BIOLOGY 2301 UNIT 3 LECTURE
UPDATED Exam Questions and
CORRECT Answers
filtration - CORRECT ANSWER - hydrostatic pressure forces water and solutes from
glomerular capillaries into Bowman's capsule
reabsorption - CORRECT ANSWER - active transport, diffusion and osmosis recovers
much of what was filtered
secretion - CORRECT ANSWER - some materials not filtered are actively transported into
distal convoluted tubule
where does filtration occur? - CORRECT ANSWER - glomerular membrane
where does reabsorption occur? - CORRECT ANSWER - proximal convoluted tubule,
descending and ascending limb of hinle
where does secretion occur? - CORRECT ANSWER - distal convoluted tubules
what mechanisms move molecules in filtration? - CORRECT ANSWER - hydrostatic
pressure
what mechanisms move molecules in absorption? - CORRECT ANSWER - active
transport, diffusion and osmosis
what mechanisms move molecules in secretion? - CORRECT ANSWER - active transport
,What blood elements are not filtered across the glomerular membrane? - CORRECT
ANSWER - large proteins and cells
Where is the filtrate initially collected? - CORRECT ANSWER - glomerular membrane
capsule
How can clearance be used as an index of GFR? What kind of filtrate molecule must be used?
What is an example? - CORRECT ANSWER - if the substance is not reabsorbed,
clearance=GFR; a filtrate molecule that cannot be reabsorbed; an example would be creatinine
glomerular filtration - CORRECT ANSWER - amount of fluid filtered per unit of time
(125 mL/min)
clearance - CORRECT ANSWER - volume of plasma "cleared" of a particular substance
per unit of time
What does it mean if a molecule has a clearance of zero? - CORRECT ANSWER - the
substance has been completely absorbed
What are the responses to low blood pressure? - CORRECT ANSWER - low blood
pressure causes us to filter not fast enough, so we dilate afferent arterioles so the low blood
pressure doesn't get over the glomerular capillaries; low blood pressure causes us to increase
renin secretion to allow fluid to flow, increasing the BP
What are the responses to low flow rate and low osmolarity? - CORRECT ANSWER -
low flow rate and low osmolarity tell us we are already filtering too slow, so, we dilate afferent
arterioles so the low blood pressure doesn't get over the glomerular capillaries; low blood
pressure causes us to increase renin secretion to allow fluid to flow, increasing the BP
What are the responses to high blood pressure? - CORRECT ANSWER - high blood
pressure causes us to filter too fast, so, we constrict the afferent arterioles, so the blood that is
being filtered too fast doesn't get to the glomerular capillaries; high blood pressure causes us to
decrease renin secretion, to keep fluid in, lowering the BP
, What are the responses to high flow rate and high osmolarity? - CORRECT ANSWER -
high flow rate and high osmolarity tell us we are already filtering blood too fast, so, we constrict
the afferent arterioles, so the blood that is being filtered too fast doesn't get to the glomerular
capillaries; high blood pressure causes us to decrease renin secretion, to keep fluid in, lowering
the BP
How do the responses from I-IV help to keep GRF constant? Which of these responses adjust
systemic blood pressure and how? Which of these responses help to adjust blood osmolarity and
how? - CORRECT ANSWER -
What events occur after renin is secreted? - CORRECT ANSWER - renin causes
angiotensin II, angiotensin II constricts the peripheral blood vessels which raises blood pressure,
this then causes aldosterone to be secreted which causes sodium to be reabsorbed
What are the effects of these events on GFR, systemic BP, sodium retention, and water
retention? - CORRECT ANSWER -
What is the purpose of activating the renin-angiotensin system when blood pressure is low? -
CORRECT ANSWER - when the blood pressure is low, renin secretion is increased. the
renin-angiotensin system constricts the peripheral blood vessels, raising blood pressure.
