Physiology 3 Flashcards
name the 3 parts that make up the glomerular membrane
molecular sieve
- glomerular capillary endothelium
- basement membrane
- slit processes of podocytes
which is bigger:
afferent or efferent arteriole
afferent arteriole
is the basement membrane positively or negatively charged?
BM = negatively charged
the gaps between the endothelial cells are too small for what to pass through them?
RBCs
is the process of glomerular filtration active or passive?
passive = does not require energy
name the 4 forces that comprise net filtration pressure
- glomerular capillary blood pressure
- bowman’s capsule hydrostatic (fluid) pressure
- capillary oncotic pressure
- bowmans capsule oncotic pressure
how does the glomerular capillary blood pressure remain constant?
as afferent arteriole is wider than efferent arteriole
state whether they are going IN or OUT of the blood vessel into the bowmans capsule:
- glomerular capillary blood pressure
- bowman’s capsule hydrostatic (fluid) pressure
- capillary oncotic pressure
- bowmans capsule oncotic pressure
- glomerular capillary blood pressure - OUT
- bowman’s capsule hydrostatic (fluid) pressure - IN
- capillary oncotic pressure - IN
- bowmans capsule oncotic pressure - OUT
net filtration pressure = __ mm Hg
net filtration pressure = 10 mm Hg
name the term used to balance hydrostatic and osmotic forces
starling forces
rate at which protein-free plasma is filtered from the glomeruli into the Bowman’s capsule per unit time defines what?
GFR
what is the major determinant of GFR?
glomerular capillary fluid (blood) pressure
if you decrease GFR, you produce ____ urine
if you decrease GFR, you produce LESS urine
‘normal’ GFR?
125ml/min
GFR is regulated by both _________ and __________ regulations
GFR is regulated by both INTRINSTIC and EXTRINSIC regulations
if afferent arteriole diameter increases (smooth muscle relaxes) what happens to GFR?
increases
what is a decrease in arterial blood pressure detected by?
aortic and carotid-sinus baroreceptors
fall in blood volume due to bleeding _________ blood volume
fall in blood volume due to bleeding REDUCES blood volume
state the 2 parts to auto regulation (intrinsic) of kidney
myogenic and tubuloglomerular feedback
tubuloglomerular feedback:
If GFR rises, more NaCl flows through the tubule leading to _____________ of afferent arterioles
tubuloglomerular feedback:
If GFR rises, more NaCl flows through the tubule leading to CONSTRICTION of afferent arterioles
GFR = ? x ?
GFR = Kf x net filtration pressure
increase of decrease of GFR:
(a) kidney stone
(b) diarrhoea
(c) severely burned patients
(d) change in surface area available for filtration
(a) kidney stone - DECREASE
(b) diarrhoea - DECREASE
(c) severely burned patients - INCREASE
(d) change in surface area available for filtration - INCREASE
what equals the volume of plasma completely cleared of a particular substance per minute?
plasma clearance
units of clearance?
ml/min
clearance of substance X = ? x ? / ?
clearance of substance X = [X]urine x Vurine / [X]plasma
what foods are inulin found in?
onions and garlic
inulin measurement clearance can be used clinically to determine what?
GFR
is inulin metabolised by the kidney?
no - not absorbed or secreted
what can be measured instead of inulin?
creatinine
acts similar to inulin in kidney
what substance is completely reabsorbed and not secreted?
glucose
glucose clearance = ?
glucose clearance = 0
what substance is partly reabsorbed and not secreted?
urea
urea clearance >/< urea GFR
urea clearance < urea GFR
what substance is secreted but not reabsorbed?
H+
H+ clearance >/< H+ GFR
H+ clearance > H+ GFR
If clearance < GFR (inulin clearance) then substance is ____________
If clearance < GFR (inulin clearance) then substance is REABSORBED
If clearance ? GFR then substance is neither reabsorbed nor secreted
If clearance = GFR then substance is neither reabsorbed nor secreted
If clearance > GFR then substance is __________ into tubule
If clearance > GFR then substance is SECRETED into tubule
what substance is used to calculate renal plasma flow (RPF)?
para-amino hippuric acid (PAH)
PAH clearance = ?
650ml/min
inulin/creatinine clearance = ?
inulin/creatinine clearance = 125ml/min
what should not be toxic, be inert and be easy to measure?
clearance marker
A GFR marker should be filtered freely; ___ secreted or reabsorbed
A GFR marker should be filtered freely; NOT secreted or reabsorbed
A RPF marker should be filtered and ___________ secreted
A RPF marker should be filtered and COMPLETELY secreted
GFR = ___ ml/min
RPF = ___ ml/min
GFR = 125 ml/min
RPF = 650 ml/min
