Renal Flashcards
(277 cards)
1
Q
What are the three functions of the Renal System?
A
- Cleans the Blood2. Regulates many ECF Components3. Endocrine Tissue
2
Q
How Does the kidney Clean the Blood?
A
It removes waste products through filtering and then reabsorbs what it wants. Undesirable components are expelled through the urine.
3
Q
How does the renal system regulate ECF?
A
It receives 25% of cardiac output so it can regulate the levels of blood components especially ions (Na+, K+, and Ca2+) and acid base balance
4
Q
How is the kidney an endocrine tissue?
A
It releases hormones important for regulating BP (renin) and rBC production (EPO and Erythropoietin)
5
Q
How much cardiac out put does the kidney receive?
A
25%
6
Q
where are the kidneys located?
A
Side of spinal column in the dorsal body cavity
7
Q
In humans which kidney is more anterior?
A
Left Kidney/more cranial
8
Q
What color and texture are the kidneys?
A
Red, Brown and smooth
9
Q
How big are the kidneys in humans?
A
10-12 cm long
10
Q
What supplies the kidney with blood?
A
Each kidney has a renal artery
11
Q
What drains the kidney?
A
Each kidney has a renal vein
12
Q
What does the ureter do?
A
Moves urine from each kidney by a peristalsic motion and gravity to bladder
13
Q
Describe the bladder
A
Thin stretchy bag of muscle that stores urine
14
Q
What does the urethra do?
A
Expels urine out of the body from the bladder.
15
Q
What would we see in a sagittal section of the kidney?
A
Cortex(Dark), Medulla and Renal Pelvis(Pale)
16
Q
Why is the cortex of the kidney darker?
A
More vasculature, different cell types
17
Q
What explains the coloration difference between the cortex and medulla?
A
Different cells, more vasculature in the cortex
18
Q
What color is the renal pelvis?
A
pale, creamy yellow
19
Q
What is the renal pelvis?
A
An extension of the ureter that expands to fill out the hollow cavity of the kidney
20
Q
What does the renal pelvis do?
A
collect urine that is formed and emerges from the innermost medulla
21
Q
In what direction does the kidney work?
A
from the outside in
22
Q
Where does blood enter the kidney?
A
blood enters cortex of the kidney from the renal artery
23
Q
What happens to the blood in the cortex in general terms?
A
It gets filtered
24
Q
What fluid emerges from the medulla?
A
Urine
25
What is the boundary called between the cortex and medulla?
Cortico-medullary boundary
26
What is the kidney composed of?
Hundreds of epithelial lined tube structures called nephrons
27
What is the functional unit of the kidney?
The nephron
28
Is there connective tissue in the kidney?
no
29
Where is the Macula Densa?
Cortex
30
What part of the kidney are distal tubules found?
Cortex
31
What part of the kidney do you find loop of Henle?
Medulla
32
Where do you find proximal tubule in the kidney?
Cortex
33
Where do you find collecting duct of the kidney?
Medulla and cortex
34
Where do you find bowmens capsule?
Cortex
35
Where do you find a connecting tubule?
Cortex
36
Where is the renal corpusle?
Cortex
37
What does the renal corpusule do?
filters the blood and generates filterate
38
What does the proximal tubule do?
Selective reabsorbtion
39
What does the proximal tubule reabsorb?
Na, K, glucose, amino acids , bicarbonate
40
Where does the epithelial type change?
at the loop of henle
41
What does the loop of henle do?
Reabsorb water and Sodium Chloride
42
What is another name for the thick ascending limb?
distal straight tubule
43
Where does the distal tubule run?
From the outer medulla to the cortex
44
What does the distal tubule do?
Selective reabsorption but not as powerful as the proximal tubule
45
What does the collecting duct do?
Fine tuning (secretion and reabsorption)
46
Which molecule reabsorbs Na+ at the luminal membrane of the early proximal tubule?
Na-glucose symporter
47
How is Na+ reabsorbed at the basolateral membrane of the early proximal tubule?
