Renal Physiology Flashcards
(238 cards)
1
Q
Positive Balance
A
input > output
2
Q
Negative Balance
A
input < output
3
Q
Functional unit of kidney
A
nephron
4
Q
2 parts of nephron
A
Glomerulus + Tubule
5
Q
3 filtration layers of glomerulus
A
Endothelial cells (fenestrated)
Basement membrane (protein mesh)
Podocytes (filtration slits w/ foot processes)
6
Q
5 segments of nephron (in order)
A
Proximal Tubule
Loop of Henle
Distal Tubule
Collecting Tubule
Collecting Duct
7
Q
Afferent Arteriole –>
A
Glomerular Capillaries
8
Q
Efferent Arteriole –>
A
Peri-tubular capillaries
9
Q
Glomerulus function
A
filtration
drives fluid into Bowman’s Capsule
10
Q
Glomerulus has a high (negative/positive) charge to repel ______ from being filtered.
A
negative
proteins
11
Q
Primary site of reabsorption
A
proximal tubule
12
Q
Proximal Tubule functions
A
reabsorption + secretion
13
Q
Parts of Loop of Henle + Functions
A
Thin Descending: water reabsorption
Thick Ascending: solute reabsorption
14
Q
Function of Distal/Collecting Tubule
A
regulate reabsorption/secretion
15
Q
What is juxtaglomerular apparatus?
A
part of distal tubule that communicates with glomerulus to regulate blood flow / filtration
16
Q
Macula Densa function
A
sense change in Na+ filtration –> contact JG cells
17
Q
Juxtaglomerular cells
A
vascular smooth muscle cells that release Renin (stimulated by macula densa)
18
Q
Renin function
A
increases arterial pressure for more filtration into Bowman’s Capsule
19
Q
4 Components of Nephron Function
A
glomerular filtration
tubular reabsorption
tubular secretion
urine excretion
20
Q
3 primary functions of glomerular filtration
A
- maintain normal body fluid comp
- rapid excretion waste
- huge mag of blood filtration (60x per day)
21
Q
What two factors influence rate of filtration
A
physical properties
pressure differences
22
Q
What is the main physiological regulator of filtration?
A
Capillary Hydrostatic Pressure
23
Q
Force that drive fluid from glomerular capillaries –> capsule
A
capillary hydrostatic pressure
24
Q
2 Forces that are driving fluid from capsule –> glomerular capillaries
A
capsule hydrostatic pressure
capillary osmotic pressure (plasma proteins)
25
Definition of GFR (glomerular filtration rate)
volume plasma filtered per unit time
26
GFR equation
GFR = Kf x NFP
27
What two factors determine GFR?
Kf (filtration coefficient)
NFP (net filtration pressure)
28
What determines Kf (filtration coefficient)?
permeability + surface area
29
What determines NFP (net filtration pressure)?
pressure differences between capillaries + capsule
30
Glomerular capillaries have a (higher/lower) permeability, surface area, and pressure differences than systemic capillaries.
higher
31
Resistance in glomerular capillaries is (greater/less) than systemic capillaries.
greater
32
Physiologically, if the afferent arteriole constricts, that will (increase/decrease) GFR.
decrease
33
Physiologically, if the efferent arteriole constricts, that will (increase/decrease) GFR.
increase
34
What 4 diseased states alter GFR?
hemorrhage
heart failure/hypovolemic shock
diabetes mellitus
urinary obstruction
35
How does the body alter GFR during hemorrhage?
constricts afferent + efferent arteriole = reduce GFR & retain blood volume
36
How does the body alter GFR during Heart failure?
decreased CO --> decreased renal blood flow/pressure --> decreased GFR
37
How is GFR altered during Diabetes Mellitus?
BM thickens --> lose permeability (Kf down) = decreased GFR
38
How is GFR altered during urinary obstruction?
