The nephron:
has endocrine functions
is lined by a single layer of epithelial cells
is under endocrine control
absorbs more ions and molecules than it secretes
all of the above
The control of water excretion in the kidney is controlled by:
the antidiuretic hormone (ADH)
the medulla oblongata
blood plasma
sodium amount in the blood
potassium amount in the blood
The kidneys have a direct effect on which of the following?
blood pressure
how much water a person excretes
total blood volume
pH
Glucose reabsorption occurs in the:
proximal tubule
loop of Henle
distal tubule
cortical collecting duct
medullary collecting duct
Renin is secreted by:
cells in the macula densa
cells in the proximal tubule
cells in the distal tubule
juxtaglomerular cells
cells in the peritubular capillary bed
Renin release:
is promoted by reduced arteriolar stretch in. the glomeruli
increases when systemic arterial pressure rises
directly activates angiotensin converting enzyme
tends to expand the plasma volume
a and d
The glomerulus:
has both afferent and efferent arterioles
contains capillaries, which are at a higher hydrostatic pressure than the peritubular capillaries
filters 20% of the renal plasma flow
contains renin-secreting cells
The acid-buffering power:
of HCO3- in blood is increased by respiratory control of pCO2
of haemoglobin exceeds that of HCO3- in blood
of HCO3- is increased by the action of carbonic anhydrase
of venous blood is normally greater than that of arterial blood
a, b, and d
Urinary volume is increased with:
consumption of alcohol
hyperglycemia
increased aldosterone secretion
damage to the posterior pituitary
The following occurs in the proximal tubule of the nephron:
reabsorption of all glucose
reabsorption of most water
active reabsorption of sodium
secretion of bicarbonate
a, b, and c
The antidiuretic hormone (ADH):
decreases the osmolarity of urine
decreases the volume of urine
increases the reabsorption of water in the proximal tubules
is synthesised in the posterior posterior pituitary gland
increases the excretion of glucose
Regarding the kidneys:
there are 1.3 million nephrons in each kidney
they produce aldosterone
they receive 12% of the cardiac output at rest
more blood flows through the renal cortex than the renal medulla
a, and d
Which of the following causes hyperkalemia
exercise
alkalosis
insulin injection
decreased serum osmolality
increased serum osmolality
Glucose is reabsorbed:
by active transport
by passive transport
by Na+ co-transport
by H+ counter-transport
a, and c
Simulation of the sympathetic nerves cause the following effects;
low diuresis
decreased net filtration pressure
increased glucose urine level
decreased glucose urine level
a, and b
The glomerular capillaries have the following functions:
blood plasma filtration
hormone secretion
water secretion
formation of primary urine
Obligatory water loss from the body is:
400 ml in faeces
300 ml from the lungs
loss from skin & lungs
insensible water loss
500 ml in urine
Blood flow at rest is most for:
brain
liver
kidneys
heart
skin
Renal blood flow is dependent on:
juxtaglomerular apparatus
[Na+] at macula densa
afferent vasodilatation
arterial pressure
efferent vasoconstriction
Which of the following substances has the highest renal clearance?
PAH
Glucose
Urea
Water
Insulin
The ascending limb of the loop of Henle is:
impermeable to Na+
involved in active transport of K+ into the lumen
involved in active transport of Cl- out of lumen
involved in active transport of Na+ into lumen
hypotonic at the top
Which of the following ls involved in the regulation of glomerular filtration rate (GFR)?
