Human Physio Ch. 19 Kidney
1.glomerular capillary endothelium 2. basal lamina 3. Bowman's capsule epithelium
Filtered solutes must pass first through ___, then through a ___, and finally through ___ before reaching the lumen of Bowman's capsule
blood cells and most plasma proteins
Filtration allows most components of plasma to enter the tubule but excludes
distal
Finely regulated reabsorption takes place in the more ___ segments of the nephron
proximal tubule, loop of Henle, distal tubule, and collecting duct, then drains into the renal pelvis.
Fluid filters from the glomerulus into Bowman's capsule. From there, it flows through the
Filtration
GFR - filter plasma into Bowman's capsule
Why is inulin administration an effective way of measuring renal clearance rates?
Inulin is neither secreted nor reabsorbed.
What is the most important function of the kidneys (in the sense that loss of this function results in serious medical problems before loss of other functions become problems)?
Regulation of water and ion content of the blood
afferent arteriole to glomerulus to ef- ferent arteriole to peritubular capillaries
Renal blood flow goes from
urea and other solutes
The active transport of Na+ and other solutes creates concentration gradients for passive reabsorption of ____
the amount filtered minus the amount reabsorbed plus the amount secreted
The amount of a solute excreted equals
The segment of the nephron between the proximal and distal tubules that loops down into the medulla of the kidney and returns back to the cortex is called the ________. ANSWER: minor calyx Bowman's capsule collecting duct loop of Henle vasa recta
loop of henle
The ________ cells lie between and around the glomerular capillaries. ANSWER: mesangial granular juxtaglomerular macula densa
mesangial
Urine is carried to the urinary bladder by ANSWER: the urethra. blood vessels. lymphatics. the ureters. All of the answers are corre
The ureters.
retroperitoneal
pertaining to the region behind the peritoneal membrane; used to refer to the kidneys because of their location outside and behind the peritoneum.
renal threshold
plasma concentration at which a substance first appears in the urine
Which structure is NOT part of the blood circulation through the kidney? ANSWER: loop of Henle renal corpuscle vasa recta glomerulus
loop of Henle
The excretion rate of a solute depends on
(1) its filtered load and (2) whether it is reabsorbed or secreted as it passes through the nephron.
Match each of the following substances with its mode(s) of transport in proximal tubule reabsorption. (a) Na+ (b) glucose (c) urea (d) plasma proteins (e) water 1. simple diffusion 2. primary active transport 3. indirect active transport 4. facilitated diffusion 5. movement through open channels 6. endocytosis 7. paracellular movement
(a) 2, 3, 5; (b) 3, 4; (c) 4, 7; (d) 6; (e) 5, 7
Identify the following structures, then explain their significance in renal physiology: (a) juxtaglomerular apparatus (b) macula densa (c) mesangial cells (d) podocytes (e) sphincters in the bladder (f) renal cortex
(a) Found where distal tubule passes between afferent and efferent arterioles. Composed of macula densa cells in the distal tubule and granular cells in arteriole wall. (b) Macula densa paracrine signals control autoregulation of GFR and renin secretion. (c) Alter the size of filtration slits. (d) Specialized epithelial cells that surround glomerular capillaries. Changes in slit size alter GFR. (e) An internal smooth muscle sphincter that is passively contracted and an external skeletal muscle sphincter that is tonically (actively) contracted. (f) Outer layer of the kidney that contains renal corpuscles, proximal and distal tubules, and parts of the loop of Henle and collecting ducts.