increased urinary pressure --> increased hydrostatic pressure = decrease GFR
39
Function of Reabsorption
move water/solute from tubule --> peritubular capillaries
40
Function of Secretion
move substances from peritubular capillaries --> tubule
41
Paracellular pathway
movement through tight junctions between cells
42
Transcellular pathway
movement through cells (luminal/apical --> basolateral)
43
Simple Diffusion
across electrical/chemical gradient
44
Facilitated Diffusion
across gradient + transport protein
45
Primary Active Transport
uses ATP directly (against gradient)
46
Secondary Active Transport
downhill movement of one solute drive uphill movement of another
47
Simple Diffusion example
chloride
48
Facilitated Diffusion example
urea
49
Primary Active Transport example
Na/K ATPase
50
Secondary Active Transport example
Na+/glucose tranporter
51
Secondary Active Transport example
Na+/glucose transporter
52
Speed of movement of carrier-mediated transport controlled by (3):
specificity (how specific carrier is to substance)
competition (between substrates)
saturation (how bound transporters are)
53
Transport Maximum (Tm)
maximum amount of solute in system where all transporters are bound
("maxed out")
54
Afferent arterioles constricting causes (increase/decrease) renal blood flow & (increase/decrease) GFR.
decrease flow
decrease GFR
55
Efferent arterioles constricting causes (increase/decrease) renal blood flow & (increase/decrease) GFR.
decrease flow
increase GFR
56
Afferent + Efferent arterioles constrict (during hemorrhage) causes:
decrease in renal blood flow + decrease GFR = conserve blood volume
57
Pressure in the glomerular capillaries is (higher/lower) than systemic capillaries to allow for _____.
higher
filtration
58
Pressure in the peritubular capillaries is (higher/lower) than systemic capillaries to allow for _____.
lower
reabsorption
59
(Autoregulation/Tubuloglomerular Feedback) is at the level of the individual nephron, while (autoregulation/tubuloglomerular feedback) effects vascular supply to all nephrons.
tubuloglomerular feedback
autoregulation
60
What is renal autoregulation?
global regulation of blood flow
affects vascular supply to all nephrons
responds to changes in arterial pressure
61
What is the mechanism of renal autoregulation?
increase in pressure --> afferent arteriole constricts = decreased GFR + renal blood flow
62
What is the mechanism for tubuloglomerular feedback?
decrease pressure --> increase GFR (back to normal)
^release Renin + Angiotensin II locally which constricts efferent arteriole
63
3 factors cause Renin secretion
-decreased tubular Na+
-changes in arteriolar pressure
-SNS
64
NE release stimulates B-adrenergic receptors on JG cells which releases ______ via (indirect/direct) mechanism of controlling GFR/blood flow.
Renin
direct
65
NE release stimulates ______ on tubular cells to increase _____ reabsorption in the proximal tubule. This is a (direct/indirect) mechanism in controlling renal blood flow/GFR.
Na/K ATPase
Na+
indirect
66
Another way SNS controls renal blood flow/GFR: SNS innervates afferent + efferent arterioles. NE release stimulates ___ receptors which constricts arterioles and (increases/decreases) blood flow/GFR.
a-adrenergic
decreases
67
What 3 things does Angiotensin-II stimulate?
- vasoconstriction
- aldosterone production
- ADH production
68
What do ADH + Aldosterone do?
help maintain blood volume (by increasing reabsorption of Na+ & H2O)
69
Sodium reabsorption transport mechanism
primary active transport
70
Chloride reabsorption transport mechanism
passive + active transport
71
H2O reabsorption transport mechanism
passive transport
72
___ + ___ reabsorption is coupled to ___. reabsorption.
Chloride + H2O
Sodium
73
Where is sodium reabsorbed in the tubule?
proximal tubule (majority)
ascending loop (1/4)
distal/collecting tubule (regulation)
74
Na+/K+ ATPase is on the (apical/basolateral) membrane.
basolateral
75
Order of reabsorption (by location)
tubular lumen --> tubular cells --> interstitial fluid --> peritubular capillaries
76
Movement of solutes from the ISF --> peritubular capillaries is primarily by:
passive / bulk flow
77
Na+ transport on apical membrane - proximal tubule (3 types)
Co-transport w/ organic substances
Counter-transport w/ H+ ions
Paracellular diffusion (passive)
78
What 2 specific transporters are used to transport Na+ across apical membrane by co-transport w/ organic substances?
Na+/glucose transporter (2nd active)
Na+/amino acid transporter (2nd active)
79
What specific transporter does Na+ use as counter-transport w/ H+ ions in the proximal tubule?
Na+/H+ exchanger (2nd active)
80
What 3 types of transport does Na+ use in Loop of Henle?
Co-transport w/ K+ & Cl- ions
Counter-transport w/ H+ ions
Paracellular diffusion (passive)
81
What specific transporter does Na+ use (co-transport w/ K+ & Cl- ions) in Loop of Henle?
