Physiology of the Kidneys Flashcards
The main function of the kidneys is the regulation of the intracellular fluid
False
Blood pressure is regulated through the action of the kidneys
True
The action of the kidney includes regulation of
Blood plasma pH
Blood plasma volume
Blood plasma electrolyte concentration
What structures carry urine from the kidneys to the urinary bladder?
Ureters
Urine collects in the urinary bladder prior to entry into the urethra
True
Damage to the lumbar region of the spinal cord could impair micturition
False
The renal pelvis receives urine form the
Major calyses
Damage to which neurons would impair micturition
Parasympathetic neurons
Sympathetic neurons
Pudendal somatic motor neurons
___ are composed of crystals and proteins that grow until they break loose and pass into the urine collection system
Renal calculi
Shock-wake lithotripsy is used to treat
Renal calculi
Incontinence could develop as a result of
Pressure on the detrusor muscle
Poor bladder compliance
Damage to the external urethral sphincter
The process of urination is called
Micturition
The ___ is the functional unit of the kidney
Nephron
The ___ is a capillary network that produces a blood filtrate that enters the urinary tubules
Gomerulus
___ is an autosomal dominant inherited condition in which progressive renal failure develops due to expanded potions of the renal tubule
Polysystic kidney disease
The ___nephrons play an important role in producing concentrated urine
Juxtamedullary
What structure is an arteriole capillary bed - drained by an arteriole intend of a venule
Glomerulus
The efferent arteriole delivers blood to the
Peritubular capillaries
Which is the correct order of the nephron tubule structures
Bowman’s capsule, proximal convoluted tubule, loop of Henle, distal convoluted tubule
The guarding reflex allows the urinary bladder to fill by
Inhibiting parasympathetic stimulation of the detrusor muscle
Stimulating sympathetic nerves to the external urethral sphincter to contract
Responding to the stretch receptors in the bladder wall
Where is the micturition center
Pons
Which sphincter is under voluntary control
External urethral sphincter
The guarding reflex prevents voiding
True
Which are potential filtration barriers in the glomerular capsule
Glomerular basement membrane
Capillary fenestrate
Slit diaphragm
The primary filter to exclude proteins from the filtrate is the
Slit diaphragm
What type of cells form the third filtration barrier
Podocytes
What is the order that filtrate must pass through to the glomerular capsule
Capillary fenestrae, glomerular basement membrane, podocytes of visceral glomerular epithelium
What is the net filtration pressure of the glomerular capillaries
10 mmHg outward
Which of the following is a layer or the renal corpuscle
Glomerular visceral epithelium
Glomerular parietal epithelium
Glomerular endothelium
Dilation of the afferent arteriole would increase glomerular pressure
True
Highly elevated blood pressure would stimulate an increased glomerular filtration rate
True
A decrease in blood pressure will cause an increase in GFR through sympathetic stimulation
False
The average glomerular filtration rate is equal to
180 L/day
An increase in GFR leads to an increase in urine production
True
Increased sympathetic neuron activity will cause
Vasoconstriction of afferent arterioles
Macula dense cells of the juxtaglomerular apparatus are part of the tubuloglomerular feedback mechanism
True
ATP and adenosine fram macula densa cells stimulate vasodilation of the afferent arteriole
False
The ability of the kidneys to maintain a relatively constant GFR despite fluctuating blood pressures is called
Renal auto regulation
Hypotension would induce ___ of afferent arterioles
Dilation
The sensor in tubuloglomerular feedback is a group of cells called the
Macula densa
Glomerular filtration would be decreased by
Decreased glomerular hydrostatic pressure
Through renal auto regulation, an increase in blood pressure will cause the afferent arteriole to ___ and therefore the GFR will ____.
Constrict, not change
Under condition of severe dehydration approximately 99.2% of the glomerular ultra filtrate volume is reabsorbed
False
The minimum urine volume needed to excrete metabolic waste produced by the body is called as
Obligatory water loss
The return of molecules from the tubules to the blood is called
Reabsorption
The majority of reabsorption occurs in the
Proximal convoluted tubule
The obligatory water loss needed to excrete metabolic waste is ___ per day.
400 mL
The transport of water is always an active process
False
The proximal convoluted tubule reabsorbs approximately 65% of water and ions salt entering it
True
The ___ surface of the simple cubical epithelia in the proximal convoluted tubule contains microvilli
Basal
Na+ reabsorption is a(n) ___ process, while Cl- reabsorption is a(n) ___ process.