Via Active Transport
48
What molecule reabsorbs Na+ at the luminal membrane of the early proximal tubule?
the Na-Glucose symporter
49
Where does the Na-Glucose symporter reabsorb Na+ in the early proximal tubule?
At the luminal membrane
50
What is the number one job of the kidney?
To clean the blood
51
What is the second most important function of the kidney?
regulate many components of the extracellular fluid
52
What are the two parts of the renal corpusle?
1. A bundle of capillaries (glomerulus)2. Bowmans Capsule (surrounds glomerulus)
53
Where does the glomerulus receive blood from?
An Afferant Arteriole
54
Where does blood leave the glomerulus?
An Efferent Arteriole (E for Exit)
55
Where does the blood get filtered?
in the glomeruli
56
As the blood flows through the capillaries of the glomerulus is it under high or low pressure?
High because part of the fluid portion of the blood is squeezed through capillaries into bowmans capsule
57
How much of the fluid portion of the blood is squeezed into bowmens capsule during filtration?
20-25%
58
Where does the filterate go from bowmans capsule?
To the proximal tubule where selective reabsorbtion occurs
59
If a sodium ion wants to enter bowmans capsule from the glomerulus what does it have to do?
Cross the wall of the capillary and then the wall of bowmans capsule
60
What makes up the filteration barrier in the renal corpuscle?
Wall of the capillary in the glomerulus and the lining of bowmans capsule.
61
What can cross the filteration barrier of the renal corpuscle?
Anything super small : Ions (Na,K, Mg)Anything with a neutral charge or no net charge Example: glucose, Water, very small proteins
62
What cannot cross the filteration barrier of the renal corpuscle?
Cells (RBCs and WBCs)antibodies (large blood borne molecules)Most Protein
63
T/F The blood has lots of protein
TRUE
64
Describe the path of the proximal Tubule in the kidney.
1. Begins in the cortex and winds around
2. Dives into the medulla and turns into the loop of henle
3. goes down the descending limb
4. makes a hairpin loop in the deep medulla
5. Comes back out in the ascending limb
6. Turns into the distal straight tubule
7. distal straight tubule goes back to glomerulus where it touches it at the vascular pole
65
Where is the vascular pole located in the renal corpuscle?
Where the afferent and efferent enter and exits
66
What is the distal tubule associated with?
The renal corpuscle
67
What are the specialized cells are the interface of the distal tubule and glomerulus called?
The macula densa
68
What are the cells of the macula densa important for?
regulation of control of filtration but not filtration itself
69
Why compels something to move out of the bloodstream to cross the glomerulus into bowmans capsule and then into the proximal tubule?
Starlings forces combined (net filtration pressure)
70
Are starlings forces unique to the glomerulus?
no, they function at any capillary bed
71
Define Hydrostatic Pressure
the pressure exerted by the fluid on the container that contains it. Fluid pushing out against cup
72
What are the two categories of starlings forces?
Hydrostatic and Oncotic Pressure
73
Define Oncotic Pressure
Osmosis generated by proteins in the blood
74
If there was a container with two fluids (one of water and one with sodium chloride) and a semipermeable membrane what way would the water move?
Toward the sodium chloride due to osmosis. (Sodium Chloride generates an osmotic pressure by pulling water across the membrane)
75
What can generate osmotic pressure?
Na+, Cl-, glucose, colloids, proteins
76
What is a colloid?
High molecular weight particle in the ECFUsually proteins
77
What are the two hydrostatic pressure?
Glomerular hydrostatic pressure and Bowmans space pressure
78
What is Glomelular (Capillary) Hydrostatic Pressure? (Pc)
As blood runs through the glomerulus it is under pressure and it exerts a pressure pushing out
79
What is bowmans hydrostatic pressure?
The pressure of the filterate in bowmans capsule pushing out. Opposes the glomerular hydrostatic pressure
80
What are the two oncotic pressures?