Arrange the following structures in the order that a drop of water entering the nephron would encounter them: (a) afferent arteriole (b) Bowman's capsule (c) collecting duct (d) distal tubule (e) glomerulus (f) loop of Henle (g) proximal tubule (h) renal pelvis
(a), (e), (b), (g), (f), (d), (c), (h)
Place the following blood vessels that carry blood to and within the kidney in the order in which blood passes through them. 1. afferent arteriole 2. efferent arteriole 3. glomerulus 4. peritubular capillary ANSWER: 1, 2, 3, 4 4, 3, 2, 1 3, 4, 2, 1 4, 2, 3, 1 1, 3, 2, 4
1,3,2,4 afferent arterioles glomerulus efferent arteriole peritubular capillary
List the 6 functions of the kidneys
1. Regulation of Extracellular fluid volume & Blood Pressure 2. Regulation of osmolarity 3. Maintenance of Ion Balance (electrolytes) 4. Homeostatic regulation of pH (acid/base) 5. Excretion of wastes 6. Production of Hormones (erythropoietin, E = renin)
Name the 3 sets of filters:
1. fenestrated capillary 2. basal lamina - negative charge repels protein 3. epithelium of Bowman's capsule - podocyte
General principle of urine formation:
1. filter all blood and collect a lot of plasma. 2. selective (& massive) Reabsorption important stuff. 3. fine tune by: a. additional selective secretion. b. concentration of remaining waste (urine) to conserve water. c. monitor actual [Na+] & [K+] to regulate body fluid content.
Autoregulation consists of two local control components:
1. myogenic response a. afferent arteriole is similar to systemic system 2. Tubuloglomerular FeedBack a. juxtaglomerular apparatus
The amount of plasma that filters into the nephrons is approximately ________ of the total volume. ANSWER: 4/5 3/4 90% 1/2 1/5
1/5
Approximately how much plasma moves through the kidneys of an adult during a 24-hour period?
180L
Measurements in a nephron reveal a glomerular hydraulic pressure of 69 mm Hg, and a fluid pressure in the Bowman's capsule of 15 mm Hg. Assuming that the plasma osmotic pressure is 30 mm Hg, and that essentially no plasma proteins are filtered by the glomerulus, what is the net glomerular filtration pressure in this case? ANSWER: 114 mm Hg -6 mm Hg 54 mm Hg 84 mm Hg 24 mm Hg
24 mm Hg
Put the following in order from where urine is produced to where it exits the body: 1. Urethra 2. Urinary bladder 3. Nephron 4. Ureter
3,4,2,1
Put the following in order from where urine is produced to where it exits the body: 1..Urethra 2. Urinary bladder 3. Nephron 4. Ureter 2, 3, 4, 1 3, 4, 2, 1 1, 2, 3, 4 4, 2, 1, 3
3,4,2,1 Nephron, Ureter, Urinary Bladder, Urethra
In which segment of the nephron does most reabsorption take place? When a molecule or ion is reabsorbed from the lumen of the nephron, where does it go? If a solute is filtered and not reabsorbed from the tubule, where does it go?
70% occurs in the proximal tubule. Reabsorbed molecules go into the peritubular capillaries and the systemic venous circulation. If filtered and not reabsorbed, a molecule is excreted in the urine.
What dictates filtration?
A competition between hydrostatic and oncotic pressure
Match each step in urine formation to its description. A. excretion B. filtration C. reabsorption D. secretion movement from the nephron lumen to the external environment
A. excretion
Secretion into the nephron is a/an ________ process because the direction is ________ the concentration gradient.
Active, against
If the afferent arteriole of a nephron constricts, what happens to GFR in that nephron? If the efferent arteriole of a nephron constricts, what happens to GFR in that nephron? Assume that no autoregulation takes place.
Afferent arteriole constricts, GFR decreases. Efferent arteriole constricts, GFR increases.
Net handling of a solute & thus excretion by kidney determined by:
Amount filtered - Amount reabsorbed + Amount secreted = Amount of solute excreted
myogenic response; tubuloglomerular feedback
Autoregulation of glomerular filtration is accomplished by a ___ of vascular smooth muscle in response to pressure changes and by ____
125 mL/min, or 180 L/day
Average GFR is
Match each substance with its primary mode of transport across the kidney epithelium. A. transcytosis B. active transport C. symport with a cation D. passive reabsorption/diffusion sodium
B. active transport
glomerulus
Blood flows from the afferent arteriole into a ball-like network of capillaries
The nephron begins with a hollow, ball-like structure called ANSWER: Bowmans capsule. macula densa. vasa recta. glomerulus.
Bowman's Capsule
podocytes; filtration slits
Bowman's capsule epithelium has specialized cells called ____ that wrap around the glomerular capillaries and create ____
Match each step in urine formation to its description. A. excretion B. filtration C. reabsorption D. secretion movement from the nephron lumen to the blood
C. reabsorption
What force(s) promote(s) glomerular filtration? What force(s) oppose(s) it? What is meant by the term net driving force?