afferent arteriolar tone
efferent arteriolar tone
chloride transport at the macula densa
Water excretion by the kidney is due to:
osmosis
active transport into the lumen
passive secretion in the collecting tubule
solvent drag
facilitated diffusion
Kidneys produce:
Erythropoietin
ADH
Angiotensin ll
ANP
Cholecalciferol
Increase in GFR occurs when there is:
increased sympathetic stimulation
decreased renal blood flow
hypoproteinaemia
ureteric obstruction
none of the above
The clearance (or ‘renal regulation') of which one of the following is not regulated by a hormone:
sodium
potassium
calcium
phosphate
sulphate
The kidneys filter from the blood every day about:
1000 ml
180 l
18 l
50 l
8 l
Direct control of water excretion in the kidney is controlled by:
the antidiuretic hormone
aldosterone
sodium amounts in the blood
adrenal cortex
Kidneys have a direct effect on which of the following:
The countercurrent exchange system includes:
glomerulus and macula densa
proximal convoluted tubule and distal convoluted tubule
loop of Henle and collecting tubule
afferent arteriole and efferent arteriole
ureters and bladder
Tubular reabsorption of a filtered substance is likely to be active rather than passive if:
its concentration in the tubular fluid is lower than in peritubular capillary blood
is carried out by the mechanism of simple diffusion
renal clearance is lower than that of insulin
renal clearance rises at low plasma levels
osmolality there is higher than the plasma one
The renal clearance of a substance:
is inversely related to its urinary concentration, U
is directly related to the rate of urine formation, and is expressed in units of volume per unit time
is directly related to its plasma concentration, P
is expressed in mm Hg
must fall in the presence of metabolic poisons
In the fluid in the distal part of the proximal convoluted tubule:
urea concentration is higher than in Bowman’s capsule
pH is less than 6 when the kidneys are excreting an acid urine
glucose concentration is similar to that in plasma
osmolality is about 25 per cent that of glomerular filtrate
bicarbonate concentration is higher than in plasma
Renal tubules normally reabsorb:
fluids with osmolality lower than the plasma one
all filtered HCO3- in respiratory alcalosis
substances closely related to Cl-
all filtered plasma proteins
more K+ and Cl-
In the nephron, the osmolarity or the fluid in the:
Tip of the loop Of Henle is less than that of plasma
Bowman's capsules is less than that in the distal tubules
Collecting duct rises when vasopressin is being secreted
Proximal convoluted tubule rises along its length
Proximal tubule is with lower osmolality than plasma one
Transport maximum (Tm) - limited reabsorption of a substance implies that its:
reabsorption is active
reabsorption is critically related to tubular transit time
reabsorption is passive
renal clearance falls with its plasma concentration
reabsorbtion is carried out by the mechanism of faciliated diffusion
When a patient’s mean arterial blood pressure falls by 50%
renal blood flow increases
glomerular filtration increases
there is a decrease in the circulating aldosterone level
renal vasoconstriction occurs
urinary output is increased
The cells of the distal convoluted tubule:
reabsorb about 50 % of the water filtered by the glomeruli
reabsorb all filtered aminoacide
reabsorb all filtered proteins
reabsorb sodium in exchange for hydrogen or potassium ions
determine the final composition of urine
Renal blood flow falls:
about 10 % when arterial pressure increases 10% above normal
about 5% when metabolic activity in the kidney falls by 5%
during emotional stress
after small haemorrhage
gradually from the inner medulla to the outer cortex per unit weight of tissue
Urea:
and glucose have different molar concentrations in normal blood
clearance is higher, than creatinins one
is actively secreted by the renal tubular cells into the tubular fluid
concentration in blood may rise ten-fold after a high protein meal
causes diuresis when its blood concentration is increased
The renal clearance of:
Inulin provides an estimate of glomerular filtration rate
Chloride increases after an injection of aldosterone
PAH falls when the PAH load exceeds the Tm for PAH
Urea is higher than that of insulin
Inulin is dependent of its plasma concentration
Aldosterone:
is a steroid hormone, secreted by the adrenal medulla
production ceases following removal of the kidneys and their juxtaglomerular cells
production decreases in treatment with drugs which block angiotensin-converting enzyme
secretion results in increased potassium reabsorption by the nephron
secretion results in a fall in plasma volume
In healthy people, urinary:
clearance of glucose differs 0, if its plasma concentration is below 11,1mmol.1-1
osmolality ranges from 200-400 mosmol/litre
colour is due to small quantities of bile pigments
pH falls as dietary protein rises
calcium excretion is decreased by parathormone
The renal clearance
glucose is above 0, if the plasma concentration of a given substance is below 11, mmol.1-1
of urea is higher than creatinin‘s one
of glucose provides an estimate of renal plasma flow
of phosphate is decreased by parathormone
of protein is normally zero
Secretion of renin:
occurs in the stomach during infancy
is stimulated by the hormone angiotensin 1
is stimulated by a fall in extracellular fluid volume and leads to raised levels of angiotensin II in the blood
inhibits the secretion of aldosterone
inhibits ACTH secretion by the pituitary gland
Diabetes insipidus (deficiency of antldiuretic hormone) causes a fall in the:
osmolality of the urine
reabsorption of water from the proximal tubules
extracellular but not intracellular fluid volume
extracellular fluid osmolality