NKCC (Na/K/Cl co-transporter)
82
What counter-transport does Na+ use in the Loop of Henle?
Na+/H+ exchanger
83
What two modes of transport does Na+ use in the Distal/Collecting Tubule?
Co-transport w/ Cl- ions
Na+ specific ion channels
84
What specific co-transporter w/ Cl- ions does Na+ use for transport in distal/collecting tubule?
NCC (Na, Cl co-transporter)
85
What specific transporter does Na+ use in the distal/collecting tubule that is a Na+ specific ion channel?
ENAC (epithelial sodium channel)
86
3 inhibitors that are drugs used to target sodium transporters
SGLT inhibitors (Na/glu transporter)
NHE inhibitors (Na/H+ exchanger)
NKCC inhibitors (Na/K/Cl co-transporter)
87
What disease does SGLT inhibitors treat?
diabetes / hyperglycemia
88
How do SGLT inhibitors treat diabetes/hyperglycemia?
allow to excrete more glucose
89
What disease do NHE inhibitors treat?
hypertension
90
How do NHE inhibitors treat hypertension?
vasodilate vasculature & protect kidney
91
What drug is an NKCC inhibitor?
Furosemide (a diuretic)
92
How does NKCC inhibitor (furosemide) work?
blocks reabsorption of Na+ which blocks reabsorption of water --> excrete more
93
Two diuretics that work further down in the tubule (less effective potentially)
NCC inhibitors
ENAC inhibitors
94
How is Cl- reabsorbed in the proximal tubule?
passive, paracellular flow
Na+ reabsorption causes negative charge in lumen --> Cl- wants to leave!
95
How is Cl- reabsorbed in the Loop of Henle?
Co-transported (NKCC) - secondary active
96
How is Cl- reabsorbed in the distal tubule?
co-transported with Na+
NCC (secondary active)
97
Which part of the tubule has low permeability to H2O? (no water is reabsorbed)
ascending loop of henle
98
Which two parts of the tubule does water permeability vary?
cortical part of distal tubule
collecting tubule/duct
99
What two ways is water reabsorbed across the tubular epithelium?
simple diffusion (paracellular)
facilitated diffusion (transcellular w/ aquaporins!!!)
100
What are aquaporins?
water-selective channels
allow for rapid movement of water from tubule --> ISF
101
Aquaporins are present on the (apical/basolateral) membrane.
TRICK QUESTION! Both!
102
How does water move from the tubule to ISF?
Na+ reabsorption causes concentration gradient in (more in ISF) so water moves from tubule --> ISF (via aquaporins + simple diffusion)
103
What is the primary driver of H2O from ISF --> peritubular capillaries?
capillary osmotic pressure (more proteins so sucks water in)
104
Match osmolality of fluid to location in tubule: proximal tubule | bottom loop of henle | distal/collecting tubule
Proximal Tubule: isosmotic (1:1 H2O/solute moving)
Loop: hyperosmotic (concentrated - water has been reabsorbed)
Distal/Collecting: hypoosmotic (dilute b/c solutes reabsorbed)
105
Loop of Henle mechanisms of urine concentration/dilution by location (thin descending | thin ascending | thick ascending)
Thin descending: high water / low solute permeability
Thin ascending: just moving fluid
Thick ascending: low water / high solute permeability
106
What is meant by Counter-Current Flow?
parts of Loop of Henle work in coordination
Na+ reabsorption (thick ascending) --> water reabsorption (thin descending) b/c concentration gradient
107
At the end of the Loop of Henle, urine is (concentrated/dilute) and volume of water is (high/low).
dilute
low
108
Where does ADH have its effect in the tubule?
distal tubule/collecting duct
109
What does ADH do (antidiuretic hormone)?
increases water reabsorption in the distal/collecting tubule
stimulates aquaporins to move to apical membrane
110
Low ADH --> (high/low) water reabsorption --> (dilute/concentrated) and (lower/higher) volume urine.
low
dilute
higher
111
High ADH --> (high/low) water reabsorption --> (dilute/concentrated) and (lower/higher) volume urine.
high
concentrated
lower
112
What is Na+ balance regulated by? (2)
GFR
amount Na+ reabsorbed
113
What are 2 challenges to Na+ homeostasis?
changes in GFR
changes in Na+ intake
114
3 ways kidney compensates for changes in GFR
1. autoregulation (whole kidney)
2. tubuloglomerular feedback (local)
3. glomerulotubular balance
115
Explain glomerulotubular balance
amount of Na+ filtered is matched with amount of Na+ reabsorbed (so reduces Na+ loss if filtration increases)
116
Where does feedback of glomerulotubular balance occur?
proximal tubule
117
What is aldosterone? What is it produced by?
mineralocorticoid (steroid)
produced by adrenal glands
118
Where does aldosterone have its effect?
late distal tubule/collecting duct
119
Function of aldosterone
increases Na+ reabsorption (and therefore K+ secretion)
120
(T/F) Aldosterone controls whether or not all sodium in the body is secreted/absorbed.