Capillary hydrostatic pressure promotes filtration. Fluid pressure in Bowman's capsule and colloid osmotic (oncotic) pressure of plasma oppose it. Net driving force is the sum of these pressures.
nephrons
Each kidney has about 1 million microscopic
An obstruction in a glomerulus would affect the flow of blood into the ANSWER: efferent arteriole. afferent arteriole. renal vein. renal artery.
Efferent arteriole
Blood leaves the glomerulus via which vessel? ANSWER: efferent arteriole afferent arteriole vasa recta peritubular capillaries
Efferent arterioles
Cysts on the kidney can press upon nephrons, raising the pressure inside the nephrons. How will this affect glomerular filtration rate and blood pressure? ANSWER: GFR increases and blood pressure decreases GFR increases and blood pressure increases GFR decreases and blood pressure increases GFR decreases and blood pressure decreases
GFR decreases and blood pressure increases
Where does all filtration take place in the kidneys?
Glomerulus
secondary active transport
Glucose, amino acids, ions, and various organic metabolites are reabsorbed by Na+-linked ____
1/5
How much of renal plasma flow filters into the tubule lumen
55 mm Hg
Hydrostatic pressure in glomerular capillaries averages ___, favoring filtration
afferent and efferent arterioles
Hydrostatic pressure in glomerular capillaries can be altered by changing resistance in the
creatinine
In clinical settings, ___ is used to measure GFR
outer cortex and inner medulla
In cross section, a kidney is arranged into an
Vasa recta
In juxtamedullary nephrons, the long peritubular capillaries that dip into the medulla
What causes the internal urethral sphincter to open?
Increasing urine pressure due to contraction of the full bladder
Clearance
Measure GFR with; RATE a solute disappears from body per unit time (by excretion or metabolism). In PSL: volume of plasma passing through kidney that has been totally cleared of solute
paracellular
Most reabsorption involves transepithelial transport, but some solutes and water are reabsorbed by the ___pathway
proximal tubule
Most reabsorption takes place in the
transport maximum Tm
Most renal transport is mediated by membrane proteins and exhibits saturation, specificity, and competition. The ___ is the transport rate at saturation.
The functional unit of the kidney is the ________. ANSWER: juxtaglomerular apparatus loop of Henle renal corpuscle nephron
Nephron
Clearance of X is less than inulin clearance
Net reabsorption of X
Filteration is greater than excretion
Net reabsorption of X
Clearance of X is more than inulin clearance
Net secretion of X
Excretion is greater than filtration
Net secretion of X
30 mm Hg; 15 mm Hg.
Opposing filtration are colloid osmotic pressure of ___ and hydrostatic capsule fluid pressure averaging ____.
Why is the osmotic pressure of plasma in efferent arterioles higher than that in afferent arterioles?
Osmotic pressure is higher in efferent arterioles because fluid volume is decreased there, leaving the same amount of protein in a smaller volume
Glomerular Filtration Pressure
PH - pi - PF = net filtration pressure
__________ neurons cause contraction of the smooth muscle in the bladder wall._________ motor neurons leading to the external sphincter are simultaneously inhibited
Parasympathetic; somatic
hormones; autonomic nervous system
Reflex control of GFR is mediated through systemic signals, such as ___, and through the ___
_______ reabsorption drives the rest of reabsorption at the kidney.
Sodium
1. its filtered load 2. whether it is reabsorbed or secreted as it passes through the nephron
The excretion rate of a solute depends on
10 mm Hg
The net driving force is ___, favoring filtration.
peritubular capillaries
The network of tiny blood vessels that surrounds the proximal and distal tubules in the kidney
filtration fraction
The percentage of total plasma volume that filters is called the
ALL reabsorption is iso-osmotically achieved.
True
One substance has no membrane transporters to move it but can diffuse freely through open leak channels if there is a concentration gradient. Initially, this substance's concentrations in the filtrate and extracellular fluid are equal. Later, however, the active transport of Na+ and other solutes creates a gradient by removing water from the lumen of the tubule where it is located. What substance is this? ANSWER: glucose, calcium, and urea glucose and calcium glucose calcium urea
Urea
ureter to the urinary bladder
Urine flows through the
macula densa cells
When fluid flow through the distal tubule increases, the ___ send a paracrine signal to the afferent arteriole, which constricts
If net filtration out of glomerular capillaries occurs, then you know that capillary hydrostatic pressure must be (greater than/less than/equal to) capillary colloid osmotic pressure.
