Exam 3- Chapter 17 Flashcards
(204 cards)
1
Q
Kidney’s regulate the ____ ____ environment in the body including: (List 4)
A
- extracellular fluid
1. Volume of blood plasma (affecting blood pressure)
2. Wastes
3. Electrolytes
4. pH
2
Q
List the path urine made in the kidneys takes (using gross anatomy).
A
- Urine made in the kidneys pools into the renal pelvis
- Urine goes down the ureter
- Urine goes inside the urinary bladder
- Urine exits body through the urethra
3
Q
Urine is transported using ______.
A
Peristalsis
4
Q
What are the two distinct regions of the kidney?
A
- Renal cortex
2. Renal medulla
5
Q
What is the renal medulla made up of?
A
renal pyramids and columns
6
Q
List the path from the renal pyramid to the renal pelvis.
A
Each renal pyramid drains into a minor calyx —> major calyx—> renal pelvis
7
Q
What muscles line the wall of the urinary bladder?
A
Detrusor muscles
8
Q
What connects the smooth muscle cells in the wall of the urinary bladder?
A
Gap juncitons
9
Q
Are the detrusor muscles that line the wall of the urinary bladder innervated by sympathetic or parasympathetic neurons? What do these neurons release and on to what kind of receptors?
A
- Parasympathetic neurons
2. Release acetylcholine onto muscarinic ACh receptors
10
Q
What structures surround the urethra?
A
Sphincters surround urethra
11
Q
Is the internal urethral sphincter composed of smooth or skeletal muscle?
A
smooth muscle
12
Q
Is the external urethral sphincter composed of smooth or skeletal muscle?
A
skeletal muscle
13
Q
What is a nephron?
A
functional unit of the kidney
14
Q
How many nephrons does EACH kidney have?
A
Each kidney has more than a million nephrons
15
Q
What does a nephron consist of?
A
Nephron consists of small tubules and associated blood vessels
16
Q
Glomerular (Bowman’s) capsule surrounds what?
A
the glomerulus
17
Q
Together the Glomerular (Bowman’s) capsule surrounding the glomerulus make up what?
A
renal corpuscle
18
Q
Filtrate produced in the renal corpuscle passed into the what?
A
proximal convoluted tubule
19
Q
After the proximal convoluted tubule, where does filtrate pass into?
A
the descending and ascending loop of Henle
20
Q
After the descending and ascending loop of Henle, where does filtrate pass into?
A
distal convoluted tubule
21
Q
After the distal convoluted tubule, where does filtrate pass into?
A
collecting duct
22
Q
When filtrate is finally in the collecting duct, what is it called? List its path up until the renal pelvis.
A
- Urine
2. Minor calyx —-> Major calyx —> Renal pelvis
23
Q
What are the names of the two different types of nephrons?
A
- Juxtamedullary Nephrons
2. Cortical Nephrons
24
Q
Which type of nephron is better at making concentrated urine?
A
Juxtamedullary Nephrons
25
Capillaries of the glomerulus are ________.
fenestrated
26
Since the capillaries of the glomerulus are fenestrated this means it has ___ ___ in the wall.
large pores
27
Since the capillaries of the glomerulus are fenestrated (has large pores), what can and cannot leave?
Can leave the capillaries & come into the glomerulus:
1. Water
2. Solutes
Can't Leave the capillaries & can't come into the glomerulus:
1. Blood Cells
2. Plasma Proteins
28
What is the fluid that enters the glomerular capsule called?
Filtrate
29
Grossly describe the path of fluid from the capillaries of the glomerulus to the glomerular capsule.
1. Fluid is in the capillaries of the glomerulus
2. Fluid exits through large pores into the glomerulus
3. Fluid passes through the layers of the glomerular capsule into the capsule.
30
To fully enter the glomerular capsule, what 3 things must the filtrate pass through?
1. Capillary fenestrae
2. Glomerular basement membrane
3. Visceral layer of the glomerular capsule composed of cells called podocytes with extensions called pedicles
31
What are the cells that compose the visceral layer of the glomerular capsule called? What are their extensions called?
