REB Renal Flashcards
(291 cards)
1
Q
what part of the nephron is involved in converting vitamin D to active form
A
PCT
2
Q
what organ produces erythropoietin
A
kidney
3
Q
what is the renal capsule
A
tuft of capillaries and bowman’s capsule
4
Q
where does ultrafiltration take place
A
glomerulus
5
Q
ultrafiltration is dependant on
A
string hydrostatic pressure in the nephron
6
Q
approximately how much filtrate is formed everyday?
A
180L
7
Q
how much filtrate is excreted in urine?
A
1.5L
8
Q
how much filtrate is reabsorbed?
A
178.5L
9
Q
how much water, glucose and salt is reabsorbed (%)?
A
water - 99
glucose - 100
salt - 99.5
10
Q
Reabsorption of which of the following are active and which are passive water glucose amino acids na cl
A
passive
cl
water
active
glucose
amino acids
na
11
Q
What is the passage of substances which are are reabsorbed in the kidney?
A
Lumen to cells to ECF
12
Q
What is the passage of tubular secretions?
A
Peritubular capillaries to tubular lumen
13
Q
What’s molecules are involved in tubular secretion and what is the importance of this process?
A
H+, K+, organic ions, wastes
Important for removal of waste and maintaining blood pH by secreting H+ and NH4+
14
Q
How much urine is formed per min?
A
1 ml/min
15
Q
What is the typical pH of urine?
A
Six
16
Q
What does substances are commonly found in urine?
A
Water urea creatinine ions phenol
17
Q
Outline the blood supply to the glomerulus
A
Renal - interlobular - arcuate - interlobular - afferent
18
Q
What is a normal BP range? (MAP)
A
MAP - 80-180 mmHg
19
Q
How is the afferent arteriole affected by changes in arterial pressure?
Why is this important?
A
Changes in arterial pressure or matched by a corresponding change and afferent arteriole resistance
This maintains a constant flow rate
20
Q
What are the types of intrinsic regulation of renal blood flow?
A
myogenic
Tubuloglomerular feedback
21
Q
What is myogenic regulation of renal blood flow?
A
Stretch of walls of afferent arteriole followed by reflexed contraction of smooth muscle which increases pressure and stretch –> activates nonselective cation channels in smooth muscles –> Ca2+ depolarises
22
Q
In myogenic regulation of renal blood flow, what cation channels are activated and cause depolarisation?
A
Calcium
23
Q
Where are macula densa cells found?
A
At the junction between the ascending loop of Henle and the distal convoluted tubule
24
Q
Macular densa sells changes tone in response to
A
Changes in the rate of blood flow
25
When there is an increased glomerular filtration rate, there is an increase in the delivery of which ions to the macula densa?
Sodium and chloride
26
What paracrine agents does the macula densa release?
ATP and adenosine (to increase GFR)
| NO ( to decrease GFR)
27
How do macula densa cells increase tone?
increased pressure --> increased glomerular filtration rate --> increased Na+/Cl- delivery to macula densa --> activates non-selective cation channels --> macula densa to releases paracrine agents such as ATP and adenosine --> increases the tone of afferent arterioles
28
How do you glomerular capillaries maintain GFR
They are fragile
| COOL!
29
Can GFR be extrinsically controlled?
No
30
explain extrinsic control of renal blood flow?
1.nerves - sympathetic fibres
noradrenaline --> constriction --> decreases GFR
2.hormones - the vascular smooth muscle cells are sensitive to adrenaline and angiotensin II
31
the release of what neurotransmitter decreases GFR
noradrenaline
32
how is renal blood flow controlled at rest?
autoregulation only
33
how is renal blood flow controlled during severe exercise?
sympathetic NS
adrenaline
--> cause constriction
34
how is renal blood flow controlled if there is a hemorrhage?
heavy SNS activity
adrenaline
--> reduces fluid loss in urine
35
how is renal blood flow controlled if there is a long hemorrhage?