When net filtration out of the glomerular capillaries occurs, the capillary hydrostatic pressure must be greater than the capillary colloid osmotic pressure.
If net reabsorption into peritubular capillaries occurs, then capillary hydrostatic pressure must be (greater than/less than/ equal to) the capillary colloid osmotic pressure.
When net reabsorption into the peritubular capillaries occurs, the capillary hydrostatic pressure must be less than the capillary colloid osmotic pressure.
Renal Corpuscle
Where filtration occurs within the Bowman's capsule. structure of corpuscle creates filtration barrier two different epithelial like cells (endothelial and podocye) as well as basal lamina
Clearance of X is equal to inulin clearance
X is neither reabsorbed or secreted.
Match each step in urine formation to its description. A. excretion B. filtration C. reabsorption D. secretion movement from the glomerulus to the nephron lumen
filtration
A glomerulus is
a "knot" of capillaries that lies within the Bowman's capsule.
A glomerulus is ANSWER: -the portion of the nephron that attaches to the collecting duct. -the portion of the nephron closest to the renal corpuscle -the hairpin-shaped segment of the nephron. -the expanded end of a nephron. -a "knot" of capillaries that lies within the Bowman's capsule.
a "knot" of capillaries that lies within the Bowman's capsule.
Functions of the kidneys include all but one of the following. Identify the exception: -regulation of blood protein levels -regulation of extracellular fluid volume -maintenance of ion balance in body fluids -homeostatic regulation of blood pH -regulation of blood osmolarity
a. regulation of blood protein levels
Match each substance with its primary mode of transport across the kidney epithelium. A. transcytosis B. active transport C. symport with a cation D. passive reabsorption/diffusion glucose
active transport
Match each substance with its primary mode of transport across the kidney epithelium. A. transcytosis B. active transport C. symport with a cation D. passive reabsorption/diffusion sodium
active transport
The percentage of total plasma volume that filters is called the ANSWER: glomerular filtration rate. excretion rate. filtration fraction. clearance rate.
filtration fraction
glomerular filtration rate (GFR)
amount of fluid filtered through Bowman's capsule per unit time
glomerular filtration rate (GFR)
amount of fluid that filters into Bowman's capsule per unit time
basal lamina
an acellular layer of extracellular matrix that separates the capillary endothelium from the epithelial lining of Bowman's capsule. The basal lamina consists of negatively charged glycoproteins, collagen, and other proteins. The lamina acts like a coarse sieve, excluding most plasma proteins from the fluid that filters through it.
Active transport in the kidney is on the ________ side
basal
Technically, the kidneys are located ANSWER: behind the peritoneal membrane. in the pelvic cavity. in the thoracic cavity. in the abdominal cavity. behind the pleural membranes.
behind the peritoneal membrane
The force for glomerular filtration is the ANSWER: -osmotic pressure in the glomerular capillaries. -fluid pressure produced by the displacement of the fluid in the lumen of the tubules. -blood pressure in the glomerular capillaries. -ATP-dependent processes in the nephron. -None of the answers are correct.
blood pressure in the glomerular capillaries
Which statement is NOT true? ANSWER: a Women are more likely to develop urinary tract infections than men. b The urinary bladder is filled by two ducts, called ureters, and emptied by the single urethra. c The kidneys do not reabsorb filtered waste products. d The blood supply to the kidneys comes through the renal arteries. e As much as one fourth of the cardiac output may flow to the kidneys at any given moment.
c The kidneys do not reabsorb filtered waste products.
The characteristic yellow color of urine is attributed to the presence of: a. bile. b. urea. c. urobilinogen. d. uric acid. e. renin.
c. urobilinogen
inulin
clearance is equal to GFR.
