surrounds each kidney
fibrous capsule
which two structures make up each nephron
- renal corpuscle
- renal tubule
specialized mechanoreceptors
granular cells of the juxtaglomerular complex
every day, the kidneys filter nearly … of fluid from the bloodstream
200 L
long nephrons that deeply invade the medulla
juxtamedullary nephrons
which vessels closely surround renal tubules
peritubular capillaries
large branches of the renal pelvis
major calyces
under normal resting conditions, which arteries deliver 1/4 of the total cardiac output (~1200ml) to the kidneys each minute
renal blood flow
sequence in which urine passes through structures to the external environment
- calyx
- renal pelvis
- ureter
- urinary bladder
- urethra
- blood vessel that leads directly into the glomerulus
- blood supply to the nephron
afferent arteriole
continuous with the ureter
pelvis
cushions the kidney and helps attach it to the posterior body wall
perirenal fat capsule
the renal hilum lies on which surface of the kidney
medial
which blood vessel directly drains the glomerulus
efferent arteriole
structural and functional units of the kidneys
nephrons
major indicator of renal trauma
hematuria
primary site of glucose and amino acid reabsorption
proximal convoluted tubule
into which part of the nephron is plasma filtered
glomerular capsule
functions of the urinary system
- helps maintain homeostasis by controlling the composition, volume, and pressure of blood
- maintains blood osmolarity
- regulates blood glucose levels and produces hormones
- bean shaped, right is lower than left, about 11cm long
- located in the retroperotineal space in the lower abdomen at about the level of the psoas muscle
- surrounded in a fibrous connective capsule and a protective renal fat pad
kidneys
small raised portion on the medial side of the kidney where the renal artery, nerve, and veins enter and exit
renal hilum
most superficial layer of the kidney, light in color
renal cortex
where blood flow comes in between the pyramids
renal columns
deeper layer of the kidney, reddish brown
renal medulla
where urine is formed
renal pyramids
where the urine exits the pyramid and enters the minor calyces
renal papillae
pathway of urine from the renal pyramids to the external
- renal papillae of pyramid
- minor calyces
- major calyx
- renal pelvis
- ureter
- bladder
- urethra
renal arteries deliver about how much blood to kidneys
1200 ml/min
pathway of blood supply to and from the kidneys
- aorta
- renal arteries
- segmental artery
- lobar artery
- interlobar artery
- arcuate artery
- interlobar artery
- efferent arterioles
- glomerular capillaries
- afferent arterioles
- peritubular capillaries and vasa recta
- interlobar vein
- arcuate vein
- interlobar vein
- renal vein
- inferior vena cava
about 90% of the blood entering the kidney goes where
renal cortex
network of sympathetic vasomotor ANS fibers that innervate the kidney
renal plexus
- basic histological and functional unit of the kidney
- about 1 million per kidney
- all parts about 1 cell layer thick
nephron
what type of tissue makes up the distal convoluted tubule and the collecting duct?
- simple cuboidal epithelia
- fewer microvilli
what type of tissue makes up the proximal convoluted tubule
- cuboidal
- many mitochondria (active transport)
- numerous microvilli
what type of tissue makes up the descending limb
simple squamous
freely permeable to water
what type of tissue makes up the ascending limb
simple cuboidal
- loops only extend a short way into the medulla
- 85% of nephrons
cortical nephrons
- loops extend deep into the medulla and are important in the production of very concentrated urine
- 15% of nephrons
juxtamedullary nephrons
types of nephronal capillary beds
- glomerulus
- peritubular capillaries
- contains an afferent and efferent arteriole to supply and take blood away from it
glomerulus
surrounds the glomerulus
bowman’s capsule
bowman’s capsule + glomerulus
renal corpuscle
which part of the nephron forms the filtrate
glomerular capillaries
visceral layer of Bowman’s capsule and have many filtration slits in them
Podocytes
the glomerular capillaries are …, which allows filtration of blood plasma to occur from the capillaries into the surrounding capsule and proximal convoluted tubule
fenestrated
- arise from the efferent arterioles
- run close to the nephron tubules and collect the substances that pass out of the nephron
- reabsorb filtrate
peritubular capillaries