NO2 and prostaglandins (PGE2, PGI2) released by macula densa cells
36
what is the effect of a long-term hemorrahage?
renal ischemia --> hypoxia --> tubular necrosis
37
how much plasma entering the nephron is filtered in bowman's capsule
20%
38
what factors influence glomerular filtration (3) and give their values
1. glomerular capillary pressure - 55mm Hg
2. plasma colloid osmotic pressure - 30 mmHg
3. bowman's capsule hydrostatic pressure - 15 mmHG
39
what is the net filtration pressure?
10 mmHg
40
Creatinine come from _____ which is stored in _____ and synthesised from _____ in the ______ for quick bursts of energy.
Creatinine is formed spontaneously by ______ at a constant rate of ___% and its level depends on _____.
It composes ___% of the nitrogenous component of urine
creatine
skeletal muscles
arginine
liver
phosphocreatine
2%
muscle mass
4%
41
what conditions change GFR
1. alterations in the forces:
- decrease in plasma protein --> increases GFR
- urinary tract blockage --> decreases GFR and increases pressure in bowman's capsule
- diarrhea --> increased plasma colloid --> decreased GFR
2. autoregulation and extrinsic control
42
how does a decrease in plasma protein affect GFR
increases GFR
43
how does a urinary tract blockage affect GFR and p in the BC
decreases GFR and increases pressure in bowman's capsule
44
how does diarrhea affect GFR
increased plasma colloid --> decreased GFR
45
compare the value of osmolarity in the renal corpuscle and in plasma
same - 300 mosm/L
46
what is the pH of the filtrate in the renal corpuscle
6
47
what part of the nephron has cuboidal epithelial cells?
PCT
| thick limb LoH
48
what part of nephron has microvilli?
PCT
49
what part of nephron has squamous epithelium
thin LoH
50
what part of nephron has a lot of mitochondria?
PCT
| thick limb LoH
51
function of microvilli
increase reabsorption
52
what does water move through in the nephron?
tight junctions
| aquaporins
53
the PCT and thin descending limb have what type of aquaporin?
1
54
the DCT and collecting tubules have what type of aquaporin?
2 (3,4)
55
what aquaporins are mediated by ADH?
2 (3,4)
56
are all aquaporins bidirectional?
yup!
57
are the Na/K pumps located on the basal or apical membrane?
basal
58
the apical membrane borders the _____ whilst the basal membrane borders the ____
lumen
| ECF
59
```
what % of the following is reabsorbed in the PCT
glucose
aa
HCO3-
phosphate
Na
K
H2O
urea
lactate
```
100%
glucose
aa
HCO3- 90%
phosphate - 85%
70%
Na
K
H2O
50%
urea
lactate
60
where does NaCl reabsorption occur
early PCT
| late PCT
61
what transporters are involved in the reabsorption of NaCl?
early PCT
Na/organic solute cotransporter
Na/H exchanger
**impermeable to CL-
Late PCT
only Na/H exchanger
62
where is this transporter found:
| Na/organic solute cotransporter
early PCT
63
where is this transporter found:
| Na/H exchanger
early PCT
| Late PCT
64
the early PCT is impermeable to
Cl-
65
how Cl get through the late PCT?
passively diffuses through paracellular pathway
66
where does glucose reabsorption occur
early PCT
67
what transporters are involved in the reabsorption of glucose?
```
SGLT2 cotransporter (na and glucose in)
exit through GLUT 2 (1 way)
```
68
which transporter is a target for diabetic medications to lower glucose level?
SGLT2 cotransporter
69
all glucose is reabsorbed until maximum (Tmg) of
2 mmol/min
| ** 3 times the normal amount
70
where does protein reabsorption occur?
**only some enters filtrate
| PCT
71
how is protein reabsorbed in the PCT?
through receptor-mediated endocytosis where they are digested by lysosomes into AA
72
where does AA reabsorption occur?
**either directly from glomerular filtration through digestion of protein by lysosomes or through peritubular blood
early PCT but if there is a lot in the filtrate, it can occur throughout PCT
73
what transporters are involved in the reabsorption of AA?