Glomerular colloid oncotic pressure
| Bowmans space oncotic pressure (should be very small)
81
In the renal corpuscle, where is the protein that exerts oncotic pressure?
It should be in the blood and not in bowmans space
82
What is capillary oncotic pressure? (symbol pi subscript c)
It is the pressure generated by protein in the blood pushing inward in the glomerulus
83
Why is the oncotic pressure small in bowmans space?
There is only a small amount of protein generating that pressure
84
What way does the oncotic pressure in bowmans space pull?
Out
85
What way does the hydrostatic pressure in bowmans space pull?
in
86
How do we calculate the net filteration pressure in the glomerulus?
Glomerular Hydrostatic Pressure - Bowmans capsule pressure (Hydrostatic) - Glomerular oncotic pressure
87
Given the following Starlings forces, what is the net pressure at the glomerulus? Bowmans space hydrostatic pressure = 24 mmHgCapillary Oncotic Pressure = 26 mmHgBowmans space oncotic pressure = 0 mmHgCapillary Hydrostatic pressure = 58 mmHg
58 mmHg - 24 mmHg - 26mmHg = 8mmHg
88
How does the kidney regulate the rate at which filtrate is generated? (Glomerular filtration rate)
The capillary hydrostatic pressure determines the glomerular filtration rate. If it increases so does the filtration rate.
89
How does the kidney increase or decrease the capillary hydrostatic pressure to change the glomerular filtration rate?
Constricting or dilating the arterioles controls how much blood can flow in and out of the glomerulus and then change the capillary hydrostatic pressure. (
90
Are arterioles a good conduit of blood alone?
No, they are small
91
What do the arterioles at the vascular pole of the renal corpuscle have that aid in changing the filtration rate?
Smooth muscle in their walls:If the smooth muscle tightens the arteriole constricts and less blood flows through (Pc decreases and filtration rate decreases)If the smooth muscle relaxes, the arteriole expands and more blood can go through.
92
What happens when the afferent arteriole constricts?
Pc decreases and GFR decreases
93
What are extra renal triggers?
They tell the kidney to adjust (constrict or dilate the afferent or efferent arterioles)
94
What is autoregulation?
When an organ detects a change and adjusts to correct it
95
How does the kidney autoregulate the GFR?
As systemic blood pressure increases more blood flows through the kidney and GFR increases but there is a range where the GFR and blood flowing in will not change even if the mean arteriole pressure increases or decreases
96
What is mean arterial pressure?
(x axis) systemic blood pressure
97
What is Renal Blood Flow?
(Y axis) How much blood is flowing through the kidneys
98
As Mean Arterial pressure increases blood flow ______ and GFR _________
As Mean Arterial pressure increases blood flow increases and GFR increases
99
As more blood flows into the glomerulus capillary hydrostatic pressure ______ and GFR_______.
increases, increases
100
What is the goal of renal autoregulation?
To keep blood flow and GFR steady even though systemic BP changes dramatically
101
Why does the kidney want to autoregulate?
1. Prevents mechanical damage to glomeruli caused by spiking BP2. Prevents fluctuations in BP from changing delivery of filtrate to nephron (maintain constant GFR despite changes in BP)
102
What would happen if the nephron became overwhelmed with the amount of filtrate generated?
It could lose some important components in the urine rather than reabsorbing them
103
What happens to blood pressure and renal blood flow during anesthesia?
BP fluctuates while renal blood flow stays steady (autoregulation)
104
What are the two mechanisms that the kidney autoregulates?
Myogenic mechanism
| Tubuloglomerular feedback
105
Describe the Myogenic mechanism
The afferant arteriole can sense if it should constrict or dialate based on if its smooth muscle is streched or relaxed and this adjusts the GFR
106
What happens when smooth muscle is stretched?
It contracts
107
T/F when smooth muscle is not stretched it is contracting
False, it is relaxed
108
If BP is high, the smooth muscle in the afferent arteriole will ________ , intracellular Ca+ will ______, vascular resistance will _________ and the arteriole will ______. Renal Blood flow will _____, _______GFR.
