Section 4 Flashcards
1
Q
Avg plasma conc of Na+, Cl-, HcO3-, K+, Ca2+, and P:
A
140mM, 100mM, 24mM, 4mM, 2.5mM, 1mM
2
Q
Osmolarity of blood:
A
300 mOsm
3
Q
Fxns of kidney:
A
To REGULATE body fluid osmolality and V, electrolyte balance and acid balance, to EXCRETE wastes and foreign substances, and to PRODUCE and SECRETE hormones
4
Q
How many liters do the kidneys filter per day?
A
180L
5
Q
Daily urine output:
A
1.5L
6
Q
Plasma V:
A
2L
7
Q
% of plasma that enters the glomerular capillaries that is filtered into the nephrons:
A
15%
8
Q
Blood supply to the renal tubules:
A
efferent arteriles
9
Q
What are the renal tubules?
A
peritubular capillaries
10
Q
The peritubular capillaries merge to form:
A
renal vein
11
Q
What type of a filtrate enters Bowman’s space?
A
Protein-free plasma unltrafiltrate
12
Q
What makes up the glomerulus?
A
Glomerular capillaries and mesangial cells
13
Q
What are mesangial ells?
A
modified s.m. cells, regulatory roles
14
Q
Components of renal corpuscle:
A
Glomerulus and Bowman’s Capsule
15
Q
Components of juxtaglomerulus apparatus:
A
Mesangial cells of G, macula dense (ThickAL), and Renin secreting granular cell (afferent arteriole/ juxtaglomerular apparatus)
16
Q
What cells secrete renin?
A
Granular cells of afferent arteriole
17
Q
In which portion of the tubule system are the macula densa?
A
ThickAL
18
Q
Solutes entering cells of macular dense from tubules:
A
Na, Cl, and K
19
Q
Solutes moving in and out of cells of macula dense on side opposite tubule:
A
K in, Na and ATP out
20
Q
ATP released from manual dense cells acts on:
A
ADO/A1 and ATP/P2X (of Granular and VSM cells) (check)
21
Q
Too much fluid fluid through G and into Bowman’s space is controlled via signaling from:
A
cells of macula densa that sense high NaCl conc in the DT fluid
22
Q
Where in tubule system are macula dense cells found?
A
ThickAL and DT? Or do the cell of the ThickAL sense the higher conc of NaCl in the adjacent DT?
23
Q
What signals inhibit renin release?
A
Ca2+
24
Q
Effects of inhibition of renin release:
A
constriction of afferent arterioles and decrease in GFR
25
Filtration barrier is formed by;
leaky endo cells of G caps, BM around endo cells, foot processes of podocytes
26
What type of barrier is the BM?
Charge-selective
27
What type of barrier is the filtration slit?
size-selective
28
GFR:
fluid flow across filtration barrier (V/t)
29
Often a first sign of kidney disease:
fall in GFR
30
How is GFR monitored?
blood/urine tests
31
What is used for the calculation of GFR?
clearance, also (V/t)
32
Clearance:
volume of blood that can be cleared of a substance/ t
33
T or F? The clearance rate is always the same as the urine flow.
F.
34
Rate of appearance of a substance in urine must equal:
its rate of removal from plasma
35
Rate of appearance in urine:
U(x) (conc of X in urine) X (V*) (urine flow rate)
36
Rate of removal from plasma:
P(x) (conc of X in plasma) X Clearance
37
Clearance =
(conc of X in urine / conc of X in plasma) X flow rate: part over whole times flow rate
38
Large clearance value indicates:
well removed from plasma
39
When does clearance = renal plasma flow?
when substance is completely cleared
40
Clearance for an substance that is not completely cleared is calculated using;
sum of filtration, reabsorption, and secretion
41
Substances hat are neither reabsorbed or secreted:
inulin and creatine
42
Estimate for GFR:
usually from plasma conc of creatinine, can also be done by dividing urine conc by blood conc and multiplying by the urine output in that 24 hour time frame
43
How is GFR controlled?