1. Podocytes
| 2. Pedicles
32
What are the slits in the pedicles that are the major barrier for the filtration of plasma proteins called?
slit diaphragm pores
33
What is the major barrier for the filtration of plasma proteins called?
slit diaphragm pores
34
Defect in the slit diaphragm pores causes what? What does this mean?
proteinuria = proteins in urine
35
Albumin is a blood protein. Does it get into the glomerular capsule? If yes, what happens?
Yes; but it is reabsorbed by active endocytosis
36
Fluid in glomerular capsule gets there via what 3 mechanisms?
1. Hydrostatic pressure of the blood
2. Colloid Osmotic Pressure
3. Very permeable capillaries
37
What is the Glomerular filtration rate (GFR)? What is the actual number? What is this equal to per day in liters and gallons?
1. volume of filtrate produced by both kidneys each minute
2. 115−125 ml
3. 180 L/50 gallons
38
The total blood volume is filtered every ____ minutes. When is most reabsorbed?
40/ immediately
39
_______ or _____ of afferent arterioles changes filtration rate.
Vasoconstriction/dilation
40
What is extrinsic regulation of filtration rate controlled by? Intrinsic?
1. Extrinsic regulation via sympathetic nervous system
| 2. Intrinsic regulation via signals from the kidneys; called renal autoregulation
41
Intrinsic regulation filtration rate is controlled by signals from the kidneys. What is this called?
renal autoregulation
42
In a fight/flight reaction, there is ______ of the afferent arterioles. The GFR (choose: increase or decrease)
1. vasoconstriction
| 2. decreases
43
In a fight/flight reaction, there is vasoconstriction of the afferent arterioles.
1. Is this extrinsic or intrinsic regulation of filtration rate?
2. What does the purpose of this?
3. Does urine formation increase or decrease?
1. Extrinsic
2. Helps divert blood to heart and muscles
3. Urine formation decreases
44
During renal auto regulation, when the BP fluctuates greatly, what happens to GFR?
GFR is maintained at a constant level even when blood pressure (BP) fluctuates greatly
45
Renal Autoregulation:
1. If BP < 70, afferent arterioles _____.
2. If BP > normal, afferent arterioles _____.
3. What is the purpose of these two mechanisms?
1. Dilate
2. Constrict
3. To make sure that GFR is maintained at a constant level
46
What are the two types of renal auto regulation?
1. Myogenic constriction
| 2. Tubuloglomerular feedback
47
How does renal auto regulation through myogenic constriction work?
Smooth muscles in arterioles sense blood pressure
48
Renal auto regulation through tubuloglomerular feedback :
1. Where are the cells that sense blood pressure located?
2. What are these cells called
3. What exactly do they sense
4. What is their response?
1. Cells in the ascending limb of the loop of Henle
2. Macula densa
3. Sense a rise in water and sodium as occurs with increased blood pressure (and filtration rate)
4. They send a chemical signal to constrict the afferent arterioles
49
If ether of the two form of auto regulation sense low BP will they constrict or dilate?
Dilate
50
Of the 180L of water filtered per day, how much in L is exerted in urine?
1-2L
51
Will the amount of actual water exerted in urine increase or decrease when well hydrated? Dehydrated?
1. Increase
| 2. Decrease
52
What is the minimum amount of water that must be exerted to rid the body of wastes? What is this called?
1. 400mL
| 2. Obligatory water loss
53
- 85% of reabsorption occurs in the ____ _____ and _____ _____ __ ____.
- Is this regulated or unregulated?
1. proximal tubules
2. descending loop of Henle
3. unregulated
54
How does the osmolality of filtrate in the glomerular capsule compare to that of the blood plasma?
they are equal
55
How is Na+ transported out of the filtrate into the peritubular blood?
via active transport
56
What is actively transported out of the filtrate into the peritubular blood? What is the purpose of this?
1. Na+
| 2. To set up a concentration gradient to drive osmosis
57
Cells of the proximal tubules are joined by ___ ____ on the apical side
tight junctions
58
The apical side of the cells of the proximal tubules are facing what? What is the opposite side called?
1. facing inside the tubule
| 2. basal side
59
Which side of the cells of the proximal tubules contain microvilli?
apical side
60
Do the cells on the walls of the proximal tubules have a higher or lower concentration of Na+ compared to the filtrate inside of the tubule? What is this due to?