angiotensin secretion causes aldosterone, which causes sodium reabsorption by the kidneys
What is the purpose of activating the renin-angiotensin system when tubular osmolarity is low? -
CORRECT ANSWER - when osmolarity is low, this change tells you you're filtering
blood too slow, so renin secretion is increased. the renin-angiotensin system constricts the
peripheral blood vessels, raising blood pressure. angiotensin secretion causes aldosterone, which
causes sodium reabsorption by the kidneys
How does the sympathetic NS affect GFR? what is the purpose of this response? - CORRECT
ANSWER - sympathetic nervous system reduces GFR by constricting the peripheral
vasculature including the afferent arterioles and also stimulates renin secretion, increasing
angiotensin II and aldosterone; all this shunts blood to essential areas and raises systemic blood
pressure
UPDATED Exam Questions and
CORRECT Answers
filtration - CORRECT ANSWER - hydrostatic pressure forces water and solutes from
glomerular capillaries into Bowman's capsule
reabsorption - CORRECT ANSWER - active transport, diffusion and osmosis recovers
much of what was filtered
secretion - CORRECT ANSWER - some materials not filtered are actively transported into
distal convoluted tubule
where does filtration occur? - CORRECT ANSWER - glomerular membrane
where does reabsorption occur? - CORRECT ANSWER - proximal convoluted tubule,
descending and ascending limb of hinle
where does secretion occur? - CORRECT ANSWER - distal convoluted tubules
what mechanisms move molecules in filtration? - CORRECT ANSWER - hydrostatic
pressure
what mechanisms move molecules in absorption? - CORRECT ANSWER - active
transport, diffusion and osmosis
what mechanisms move molecules in secretion? - CORRECT ANSWER - active transport
,What blood elements are not filtered across the glomerular membrane? - CORRECT
ANSWER - large proteins and cells
Where is the filtrate initially collected? - CORRECT ANSWER - glomerular membrane
capsule
How can clearance be used as an index of GFR? What kind of filtrate molecule must be used?
What is an example? - CORRECT ANSWER - if the substance is not reabsorbed,
clearance=GFR; a filtrate molecule that cannot be reabsorbed; an example would be creatinine
glomerular filtration - CORRECT ANSWER - amount of fluid filtered per unit of time
(125 mL/min)
clearance - CORRECT ANSWER - volume of plasma "cleared" of a particular substance
per unit of time
What does it mean if a molecule has a clearance of zero? - CORRECT ANSWER - the
substance has been completely absorbed
What are the responses to low blood pressure? - CORRECT ANSWER - low blood
pressure causes us to filter not fast enough, so we dilate afferent arterioles so the low blood
pressure doesn't get over the glomerular capillaries; low blood pressure causes us to increase
renin secretion to allow fluid to flow, increasing the BP
What are the responses to low flow rate and low osmolarity? - CORRECT ANSWER -
low flow rate and low osmolarity tell us we are already filtering too slow, so, we dilate afferent
arterioles so the low blood pressure doesn't get over the glomerular capillaries; low blood
pressure causes us to increase renin secretion to allow fluid to flow, increasing the BP
What are the responses to high blood pressure? - CORRECT ANSWER - high blood
pressure causes us to filter too fast, so, we constrict the afferent arterioles, so the blood that is
being filtered too fast doesn't get to the glomerular capillaries; high blood pressure causes us to
decrease renin secretion, to keep fluid in, lowering the BP
, What are the responses to high flow rate and high osmolarity? - CORRECT ANSWER -
high flow rate and high osmolarity tell us we are already filtering blood too fast, so, we constrict
the afferent arterioles, so the blood that is being filtered too fast doesn't get to the glomerular
capillaries; high blood pressure causes us to decrease renin secretion, to keep fluid in, lowering
the BP
How do the responses from I-IV help to keep GRF constant? Which of these responses adjust
systemic blood pressure and how? Which of these responses help to adjust blood osmolarity and
how? - CORRECT ANSWER -
What events occur after renin is secreted? - CORRECT ANSWER - renin causes
angiotensin II, angiotensin II constricts the peripheral blood vessels which raises blood pressure,
this then causes aldosterone to be secreted which causes sodium to be reabsorbed
What are the effects of these events on GFR, systemic BP, sodium retention, and water
retention? - CORRECT ANSWER -
What is the purpose of activating the renin-angiotensin system when blood pressure is low? -
CORRECT ANSWER - when the blood pressure is low, renin secretion is increased. the
renin-angiotensin system constricts the peripheral blood vessels, raising blood pressure.
angiotensin secretion causes aldosterone, which causes sodium reabsorption by the kidneys
What is the purpose of activating the renin-angiotensin system when tubular osmolarity is low? -
CORRECT ANSWER - when osmolarity is low, this change tells you you're filtering
blood too slow, so renin secretion is increased. the renin-angiotensin system constricts the
peripheral blood vessels, raising blood pressure. angiotensin secretion causes aldosterone, which
causes sodium reabsorption by the kidneys
How does the sympathetic NS affect GFR? what is the purpose of this response? - CORRECT
ANSWER - sympathetic nervous system reduces GFR by constricting the peripheral
vasculature including the afferent arterioles and also stimulates renin secretion, increasing
angiotensin II and aldosterone; all this shunts blood to essential areas and raises systemic blood
pressure