What part of the nephron is responsible for the greatest possible increase in urine concentration? ANSWER: Bowman's capsule collecting duct loop of Henle proximal convoluted tubule
collecting duct
Damage to the renal medulla would interfere first with the functioning of the ANSWER: collecting ducts. Bowman's capsule. proximal tubule. distal tubule. glomerulus.
collecting ducts
During the micturition reflex, what does activation of parasympathetic efferent neurons cause the bladder to do?
contract
Eighty percent of the nephrons in a kidney are contained within the ________, but the other 20%, called the ________ nephrons, dip down into the ________.
cortex, juxtamedullary, medulla
Eighty percent of the nephrons in a kidney are contained within the ________, but the other 20%, called the ________ nephrons, dip down into the ________. ANSWER: medulla, cortical, cortex renal pelvis, juxtamedullary, vasa recta cortex, juxtamedullary, medulla vasa recta, cortical, cortex
cortex, juxtamedullary, medulla
What solute that is normally present in the body is used to estimate GFR in humans?
creatinine
Which of the following statements about autoregulation is TRUE? ANSWER: -Myogenic response is a paracrine signaling mechanism. -In tubuloglomerular feedback, stretch-sensitive ion channels open, resulting in depolarization of smooth muscle cells. -In myogenic response, the macula densa cells send a paracrine message to the neighboring afferent arteriole. -Myogenic response is the intrinsic ability of vascular smooth muscle to respond to pressure changes.
d Myogenic response is the intrinsic ability of vascular smooth muscle to respond to pressure changes.
Myogenic Response
decreasing resistance in AFFERENT (brings blood) can in theory increase GFR, but it is normally fairly relaxed so plays only minor role (Also have to worry about the EFFERENT arteriole - takes blood away)
clearance
describes how many milliliters of plasma passing through the kidneys have been totally cleared of a solute in a given period of time
Presence of glucose in the urine is evidence of what condition?
diabetes mellitus
The portion of the nephron that attaches to the collecting duct is the ANSWER: proximal tubule. loop of Henle. collecting duct. minor calyx. distal tubule.
distal tubule
Ions directly regulated by the kidney include all EXCEPT which of the following? a. Ca2+ b. HCO3- c. K+ d. Na+ e. OH-
e. OH-
Blood leaves the glomerulus via which vessel?
efferent arteriole
secretion
enhances excretion by removing solutes from the peritubular capillaries. K+, H+, and a variety of organic compounds are secreted.
All of the following will normally be found in the filtrate EXCEPT ANSWER: urobilinogen glucose potassium erythrocytes
erythrocytes
When the plasma concentration of a substance exceeds its renal concentration, more of the substance will be ANSWER: excreted. secreted. reabsorbed. filtered. None of the answers are correct.
excreted
Match each step in urine formation to its description. A. excretion B. filtration C. reabsorption D. secretion movement from the nephron lumen to the external environment
excretion
Which equation correctly describes the relationship between excretion, filtration, reabsorption, and secretion?
excretion = filtration - reabsorption + secretion
Urine is produced by the ANSWER: urinary bladder. urethra. kidney. ureter. gallbladder.
kidney
The amount of filtrate entering the proximal tubules of the kidneys each minute is the ________ rate. ANSWER: glomerular filtration excretion clearance collecting
glormerular filtration rate
The excretion of glucose in the urine is called ANSWER: hypoglycemia. micturation. glucosuria. glucose secretion.
glucosuria
Renal Blood Flow
goes from afferent arteriole to glomerulus to efferent arteriole to peritubular capillaries. The vasa recta capillaries dip into the medulla
Approximately what percent of the total filtered volume is excreted as urine each day?
less than 1%
Approximately what percent of the total filtered volume is excreted as urine each day? ANSWER: 30% 100% 10% less than 1%
less than 1%
sympathetic nervous system in kidneys
innervate BOTH afferent & efferent arterioles; induces vasoconstriction ONLY if severe drop in Blood pressure, i.e. conserve fluid
In the lumen of the proximal tubule, Na+ concentration ________ the Na+ concentration inside the cells of the tubule wall. ANSWER: is much higher than is slightly lower than is slightly higher than is much lower than is about the same as
is much higher than
mesengial cells
lie between and around the glomerular capillaries. They have cytoplasmic bundles of actin-like filaments that enable them to contract and alter blood flow through the capillaries. In addition,they secrete cytokines associated with immune and inflammatory processes.