1. Lower Na+ concentration
| 2. Due to Na+/K+ pumps on the basal side of the cells
61
What happens to the Na+ in the filtrate of the proximal tubules? What then happens?
1. Na+ from the filtrate diffuses into the cells on the wall of the tubule.
2. The Na+ is then pumped out the other side (to the interstitial fluid)
62
When the Na+ from the filtrate of the proximal tubules diffuses into the cells walls of the tubule is this active or passive transport? How about when it is then pumped into the interstitial fluid?
1. Passive because of the concentration gradient
| 2. Active via Na+/K+ pump
63
The pumping of sodium into the interstitial space attracts what out of the filtrate?
negative Cl− out of the filtrate
64
What follows Na+ and Cl− into the tubular cells and the interstitial space?
Water via osmosis (following natural gradient from high to low concentration of water)
65
Osmosis makes water travel from a ___ concentration of water to a ___ concentration of water.
High ---> Low
66
When the water, Na+ and Cl- are in the interstitial what happens?
They diffuse into the peritubular capillaries
67
Is the process of the Cl- following Na+ into the interstitial fluid active or passive transport?
Passive
68
1. After the water, Na+ and Cl- have diffused into the peritubular capillaries, how much is the proximal convoluted tubular fluid reduced by?
2. How as its relationship to the blood plasmas osmolality changed, and explain this.
3. Is the plasma membrane permeable to water and salts?
1. Reduced by 1/3
2. Still isosmotic because as long as the water is leaving with the salts the osmolality has not changed
3. Plasma membrane is freely permeable to water and salts
69
How much more water is reabsorbed at the descending Loop of Henle, after the 1/3 reabsorbed at the proximal convoluted tubule?
20%
70
Is the water reabsorption regulated? If yes, explain why. If not explain how it is controlled.
NO; happens continuously and is unregulated
71
So far, 85% of water reabsorption has occurred after the filtrate leaves the descending loop of henle. Where/ and in what control is the other 15% under?
The final 15% of water (~27 L) is absorbed later in the nephron under hormonal control
72
1. How much water is reabsorbed in the proximal convoluted tubule/how is it regulated?
2. How much water is reabsorbed in loop of Henle/how is it regulated?
3. How much water is reabsorbed after the loop of henle (also say the amount in L)/how is it regulated?
1. 1/3 ( about 35%)/unregulated
2. 20%/unregulated
3. 15% (27L)/ regulated under hormonal control
73
How does the fluid entering loop of Henle compare to the osmolality of the extracellular fluids?
isotonic to extracellular fluids
74
1. When fluid is entering the descending loop of Henle, what is the problem with reabsorption?
2. What is a solution for this and what allows it?
3. What portion of the Loop of Henle sets this gradient up?
1. Water cannot be actively pumped out of the tubes, and it will not cross if isotonic to extracellular fluid
2. A solution is to have a concentration gradient to be set up for the osmosis of water. The structure of the loop of Henle allows for this.
3. Ascending potion
75
Very generally state how the ascending Loop of Henle will set up the concentration gradient up for the osmosis of water.
Salt (NaCl) is actively pumped into the interstitial fluid
76
1. What is the first step that takes place as the ascending Loop of Henle will set up the concentration gradient up for the osmosis of water? Second step?
1. Movement of Na+ down its electrochemical gradient from filtrate into tubule cells powers the secondary active transport of Cl− and K+.
2. Na+ is moved into the interstitial space via Na+/K+ pump
3. Cl− follows Na+ passively due to electrical attraction
4. K+ passively diffuses back into filtrate
77
In the first step that takes place as the ascending Loop of Henle sets up the concentration gradient up for the osmosis of water; Why does Na+ move from the filtrate into the tubule cells in the first place?
Because of the Na+/K+ pump, there is a lesser concentration of Na+ in the cells vs. the filtrate. This means the Na+ will move into the cells to lessen this difference.
78
In the first step that takes place as the ascending Loop of Henle sets up the concentration gradient up for the osmosis of water; Is the secondary active transport of Cl− and K+ symport or antiport? Explain why.