False: only controls 2-3%
max aldosterone = NO Na+ excreted
min aldosterone = 2-3% filtered Na+ is excreted, rest reabsorbed
121
Which two Na+ transport mechanisms does aldosterone increase synthesis of to increase reabsorption?
Na/K ATPase (basolateral)
ENAC (apical)
122
4 factors that stimulate aldosterone secretion
decreased plasma Na+
increased K+
increase plasma ACTH
large increases in Angiotensin II (hemorrhage)
123
How does aldosterone contribute to the response to hemorrhage?
increase Na+ reabsorption -->
increase H2O reabsorption = conserve blood volume
124
What is ADH? What secretes it?
peptide hormone that increases water reabsorption in late distal tubule/collecting duct
secreted by pituitary
125
What 3 things regulate ADH secretion?
1. Baroreceptors
2. Osmoreceptors
3. Angiotensin II
126
Baroreceptors sense changes in _____ and (activate/inhibit) ADH secretion.
blood volume
inhibit
127
Osmoreceptors sense changes in ____ and (activate/inhibit) ADH secretion.
osmolality/concentration
stimulate
128
High elevations in Angiotensin II (hemorrhage) can directly (stimulate/inhibit) ADH secretion.
stimulate
129
How does ADH increase water reabsorption in the late distal tubule/collecting duct?
ADH binds to receptor --> Gs signaling activates Protein Kinase A = aquaporins move to apical membrane
130
Water diuresis (urine volume + concentration)
high volume urine
hypoosmotic (dilute)
131
Osmotic diuresis (urine volume + concentration)
high volume urine
isosmotic (not dilute)
132
Causes of water diuresis
increased water intake, drugs, disease/inury
133
Causes of osmotic diuresis
disease, drugs (mannitol)
134
(Diabetes Mellitus/Diabetes Inspidus) can cause water diuresis.
Diabetes Insipidus
135
(Diabetes Mellitus/Diabetes Insipidus) can cause osmotic diuresis.
Diabetes Mellitus
136
How does increased water intake cause water diuresis?
increased blood volume / decreased osmolarity --> decreased ADH = decreased water reabsorption
137
What kind of drugs have a central effect on ADH?
glucocorticoids
138
What kind of drugs have a nephrotoxic effect on the kidney (ADH not effective)?
antifungal agent (amphotericin B)
139
Which drug blocks NKCC for clinical treatment?
furosemide
140
Which drug blocks NCC for clinical treatment?
hydrochlorothiazide
141
Which drug blocks ENAC channels and are K+ sparing?
amiloride
142
Which drug is an aldosterone antagonist and K+ sparing?
spironolactone
143
What are the 2 types of diabetes insipidus?
Central
Nephrogenic
144
In (central/nephrogenic) diabetes insipidus, ADH production is normal but not effective.
nephrogenic
145
In (central/nephrogenic) diabetes insipidus, ADH secretion is reduced.
Central
146
Who does Diabetes Mellitus induce osmotic diuresis?
increased glucose --> increased urine osmolality = water retained in tubule
147
How does mannitol induce osmotic diuresis?
shifts small amount of water in the wrong place (treat glaucoma, head injury)
148
Clearance
amount of plasma cleared of a substance over time
149
Excretion
amount of substance coming out in urine
150
What substance does clearance = GFR?
inulin
no reabsorption, no secretion
151
What substance is when clearance is LESS than GFR?
Na+
some reabsorbed, none secreted
152
What substance is clearance = 0?
glucose
everything is reabsorbed
153
What substance does clearance = renal blood flow?
PAH
not reabsorbed, is secreted so 100% is excreted
154
What substance uses clearance to determine GFR? (and therefore kidney function)
inulin
155
Not reabsorbed | Secreted =
clearance > GFR
156
Not reabsorbed | Not secreted =
clearance = GFR
157
Partially reabsorbed | Not secreted =
clearance < GFR
158
Fully reabsorbed | Not secreted
clearance << GFR (clearance = 0)
159
Name 2 exogenous substances that can used to measure GFR (and therefore renal function)?