The hairpin-shaped segment of the nephron is the
loop of Henle
The hairpin-shaped segment of the nephron is the ANSWER: vasa recta. distal tubule. loop of Henle. proximal tubule. minor calyx.
loop of Henle
Which is NOT a kidney filtration barrier? ANSWER: glomerular capillary endothelium juxtaglomerular apparatus Bowman's capsule epithelium basal lamina
juxtaglomerular apparatus
reabsorption
movement of filtered materials from tubule to blood
filtration
movement of fluid from plasma into Bowman's capsule
secretion
movement of selected molecules from blood to tubule
The functional unit of the kidney is the ________.
nephron
Filtration and secretion are the same
no net reabsorption/secretion
In normal kidneys, blood cells and plasma proteins are ANSWER: secreted then reabsorbed. filtered and secreted. filtered then reabsorbed. not filtered.
not filtered
Match each substance with its primary mode of transport across the kidney epithelium. A. transcytosis B. active transport C. symport with a cation D. passive reabsorption/diffusion urea
passive reabsorption/diffusion
Urea is ANSWER: -actively reabsorbed in the proximal tubule. -actively secreted in the distal tubule. -actively transported into the filtrate by the cells of the collecting duct. -completely eliminated in the urine. -passively reabsorbed in the proximal tubule.
passively reabsorbed in the proximal tubule.
List three solutes secreted into the tubule lumen.
penicillin, K+, and H+
Which word means to selectively move molecules from the blood and add them to the tubule lumen?
secretion
The specialized cells found in the capsule epithelium are called ________. These cells have long cytoplasmic extensions called ________. ANSWER: juxtaglomerular cells, loops of Henle mesangial cells, cilia podocytes, foot processes granular cells, flagella
podocytes, foot processes
Inulin
polysaccharide that is filtered & excreted, not resorbed, not secreted
Blood flow through the kidney includes a feature seen in only a few organs. What is it? ANSWER: arterial shunts veins containing highly oxygenated blood anastomoses vascular sinuses portal system
portal system
angiotensin II
potent vasoconstrictor
prostaglandins
potent vasodialator
Reabsorption utilizes these types of transport:
primary active, secondary active, and passive diffusion.
Most reabsorption takes place in the_________ _________. Finely regulated reabsorption takes place in the more distal segments of the nephron.
proximal tubule
The portion of the nephron closest to the renal corpuscle is the ANSWER: collecting duct. proximal tubule. distal tubule. minor calyx. loop of Henle.
proximal tubule
Secretion
selective removal of a compound from plasma to lumen - active process. active removal of solute from (usually) peritubular capillaries/ECF to lumen of nephron
Renal clearance
rate of excretion of a solute relative to plasma concentration
Peritubular capillaries
reabsorb fluid along their entire length.
Match each step in urine formation to its description. A. excretion B. filtration C. reabsorption D. secretion movement from the nephron lumen to the blood
reabsorption
The primary function of the proximal tubule is ANSWER: -secretion of acids and ammonia. -reabsorption of ions, organic molecules, and water. -adjusting the urine volume. -filtration. -secretion of drugs.
reabsorption of ions, organic molecules, and water.
The kidneys function to produce hormones, excrete wastes, regulate blood pressure, and maintain ion balance. Which of the following is another function of the kidneys?
regulation of osmolarity
The process of filtration in the kidney is most accurately described as
relatively nonspecific
The process of filtration in the kidney is most accurately described as ANSWER: relatively nonspecific. completely nonspecific. highly specific.
relatively nonspecific
Excretion
remove from the body
The ________ branch off the ________ and supply blood to the kidneys. ANSWER: afferent arteries, abdominal aorta renal arteries, inferior vena cava arcuate arteries, inferior vena cava renal arteries, abdominal aorta
renal arteries, abdominal aorta
The Bowman's capsule and glomerulus make up the ANSWER: renal corpuscle. renal papilla. loop of Henle. collecting system. renal pyramid.
renal corpuscle.