Starling Forces (hydrostatic vs. oncotic P's)
44
Hydrostatic P:
force exerted by plasma fluid on cap walls
45
Oncotic P:
Osmotic pull exerted by plasma proteins
46
Afferent arteriole P vs. efferent:
17 mm Hg vs. 8 mm Hg
47
What does the ultrafiltration coefficient account for?
variations in permeability and s.a. of the cap
48
3 forces to bo considered in the the filtration capsule when calculating ultrafiltration pressure:
hydrostatic P's of both GC and BS and ONLY oncotic P of GC (no protein in BS)
49
Precise equation for GFR:
K(f) X ultrafiltration P
50
ultrafiltration P:
P(GC) - P(BS) - pi (GC)
51
What changes the GFR bw the afferent and efferent arterioles?
difference in resistances
52
Cells of the DT and CD:
principal and intercalated cells
53
Portions of tubules in outer medulla:
Thick and DL, Thick AL, and CD
54
Portions of tubules in inner medulla:
ThinDL, ThinAL, and CD
55
Proteins forming tight junctions:
claudins
56
Are the N terminal and C terminal ends of the cloudiness facing the apical side?
N terminal
57
How many mOsmol per day must the kidney excrete?
600, regardless of water V excreted
58
Omolar clearance =
(Urine osmolarity / Plasma osmolarity) X Urine flow
59
Urine flow =
osmolar clearance + free water clearance
60
What info does the value of free water clearance provide?
ability of kidney to conc or dilute urine
61
Will C water be positive or negative if water is being generated in the tubule lumen?
positive
62
How do the kidneys create a positive free water in tubule lumen?
reabsorbing NaCl and urea in excess of water along nephron segments with low water permeability
63
How is water added to the the tubule fluid to create a positive free water in the tubule lumen?
Its not! NaCl and urea are taken out in a segment not permeable to water so it can't follow
64
How does the kidney remove water from the tubule fluid to create a negative C water?
by allowing water to exit down its gradient into medullary interstitial fluid
65
Is more or less water being excreted if there is a neg C water?
less
66
How is the fluid in the loop of Henle diluted?
both the single effect and countercurrent multiplier
67
Effects of the the single effect and countercurrent multiplier:
dilute tubule fluid in loop of Henle and concentrate fluid in the medullary interstitium
68
in which segments of the tubule system is the concentration of the tubule fluid compared to that of the plasma remaining constant?
PT, early part of CD, and urine
69
in which segments of the tubule system is the concentraion of the tubule fluid compared to that of the plasma rising?
DL of loop of Henle, DT, and later part of CD
70
only segment of the tubule in which the concentraion of the tubule fluid compared to that of the plasma is decreasing:
Ascending limb of loop of Henle
71
ADH affects which part of the tubule system?
CD
72
How does ADH increase permeability of the CD?
inc # of AQP2 in pm
73
The macula dense of the ThickAL is adjacent to:
afferent and efferent arterioles entering G
74
1st half of PT paracellular pwy:
water, K, and Ca
75
1st half of PT transcellular pwy:
Lumen side: Na, Ca, glucose/P/ or AA and water in, H out plasma membrane: Na, Ca, (glucose/P/ or AA), HCO3-, water out and K, Na, H, and Ca in
76
Solutes reabsorbed via transcellular pwy in the 1st part of PT:
Na, P, glucose, AA
77
Via which route(s) does water follow along an osmotic gradient in the
both trans and para
78
What solutes are moved via solvent drag in the PT?
K and Ca via the para pwy
79
Major site of HCO3- reabsorption, HCO3- generation, and H+ secretion:
first half of PT
80
Movement of what solutes in the PT require energy?
Na, K, and H
81
2nd half of PT transcellular pwy:
Lumen: Na, Ca, Cl in, H and OA- (organic acid) out, plasma membrane: Na, K, Ca, and Cl out, K, H, Na, OA- in
82
2nd half of PT para pwy:
Cl, Na, K, Ca2+, H20
83
Site of transcellular organic acid secretion:
2nd half of PT
84
Site of Cl reabsorption:
2nd half of PT
85
T or F? Cl is reabsorbed in both 1st and 2nd half of PT.