peritubular capillaries found in the deepest parts of the medulla, have a different structure than other peritubular capillaries
vasa recta
found where the distal convoluted tubule lies to the afferent arteriole
juxtaglomerular apparatus (JGA
enlarged smooth muscle cells in the walls of the arterioles that act as mechanoreceptors and control the amount of vasoconstriction in the afferent arterioles
juxtaglomerular cells
distal convoluted tubule cells that act as chemoreceptors and monitor the solute concentration of the filtrate
macula densa
populations of cells that play important roles in blood pressure regulation and urine production
- juxtaglomerular cells
- macula densa
- made up of fenestrated glomerular endothelium
- podocytes (visceral Bowman’s capsule)
- basement membrane between the two
- allows passage of filtrate
allows passage of filtrate but not blood cells or macromolecules
filtration membrane
- exit the hilum, run inferiorly and medially to where the enter the bladdder (trigone)
- narrow muscular tubes
ureters
what tissue makes up the ureters
transitional epithelium and smooth muscle
urine is forced towards the bladder by which force
peristalsis
- located in the pelvic cavity just posterior to the pubic symphysis
- composed of transitional epithelium (except trigone) surrounded by a smooth muscle layer
urinary bladder
when distended fully (2-3 cell layers thick) can hold how much urine
500-600 ml
urine output is controlled by which reflex, which stimulates two sets of sphincters (internal urinary and external urinary)
micturition reflex
urinary sphincter made of smooth msucle
internal urinary sphincter
urinary sphincter made of skeletal muscle; voluntary
external urinary sphincter
urge to urinate occurs when about how much urine has accumulated
200ml
If voiding is resisted, urge goes away until another 200 ml or so have collected
control of the micturition reflex is stimulated by what
- sacral spinal nerves
- brainstem
- voluntary centers in the cortex
- lined with primarily stratified squamous epithelia
- female: 3-4 cm in lengh
- male: 20cm in length; combination of urinary and reproductive functions
urethra
key processes in urine formation
- glomerular filtration
- tubular reabsorption
- tubular secretion
hydrostatic pressure pushes fluid across the filtration membrane into nephron tubules
filtration
movement of fluid from filtrate backinto the blood vessels
reabsorption
movement of wastes from the blood vessels into the filtrate
secretion
contains everything that plasma does except for proteins
filtrate
mainly metabolic wastes, and unneeded substances
urine
of about the 180 L of filtrate produced each day, how much leaves as urine?
1.8 L
nephr-
kidney
glomerul(o)-
glomerulus of the kidney
ur-
urine, urinary tract, or urea
juxta-
situated near
the specialized capillary bed responsible for the pressure that drives filtration is
the glomerulus
structural and functional unit of the kidney
nephron
renin is released by the cells of … in response to afferent arteriole pressure and the degree of stretch of the arteriole wall
juxtaglomerular complex
an elevated level of urea in the blood
uremia
why is the right kidney slightly lower than the left
crowded by the liver
function of the kidneys
- carry out gluconeogenesis during prolonged fasting
- metabolized vitain D to its active form
- regulate blood volume and osmolality, and maintain acid-base balance
where is the majority of nephron loops located
renal pyramid
ureter entrances and opening to the urethra
trigone
pain perceived at a location other than a site of the painful stimulus
referred pain
when renal calculi obstruct a ureter, pain is perceived to radiate from the lower back to the anterior abdominal wall on the same side. this is an event that …
is called referred pain
the mucosa of the urinary bladder is composed of
transitional epithelium
correct sequence from the formation of a drop of urine to its elimination from the body
- nephron
- collecting duct
- minor calyx
- major calyx
- ureter
- urethra
true or false
the position of the kidneys behind the peritoneal lining of the abdominal cavity is described by the term retroperitoneal
true
what two structures constitute the renal corpuscle
glomerulus and bowman’s capsule
which capillary bed produces filtrate
glomerulus
The glomerulus (capillary bed) in the glomerular capsule produces filtrate due to the high fluid pressure within the vessels.