Inulin
Iohexol
160
Inulin
standard agent for GFR measurement
sugar in wheat, injected, takes a while for excretion
Needs electrochemical equipment
161
Iohexol
iodinated contrast agent, fast clearance, nephrotoxic
cannot give repeatedly
uses CT scanning
162
What two endogenous substances are used to measure GFR (and therefore kidney function)?
creatinine
SDMA
163
Creatinine
easily measured, not injected
slightly overestimates GFR
164
SDMA
amino acid, sensitive to early kidney dysfunction
Need IDEXX equipment
165
____ & ____ are two essential nutrients that need to be (reabsorbed/secreted).
glucose
amino acids
reabsorbed
166
Urea is (reabsorbed/secreted).
TRICK QUESTION: both!
167
Glucose & Amino acids are completely reabsorbed in the ______ via _____ transport and coupled to _____ reabsorption.
proximal tubule
secondary active
Na+
168
Explain why/how glucose + amino acids use secondary active transport for reabsorption.
downhill movement of Na+ is used to move them uphill against their concentration gradient
*need Na+ reabsorption to move*
169
What are the 2 Na/glu transporters on the apical membrane of the proximal tubule? Which is majority?
SGLT1 & SGLT2 (majority)
170
Match SGLTs with:
specificity (high/low)
competition (high/low)
efficiency (high/low)
high specificity (only bind glucose)
low competition (no substrate comp)
highly efficient (high Tm)
171
Tm () glucose filtered.
> (much greater, none excreted)
172
Match Amino Acid Transporters with:
specificity (high/low)
competition (high/low)
efficiency (high/low)
low specificity (multiple AAs)
high competition (multi substrates comp)
low efficiency (less than glucose)
173
Tm () filtered amino acids.
> (greater but lower than glucose)
174
What process is the small amount of protein filtered reabsorbed by?
endocytosis
175
What type of transport does protein get reabsorbed through?
primary active transport
176
What is urea?
nitrogen waste product made by protein metabolism
177
The amount of urea excreted depends on (aldosterone/ADH/angiotensin).
ADH
178
What type of transport does urea use for reabsorption?
passive transport (w/ urea transporters)
179
Urea is coupled to _____.
water (and therefore sodium)
180
What substance is recirculated to help increase hyperosmotic medulla for increased urine concentration/water conservation?
urea
181
ADH (increases/decreases) urea transporters --> (increased/decreased) reabsorption --> (increased/decreased) excretion.
increased
increased
decreased
182
Increased urine flow --> (increased/decreased) urea concentration gradient --> (increased/decreased) reabsorption --> (increased/decreased) urea excretion.
decreased
decreased
increased
183
Azotemia
increase in blood urea nitrogen (BUN) with or without increase in blood creatinine
184
3 types of azotemia
pre-renal
renal
post-renal
185
Explain pre-renal azotemia
decreased blood flow to kidneys (dehydration) --> increased BUN
186
Explain renal azotemia
decreased functional nephrons --> increased BUN (from toxin)
187
Explain post-renal azotemia
urinary blockage (urolithiasis) --> increased BUN
188
Organic ions are (reabsorbed/secreted).
secreted
189
Where are organic ions secreted?
proximal tubule
190
What type of transport is used for organic ion secretion?
active transport
191
Two types of organic ions
cations
anions
192
List 2 types of cations (organic ion type)
neurotransmitters
histamine
193
Match to organic ion transporter properties:
specificity (high/low)
competition (high/low)
efficiency (high/low)
low specificity
high competition
inefficient (low Tm - easily excreted)
194
(T/F) The ratio of K+ filtration to reabsorption = 1:1
True
195
What type of transport does K+ reabsorption use in the proximal tubule?
passive/paracellular transport
196
What type of transport does K+ reabsorption use in the Loop of Henle?
secondary active transport
(via NKCC using energy from Na/K ATPase)
197
What kind of transport does K+ reabsorption use in the distal/collecting tubule?
primary active transport
(via H+/K+ ATPase)
198
Where is K+ reabsorbed?
proximal tubule (most)
thick ascending loop (some)
distal/collecting tubule (little)
199
Where is K+ secreted?