Na/aa cotransporter
| they exit through different separate passive channels on basal membrane
74
can HCO3- cross the apical membrane?
NOPE
75
explain the reabsorption of HCO3-
HCO3- combines with H+ (which are secreted by Na/H exchangers) to produce H2CO3 which is then broken down into H2O and CO2 by carbonic anhydrase
CO2 and H2O enter passively and then recombine to form HCO3- and H+
HCO3- leaves through the HCO3/Na symporter (basal)
76
what reaction is catalysed by carbonic anhydrase
H2CO3 --> H2O and CO2
77
explain organic ion secretion in the PCT include the transporters
secretion --> body --> lumen
this the main method for transporting wastes and drugs
this occurs through MDR1 (multidrug) or Na/K-dependant transport
78
HCO3- leaves through the
HCO3/Na symporter (basal)
79
what is Fanconi syndrome
disease of PCT dysfunction
80
Fanconi syndrome is characterised by
excess loss of glucose, aa, phosphate, HCO3- into urine
| this leads to acidosis and dehydration
81
Fanconi syndrome is treated by
hydration and supplements
82
what the 3 divisions of the LOH
Thin descending
thin ascending
thick ascending
83
what is the main function of the LoH
maintenance of the highly concentrated medulla and reabsorption of water
84
osmolarity varies from ____ to ___ in the LoH to _____ in the DCT
300 mosm/L
1200
100
85
the thin descending LoH has a low permeability to _____ but high permeability to _____
solutes
| water
86
what happens to [filtrate] as water is reabsorbed in the LoH
the filtrate becomes more concentrated
87
the thin ascending LoH has a impermeable to _____ but permeable to _____
water
| solutes
88
what happens to [filtrate] as NaCl is reabsorbed in the thin ascending LoH
the filtrate becomes less concentrated
89
what is reabsorbed in the thin ascending LoH
NaCl
90
the thick ascending LoH actively reabsorbs what ions
na
k
cl
91
what transporters are involved in the reabsorption of ions in the thick ascending LoH
NKCC2
92
how do the reabsorbed ions from the thick ascending LoH exit the nephron
cl and k through basolateral transporters
na through the Na/K pump
some K leaks back into the cell through the apical membrane
93
what is the effect of K+ leaking into the lumen
positive lumen --> cation absorption via tight junction
94
how do loop diuretics work
inhibiting the NKCC2 transporter in the thick ascending LoH which inhibits salt reabsorption and increases water excretion
95
what patients use loop diuretics
suffer from renal insufficiency or severe edema
96
in the early DCT, Na+ enters the apical membrane through
Na/Cl transporters
| or NCC
97
the early DCT reabsorbs ____ but not ____.
| how does it affect [filtrate]?
NaCl
water
filtrate is dilute
98
what hormone acts at the DCT to cause calcium reabsorption
parathyroid hormone
99
explain calcium reabsorption in the early DCT (include transporter)
enters apical site through facilitated diffusion and exits through the 3Na/Ca exchanger at the basolateral membrane
100
what are the 2 types of epithelial cells in the late DCT and the CD? what do they control?
principal cell - NaCl transport
| intercalated cells - acid/base balance
101
in principal cells, Na+ is reabsorbed through ___ channels and _____
NCC
| ENaC (electrogenic)
102
ENaC is under the control of
aldosterone
103
what regulates the concentration of urine based on body's needs?
combined effect of ADH and Aldosterone
104
ENaC transports ___ ions into the cell from the lumen, leaving a _______ charge where the ___ ion exits
na
negative
k
105
there is a dramatic increase in ___ ion secretion in the late DCT and CD
K
106
K+-sparing diuretics target
ENaC
107
ADH or vasopressin regulates what aquaporin? where is this aquaporin located?
2
| DCT and CD
108
other than the opening of aquaporins, ADH also regulates
urea absorption
109
what is the importance of urea absorption regulation by ADH
to maintain hypertonic medulla
110
ADH is released in response to
thirst
| low Bp
111
in the intercalated cells, H+ is excreted across the apical membrane into the tubular fluid wia what transporters?
