BIOLOGY 2301 UNIT 3 LECTURE
EXAM-QUESTIONS AND ANSWERS|
2026 UPDATE
filtration - Ans--hydrostatic pressure forces water and solutes from
glomerular capillaries into Bowman's capsule
reabsorption - Ans--active transport, diffusion and osmosis recovers much
of what was filtered
secretion - Ans--some materials not filtered are actively transported into
distal convoluted tubule
where does filtration occur? - Ans--glomerular membrane
where does reabsorption occur? - Ans--proximal convoluted tubule,
descending and ascending limb of hinle
where does secretion occur? - Ans--distal convoluted tubules
what mechanisms move molecules in filtration? - Ans--hydrostatic pressure
what mechanisms move molecules in absorption? - Ans--active transport,
diffusion and osmosis
what mechanisms move molecules in secretion? - Ans--active transport
What blood elements are not filtered across the glomerular membrane? -
Ans--large proteins and cells
Where is the filtrate initially collected? - Ans--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? - Ans--if the substance is not
reabsorbed, clearance=GFR; a filtrate molecule that cannot be
reabsorbed; an example would be creatinine
glomerular filtration - Ans--amount of fluid filtered per unit of time (125
mL/min)
clearance - Ans--volume of plasma "cleared" of a particular substance per
unit of time
What does it mean if a molecule has a clearance of zero? - Ans--the
substance has been completely absorbed
What are the responses to low blood pressure? - Ans--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? - Ans--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? - Ans--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? - Ans--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? - Ans--
What events occur after renin is secreted? - Ans--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? - Ans--
What is the purpose of activating the renin-angiotensin system when blood
pressure is low? - Ans--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? - Ans--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? - Ans--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
By what mechanism does the sympathetic nervous system alter sodium
and water retention by the kidneys? - Ans--stimulating renin secretion,
increasing angiotensin II and aldosterone secretion; aldosterone secretion
causes sodium reabsorption
What are the sympathetic nervous systems effects on blood pressure,
blood flow, and fluid and electrolyte balance? - Ans--constriction of
EXAM-QUESTIONS AND ANSWERS|
2026 UPDATE
filtration - Ans--hydrostatic pressure forces water and solutes from
glomerular capillaries into Bowman's capsule
reabsorption - Ans--active transport, diffusion and osmosis recovers much
of what was filtered
secretion - Ans--some materials not filtered are actively transported into
distal convoluted tubule
where does filtration occur? - Ans--glomerular membrane
where does reabsorption occur? - Ans--proximal convoluted tubule,
descending and ascending limb of hinle
where does secretion occur? - Ans--distal convoluted tubules
what mechanisms move molecules in filtration? - Ans--hydrostatic pressure
what mechanisms move molecules in absorption? - Ans--active transport,
diffusion and osmosis
what mechanisms move molecules in secretion? - Ans--active transport
What blood elements are not filtered across the glomerular membrane? -
Ans--large proteins and cells
Where is the filtrate initially collected? - Ans--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? - Ans--if the substance is not
reabsorbed, clearance=GFR; a filtrate molecule that cannot be
reabsorbed; an example would be creatinine
glomerular filtration - Ans--amount of fluid filtered per unit of time (125
mL/min)
clearance - Ans--volume of plasma "cleared" of a particular substance per
unit of time
What does it mean if a molecule has a clearance of zero? - Ans--the
substance has been completely absorbed
What are the responses to low blood pressure? - Ans--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? - Ans--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? - Ans--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? - Ans--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? - Ans--
What events occur after renin is secreted? - Ans--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? - Ans--
What is the purpose of activating the renin-angiotensin system when blood
pressure is low? - Ans--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? - Ans--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? - Ans--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
By what mechanism does the sympathetic nervous system alter sodium
and water retention by the kidneys? - Ans--stimulating renin secretion,
increasing angiotensin II and aldosterone secretion; aldosterone secretion
causes sodium reabsorption
What are the sympathetic nervous systems effects on blood pressure,
blood flow, and fluid and electrolyte balance? - Ans--constriction of