ONLY in distal tubule / collecting duct
200
How is K+ secreted?
K+ specific channels (ROMK) on apical membrane
201
Where is K+ balance primarily regulated?
distal tubule/collecting duct
202
What 4 factors influence K+ secretion?
1. Na/K ATPase activity
2. Concentration gradient
3. Electrical gradient
4. Permeability of apical membrane to K+
203
How does Na/K ATPase activity influence K+ secretion?
up ATPase activity = up K+ secretion
204
How does electrical gradient influence K+ secretion?
more Na+ reabsorbed = increased K+ secretion
205
How does concentration gradient influence K+ secretion?
more K+ gradient = increased K+ secretion
206
How does permeability of apical membrane influence K+ secretion?
more K+ channels (ROMK) = increased K+ secretion
207
(T/F) K+ reabsorption increases when K+ intake decreases.
False
reabsorption rate constant & not influenced by changes in K+ intake
208
What is the only way to change K+ excretion?
regulation of K+ secretion in the distal/collecting tubule
209
How does K+ secretion increase in the distal/collecting tubule directly?
stimulates Na+/K+ ATPase on basolateral membrane
210
How does K+ secretion increase in the distal/collecting tubule indirectly?
stimulates aldosterone release --> K+ secretion, Na+ reabsorption
211
What substance is the primary controller of K+ secretion (and therefore K+ excretion)?
aldosterone
212
What are the effects of increased plasma K concentration on aldosterone
increased aldosterone secretion
213
2 mechanisms by which aldosterone increases K+ secretion in response to K+ intake
increase synthesis of Na/K on ATPase (basolateral)
increase ROMK expression (apical)
214
4 ways the two above mechs increase K+ secretion by aldosterone
1. increase Na/K ATPase activity
2. Increase concentration gradient
3. increase electrical gradient
4. increase apical permeability
215
Without aldosterone, there would be a huge (increase/decrease) in K+.
increase
216
Aldosterone secretion = increased __ reabsorption and increased __ secretion.
Na+
K+
217
If Na+ load increases, what happens to K+?
increased K+ secretion/excretion
218
What two ways goes Na+ handling impact K+ excretion?
increased Na+ load
increased Na+ flow
219
If Na+ flow increases, what happens to K+?
if less Na+ reabsorbed, less H2O is reabsorbed = K+ concentration diluted in distal/collecting tubule = increased K+ secretion
220
What do diuretic drugs do to Na+? K+?
Na: increase load + flow
K: increase secretion, decrease reabsorption
221
Which drug inhibits NKCC (in loop of henle)
Furosemide
222
Which drug inhibits NCC (early distal tubule)?
Thiazides
223
Two causes of diuresis
disease (diabetes mellitus)
diuretic drugs
224
How does alkalosis influence K+ secretion?
increases secretion (body tries to retain K+ to keep positive charge but increases K+ gradient)
225
What important renal enzyme stops functioning outside of physiological pH levels?
Na/K ATPase
226
3 examples of intracellular fluid buffers in blood
hemoglobin (primary)
organic phosphates
proteins
227
3 examples of extracellular fluid buffers in blood
bicarbonate (primary)
phosphate
proteins
228
How do the lungs control the HCO3-CO2 buffer system?
PCO2
increase resp in acidosis to decrease CO2
decrease resp in alkalosis to increase CO2
229
What do the kidneys do to control HCO3-CO2 buffer system?
increase HCO3 in acidosis
decrease HCO3 in alkalosis
230
What 2 mechanisms does the kidney use to increase HCO3- when the body is in acidosis?
1. increase reabsorption of HCO3
2. add "new" HCO3 in
231
Increase HCO3 = (increase/decrease) pH
increase
232
Increase PCO2 = (increase/decrease) pH
decrease
233
Metabolic/kidney compensation during acid-base disorders is (fast/slow) while Respiratory/lung compensation is (fast/slow)
slow
fast
234
Where are the majority of H+ ions secreted?
proximal tubule
235
What transport process + transporter are used for H+ transport across the apical membrane?
Na/H+ exchanger (secondary active)
236
HCO3 reabsorption is coupled to H+ secretion (directly/indirectly)
indirectly
do not reabsorb the same HCO3- ion that was filtered
237
Explain excretion of titratable acid
H+ is excreted as an acid (by combining = urine is acidified
238
Explain excretion of ammonia
H+ combines with ammonia (NH3) + chloride = excreted as a salt