F. 2nd half only and via both trans and para
86
Solutes that move across both para and trans pwys in the 2nd part of PT:
Na, Cl, K,
87
Solutes that move via the para pwy only in the 2nd part of PT:
Ca and water
88
Solutes that move via the trans pwy only in the 2nd part of PT:
H, OA-
89
What generates a transepi electrical gradient that promotes paracellular Na, K, and Ca reabsorption?
movement of unaccompanied Cl
90
T or F? Cl moves via the para pwy in the 2nd part of PT but water can not follow.
F. it does
91
How is Ca moved transcellularly?
bound to calbindin
92
What prevents in inc in intracellular Ca concentration when moving Ca through the cell?
it is bound to calbindin
93
In which portion of the cell does Ca/calbindin binding occur?
cytosol
94
How can Ca sequestered by proteins in plasma be released?
H+ in acidosis
95
is the thin DL permeable to water?
yes
96
Via what pwy does water leave the thin DL?
trans
97
Via which type of aquaporin does water flow out of the thin DL?
AQP1
98
t or F? The thin DL contributes tot he countercurrent multiplier mechanism.
T
99
AQP1 is found here and AQP2 is found here:
thin DL, CD
100
T or F? The Thin AL is permeable to salt.
T
101
T or F? The Thin AL is permeable to water.
F.
102
Why does the conc of the tubular fluid decrease as the fluid ascends in the ascending limb?
salt leaves via para pwy
103
Via what pwy does salt leave the ascending limb?
para
104
T or F? The Thin AL contributes to the countercurrent multiplier system.
T
105
What solutes are reabsorbed via the trans pwy in the Thick AL?
Na, K, and Cl
106
Is the Thick AL permeable to water?
no
107
T or F?The Thick AL contributes to both the single effect and the countercurrent mechanisms.
T
108
The single effect and the countercurrent mechanisms both contribute to:
urine concentration and transepi voltage that promotes reabsorption of Na, K and Ca via the para route
109
Solutes moved via trans pwy in the Thick AL:
Lumen: Na, K, Ca, and Cl in, K out, plasma membrane: Na, K, Ca, and Cl out, K, Na, and H in
110
Solutes moved via the para pwy in the Thick AL:
Na, K and Ca
111
The early DT is similar to the TAL except:
it is independent of K
112
Is the lumen side apical or basal?
apical
113
What provides the permeability to the apical side of the early DT?
Na/Cl contransporter (NCC)
114
What is the NCC?
Na/Cl co-transporter
115
What hormone increases the abundance of NCC?
aldosterone
116
What does increasing the abundance of NCC do?
inc salt reabsorption when BP is low
117
Solutes moved via the trans pwy in the early distal tubule:
Lumen side: Na and Cl in, plasma membrane: Na and Cl out, K in
118
What cells provide transcellular water permeability?
principal cells
119
Na permeability of the principal cells is provided by these channels:
ENac
120
T or F? ENac channel are found on both eh apical and basal side of the principal cells.
F. (check, only shown on apical side)
121
What provides an electrical driving force for transcellular K secretion ad Cl reabsorption in the principal cells?
na reabsorption
122
What channels provide an electrical gradient in principal cells by transporting K into the lumen?
ROMK
123
What channels provide an electrical gradient in principal cells by transporting Na into the cell from the lumen?
ENac
124
What solutes are transported via the paracellular pwy bw principal cells?
Cl-
125
What cells do all the fine tuning of urine/plasma content?
Principal
126
This is a major site of regulation in the tubule system?
Principal cells
127
Does aldosterone increase or decrease the activity of ENac when BP is low or K plasma conc is too high? ? what about ROMK? What about Na,K ATPase?
increase activity of all
128
Location of low pressure sensors:
wall of atria, R vent, and pulmonary vessels
129
T or F? An increase in dissension of the low-pressure sensors causes signals to be sent to the brainstem that stimulate sym n. activity.