the glomerulus differes from other capillaries in the body in that it
is drained by an efferent arteriole
the thin segment of the nephron loop’s descending limb aids
in the passive movement of water out of the tubule
what is the chief force pushing water and solutes out of the blood and across the filtration membrane of the glomerulus
hydrostatic pressure in glomerular capillaries
which artery lies on the boundary between the cortex and medulla of the kidney
arcuate artery
…. collects urine, which drains continuously from the papillae, and empty it into the …
calcyes; renal pelvis
fatty tissue surrounding the kidneys is important because
it cushions the kidneys against blows
primary function of the juxtaglomerular complex
releases chemical signals that regulate the rate of filtrate formulation
reabsorption of sodium in the medulla by active transport is undertaken by cells that compose
ascending nephron loop
why does the PCT contain so many mitochondria
a great deal of active transport takes place in the PCT
if the diameter of the efferent arterioles leading away from the glomerulus increases, which is likely to occur
- urine output will decrease
- net filtration pressure will decrease
- glomerular filtration rate will decrease
true or false:
capspular hydrostatic prssure is the chief force pushing water and solutes out of the blood and across the filtration membrane
false
Glomerular hydrostatic (blood) pressure is the chief (outward directed) force pushing water and solutes out of the blood and across the filtration membrane
function of angiotensin II
constrict arterioles and increase blood pressure
glomerular filtration rate control method
- hormonal regulation
- renal autoregulation
- neural regulation
your patient’s urinalysis shows a large amount of protein in the urine. this suggests a problem in the
glomerulus
true or false:
blood pressure in the renal glomerulus is lower than in most parts of the body in order to conserve body water
false
what hormone promotes active tubular secretion of potassium ions and reabsorption of sodium ions in the distal convoluted tubule (DCT) and collecting ducts?
aldosterone
what area of the nephron is responsible for the reabsorption of most of the water from the filtrate as well as most nutrients
proximal convoluted tubule
Reabsorption of nutrients like glucose and amino acids takes place in the proximal convoluted tubule (PCT) via cotransporters that utilize secondary active transport. Which of the following would stop the reabsorption of glucose at the apical surface of the cells in the PCT?
loss of Na+-K+ ATPase in the basolateral surface of PCT cells
The kidneys are stimulated to produce renin when
there is a decrease in blood pressure
the descending limb of the nephron loop
contains fluid that becomes more concentrated as if moves down into the medulla
what is the effect of antidiuretic hormone on the cells of the collecting duct?
causes aquaporins to be inserted into the apical membrane
true or false:
in the absence of hormones, the distal tubule and collecting ducts are relatively impermeable to water
true
responsible for the reabsorption of water
proximal convoluted tubule
responsible secretion of K+
distal convoluted tubule
responsible for the filtration of plasma
glomerulus
alcohol acts as a diuretic because it
inhibits the release of ADH
which of these should not normally appear in urine
a. sodium
b. creatine
c. glucose
d. urea
glucose
which part of the nephron is influenced by hormones to absorb sodium and water
distal convoluted tubule
the most important factor affecting the net filtration pressure in the glomerulus is
hydrostatic pressure in the glomerulus
if the afferent arteriole constricts while the efferent arteriole remains unchanged, the glomerular filtration rate
decreases
if the afferent arteriole constricts while the efferent arteriole remains unchanged, the glomerular filtration rate
decreases
pressure exerted by filtrate in the glomerular capsule
hydrostatic pressure in the capsular space
which of the regions of the nephron do not absorb Na+ by primary active transport
descending limb of the nephron loop
which substance would not normally be expected in urine
protein
regulates water reabsorption at the collection duct
ADH
aldosterone-induced reabsorption of Na+ is coupled with
K+ secretion
the energy needed for secondary active transport is provided by the
concentration gradient established by Na+
how is Na+ reabsorbed
by active transport using ATP
which glomerular regulator responds to filtrate NaCl concentrations
tubuloglomerular feedback mechanism
which substance is typically used to measure GFR
inulin
which homeostatic imbalance suggests that glomerular blood pressure may be too low to cause filtration
anuria
glomerular filtration is based on
particle size
stimulates the release of renin from granular cells
- stimulation of the granular cells by the sympathetic nervous system
- reduced stretching of the granular cells
- hemorrhaging or dehydration
anuria causes
- acute nephritis
- transfustion reactions
- crush injuries
rising systemic blood pressure stretches vascular smooth muscle in the arteriolar walls, causing the afferent arterioles to constrict
myogenic mechanism
how would afferent arteriole dilation in response to a fall in blood pressure affect the GFR
increases GFR
refers to the force of blood against the walls of the glomerular capillaries
glomerular hydrostatic pressure (HPgc)
uses neural signals to override autoregulatory mechanisms
sympathetic nervous system
a powerful vasoconstrictor that also stimulates the secretion of aldosterone
angiotensin II
which process results in increased blood pressure in response to hormone release
renin-angiotensin-aldosterone mechanism
pressure in or around the glomerulus that is the result of all pressures and is responsible for filtrate formation
net filtration pressure
when the concentration of ADH increases
less urine is produced
which pressure is exerted by the proteins in the blood that “sucks” water into the capillary
colloid osmotic pressure (OPgc)
components of the filtration membrane
- podocytes
- endothelium
- basement membrane