H+ATPase pump
or
H+/K+ ATPase exchangers
112
H+ secretions in the DCT and CD affect urinary pH to a minimum of
4.5
113
how much filtrate enters the CD on average
12 ml/min
114
discuss the changes to urine production when the is no ADH, average ADH and high ADH
no - 12 ml/min (o ml reabsorbed)
average - 2 ml/min (10 ml reabsorbed)
high - 0.5 ml/min (11.5 ml reabsorbed)
115
___% of the filtrate left with variable NaCl and H2O reabsorption at DCT and CD
10
116
__% of nephrons are juxtamedullary nephrons
15
117
salt pumps in the thick ascending limb maintains the ____mosm/L difference between the filtrate and surrounding interstitium
200
118
what is the anatomical arrangement of vessels so that one vessel is in the opposite direction of adjacent vessels?
countercurrent exchanger system
119
what is the anatomical arrangement of the LoH so that it concentrates solutes in renal medulla?
countercurrent multiplier
120
what is the main driving force of the countercurrent mechanism
active salt pump in thick ascending limb transports NaCl actively out of lumen and into interstitium until the interstitium is 200 mosm/L more conc than filtrate
121
which parts of the nephron are completely impermeable to urea
LoH
| DCT
122
does urea concentration increase or decrease in the LoH and DCT
increases
123
how does ADH affect the reabsorption of urea. (include RECEPTORS)
ADH acts on collecting ducts to increase permeability of urea by promoting UTA1 and UTA3.
124
explain the recycling of urea.
some urea excreted goes to the medulla to increase concentration while some diffuses back into the LoH to be recycled
125
how much urea ends up in urine? (%)
20%
126
why isn't the hypertonic interstitium washed away?
1. blood flow to medulla is very low
2. vasa recta capillaries operate as countercurrent exchange flow (equilibrates the medulla so net change is 0) --> goes up to 300 mosm/L
127
fluid movement from the ICF to the IF is _______ pressure
osmotic
128
fluid movement from IF to plasma is _____ pressure
hydrostatic
129
what is the function of RAAS
to control volume and blood pressure
130
what would happen if RAAS is not present
| what condition is RAAS particularly important in
ischemia due to lower oxygen perfusion
| hemorrhage
131
what is the rate limiting step of the RAAS
fall in Bp causes renin (produced by kidneys) to convert angiotensinogen (from liver) into angiotensin I. it cleaves at the leu-val bond.
132
what triggers the release of renin
fall in Bp
133
where is renin produced
juxtaglomerular cells in the kidney
134
what bond does renin cleave
leu - val
135
where is angiotensinogen produced?
liver
136
where is ACE located?
endothelial cells of the lung
137
what is the action of ACE
activated ang I by converting it to ang II (main effector)
138
what bond is cleaved by ACE
his - leu
139
what is renin first produced as
pre prorenin
140
where is renin stored
secretory granules until release when Bp is low
141
where are juxtaglomerular cells found
| what type of cells are they
juxtaglomerular apparatus formed by DCT and glomerular afferent arteriole
specialised smooth muscle
142
the position of juxtaglomerular cells at the glomerular afferent arteriole allows it to sense
Bp and GFR
143
what do the macula densa cells sense
NaCl absorption
144
how do the macula densa cells and the juxtaglomerular cells communicate
macula densa secretions of PHE2 and PGI1
145
what receptor is involved when factors induce renin release (and 2nd messenger)
GsPCR and camp
146
what receptor is involved when factors inhibit renin release (and 2nd messenger)
GqPCR and Ca2+
147
use of ACE and renin inhibitors
used for patients with high Bp to decrease it
148
a decrease in Bp in the afferent arteriole is sensed by
baroreceptors on the juxtaglomerular cells
149
what factors induce renin secretion
1. decrease in Bp in the afferent arteriole
2. decreased NaCl reabsorption
3. increase in adrenergic activity by sympathetic stimulation via B-adrenergic receptors and arteriole constriction via alpha adrenoreceptors
150
An increase in adrenergic activity by sympathetic stimulation via _____ receptors and arteriole constriction via _____ induces renin release.