If BP is high, the smooth muscle in the afferent arteriole will stretch, intracellular Ca+ will increase, vascular resistance will increase and the arteriole will constrict. Therefore renal blood flow will decrease, decreasing GFR.
109
If BP is low, the afferent arteriole will ________ , intracellular Ca+ will ______, vascular resistance will _________ and the arteriole will ______. Renal Blood flow will _____, _______GFR.
If BP is low, the afferent arteriole will relax and dilate, intracellular Ca+ will decrease, vascular resistance will decrease . Renal Blood flow will increase, increasing GFR.
110
What is the response time of the myogenic mechanism?
1-2 seconds
111
What is the myogenic response to increased BP?
Afferant arteriole constricts
112
What is the trigger for Tubuloglomerular Feedback?
changing distal tubule fluid compositon
113
What is the response time for Tubuloglomerular Feedback to occur?
10-12 seconds (many more steps than the myogenic mechanism)
114
How does the Tubuloglomerular mechanism work?
The macula densa senses changes in the distal tubule fluid caused by fluctuations in the GFR and responds by changing the resistance of arterioles to correct the GFR by regulate the amount of blood
115
In the tubuloglomerular feedback mechanism of autoregulation what happens when the BP increases?
Normally a BP increase will increase Pc and GFR would then increase, due to the increase there is more filtrate. The macula densa senses the higher concentration of ions in the distal tubular fluid and transmit a signal to the wall of the afferent arteriole tell the smooth muscle to constrict and thus reduce the GFR
116
What does it mean when we say the GFR is increased?
More filterate is being dumped into the system.
117
In the tubuloglomerular feedback mechanism of autoregulation what happens when blood pressure is low?
GFR decreases normally due to lower capillary hydrostatic pressure. In the fluid at the distal tubule thereare less ions and the macula densa senses this. It then needs to increase GFR. The efferant arteriole constricts in the presence of angiotensin II released by renin and the afferent arteriole dilates when prostaglandin is sensed and GFR increases
118
What is the tubuloglomerular response to lower than expected solute concentration in the distal tubule?
GFR will be increased
119
What is reabsorption?
The movement of molecules in the tubular fluid accross the epithelial lining of the nephron back into the bloodstream via the peritubular capillary network
120
After going through the peritubular capillary network in the kidney where does the blood go?
Dumps into the renal vein to exit the kidney
121
What is the oppostite of reabsoption when talking about the kidney?
Secretion
122
What is the opposite of reabsoption when talking about the kidney?
Secretion
123
In the kidney, what is the luminal membrane>
Seperates tubular cell from tubular fluid
124
In the kidney, what is the basolateral membrane?
The other side of the cell, seperates the cell from the peritubuler interstitium
125
What is the goal of reabsorption?
To move stuff from the lumen of the tubular cells to the blood
126
What part of the cell directly interacts with the filterate produced in the kidney?
The luminal membrane
127
what are the pathways from the luminal membrane to the blood in kidney reabsorption?
Transcellular route and paracellular route
128
Describe the transcellular route in reabsorption
Reabsorption through the cytoplasm of tubular cells (Through cells)
129
Describe the paracellular route of reabsorption in the kidney
Reabsorption between tubular cells across tight junctions (Between Cells)
130
What pathway is used for the majority of reabsorption in the kidneys?
Transcellular
131
Define passive transport
#NAME?
132
What are the types of passive transport?
Diffusion and facilitated diffusion
133
What types of things move using facilitated diffusion?
molecules that don't easily cross biological membranes (Charge, polar (inbalance of charge) (Na, K, Mg, glucose)
134
What does facilitated diffusion require?
a transporter
135
What is a polar molecule?
A molecule with an uneven distribution of charge (Glucose)
136
What is active transport?
energy is required
137
What are the types of active transport?
Primary and Secondary
138
What is all reabsorbtion linked in some way to?
NaK+ ATPase
139
Where is Na K+ATPase located?