Symport because they are moving in the same direction
79
In the fourth step that takes place as the ascending Loop of Henle sets up the concentration gradient up for the osmosis of water; Why does K+ passively diffuse back into filtrate?
There is a high concentration of K+ inside the cell due to the Na+/K+ pump thus, the K+ will move outside the cell and into the filtrate.
80
What is the end result of the actions of the ascending Loop of Henle to set up the concentration gradient up for the osmosis of water?
1. Na+ and Cl- are now in the interstitial fluid making it much more concentrated
2. K+ is passively diffused back into the filtrate
81
Can osmosis occur from the ascending Loop of Henle? Explain why or why not.
NO because the walls are not permeable to water!
82
Is the ascending Loop of Henle permeable to water or salt?
Salt/NOT water
83
Is the descending Loop of Henle permeable to water or salt?
Water/NOT salt
84
After the the ascending Loop of Henle set up the concentration gradient up for the osmosis of water, in what direction is the interstitial fluid becoming increasingly solute concentrated in?
Surrounding interstitial fluid becomes increasingly solute concentrated at the BOTTOM of the tube
85
Tubular fluid entering the descending loop of Henle becomes more _____ as it descends the loop
hypotonic
86
Tubular fluid entering the descending loop of Henle becomes more hypotonic as it descends the loop. Why?
The fluid has the same osm as the interstitial fluid BEFORE the ascending loop set up a gradient. The interstitial fluid is now becoming more increasingly solute concentrated as it reaches the bottom. This means the tubular fluid is becoming more hypotonic (as compared to the interstitial fluid) as it descends the loop.
87
When tubular fluid enters the descending loop of Henle what happens?
Osmosis; water is drawn out of the filtrate and into the interstitial space
88
In the descending loop of Henle, after water is drawn out of the filtrate and into the interstitial space what happens?
it is quickly picked up by capillaries
89
As the fluid in the descending loop of henle descends (AS OSMOSIS IS OCCURRING) the fluid becomes more solute concentrated. Why?
Since it is more hypotonic as it descends, the more it descends the more strongly osmosis will occur. As more water is leaving it is becoming more solute concentrated.
90
As the fluid in the descending loop of henle descends, the fluid becomes more solute concentrated. What is this perfect for?
salt transport out of the fluid in the ascending portion
91
What does "Countercurrent Multiplication" refer to?
Positive feedback mechanism is created between the two portions of the loop of Henle.
92
1. The more salt the ascending limb removes, the ____ the fluid entering it will be
2. What is this due to?
3. Is this positive or negative feedback?
4. What is this mechanism referred to as?
1. Saltier
2. Due to loss of water in descending limb
3. Postive
4. Countercurrent Multiplication
93
What are the specialized blood vessels around loop of Henle, which also have a descending and ascending portion's called?
Vasa Recta
94
What mechanism do the vasa recta help in?
Countercurrent Multiplication System
95
What is the goal of the vas recta in helping the countercurrent multiplication system? How do they accomplish this?
1. Keep salts in the interstitial space
| 2. They take in salts in the descending region but lose them again in the ascending region
96
What is urea?
waste product of protein metabolism
97
What system does urea contribute to?
countercurrent system
98
What is urea transported out of and into what? What does it then diffuse into? What is the purpose of this?
1. Transported out of collecting duct and into interstitial fluid
2. Diffuses back into ascending limb and cycles around continuously
3. Helps set up solute concentration gradients
99
What is the last stop in urine formation?
Collecting duct
100
Can water leave in the collecting duct?
YES
101
Is the collecting duct also influenced by hypertonicity of interstitial space?
YES
102
By what means will water leave the collecting duct if it is capable to?
Osmosis
103
What does the permeability to water of the collecting ducts membrane depend on?
depends on the number of aquaporin channels
104
What is the availability of aquaporin channels in the membrane of the collecting duct controlled by?
ADH
105
What secretes ADH? What tells it to secrete ADH?
1. Posterior pituitary
| 2. Osmoreceptors in the hypothalamus
106
High osmolality of blood plasma means what? What can this be called?
1. High solute/Less water
| 2. Dehydration
107
Low osmolality of blood plasma means what? What can this be called?