B-adrenergic
| alpha adrenoreceptors
151
what factors inhibit renin secretion
1. increased NaCl reabsorption
2. increased afferent arteriole Bp
3. decreased adrenergic activity / sympathetic stimulation
4. Ang II by negative feedback
152
what are the ang II receptors?
AT1R
| AT2R
153
AT1R primarily mediates
cardiovascular effects of ANd II
154
what are AT1R receptors located
AT1Ra - blood vessels
| AT1Rb - adrenal cortex and ant pit
155
what type of receptor is AT1R
GPCR linked to Phospholipase C with Ca+ as its second messenger as well as cAMP
156
use of AT1R inhibitors
treat hypertension and heart failure
157
where are AT2R located
fetus
| neonate
158
function of the AT1R (5)
1. tubular Na+ reabsorption in PCT by stimulating Na/H exchanger, Na/K ATPase and NA/HCO3- cotransporter
2. vasoconstriction
3. aldosterone release
4. ADH release
5. negative feedback to renin release in juxtaglomerular cells
159
tubular Na+ reabsorption in PCT is done by stimulating
Na/H exchanger
Na/K ATPase
NA/HCO3- cotransporter
160
what is the function of aldosterone
enhanced reabsorption of Na+ in the DCT --> water follows and K+ is excreted
161
aldosterone increases the expression of
ENaC
| Na/K ATPase
162
effects of hyperaldosteronism
hypertension and hypokalemia
adenoma (gland - primary)
decreased renal perfusion (not in gland - secondary)
163
effects of hypoaldosteronism
hypotension and dehydration
addison's (primary)
decreased renin production (SECONDARY)
164
what receptors are acted on by ATP
aquaporin 2
| UTA 1 and 3
165
GFR is the main diagnostic tool to determine
renal fxn (index of renal fxn)
166
renal clearance is the
ml of plasma cleared of a substance in 1 min or Cs in ml/min
167
renal clearance is involved in measuring
the rate of excretion of a substance in relation to its plasma concentration
168
equation for Cs
(Us x V)/Ps
169
a decrease in GFR is a clinical sign of
renal disease
170
what is the criteria for substances that can be used to find clearance
must enter filtrate through filtration only
| flows through the nephron and exits urine without being absorbed
171
relationship between inulin excretion and its plasma concentration
inulin excretion proportional to its plasma concentration
172
how does the plasma concentration of inulin affect the amount of inulin filtered
as plasma conc rises, more inulin is filtered in and ready to be excreted
173
the slope between rate of excretion and plasma conc represents the
clearance of inulin
174
is clearance dependent or independent of plasma conc?why?
independent
| as plasma conc of inulin increases, clearance remains the same
175
how is inulin administered?
through IV
176
is inulin produced in the body?
NOPE
177
other than inulin, what substance can be used to find clearance
creatinine
178
what is creatinine
waste product of muscle cell's creatine
179
is creatinine accurate to calculate clearance? explain.
