B5-036 Renal Physiology I Flashcards
1
Q
blood enters the glomerulus via
A
afferent arteriole
2
Q
blood exits the glomerulus via
A
efferent arteriole
3
Q
all the glomeruli are located in the
A
cortex
4
Q
3 layers of the glomerular filtration membrane
A
- endothelial cells
- basement membrane
- podocytes
5
Q
space between podocytes
A
slit diaphragm
6
Q
- plasma without proteins
- only ions and small molecules
A
renal ultrafiltrate
7
Q
is albumin normally able to filter through the membrane?
A
no, too big
8
Q
the charge of albumin is […] than hemoglobin
A
more negative
this is why hemoglobin can filter and albumin cannot
9
Q
are positive or negative ions more favorable for filtration?
A
positive
basement membrane is negatively charged
10
Q
the basement membrane is […] charged
A
negatively
why positively charged ions filter better
11
Q
infection can cause loss of […] at the basal membrane
A
negative charge
causes leakage of proteins in the urine
12
Q
damage to the GBM will cause […] decreasing plasma oncotic pressure
A
hypoproteinemia
will cause edema
13
Q
what is beneficial about the biphasic curve of pressures along the nephron?
A
maintains high hydrostatic pressure for filtration
14
Q
hydrostatic pressure - oncontic pressure =
A
filtrating pressure
15
Q
sites of major resistance within nephron
2
A
afferent and efferent arterioles
16
Q
hydrostatic pressure > oncotic pressure in the glomerular capillaries, thus…
A
filtration
17
Q
oncotic pressure > hydrostatic pressure in peritubular capillaries, thus…
A
absorption
18
Q
describe forces involved in ultrafiltration
A
major force: hydrostatic pressure of glomerular capillary bed PGC
opposed by: hydrostatic pressure of tubule PBS
colloid osmotic pressure of blood (PGC)
19
Q
normal PUF=
A
10 mmHg
PUF= PGC - PBS - IIGC
20
Q
besides the pressure […] and […] of the GBM are important factors
A
surface area
permeability
together= KUF
21
Q
normal KUF=
A
12 ml/min/mmHg
22
Q
GFR=
equation and normal value
A
KUF x PUF
normal about 120
23
Q
main pressure that can be changed to regulate filtration
A
hydrostatic pressure
24
Q
increased pressure in glomerulus causes […] filtration
more or less
A
more
25
obstruction of the renal arteries will [...] hydrostatic pressure
decrease
| cause low GFR
26
obstruction of the ureter will [...] the pressure in the glomerulus
increase
| decreased GFR due to increased capsule pressure
27
changes in resistance of afferent and efferent arterioles causes changes in
GFR
28
# describe the changes to pressures
**afferent constriction**
glomerular capillary pressure:
peritubular capillary pressure:
renal blood flow:
glomerular capillary pressure: decrease
peritubular capillary pressure: decrease
renal blood flow: decrease
29
# describe the changes to the pressures
**afferent dilation**
glomerular capillary pressure:
peritubular capillary pressure:
renal blood flow:
glomerular capillary pressure: increase
peritubular capillary pressure: increase
renal blood flow: increase
30
# describe the changes to the pressures
**efferent constriction**
glomerular capillary pressure:
peritubular capillary pressure:
renal blood flow:
glomerular capillary pressure: increase
peritubular capillary pressure: decrease
renal blood flow: decrease
31
# describe the changes in the pressures
**efferent dilation**
glomerular capillary pressure:
peritubular capillary pressure:
renal blood flow:
glomerular capillary pressure: decrease
peritubular capillary pressure: increase
renal blood flow: increase
32
# describe the changes in the pressures
**afferent-efferent constriction**
glomerular capillary pressure:
peritubular capillary pressure:
renal blood flow:
glomerular capillary pressure: no change
peritubular capillary pressure: decrease
renal blood flow: decrease
33
# describe the changes in the pressures
**afferent-efferent dilation**
glomerular capillary pressure:
peritubular capillary pressure:
renal blood flow:
glomerular capillary pressure: no change
peritubular capillary pressure: increase
renal blood flow: increase
34
autoregulation of RBF and GFR is done via
| 2 mechanisms
* tubuloglomerular feedback
* myogenic response
35
if you transplant a kidney, innervation is not maintained but [...] is
autoregulation
36
describe the myogenic response
* increase in blood pressure
* arteriolar smooth muscles stretch
* arteriolar muscle contraction
* increases resistance
* net result: little change in RBF
37
describe the tubuloglomerular feedback mechanism
1. increase in GFR
2. increases tubular fluid flow rate
3. increases Na+ and Cl- delivery to macula densa
4. increases vasoconstrictor signals (adenosine)
5. causes afferent arteriolar constriction
38
regulates GFR to prevent overloading of the tubules
tubuloglomerular feedback mechanism
39
maintains pressure in the glomerulus
myogenic response
40
maintance range for myogenic response and TGF
| of arterial pressure
about 50-200
41
the glomerular filtration barrier contains [....] charged glycoproteins
negatively
| prevents the entry of negatively charged molecules (albumin)
## Footnote
FA pg. 605
42
slit diaphragm prevents entry of molecules greater than
| size
40 nm
## Footnote
FA pg 605
43
how does angiotensin II lead to an increase in blood pressure?