1. Less solute/A lot of water
| 2. Very well hydrated
108
If the Osmoreceptors in the hypothalamus detect a high osmolality (high solute/less water):
1. Is ADH secretion increased or decreased?
2. Effect on urine volume?
3. Effect on blood volume & osmolality?
1. Increased
2. Decreased
3. Increased volume (water retention) and decreased osmolality
109
If the Osmoreceptors in the hypothalamus detect a low osmolality (low solute/more water):
1. Is ADH secretion increased or decreased?
2. Effect on urine volume?
3. Effect on blood volume & osmolality?
1. Decreased
2. Increased
3. Decreased volume (water lost) and increased osmolality
110
What receptors detect blood osmolality? What receptors detect blood volume?
1. Osmoreceptors in the hypothalamus
| 2. Stretch receptors in left atrium
111
If the stretch receptors in the left atrium detect a high blood volume:
1. Is ADH secretion increased or decreased?
2. Effect on urine volume?
3. Effect on blood volume & osmolality?
1. Decreased
2. Increased
3. Decreased volume (water lost) and increased osmolality
112
If the stretch receptors in the left atrium detect a low blood volume:
1. Is ADH secretion increased or decreased?
2. Effect on urine volume?
3. Effect on blood volume & osmolality?
1. Increased
2. Decreased
3. Increased volume (water retention) and decreased osmolality
113
Is the role of ADH is blood volume/osmolality a positive or negative feedback loop?
Negative
114
How does ADH make aquaporin channels available in the collecting duct?
1. ADH binds to receptors on collecting duct cells
2. cAMP
3. Protein kinase
3. Vesicles with aquaporin channels fuse to plasma membrane
115
Without ADH what happens to the aquaporins (water channels) in the collecting duct
They are removed
116
ADH uses _______ to make the aquaporin channels available in the collecting duct
Exocytosis
117
ADH uses _______ to take away the aquaporin channels in the collecting duct
Endocytosis
118
Kidneys must also remove excess ions and wastes from the blood. This is called what?
renal plasma clearance
119
What is renal plasma clearance (kidneys removing excess ions and wastes from the blood) accomplished by?
secretion
120
What is the opposite of reabsorption?
secretion
121
What begins the secretion process? When is the secretion processed finished?
1. Filtration in the glomerular capsule begins this process
| 2. When substances are moved from the peritubular capillaries into the tubules
122
What is the excretion rate equation? Explain it.
Excretion rate = filtration rate + secretion rate – reabsorption rate
(we don't count reabsorption rate because its obviously not being excreted)
123
What is the excretion rate used to measure? What is it an indicator of?
Used to measure glomerular filtration rate (GFR), an indicator of renal health
124
Define Xenobiotics.
Molecules foreign to the body
125
How is the secretion of drugs accomplished?
Membrane carriers specific to foreign substances transport them into the tubules
126
What are the membrane carriers used in the secretion of drugs called?
Organic anion transporters (OATs) or organic cation transporters (OCTs)
127
Is the secretion of drugs fast or slow? What is a problem with this?
Very fast; may interfere with action of therapeutic drugs
128
What is inulin found in?
found in garlic, onion, and artichokes
129
What is inulin a great marker of? Why?
1. Great marker of glomerular filtration rate
| 2. Because it is filtered but not reabsorbed or secreted
130
State the GFR Equation. What does each variable indicate.
GFR = V * U/P
- V= rate of urine formation
- U= inulin concentration in urine
- P= inulin concentration in plasma
131
What exactly is the renal plasma clearance?
Volume of plasma from which a substance is completely removed by the kidneys in 1 minute
132
If only inulin is filtered the renal plasma clearance is the same as the what?
GFR
133
Anything that can be reabsorbed has a clearance __ GFP..
less than
134
If a substance is filtered and secreted, it will have a clearance __ GFR.
greater than
135
Renal plasma clearance uses same formula as what?
GFR
136
What is PAH?
Exogenous molecule injected for measurement of total renal blood flow
137
How can PAH measure total renal blood blow?