Active, passive
Epithelial cells of the proximal tubule have a lower concentration of Na+ than the filtrate
True
What create a Na+ concentration gradient in the proximal tubule
Na+/K+ pump
Na+ moves by ___ from the filtrate into the epithelial cells of the proximal tubule
Diffusion
The reabsorption of Na+ in the proximal tubule creates an osmotic gradient for the diffusion of ___ to occur
H2O
Since water follows the reabsorption of Na+ in the proximal tubule, the filtrate is isomotic with the blood
True
The proximal tubule and loop of Henle are subject to hormonal regulation of sodium and water
False
As the tubular filtrate moves through the descending limb of the loop of Henle, the osmolality of the filtrate increases
True
Na+ is actively transported into the tubule cells of the ascending limb of the loop of Henle from the tubular lumen
False
The ___ limb of the loop of Henle is impermeable to water
Ascending
The ___ limb of the loop of Henle is impermeable to salt
Descending
The tubular filtrate osmolarity ___ as it flows through the ascending limb of the loop of Henle
Decreases
Inhibition of the functions of the descending limb of the loop of Henle would stimulate
Decreased water reabsorption
The vasa recta have the net effect of concentrating solutes in the interstitial fluid of the renal medulla
True
The ___ acts as a countercurrent exchanger
Vasa recta
Salt leaving the ascending limb of the loop of Henle causes the loos of water from the descending limb of the loop of Hnele
True
The concentration of renal filtrate is highest in the
Base of the Loop of Henle
What is present in the casa recta to remove water for the interstitial fluid of the renal medulla
Aquaporins
Countercurrent multiplication occurs by the action sod the
Both vasa recta and loop of Henle
___ is a nonsalt molecule that contributes to the hyportonicity of the interstitial fluid of the renal tubules
Urea
Urea transport in the collecting duct is a(n) ___ process
Passive
Urea is transported out of the descending limb of the loop of Henle to add to the high osmolarity of the medulla
False
The collecting duct is naturally impermeable to salt but permeable to water
True
Diabetes mellitus is a disease associated with the inadequate secretion or action of ADH
False
Water permeability in the collecting duct is varied by altering the number of aquaporins present
True
The maximal response to antidiuretic hormone occurs int he cortical nephrons
False
Water permeability of the proximal convoluted tubule is regulated by antidiuretic hormone
False
The presence of antidiuretic hormone causes aquaporins to be formed in the collecting duct cells
True
Antidiuretic hormone exerts its effect via a cAMP second messenger system
True
Neurohypophyseal secretion os ___ stimulates formation of concentrated urine
Antidiuretic hormone
An increase in plasma osmolality will cause the secretion of ADH
True
An increase of blood volume will cause secretion of ADH
False
Tubular ultrafiltrate enters the collecting duct from the
Distal convoluted tubule
Antidiuretic hormone
Stimulates water reabsorption by the kidney
Induces fusion of aquaporin containing vesicles with the plasma membrane
Is secreted in response to dehydration
Tubular secretion of small xenobioticsis often accomplished by polyspecific organic anion transporters
True
The ability of the kidneys to remove molecules from the blood plasma by excreting them in the urine is known as
Renal clearance
Which transporters in the proximal tubule are polyspecific and transport small molecules of drugs and toxins to the ultrafiltrate
Organic anion transporters
The effectiveness of some antibiotics, such as penicillin, is enhanced by preventing their exertion by use of
Probenecid
The movement of molecules and ions from the peritubular capillaries into interstitial fluid and then into the nephron tubule is called
Secretion
Renal clearance is decreased by reabsorption and increased by secretion
True
Where are OATs located
Basolateral membrane of proximal tubule cells
Inulin clearance gives a measurement of the glomerular filtration rate
True
Inulin is a good measure of GFT because it is filtered but neither reabsorbed nor secreted by the kidneys
True
Plasma measurement of creatinine is a close estimate of GFT
True
Decreased glomerular filtration rate would
Decrease plasma creatinine clearance rate
The renal plasma clearance of a substance that is filtered and reabsorbed must be less than the GFR
True
The renal plasma clearance of a substance that is filtered and secreted is ___ the GFR