F. dec in distension
130
Activation of low-pressure sensors leads to:
inc sym n. activity to inc Na reabsorption, stimulate renin/angiotensin/ aldosterone release to inc BP and Na reabsorption, stimulate ADH release to inc water reabsorption
131
These effects inc Na reabsorption:
sym n activity and renin/angiotensin/aldosterone release
132
T or F? ADH release leads to Na reabsorption.
F. water reabsorption
133
Location of high-pressure sensors:
walls of aortic arch, carotid sinus, and afferent arterioles
134
Activation of high-pressure sensors leads to:
reduce sym n. activity to increase Na excretion, inhibit ADH release to inc water excretion, heart cells release ANP and BNP
135
ANP and BNP are both:
natriuretic peptides
136
Effect of natriuretic peptides:
inc salt and water excretion
137
When is the RAAS activated?
dec Na/water reabsorption that lowers the ECF
138
From where is renin released?
granular cells, also produced and stored here
139
Where are the granule cells that store renin located?
afferent arteriole
140
What leads to the release of renin?
dec P in arteriole, low P in BV's, dec Na delivery sensed by macula densa
141
What happens when the macula densa senses a reduction in Na delivery?
the macula densa stops sending inhibitory input to the renin producing cells
142
What intrinsic signaling capability does the macula dense have?
none
143
T or F? Renin is a protease.
T. helps generate Angiotensin II
144
Effects of Ang II:
sm contraction in BVs to inc BP during water/salt depletion, inc Na/H20 reabsorption by the PT, release of aldosterone
145
What hormone triggers the release of aldosterone?
Ang II
146
On what transporters does activated Ang II receps act?
Na/H exchangers, Na/K pump, and Na?HCO3- co-transporter
147
What type of hormone is aldosterone?
steroid hormone
148
Where is aldosterone both synthesized and secreted?
glomerulosa cells in cortex of adrenal gland
149
Triggers for aldosterone secretion:
inc levels of Ang II indicating dec Bp and Na delivery to macula densa, inc innervation of the adrenal cortex by symp nn. triggered by low P sensors in circulation
150
On which portions of the tubules does aldosterone exert its effects?
DT ad CD
151
Where does Ang II exert its effects?
PT and vasculature
152
2 types of intercalated cells:
alpha and beta
153
alpha intercalated cells:
secrete acid, maximize H+ secretion in acidosis
154
B-intercalated cells:
secrete base, secrete HCO3- in alkalosis
155
Which cells are active during acidosis?
alpha intercalated cells
156
What cells are active during alkalosis?
beta-intercalated
157
Difference bw alpha and beta intercalated cells in terms of location of channels:
alpha: Cl/HCO3- exchanger on plasma membrane and pumps H and Cl out into lumen, beta: Cl/HCO3- exchanger on lumen side and pumps H and Cl out into blood
158
On which side of the beta intercalated cell is the Cl/HCO3- exchanger?
luminal side
159
Changes in HCO3- concentration can lead to both:
metabolic acidosis and alkalosis
160
changes in dissolved CO2 concentrations can lead to both:
respiratory acidosis and alkalosis
161
When the efferent arteriole is constricted does P(GC) increase or P(GS)?
P(GC)
162
Ultrafiltration calculation:
Hydro P of G - Hydro P of Bowman's Space - oncotic P of G
163
Who does aldosterone increase the Na permeability of the DT?
inc # of Na/Cl co-transporters in the plasma membrane
164
A dec in plasma Co2 conc wo a change in plasma HCO3- conc is:
resp alkalosis
165
This leads to dec in renal Na reabsorption:
ANP release
166
Why is it called a multiplier system/
Bc the effects of the gradient are multiplied by the countercurrent system.