The ________ carries blood from the kidneys back to the ________. ANSWER: renal vein, inferior vena cava efferent arteriole, abdominal aorta vasa recta, renal artery arcuate vein, inferior vena cava
renal vein, inferior vena cava
Tubuloglomerular FeedBack
salt detector; The juxtaglomerular apparatus is involved. Increases in renal arterial perfusion pressure increase GFR. Cells of the macula densa sense the increased flow by detecting changes in tubular sodium chloride concentration/transport. They respond by increasing production and secretion of a vasoconstrictor substance which acts locally to increase afferent arteriolar resistance. modified tubular epithelium = macula densa granular cells = modified sm muscle cells contain granules of E= RENIN
Contents in the peritubular capillaries are actively transported into proximal and distal convoluted tubules in a process known as: ANSWER: excretion filtration reabsorption secretion
secretion
Match each step in urine formation to its description. A. excretion B. filtration C. reabsorption D. secretion movement from the peritubular capillaries to the nephron lumen
secretion
Which of the following kidney processes is always active and always requires energy to occur? ANSWER: secretion reabsorption filtration excretion
secretion
The internal sphincter of the bladder is controlled by ______ muscle while the external sphincter is controlled by _______ muscle
smooth; skeletal
If blood flow through the afferent arterioles increases, ANSWER: -the stretch triggers further relaxation of the arteriolar wall, lessening blood pressure. -stretch reflexes trigger vasoconstriction to reduce the flow. -the smooth muscle in the vessel walls stretches to accommodate the increased flow and the stretch triggers further relaxation of the arteriolar wall, lessening blood pressure. -the smooth muscle in the vessel walls stretches to accommodate the increased flow.
stretch reflexes trigger vasocontriction to reduce the flow.
Neural control of GFR is mediated by ________ that innervate ________ receptors on vascular smooth muscle causing ________. ANSWER: sympathetic neurons, alpha, vasoconstriction somatic neurons, nicotinic, vasodilation parasympathetic neurons, alpha, vasodilation parasympathetic neurons, beta, vasoconstriction
sympathetic neurons, alpha, vasoconstriction
SGLT protein
symport on the apical side of kidney cell that transport sodium down its gradient and glucose against its gradient. glucose is later transported out the other side by a uniporter and sodium by Na+-K+-ATPase.
The typical pattern for molecules absorbed by Na+-dependent transport involves this: an apical ________ and a basolateral ________. ANSWER: symport protein, osmotic gradient osmotic gradient, symport protein facilitated diffusion carrier, osmotic gradient symport protein, facilitated diffusion carrier facilitated diffusion carrier, symport protein
symport protein, facilitated diffusion carrier.
Glucose and amino acids are reabsorbed by ANSWER: symport with sodium. cotransport. countertransport. diffusion.
symport with sodium
Reabsorption
take back most of what is filtered - PCT does >80%
vasa recta
the ___ capillaries dip into the medulla
What part of the nephron forms the juxtaglomerular matrix?
the ascending limb joining the distal tubule
Renal threshold
the plasma concentration at which a substance first appears in the urine
transport maximum (Tm)
the transport rate at saturation.
The plasma concentration at which all of the renal carriers for a given substance are saturated is the renal ANSWER: handling. threshold. ceiling. permissiveness.
threshold
Match each substance with its primary mode of transport across the kidney epithelium. A. transcytosis B. active transport C. symport with a cation D. passive reabsorption/diffusion small plasma proteins
transcytosis
When fluid flow through the distal tubule increases as a result of increased GFR, the macula densa cells send a chemical message to the neighboring afferent arteriole. The afferent arteriole constricts, increasing resistance and decreasing GFR. This type of autoregulation involving both the kidney tubule and the arteriole is known as ________ feedback. ANSWER: tubuloglomerular positive neuroendocrine autonomic
tubuloglomerular
Urine is carried to the external environment by the ANSWER: glomerulus. collecting duct. ureter. urethra.
urethra
After it is formed, urine is temporarily stored in the ANSWER: urinary bladder. ureter. renal pelvis. nephron.
urinary bladder
two kidneys, two ureters, a bladder, and a urethra
urinary system is composed of
The ________ are the long peritubular capillaries that dip into the medulla. ANSWER: vasa recta renal pyramids Bowmans capsules glomerulus
vasa recta
Mesangial cells
what cells are associated with the glomerular capillaries