Basolateral membrane
140
Where is NaK+ATPase not located in the basolateral membrane in the kidney?
Loop of henle
141
Is there a difference in concentration of molecules that are found in the filterate vs. the molecules in the interstiticial fluid?
No there is no gradient
142
What makes the nephron tick?
The energy in NaKATPase
143
How many sodium and potassium molecules does NaK+ATPase move?
3 Na+ ions out and 2 K+ ions in
144
Does ATPase require energy?
Yes
145
What is the Na K+ATPase mechanism in the basolateral membrane in the kidney?
To pump 3 Na+ out energy is required because it is moving against its electrochemical gradient
146
What is the Na K+ATPase mechanism in the basolateral membrane in the kidney?
To pump 3 Na+ out energy is required because it is moving against its electrochemical gradient but since Na is going out an electrochemical gradient is generasted
147
What is the function of NaKATPase in tubular reabsorption?
Maintains low intracellular Na+ to establish the electrochemical gradient up which all reabsorption depends
148
Which of the following statements about Na+K+ATPase is correct?AIt transports Na+ and K+ at the luminal membrane of nephron epitheliaBIt moves 3 Na+ into the cells in exchange for 2 K+ out of the cellCNa+ movement is by facilitated diffusionCorrectDIt requires energy in the form of ATPEIt moves K+ paracellularly
D
149
What does the proximal tubule reabsorb?
67% of filtered water ,Na, and Solutes
99% of filtered glucose and Amino Acids
90% bicarbonate
150
What reabsorbs most water?
Proximal tubule
151
What can get secreted from the proximal tubule?
Bases, protons, organic acids
152
What special features do you find in the cells of the proximal tubule that tell you its function?
Brush Border-microvilli-increases surface area realitive to volume
Mitochondria-generates ATP
153
What part of the membrane has the brush border in the proximal tubule?
Lumen
154
What type of transport goes on in the proximal tubule?
Active-Mitochondria indicate that ATP is being made
155
Where is the Na K ATPase located in the cells at the proximal tubule?
Basolateral membrane
156
Describe the mechanism of action in the cells of the proximal tubule by where Na is reabsorbed
1. NaKATPase pumps 3 Na ions out which creates a concentration gradient at the lumen membrane of the cell. 2. This allows Na to enter the cell via facilitated diffusion at the lumenal membrane3. Sodium goes in and then is pumped out by NaKATPase (reabsorbed)
157
How does glucose enter the cell in the proximal tubule ?
#NAME?
158
Where do transporters move glucose and amino acids into the cell?
At the basolateral membrane
159
How to amino acids enter the cell at the proximal tubule?
Secondary active transport
160
What are Na proton exhangers?
a secondary transporter
161
How does water enter the cell at the proximal tubule?
It is pulled with sodium by osmosis by NaKATPase
162
In the first half of the proximal tubule, why does chloride concentration build up?
Water is leaving and chloride is staying in the tubular fluid
163
What happens to chloride concentration in the second half of the proximal tubule?
Since it built up in the first half, there is now a concentration gradient for chloride and so chloride can move between cells by simple diffusion paracellularly into the blood. This only happens because Water was reabsorbed and water can move because of Na ion reabsorbtion
164
What happens in the last part of the proximal tubule?
Cl- attracts Na+ paracellularly and more sodium is reabsorbed
165
What does the loop of henly reabsorb?
25% of filtered NaCl and 15% of filtered water
166
Where does water reabsorption occur in the loop of henle?
descending limb
167
In the loop of henly is NaCl reabsorption passive or active?
passive
168
Where is NacL reabsorped in the loop of henle?
ascending limb
169
Where does the descending limb of the loop of henle go?
to the medulla
170
Where does the ascending limb of the loop of henle go?
To the cortex
171
What part of the loop of henle is permeable to water?
Descending Limb
172
What part of the loop of henle is permeable to sodium and chloride?
Ascending
173
What type of reabsorption occurs at the loop of henle?
passive
174
What type of cells line the proximal tubule epithelium?