167
In which limbs does water leave the tubule passively?
the descending limb and the CD
168
The characteristic yellow color of urine is attributed to:
urobilin
169
The kidneys are located:
behind the peritoneal membrane
170
Blood flow through the kidney includes a feature seen in only a few organs. What is it?
portal system
171
Glucose and amino acids are reabsorbed by:
sodium coupled symporter
172
Primary mode of transport of glucose across kidney epi:
symport with a cation
173
Primary mode of transport of urea across kidney epi:
passive reabsorption/diffusion
174
Primary mode of transport of small plasma proteins across kidney epi
transcytosis
175
These lie between and around the glomerular capillaries:
mesangial cells
176
The specialized cells found in the capsule epithelium are called __________. These cells have long cytoplasmic extensions called __________.
podocytes, foot processes
177
Damage to the renal medulla would interfere first with the functioning of the:
collecting ducts
178
If blood flow through the afferent arterioles increases:
stretch reflexes trigger vasoconstriction to reduce the flow
179
How and where is urea reabsorbed?
passively, proximal tubule
180
In the lumen of the proximal tubule, the Na+concentration __higher/less/same________ the Na+concentration inside the cells of the tubule epithelium.
is much higher than
181
One substance has no membrane transporters to move it but can diffuse freely through open leak channels if there is a concentration gradient. Initially, this substance's concentrations in the filtrate and extracellular fluid are equal. Later, however, the active transport of Na+and other solutes creates a gradient by removing water from the lumen of the tubule where it is located. What substance is this?
urea
182
Which of the following “real” volumes plays the most important role in determining an optimum effective circulating volume?
plasma volume
183
Which of the following fluid compartments has the smallest volume?
plasma volume
184
What percentage of the body weight of a normal adult human is composed of water?
60%
185
Aldosterone stimulates sodium reabsorption
cortical collecting duct.
186
Tubulo-glomerular feedback is an important mechanism that
balances tubular filtration with reabsorption
187
The primary route for ion loss from the body is the __________ system
urinary
188
Cell volume (and therefore cell function) in most cells is dependent upon careful regulation of:
osmolarity of extracellular fluid
189
The two organ systems that work together to regulate mostaspects of the body's water balance are:
urinary and cardiovascular
190
Where is most body water located?
inside cells
191
Kidneys regulate:
water loss, not water gain
192
When a body is dehydrated, water in the urinary bladder:
can be returned to the circulation directly.(?)
193
The hormone that regulates water excretion by the kidneys
ncreases water permeability throughout the kidney tubules
194
The primary osmoreceptors are located in the:
hypothalamus
195
Osmoreceptors depolarize after they __________ in response to __________ plasma osmolarity.
shrink, increase
196
2 fxns of atrial natriuretic peptide:
increases the GFR and inhibit release of renin
197
Thirst is triggered:
when plasma osmolarity is elevated above normal
198
Angiotensin I is converted to angiotensin II by enzymes primarily located in the:
blood vessels
199
The primary role of the carbonic acid-bicarbonate buffer system is:
the prevention of pH changes caused by organic and fixed acids
200
As a result of respiratory alkalosis:
the body retains less carbon dioxide
201
A person who suffers from emphysema will exhibit signs of:
resp acidosis
202
When the pH of body fluids begins to fall, proteins will
bind a hydrogen at the amino group
203
When the pH of the extracellular fluid declines:
the pH of the urine decreases
204
Dehydration may cause some ions to become concentrated. If a person was suffering from severe hyperkalemia, you would expect
the skeletal muscles to be unresponsive and cardiac arrest could occur
205
The hydrostatic pressure in the glomerular capillary is 68 mmHg. The hydrostatic pressure in Bowman’s capsule is 24 mmHg. The oncotic (colloid) osmotic pressure in the glomerular capillary is 18 mmHg. The filtration coefficient is 0.5 ml/min/mmHg. The net filtration pressure is _____ mmHg.
26
206
Which of the following is/are directly involved in autoregulation of the GFR?
A myogenic mechanism in which the afferent arteriole automatically constricts when it is stretched AND a feedback mechanism in which vasoactive chemicals released from the juxtaglomerular apparatus bring about afferent arteriolar vasoconstriction
207
The osmolality of the tubular fluid exiting the earlydistal tubule is always:
hypo-osmotic to plasma
208
Which of the following substances has the highest renal clearance?
Para-amino hippurate (PAH)
