Renal corpuscle and glomerular filtration Flashcards
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What are the three components of the glomerular filtration barrier?
Endothelium of the glomerular capillaries
Glomerular basement membrane
Viceral layer of Bowman’s capsule
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Which component of the glomerular filtration barrier contains podocytes (viceral epithelial cells)?
Viceral layer of Bowman’s capsule
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Secondary processes of podocytes are called what?
Pedicels or foot processes
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What is the space between the visceral layer and the parietal layer of Bowman’s capsule?
Bowman’s space
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The endothelium of the glomerular capillaries is fenestrated and permeable to red blood cells. T/F
F
It is fenestrated but not permeable to red blood cells.
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The endothelium is permeable to which: white blood cells, platelets, water, Na, urea, glucose, most proteins?
Water, Na, urea, glucose, most proteins
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What prevents the filtration of very large anionic proteins into the Bowman’s space?
The negatively charged endothelium of the glomerular capillaries
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At the urinary pole, Bowman’s space becomes the lumen of what?
Proximal tubule
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Which part of the glomerular filtration barrier prevents the passage of plasma proteins into the Bowman’s space?
The negatively-charged basement membrane
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The podocytes of the Bowman’s viceral layer are separated by apparent gaps called what?
Filtration slits
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The glomerular filtrate is devoid of cellular elements. T/F
T
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The glomerular filtration barrier determines the composition of the plasma ultrafiltrate on the basis of which properties of the molecules?
Size and electrical charge
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Small molecules and positive molecules become part of the ultrafiltrate. T/F
T
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Which of the Starling forces promote the movement of fluid from the glomerular capillary into the Bowman’s space?
Hydrostatic pressure of the glomerulus
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Which of the Starling forces oppose filtration?
Oncotic pressure of the glomerulus and
hydrostatic pressure of the Bowman’s space
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The hydrostatic pressure of the glomerular capillary (increases/decreases) along the length of the capillary.
Decreases
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The oncotic pressure of the Bowman’s space (increases/decreases) along the length of the glomerular capillary.
Increases
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A decrease in afferent arteriolar resistance (increases/decreases) the hydrostatic pressure of the glomerular capillary.
Increases
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A decrease in afferent arteriolar resistance (increases/decreases) the GFR.
Increases
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A decrease in efferent arteriolar resistance (increases/decreases) the GFR.
Decreases
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GFR is (directly/inversely) proportional to afferent arteriolar resistance.
Inversely
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An increase in blood pressure transiently (increases/decreases) the hydrostatic pressure of the glomerular capillary.
Increases
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GFR is (directly/inversely) proportional to efferent arteriolar resistance.
Directly
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An increase in afferent arteriolar resistance (increases/decreases) GFR.
Decreases
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A decrease in blood pressure transiently (increases/decreases) the hydrostatic pressure of the glomerular capillary.
Decreases
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An increase in efferent arteriolar resistance (increases/decreases) the GFR.
Increases
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What are the three major resistance vessels in the kidneys and thereby determine renal vascular resistance?
Afferent arterioles, efferent arterioles, interlobular artery
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Most dominant force in determining GFR
A. tubular fluid oncotic pressure
B. plasma or capillary oncotic pressure
C. glomerular capillary hydrostatic pressure
D. Bowman’s capsule hydrostatic pressure
C
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The term “autoregulation” is used because
a. Does not need arterial blood to function
b. Kidney contains baroreceptor
c. Maintains GFR in a wide range of blood pressure
d. Does not need symphathetic nerves to function
C
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Highest oncotic pressure
a. Efferent arteriole
b. Afferent arteriole
c. Midway in glomerular capillary
d. Renal artery
A
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Glomerulotubular refers to
a. Maintaining GFR constant in the face of changes of MAP
b. Increase in GFR in response to an increase in RBF
c. Increase in tubulo reabsorption in response to an increase filter load
d. AOTA
D
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Blood volume decreases as it passes through which structures?
A. afferent arteriole B. efferent arteriole C. peritubular capillaries D. glomerular capillaries E. all of the above
D
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Glomerular oncotic pressure is primarily contributed by
A. Plasma protein
B. Glucose
C. Sodium
D. Urea
A
Blood flowing into the glomerulus contains plasma proteins and blood cells that displace the water content of the blood. This creates, in effect, a counter force called oncotic pressure, as water outside the capillaries seeks to equalize with the water inside the capillaries through osmosis.
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Which of the following statements concering the process of glomerular filtration is CORRECT?
A. Bowman’s capsule hydrostatic pressure opposes filtration.
B. The glomerular filtration rate is limited by a Tm
C. All of the plasma that enters the glomerulus is filtered.
D. It is generally affected by small fluctuations in blood pressure.
A
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Which of the following is involved in autoregulation of GFR?
A. Automatic constriction of afferent arteriole when stretched.
B. Increased delivery of Na+ and Cl- to macula densa causes vasoconstriction of afferent arteriole
C. Sympathetically induced vasoconstriction of afferent arteriole
D. Vasoactive substance released from renal nerves cause afferent arteriole vasoconstriction
A
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The glomerular endothelium is negatively charged due to
A. podocalyxin
B. fibronectin
C. heparan sulphate
D. laminin
A
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Which is/are true regarding mesangial cells?
A. contain actin and myosin
B. possess phagocytic functions
C. can contract and respond to angiotensin ll
D. all of the above
D
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In minimal change disease, albumin is able to pass through the glomerular filtration barrier. The albumin passes through the glomeular filter in this order:
A. podocyte -> glomerular basement membrane -> endothelium
B. endothelium -> glomerular basement membrane -> foot process
C. lamina rara externa -> lamina densa -> lamina rara interna
D. lamina rara interna -> lamina densa -> lamina rara externa
B
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Which is not true regarding the renal caps
A. The parietal layer of Bowman’s capsule is lined by simple squamous epithelium
B. The visceral layer of Bowman’s capsule is lines by specialized stellate cells called podocytes.
C. The efferent arteriorle has a wider diameter than theafferent arteriole to allow a pressure gradient to be maintained across the glomerulos.