| 3 mechanisms
* Na+ reabsorption in proximal tubules
* Na+ retention
* vasoconstriction
44
the clearance of [...] is most **commonly** used to measure GFR
creatinine
45
the excretion of [...] provides the most **accurate** measure of GFR
inulin
46
GFR values differ with [...] and [...]
age and gender
| depends greatly on muscle mass
47
main parts of juxtaglomerular apparatus
* mesangial cells
* JG cells
* macula densa
48
sense decreased NaCl in distal convoluted tubule and stimulate the release of renin
macula densa
49
the GBM is [...] charged and facillitates the filtrations of [...] charged molecules
negative
positively
50
can glucose filter through the glomerulus?
yes
51
changes in the [...] of the GBM lead to proteinuria
charge
52
changes in the glomerular membrane effect its
KUF
53
prevents increases in blood pressure from producing significant changes in RBF and GFR
autoregulation
54
arterioles constrict in responce to stretch produced by increased hydrostatic pressure
myogenic response
55
causes constriction of the glomerular afferent arterioles
tubuloglomerular feedback mechanism
56
dilation of both the afferent and efferent glomerular arteries will increase
RBF
57
constriction of the glomerular afferent and efferent arteriole will cause
decreased RBF and GFR
58
constriction of the afferent arteriole alone will cause
decrease in RBF and GFR
59
a post renal obstruction will cause the net glomerular ultrafiltrating pressure to
decrease
60
how does autoregulation effect GFR and RBF?
remains constant
61
an ACE inhibitor blocks the conversion of
angiotensin I to angiotensin II
| decreases total aldosterone
62
main physiological factor involved in the regulation of GFR
constriction of afferent and efferent arterioles
| increases hydrostatic pressure
63
the GBM is extremely negatively charged due to
heparin sulfates
64
the lamina densa is made of type [...] collagen
4
65
spaces between podocytes
filtration slit
66
bridge slits between podocytes
slit diaphragms
67
slit diaphrams are made of
| what protein
nephrin
68
what electrolytes can get through the GBM?
* K+
* Na+
* Cl+
* Mg2+
* Ca2+
* H2O
* HCO3-
69
what molecules can get through the glomerulus?
* glucose
* amino acids
* lipids
* urea
* creatinine
* vitamins
70
phagocytose and remove trapped molecules from the slit diaphrams
mesangial cells
71
produce renin
JG cells
72
have baroreceptors and are important in the maintenance of blood pressure
JG cells
73
any fluctuations in the [...] or [...] effect GFR
net filtration pressure (NFP)
filtration coefficient (KF)
74
force that pushes plasma out of glomerular capsule into Bowman's space
GHP
75
what glomerular force is directly dependent on systolic bp?
GHP
| increases as BP increases, decreases as BP decreases
76
what force is exerted by plasma proteins (like albumin)?
colloid osmotic pressure (COP)
77
how does multiple myeloma effect COP?
increases
| increased plasma protein
78
how does hypoproteinemia affect COP?
decreases
| common cause: diarrhea
79
which force pushes fluid back into the capillary bed as fluid is being filtered out?
| pressure build up in Bowman's
capsular hydrostatic pressure
80
how do renal calculi effect CHP?
increases
81
how does hydronephrosis effect CHP?
increases
82
how does afferent arteriole constriction effect:
GFR:
RPF:
FF:
GFR: decreases
RPF: decreases
FF: -
83
how does efferent arteriole constriction effect:
GFR:
RPF:
FF:
GFR: increases
RPF: decreases
FF: increases
84
how does increased plasma protein concentration effect:
GFR:
RPF:
FF:
GFR: decreases
RPF: -
FF: decreases
85
how does decreased plasma protein effect:
GFR:
RPF:
FF:
GFR: increased
RPF: -
FF: increased
86
how does constriction of the ureter effect:
GFR:
RPF:
FF:
GFR: decreased
RPF: --
FF: decreased
87
how does dehyration effect:
GFR:
RPF:
FF:
GFR: decreased
RPF: way decreased
FF: increased
88
why does diabetic nephropathy decrease GFR?
protein deposits decrease glomerular surface area, decreasing GFR
89
why does glomerulonephritis cause a high GFR?
makes basement membrane very porous --> higher GFR
| lose more protein
90
what two factors effect the filtration coefficient?
surface area
permeability of the glomerulus
91
what factors effect the NFP?
| 3
glomerular hydrostatic pressure (GHP)
colloid osmotic pressure (COP)
capsular hydrostatic pressure (CHP)