Greater than
The renal clearance of PAH ___ glomerular filtration rate
Exceeds
PAH actually measures
Total renal blood flow
The minimum plasma concentration of a substance that results int he excretion of that substance in the urine is the
Renal plasma threshold
The renal plasma clearance of a substance that is filtered but not reabsorbed or secreted is ___ the GFT
Equal to
The concentration of glucose in the glomerular ultra filtrate is less than that of plasma
False
Only about 20% of renal blood is filtered in one pass through the kidneys
True
The ___ is the saturation point of renal carrier molecules
Transport maximum
People with diabetes mellitus have glycosuria because
The plasma glucose concentration is greater than the renal plasma threshold
People with diabetes mellitus have polyuria because
They have greater oncotic pressure in the kidney tubules
Increased aldosterone secretion stimulates renal potassium retention
False
Inhibition of ___ secretion from the adrenal cortex stimulates hyperkalemia
Aldosterone
Excessive aldosterone secretion would induce
Decreased plasma potassium
Diuretics often act on
The distal convoluted tubule
The main region of aldosterone action is the
Cortical collecting duct
Due to the action of the aldosterone, water is reabsorbed because
Sodium is reabsorbed into peritubular blood
Granular cells if the juxtaglomerular apparatus respond to decreased blood volume and increased sympathetic nerve activity by secreting
Renin
Angiotensin - converting enzyme is mostly present in the capillaries of the
Lung
The presence of renin secreting tumors may cause
Hypertension
Increased aldosterone secretion
Increased renal sodium reabsorption
Hemorrhage would induce
Increased renin secertion
An inadequate dietary intake of NaCl will cause
Increased renin secretion
Aldosterone secretion from the adrenal cortex is stimulated by a (n) ___ in blood Na+ or a(n) ___ in blood K+
Decrease, increase
The conversion of angiotensin I into angiotensin II occurs primarily in the
Lungs
Potassium secretion by the kidneys is only possible due to the action of aldosterone
False
Diuresis is stimulated by atrial natriuretic peptide
True
Changes in blood volume are detected by
Stretch receptors in the atria
Conn’s syndrome results in hypokalemia and
Both metabolic alkalosis and loss of H+
Depletion of extracellular K+ may induce
Metabolic alkalosis
An increase in extracellular H+ concentration may result in ___ extracellular K+
Increased
The buffered of urinary pH are ammonia and mono hydrogen phosphate
True
Inhibition of actions of ___ would impair the ability of the kidney to regulate pH of the blood.
Carbonic anhydrase
In response to alkalosis
The kidney excretes bicarbonate
The apical membranes of the tubular cells are impermeable to bicarbonate
True
The kidneys provide short term adjustments to maintain cody pH
False
Bicarbonate must be converted to ___ to move into tubule cells to reduce blood pH
Carbon dioxide
The kidneys can directly reabsorb bicarbonate
False
Since most filtered bicarbonate is reabsorbed, where does the bicarbonate come from that is used to compensate for acidosis
Glutamine
The osmotic diuretic mannitol inhibits salt and water absorption int eh proximal convoluted tubule
False
Hypertension and edema are often treated with diuretics
True
Neuromuscular disorders and eletrocardiographic abnormalities can result from
Hypokalemia
Excessive use of loop diuretics
Excessive use of thiazide diuretics
Spironolactone
Inhibits the actions of aldosterone
Loop diuretics such as Lasix
Inhibit active transport of salt out of the ascending loop of Henle limb
Thiazide diuretics
Inhibit salt transport in the first section of the distal tubule and the last part of the ascending limb of Henle loop
Renal damage often produces microalbuminuria
True
Glomerulonephritis may result from destruction of the glomerular capillary basement membrane
True
Renal insufficiency often results from dialysis
False
___ is believed to be an autoimmune disease affecting the kidney
Glomerulonephritis
Which test can be used to detect renal damage from diabetes or hypertension
Urinary albumin excretion rate
Renal insufficiency
May occur as a result of arteriosclerosis
CAPD utilizes the ___ as a dialysis membrane
Peritoneum
Uremial may cause
Acidosis
Hyperkalemia
Uretic coma
Kidney stones may result in
Renal insufficiency
Hypertension due to water and salt retention
Uremia
Dialysis fluid has Na+, K+ and glucose present so that those substances will not be removed from the patients blood
True