D. At the vascular pole, the podocyte layer of the glomerular capillaries becomes continuos with the parietal layerof the Bowman’s capsule.
C
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The greatest hydrostatic pressure drop is seen at the level of the
A. arcuate artery
B. afferent arteriole
C. glomerular capillary
D. efferent arteriole
D
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The most important determinant of the concentration of plasma ultrafiltrate is
A. Kf
B. hydraulic pressure of Bowman’s space
C. hydraulic pressure of glomerular capillary
D. plasma oncotic pressure
A
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Which of the following offers the greatest resistance to passage of plasma across the glomerular membrane?
A. endothelial cell
B. basement membrane
C. epithelial cell
D. mesangium
B
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The glomerular filtrate as it enters Bowman’s capsule is
A. protein-free plasma
B. identical in composition to urine
C. contains only substances that are not needed by the body
D. formed because of active transport process
A
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The following can affect the filtration coefficient except
A. surface area of the glomerular membrane
B. permeability of the glomerualr membrane
C. hydrostatic pressure of the Bowman’s capsule
D. contraction of the mesangial cells
C
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The glomerular capillary blood pressure is 55 mmHg.
The tubular hydrostatic pressure is 15 mmHg.
The colloidal osmotic pressure is 30 mmHg.
The net filtration pressure is ___________ mm Hg.
A. -10
B. 10
C. 40
D. 70
B
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The most dominant factor affecting glomerular filtration under normal condition is the:
A. glomerular capillary hydrostatic pressure
B. plasma colloidal osmotic pressure
C. hydrostatic pressure of the Bowman’s capsule
D. capillary surface area
A
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Which of the following factors would decrease the GFR?
A. a fall in plasma protein concentration
B. an obstruction such as crystal deposits in the tubules
C. vasodilation of the afferent arterioles
D. relaxation of the mesangial cells
B
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Which condition will give the highest filtration fraction?
A. constriction of the afferent arteriole and constriction of the efferent arteriole
B. constriction of the afferent arteriole and vasodilation of the efferent arteriole
C. vasodilation of the afferent arteriole and vasodilation of the efferent arteriole
D. vasodilation of the afferent arteriole and constriction of the efferent arteriole
D
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When arterial blood pressure is elevated above normal, which of the following compensatory changes in renal function occur as a result of the baroreceptor reflex?
A. efferent arteriolar vasoconstriction
B. afferent arteriolar vasodilation
C. efferent arteriolar vasodilation
D. afferent arteriolar vasoconstriction
D
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The ultrafiltrate from the glomerulus is isoosmotic to plasma. T/F
T
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Which is the only Starling force that favors filtration in the Bowman’s capsule?
Hydrostatic pressure of the glomerular capillaries
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What are the two mechanisms of autoregulation of RBF and GFR?
Myogenic mechanism and tubuloglomerular feedback
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Myogenic mechanism relies on which mechanism to regulate the afferent arteriole?
The property of vascular smooth muscles to constrict when stretched
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What is the NaCl sensor of the tubuloglomerular feedback mechanism?
Macula densa
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When arterial pressure rises, afferent arterioles are stretched, and thus, stimulated to (vasodilate/vasoconstrict).
Vasoconstrict
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When the GFR increases, NaCl in the tubular fluid (increases/decreases).
Increases
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When the NaCl in the tubular fluid increases, the macula densa cells sense this and increase the secretion of which molecules?
ATP and adenosine
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ATP and adenosine stimulate afferent arterioles to (vadoconstric/vasodilate).
Vasoconstrict
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Low ATP and adenosine production by macula densa cells stimulates the (vasoconstriction/vasodilation) of the afferent arterioles.
Vasodilation
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Macula densa also secretes NO which causes (vasodilation/vasoconstriction) of the afferent arterioles.
Vasodilation
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There is no autoregulation below which BP?
90 mm Hg
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Sympathetic nerves regulate GFR and RBF by releasing which catecholamines?
Norepinephrine and dopamine
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The hormone from the kidneys that degrades the catecholamines
Renalase
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Norepinephrine and epinephrine cause (vasoconstriction/ vasodilation) of the afferent arterioles.
Vasoconstriction
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NO (vasoconstricts/vasodilates) both afferent and efferent arterioles.
Vasodilates
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The (efferent/afferent) arterioles are more sensitive to low levels of angiotensin II.
Efferent
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Low levels of angiotensin II (increases/decreases) GFR.
Increases
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Low levels of angiotensin II (increases/decreases) RBF.
Decreases
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Natriuretic peptides (dilate/constrict) the afferent arteriole.
Dilate
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Natriuretic peptides constrict the (afferent/efferent) arteriole.
Efferent
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Dopamine stimulates (vasodilation/vasoconstriction)
Vasodilation
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Histamine vasodilates (the efferent/the afferent/both) atretiole/s.
Both
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Endothelin (decreases/increases) GFR and RBF in disease states.
Decreases
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The substance mediating the changes in afferent arteriolar diameter when there is increased delivery of Na+ and Cl- to the macula densa is:
A. Renin
B. Angiotensin
C. Adenosine
D. Aldosterone
C
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These control mechanisms are activated seconds after change in blood pressure except (paraphrased) A. RAAS B. baroreceptor C. chemoreceptor D. CNS ischemic response
A