not totally
a small quantity of creatinine is secreted into the tubule from paratubular vessels (affecting Us) but is approximately cancelled out by error in estimation of plasma concentration of creatinine (affecting Ps) which also detects another compound
180
Cin = Ccr =
125ml/min
181
formula for Ccr in males
Ccr = [(140-age) x weight (kg)] / [72 x Pcr (mg/dL)]
182
how does age, gender and weight affect Ccr
increased age - decreased Ccr
increased weight - increased
male - increased
183
formula for Ccr in females
[(140-age) x weight (kg)] / [72 x Pcr (mg/dL)] x 0.85
184
if someone is an athlete, how is their Ccr affected
increased
185
if someone if lean, how is their Ccr affected
decreased
186
freely filtered, not absorbed, not secreted
renal clearance =
give an example
GFR
| inulin, creatinine - 125ml/min
187
freely filtered, fully reabsorbed, not secreted
renal clearance =
give an example
0ml/min
| glucose and aa
188
freely filtered slightly reabsorbed, not secreted
renal clearance is
give an example
less than GFR
| urea - 65 ml/min
189
freely filtered, not reabsorbed, fully secreted
renal clearance =
give an example
renal plasma flow
| PAH - 625 ml/min
190
PAH asses and indicates ____ to the kidneys
blood supply
191
renal failure is a reduction in ____ so that kidneys cannot maintain their salt/water balance nor excrete waste
GFR
192
describe the onset of acute renal failure
fast onset
| reversible or fatal
193
what type of renal failure is characterised by:
abrupt and rapid decline in renal fxn with a rapid onset caused by altered blood supply, toxins or urinary tract abnormalities
acute
194
edema is a consequence of what type of renal failure
acute
| ** salt and water retention
195
hyperkalemia is a consequence of what type of renal failure
acute
196
cardiac arrhythmias is a consequence of what type of renal failure
acute
197
hyperphosphatemia is a consequence of what type of renal failure
acute
198
Itching due to waste-product retention is a consequence of what type of renal failure
acute
199
what are the types of renal failure
acute
subacute
chronic
200
is chronic renal failure reversible?
NOPE
201
what type of renal failure is characterised by:
| gradual irreversible loss of large numbers of functioning nephrons
chronic
202
in chronic renal failure, the electrolyte fluid balance is maintained at ____% of renal failure
20-30
203
chronic renal failure can go symptomatic until __% of the nephron is lost and is fatal after ___%
70
| 90
204
treatment of chronic renal failure
dialysis
205
what is the relationship of clearance of creatinine and plasma concentration of urea
inversely proportional
| ** used in estimating disease
206
how does a decrease of creatinine affect plasma conc of urea
increases
207
nitrogen is absorbed in our bodies from proteins in the form of ____ following fixation from bacteria in the gut
NH3
208
nitrogen is formed in the body by the ____ of proteins and nucleotides
catabolism
209
___g of nitrogen is brought in the body each day
16
210
this nitrogen is formed into urea in the _____ and excreted in the kidney
liver
211
nitrogen turnover is normally balanced where intake =
excretion
212
a positive nitrogen balance indicates ____
| where intake is ____ than excretion
growth/ pregnancy
| greater
213
a negative nitrogen balance indicates a catabolic state where excretion is ____ than intake
greater
214
does protein synthesis increase or decrease nitrogen in the body
increase
215
does protein catabolism increase or decrease nitrogen in the body
decrease
216
nitrogen turnover is dependant on the ____ turnover
aa
217
how much N is excreted as urea, as NH4+ and as uric acid/ creatinine (%)
85%
5%
10%
218
Creatine is synthesised by what amino acid in the liver?
arginine
219
Creatinine is formed at a constant rate of
2%
220
uric acid is the end product of _____ metabolism and is freely filtered in the glomerulus
purine
221
hyperuricemia is caused by
too much uric acid
222
ammonia is made from metabolism of
glutamate
223
urine is sterile and clear with ___% water and a pH of
93-97%
| 6
224
what does each colour of urine indicate
dark
bright yellow
red
more conc
vit D / meds
blood (disease)
225
what does the clarity or cloudiness of urine indicate
normal
abnormal
mucus, sperm, prostatic fluid
| blood cells, bacteria
226
a _____ (medical test) with colour identifying degree is used in the chemical analysis of urine
dipstick
227
the presence of crystals in urine indicates
kidney stones
228
the presence of epithelial cell is urine indicates
infection/ cancer
229
the presence of hyaline in urine indicates
RBC
WBC
fat
230
average pH of blood
7.35(v) - 7.45(a)
231
factors that affect ph of urine (3)
1. metabolism releases acid in the form of CO2
2. breakdown of food --> nonvolatile acids (sulphuric and phosphoric)
3. metabolic intermediates --> lactic acid --> non volatile
232
nitrogenous components of urine and the amount of each (%) present in urine
```
creatinine - 4%
uric acid - 1%
ammonia - 3%
urea - 40%
water and nacl
```
233
can non-volatile/non-carbonic acids be removed by the lungs?