Low cuboidal
175
What type if cells line the loop of henle epithelialum?
Simple squamous Epitheilium
176
Is there mitochondria in the cells of the loop of henle?
not many as no energy is needed
177
Is Cl- absorbed paracellularly or transcellularly in the proximal tubule?
both-paracellularly at the proximal tubule and transcellularly at the loop of henle
178
How much water is reabsorbed at the distal tubule and collecting duct?
9-15%
179
How much NaCl is reabsorbed at the distal tubule and collecting ducts?
7%
180
What does water permeability depend on at the distal tubule and collecting duct?
ADH must be present
181
What cell type is found in the distal tubule?
cuboidal
182
What is the job of the nephron at the distal tubule and collecting duct?
Fine tuning
183
What is reabsorbed at the distal tubule?
Na, K, Cl, ions
184
What is secreted at the distal tubule?
protons
185
In the distal tubule what are features of the cell?
Smaller brush border, some mitochondria
186
What happens in the early part of the distal tubule (straight tubule)?
There is a very strong lumen postitve potential difference (fluid that runs is positively charged paracellularly) That repels other positively charged ions and they move paracellularly
187
In the straight distal tubule (early) what is the transcellular method of reabsorbtion at the Lumenal membrane?
NaKATPase moves Na out but there is another molecule called NaKCC2 that can move 1 ion of Na, 1 ions K and 2 ions of chloride into the cell. This is based on the movement of Na.
188
How is Cl- moved into the cell at the basolateral membrane?
Cl- channels
189
What happens in the convoluted distal tubule(late)?
NaKATPase works at the basolateral membrane and a sodium chloride symporter works at the luminal membrane moving sodium and chloride in and chloride is then reabsorbed via chloride channels at the basolateral membrane
190
What transports Na+ at the luminal membrane of the late distal tubule?
Na-Cl symporter
191
What type of cells are found in the collecting duct in the cortex?
Principal cells and intercalcated cells
192
What do principal cells absorb?
Na, K+ and some Cl-
193
What is the function of intercalcted cells found in the collecting duct
Move protons and Bicarbonate (regulate pH)
194
In the medullarly collecting duct what type of cells are found?
Only principal cells
195
What do principal cells look like?
Lighter in color cuboidal
196
Where do you find larger collecting ducts?
In the medulla
197
What is the major mechanism for reabsorbtion in the collecting duct?
Ions moved basically via channels at the luminal membrane along with NaK ATPase at work in the basolateral membrane
198
How is tubular reabsorption regulated?
1. Glomerulotubular balance
2. Starlings forces at the peritubular capillary bed
3. Hormones
199
How does Glomerulotubular balance work?
The more filterate dumped into proximal tubule, the more reabsorbed so as GFR increases, so does reabsorption
200
How do starlings forces at the peritubular capillary bed regulate reabsoption?
Normally promote reabsorption in the proximal tubule Changes in the capilarry pressure and osmotic capillary pressure will change reabsorbtion
201
How can hormones regulate reabsorption?
1. Increase activity
| 2. Increase the number of transporter molecules
202
Define Osmolarity
It is the concentration of osmotically active atoms per L of solvent.
203
What way does water move in the presence of a high osmolarity substance such as NaCl?
Toward the higher osmolarity substance
204
In the loop of henle where is it permeable to Na+ and impermeable to water?
ascending limb
205
In terms of osmolarity, what is the fluid leaving the proximal tubule defined as?
isoosmotic (300 MOsm/kg)
206
What creates an osmotic gradient in the distal straight tubule?
The active reabsorbtion of Na+. Water follows the Na+ as it is being reabsorbed leaving the descending limb passively (without the use of energy) of the loop of henle
207
Where does osmolality increase in the loop of henle?
The Medullary interstitium-Na+ leaves the ascending limb contributing to osmolality. It leaves passively
208
What happens in the hairpin loop in the loop of henle?
Water reabsorption has concentrated Na+ above interstitial concentration so now there is a Na+ gradient
209
In terms of osmolarity, how do you describe the fluid going into the distal tubules at the end of the loop of henle?