intracellular fluid osmolality
Dialysis fluid used in the treatment of renal failure should contain the normal plasma levels of:
urea
osmolarity
plasma proteins
hydrogen ions
Long-standing obstruction of the urethra may cause:
enlargement of the prostate gland
dystrophy of the bladder muscle
dilation of the ureters and reduction of the glomerular filtration rate
increase and reduction of the glomerular filtration rate
a decrease in residual volume in the bladder
Emptying of the bladder may be less effective if:
the sympathetic nerves carrying afferent information from bladder to the spinal cord are cut
the pelvic nerves are cut or anticholinergic drugs are administered
cholinergic agonists are administered
alpha-adrenergic receptor antagonists are administered
beta-adrenergic receptor blockers are administered
Drugs which interfere with active transport of sodium in the proximal tubule tend to increase:
urine production
plasma osmorality
chloride reabsorbtion
intestinal fluid volume
plasma volume
A drug which inhibits carbonic anhydrase:
decreases bicarbonate formation and reabsorption in the kidney
increases plasma bicarbonate levels
increases blood pH
increases urinary loss of potassium ions
increases urinary volume and pH
A patient with chronic renal failure usually has:
an increased blood urea and blood uric acid
a decreased blood uric acid
an increased creatinine clearance
an increased acid-base disturbance when he or she vomits
an increased acid-base problem on a low protein diet
Cutting the sympathetic nerves to the bladder may cause:
difficulty in emptying the bladder
loss of tone in the internal sphincter of the bladder and loss of pain sensation in the bladder
loss of tone in the external sphincter of the bladder
increased pain sensation in the bladder
infertility in the female
Sudden (acute) renal failure differs from gradual (chronic) renal failure in that:
potassium retention tends to be more severe
blood urea levels tend to be higher
depression of bone marrow activity is unlikely to occur
metabolic acidosis is usually not a problem
dietary protein restriction is unnecessary
A long-standing increase in arterial pCO2 (respiratory acidosis) leads to:
an increase in renal bicarbonate formation
a decrease in urinary ammonium salts
a decrease in plasma potassium concentration
an increase of the monohydrogen/dihydrogen phosphate ratio in urine
a decrease in urinary bicarbonate excretion
The inhibition of the antidiurctic hormone (ADH), say by alcohol, would have what affect?
constriction of the afferent arteriole
inhibition of diuresis
stimulation of water conservation
constriction of the efferent arteriole
reduction in water conservation by the kidneys
Reabsorption of amino acids from the filtrate requires many different protein carriers because:
denaturation may occur
this transport is not competitive
there are only 10 different amino acids
transport of amino acids is typically highly specific
glucose inhibits amino acid transport
Reabsorption (transport) of both N a‘“ and glucose together from the renal lumen is an example of:
secondary passive transport
primary direct active transport
secondary indirect active antiport
secondary indirect active symport
Drinking a litre of water:
increases secretion of antidiuretic honnone
reduces the plasma sodium concentration
increases osmolarity of the urine
causes body cells to shrink
decreases the specific gravity of the body
An acid-base buffer system:
can be a mixture of a weak acid and its conjugate base
can be a solution of sodium and bicarbonate ions
prevents any change in pH when acid is added
works best when acid and base are equal in concentration
is hemoglobin as an example of intracellular buffer
Acidosis in a patient may lead to:
increased urinary excretion of potassium
hypoventilation
a blood pH of less than 5.5
an urinary pH of less than 5.5
tetany
A rise in the osmolality of extracellular fluid may lead to:
thirst and release of vasopressin
increased water reabsorption in the proximal convoluted tubules
a decrease of vasopressin secretion
an increase in intracellular fluid volume
suppression of sweat secretion
A raised blood pH and bicarbonate level is consistent with:
metabolic acidosis
partly compensated respiratory alkalosis
a reduced pCO2
chronic renal failure with a raised pCO2
a history of persistent vomiting of gastric contents
A patient with partly compensated respiratory acidosis:
must have a raised pCO2
must have a raised bicarbonate concentration [HCO3-]
may have evidence of renal compensation
may have respiratory failure due to hypoventilation
Sodium retention:
occurs for several days after major surgery
expands the extracellular fluid volume
expands the blood volume
increases the severity of oedema
Sodium depletion differs from water depletion in that:
cardiovascular changes are less pronounced
intracellular fluid volume is less affected
the haematocrit increases
thirst is more severe
antidiuretic hormone levels are higher
A high blood potassium level (hyperkalaemia):
occurs in acute renal failure
follows severe crush injuries to the limbs
may diminish cardiac performance and cause death
may be reduced by Intravenous infusion of insulin and glucose
A raised level of calcium in the blood (hypercalcaemia):
may occur when parathyrord activity decreases
may occur when the plasma protein level falls
may occur in chronic renal failure
increases the risk of stone formation in the urinary tract
causes increased excitability of nerve and muscle
Thirst is stimulated by:
increase in plasma osmolality and volume
increase in plasma osmolality and decrease in volume
decrease in osmolality and increase in volume
decrease in plasma osmolality and volume
increase in intracelular volume