NOPE
234
non-volatile/non-carbonic acids CANNOT be removed by the lungs. how are they removed and how much is removed per day.
bicarbonate buffer system by using HCO3-
| 1 mmol/day/kg
235
blood pH is maintained by what organs
lung and kidney
236
how does the lung maintain blood pH
respiratory regulation releasing Co2 as fast as it is produced
237
how does the kidney maintain blood pH
HCO3- (base) control to buffer acid
238
what are the 2 determinants of blood pH
H2CO3 (weak acid)
| HCO3- (weak base)
239
how is blood pH calculated given the concentration of the 2 determinants of blood pH
[HCO3-] / [H2CO3]
240
[H2CO3] = pCO2 x ___
| what does this number represent
0.03 - solubility of Co2 in the plasma
241
[HCO3-] is maintained at __mmol/L
24
242
pCO2 is maintained at ___mmHg
40
243
pka of H2CO3 =
6.1
244
pH of blood can be found by the equation
pka (H2CO3) + log [HCO3-] / [H2CO3]
| where [H2CO3] = pCO2 x 0.03
245
for every 1 mmol of HCO3- of non volatile acid that enters the blood, how much HCO3- is removed?
1 mmol
246
when [H+] increases beyond the capacity of the buffer system, [HCO3-] ______ and hence HCO3- must be restored by the kidney.
decreases
247
where does reabsorption of HCO3- occur
80% in the PCT
| 20% in the DCT and LoH
248
describe how HCO3- is reabsorbed from filtrate
1. H+ released from Na/H+ exchanger and binds to HCO3-
2. H2CO3 becomes Co2 and H2O which enters the cell
3. carbonic anhydrase reforms HCO3- and H+
249
tubular cells breakdown H2O into
H+ and OH-
250
H+ is secreted to the lumen through the _______ transporter and binds with ________ acids (HPO42-)
H+ATPase
| non-volatile
251
H+ is secreted to the lumen through the _______ transporter in the CD or ____ transporter in the PCT/DCT/CD and binds with ________ acids (HPO42-)
H+ATPase
Na/H+ exchanger
non-volatile
252
HCO3- IS RELEASED INTO THE BLOOD THROUGH _____ CAPILLARIES
peritubular
253
H+ is secreted more when the pH is ___
low
254
titratable acid (33%) - H+ is buffered with filtrate buffers such as.... (2)
1. phosphates (H2PO4- from HPO42-)
| 2. Creatinine (25%) in the DCT
255
acid with ammonia (67%) - the _____ is the main site of NH4+ synthesis and hence it is also the main site for ______ --> NH4+
PCT
| H+ + NH3
256
pH above ____ is alkalotic
7.45
257
pH below ____ is acidic
7.35
258
which is faster: respiratory or renal adaptation
resp
259
does an increase in pC02 increase or decrease ventilation?
what effect does it have on the kidney?
what effect does it have on H+?
increases
kidney produces HCO3- (renal compensation)
there is also increased H+ secretion
260
does a decrease in HCO3-increase or decrease ventilation?
| what effect does it have on the reabsorption of the HCO3-?