Hypoosmotic
210
Where are osmoreceptors located?
Hypothalamus
211
What do osmoreceptors do?
Shrink and swell to detect changes in osmolality
212
What do baroreceptors do?
Detect changes in plasma volume or pressure
213
What happens when ADH is low?
A high volume of dilute urine is produced
214
What happens when ADH is high?
Antidiuresis, where there is a low volume of concentrated urine produced
215
What preserves medulla hypeosmolarity?
The vasa Recta
216
What is an effective osmole?
It can generate osmotic pressure
217
In the descending limb of the loop of henle what is the osmolarity in side the limb when compared to the intersticial fluid?
It is lower inside the limb so water moves out to the intersticial fluid
218
What is countercurrent multiplication?
The thing in the loop of henle in the descending limb causes the opposite effect in the ascending limb
219
Which statement about physiology at the loop of Henle is true?
Na+ is reabsorbed passively at the descending limb
B Water is reabsorbed down an osmolarity gradient (low to high osmolarity)
CI nterstitial osmolarity decreases as you move deeper into the medulla
D Distal tubule fluid is hypertonic to insterstitium
B Water is reabsorbed down an osmolarity gradient (low to high osmolarity)
220
What are the triggers to produce ADH?
Low volume (Osmoreceptors detect shrinking) and Low pressure (Baroreceptors detect Pressure)
221
what is the PRIMARY determinent of the release ADH?
Osmoreceptor response
222
What is the response in the late distal tubule and collecting duct to ADH release?
1. Increase expression of aquaporins in the luminal membrane of the late distal tubule and entire collecting duct so water can be reabsorbed.2. Increase number of urea transporters in the luminal membrane of the medullary collecting duct so urea it is permeable to urea
223
What is the other word for ADH?
Vasopressin
224
Does ADH affect filteration in the nephron?
no
225
What happens when there is low ADH?
Diuresis and water is trapped in the distal tubule and collecting duct. A high volume of dilute urine is produced
226
What happens when ADH is high?
Antidiuresis-Water is reabsorbed and urine is concentrated
227
What is urea?
By product of protein metalbolism
228
Is urea an effective osmole in the collecting duct?
no just in the loop of henle
229
During diuresis, which of the following is true?AUrea reabsorption in medullary collecting duct is highBCollecting duct permeability to water is lowCWater reabsorption at loop is increasedDA small volume of urine is produced
BCollecting duct permeability to water is low
230
What is the vasa recta?
A group of capillaries around the late distal tubule and collecting duct
231
What is the function of the vasa recta?
To preserve medullary hyperosmolarity by keeping solutes
232
What is the main ECF ion?
Na+
233
What is changed by changing the amount of Na+?
ECF volume
234
What is changed by changing the concentration of Na+?
ECF osmolarity
235
What needs to be regulated to control the osmolarity and volume of the extracellular fluid?
ECF Na+
236
Where is most of the Na+ located in the body?
Extracellular (ECF)
237
Where does most of the K+ live in the body?
intracellularly
238
What do you find in the cell
Mg++,K+ , PO4, protein
239
Where do you find most Cl- in the body?
Extracellularly
240
Where do you find most bicarbonate?
Extracellularly
241
What is the derterminant of ECF osmolarity?
Na+ concentration
242
High ECF Concentration is called
Hypernatremia
243
What are the signs of hypernatremia?
Rupture of cerebral vesselsMuscle weaknessAtaxia,behavioral changeComa to death
244
What is low Na+ ECF Concentration called?
Hyponatremia
245
What are the signs of Hyponatremia?
Incoordination and seizures
246
What is concentration?
The amount of a specified substance (Na+) in a unit amount of another substance (water)
247
What detects change in ECF osmolarity
osmoreceptors in the pituitary gland
248
When there is high ECF osmolarity what do the osmoreceptors do?