```
increases vent (body changes HCO3- into CO2) (respiratory compensation)
increases reabsorption
```
261
primary defect of respiratory acidosis
increased pCO2
262
primary defect of meatbolic acidosis
decreased plasma HCO3- (under 24) due to an increase in other acids (other than H2CO3+)
263
uncontrolled diabetes, lactic acidosis, severe diarrhea and renal failure are causes of _______ acidosis
metabolic
264
how does insulin affect the pH (diabetic ketoacidosis)
inadequate insulin production --> decreased glucose use --> more FA metabolization and B oxidation --> ketone bodies are low in pH
265
how does hyperglycemia affect nerve excitability and cardiac contractility
insulin regulates K+ entry into the cell. hyperglycemia --> decreased aldosterone --> concentration K+ and salty urine --> K+ leaks out of cell and cannot re enter without insulin --> hyperkalemia --> decreases nerve excitability and increased cardiac contractility
266
primary defect of respiratory alkalosis
decreased pCO2
267
primary defect of metabolic alkalosis
increased [HCO3-]
268
explain the role of vomiting in metabolic alkalosis
causes H+ LOSS --> [HCO3-] remains elevated in plasma
**parietal cells secrete H+ into the lumen and HCO3- into the blood in anticipation of the reabsorption of H+ back into the blood
vomiting does not allow this to occur and hence the increase in [HCO3-] without reabsorption of H+ causes alkalosis
269
parietal cells secrete __ into the lumen and ____ into the blood in anticipation of the reabsorption of ___ back into the blood
H+
HCO3-
H+
270
how is the anion gap calculated
[unmeasured anions] = [Na+] - [Cl-] - [HCO3-] = anion gap
271
describe the difference between metabolic acidosis with a high anion gap and with a normal anion gap
include examples of illnesses
high - unknown anions such as lactic acid and ketone bodies reduce [HCO3-] such as in diabetes
low - such as in diarrhea, loss of HCO3-
in the kidney there is an increase in CL- due to metabolic acidosis and the anion gap shifts back to normal although acidosis is maintained
272
urinary epithelium is ______ epithelium
transitional
273
what is the ureterorenal reflex
blockage of ureter causes a build up of urine and back flow to the kidney
sympathetic innervation causes the decrease in urinary output of the kidney
274
what is the vesicoureteric reflux
issue with passage of ureter into the bladder causing the absence of the physiological valve --> contraction of detrusor muscle causes backflow to kidney
275
what are the 3 layers of muscle in the bladder
inner circular
outer longitudinal
detrusor
276
what characteristics of the bladder wall allow for increased volume in bladder without increasing pressure
transitional epithelium
rugae (folds in the walls)
smooth muscle plasticity
277
when holding in urine, what nerve is being fired?
pudendal nerve (SOMATIC)
278
the somatic innervation of the bladder is responsible for:
a. voiding
b. holding in urine
b
279
the parasympathetic innervation of the bladder is responsible for:
a. voiding
b. holding in urine
a
280
sympathetic innervation of the bladder is done by what nerve?
hypogastric (T10-L4)
281
parasympathetic innervation of the bladder is done by what nerve?
pelvic nerve (S2-S4)
282
somatic innervation of the bladder is done by what nerve?
S2-S4
283
what NT is released by hypogastric nerve, what receptors do they act on and what is the result
Noradrenaline
on B3 receptor --> inhibits detrusor muscle
on alpha 1 receptor --> stimulation of internal sphincter
284
what NT is released by pelvic nerve, what receptors do they act on and what is the result
ACH on M3 --> stimulates detrusor muscle
| NO on M3 --> inhibits internal sphincter
285
what NT is released by pudendal nerve, what receptors do they act on and what is the result
ACH acts on nicotinic receptor and acts on the external sphincter
286
what part of the brain receives signals from the stretch receptors of the bladder?
pontine storage center
287
high nerve firing indicates fullness and initiates the ______ maneuver (forced expiration) due to stimulation from the _______ in the brain
pontine micturition centre
288
what are the 2 phases of spinal cord injury and loss of voluntary control
1. areflexic - urinary retention **early
| 2. hyperreflexic - neurogenic detrusor overactivity **after a few weeks
289
describe the areflexic stage
no sensation of full bladder --> accumulation of urine --> reflux --> damage to kidney
290
describe the hyperreflexic stage
automatic bladder - patient has no control over the bladder or urination
the micturition reflex returns but is activated without conscious control --> overactivity of detrusor muscle
291
hyperreflexic stage is due to overactivity of the _____ muscle
detrusor