Shrink
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What are the effects of osmoreceptor shrinkage
ADH release and Thirst Body, ADH is released and aquaporins are made thus reabsorption of water takes place and ECF osmolarity decreases
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What occurs when there is more ECF in volume?
Hypervolemia (ascites and pulmonary edema)
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What happens when ECF volume is too low?
Hypovolemia-Hypovolemic shock, organ damage
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What can cause a volume change in ECF?
Na+, Blood loss, vomiting, liver failure
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What do kidneys do to when it detects a volume change of ECF.
Regardless of cause, they change the amount of ECF Na+ to correct the volume
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Does the kidney regulate protein?
no, the liver
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What will be the effect of increasing extracellular fluid sodium concentration?AECF volume will go downBECF volume will go upCECF osmolarity will go downDECF osmolarity will go up
DECF osmolarity will go up
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Where is the thirst center in the brain?
Hypothalamus
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Which statement about hyponatremia is most accurate?AA hyponatremic individual will have high ECF Na+ concentrationBThere will likely be translocation of fluid from ECF into ICFCOsmoreceptors in hypothalamus will shrinkDADH release will be increasedEThe individual will feel thirsty
BThere will likely be translocation of fluid from ECF into ICF
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What is more serious hypervolemia or hypovolemia?
Hypovolemia
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How does the kidney detect volume change in the ECF?
1. Baroreceptors2. Juxtaglomerular Apparatus
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Where are baroreceptors located?
Heart (mostly right side), aorta, carotid sinus
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What do baroreceptors sense?
Stretch (increase in volume)
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When the baroreceptors stretch what is the response?
Sympathetic nervous system and natriuretic peptide release(decreases a high ECF volume)
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How does the juxtaglomerular Apparatus regulate ECF volume?
It has stretch receptors that stretch when ECF volume goes up.
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Where is the juxtoglomerular apparatus located?
By the afferant arterioles
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How does the juxtoglomerular apparatus increase a low ECF fluid?
The Renin-Angiotensin system
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How do we increase ECF volume?
When low ecf is detected the 1. sympathetic nervous system increases Na+ reabsorption ECF volume2. Increases GFR and Pic and Pc is reduced of the peritubular capillaries of the proximal tubule to increase rebsorbtion
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What does the sympathetic nervous system specifically do in when ecf volume is low?
norepinephrine constricts the efferant arteriole which builds capilary hydrostatic pressure within the glomerulus and the GFR increases promoting the movement of sodium back into the bloodstream
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What triggers the renin -angiotensin mechanism?
The afferant arteriole detects stretch and Low ECF volume triggers the release of renin from the juxtaglomerular cells
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What happens when renin is released?
Angiotensin II is increased and Na+ reabsorbtion is increased
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Describe the renin angiotensin mechanism
1. Angiotensinogen is produced in the liver and enters the blood stream2. When it encounters renin, renin cleaves angiotensenogen to angiotensin I 3. Angiotensin I sits in the blood stream until it encounters Angiotensen converting enzyme4. This enzyme cleaves it to angiotensin II
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Where is angiotensin converting enzyme produced?
In the lungs
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What does angiotensin II do?
1. Potent vasoconstrictor that changes starlings forces in peritubular capillaries2. Stimulate Aldosterone which increases Na+ reabsorbtion via NaK+Atpase
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Where is aldosterone found?
Adrenal gland
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How is ECF Volume decreased?
Natriuretic peptides inhibit the ways sodium can be reabsorbed and it promotes Na excretion through the urine
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What is the mechanism of natriuretic peptide release?
it inhibits renin-angiotensin II, aldosterone and Na+ channels in the collecting duct all decreasing renal Na+ reabsorption
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Which statement about hypovolemia is accurate?AIt is defined as high ECF volumeBIt is caused by low ECF Na+ concentrationCIn response, sympathetic flow to the kidneys is increasedDTo correct it, the Renin-Angiotensin system will be inhibitedSubmit
In response, sympathetic flow to the kidneys is increased
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Increased sodium_______ECF Volume
Increases