- All PAH in the peritubular capillaries will be secreted by OATs
- The time it takes to clear all PAH injected indicates blood flow to these capillaries
138
Glucose and Amino Acids are _____ filtered out in the glomerular capsule.
Easily
139
Are glucose and amino acids supposed to be exerted in the urine or are they supposed to be reabsorbed back into the blood?
reabsorbed back into the blood
140
How is gluocse/amino acids completely reabsorbed?
1. via secondary active transport with sodium into the proximal tubular cells
2. facilitated diffusion into the interstitial fluids
3. simple diffusion into the capillaries
141
Where in the nephron are gluocse/amino acids completely reabsorbed?
Proximal convoluted tubule
142
When glucose is being secondary actively transported with Na+, which form of secondary transport is this?
Contratransport/Symport
143
Contratransport/Symport vs Countertransport/Antiport secondary transport
1. Contratransport/Symport: same direction
| 2. Countertransport/Antiport: opposite direction
144
Glucose/Na+ cotransporters have a transport maximum. What does this mean?
If there is too much glucose in the filtrate, it will not be completely reabsorbed
145
What is glucose in the urine called? What is this a sign of?What does this say about the amount of glucose in the filtrate?
1. Glycosuria
2. Diabetes mellitus
3. Amount of glucose in filtrate exceeds the transport maximum of Glucose/Na+ cotransporters
146
Besides, diabetes mellitus, what will extra glucose in the blood also result in?
decreased water reabsorption and possible dehydration
147
Kidneys match electrolyte (Na+, K+, Cl−, bicarbonate, phosphate) excretion to _____.
ingestion
148
Control of Na+ levels is important in what?
blood pressure and blood volume
149
Control of K+ levels is important in what?
healthy skeletal and cardiac muscle activity
150
_____ plays a big role in Na+ and K+ balance
Aldosterone
151
How does the body conduct the assessment of its needs in terms of K+ and Na+? Is this regulated?
1. About 90% of filtered Na+ and K+ is reabsorbed early in the nephron
2. NO
152
After about 90% of filtered Na+ and K+ is reabsorbed early in the nephron, what happens?
An assessment of what the body needs is made, and aldosterone controls additional reabsorption of Na+ and secretion of K+ in the distal tubule and collecting duct
153
After the body determines how much additional reabsorption of Na+ and secretion of K+ is needed, where is it carried out and by what hormone?
1. Distal tubule and collecting duct
| 2. Aldosterone
154
What is the general function of aldosterone?
Increases the RETENTION of sodium and water & increases the EXCRETION of potassium
155
Aldosterone-dependent response: What triggers the release of aldosterone? What releases the aldosterone?
1. Increase in blood K+
| 2. Adrenal cortex
156
What happens when the aldosterone-dependent response is activated?
1. Aldosterone is secreted by adrenal cortex
2. This increases K+ secretion in the distal tubule and collecting duct
3. More K+ is exerted into the urine
157
Where is the Juxtaglomerular Apparatus located?
Located where the afferent arteriole comes into contact with the distal tubule
158
How does a decrease in Na+ affect blood volume/pressure?
A decrease in plasma Na+ results in a fall in blood volume/pressure
159
What is the decrease in Na+ resulting in a fall in blood/pressure sensed by?
juxtaglomerular apparatus
160
A decrease in plasma Na+ results in a fall in blood volume, which is senses by the juxtaglomerular apparatus. What 4 things happen next?
1. Granular cells secrete renin into the afferent arteriole
2. Converts angiotensinogen into angiotensin I
3. Angiotensin-converting enzyme (ACE) converts this into angiotensin II
4. Angiotensin II stimulates adrenal cortex to make aldosterone
161
What Converts angiotensinogen into angiotensin I?
Renin
162
What converts angiotensin I into angiotensin II?
Angiotensin-converting enzyme (ACE)
163
Angiotensin II stimulates adrenal cortex to make aldosterone. What 3 things happen next?
1. Promotes the reabsorption of Na+ from cortical collecting duct
2. Promotes secretion of K+
3. Increased blood volume and raised blood pressure
164
Where does the reabsorption of Na+ after angiotensin II has stimulated the adrenal cortex to make aldosterone take place?
cortical collecting duct
165
Low salt levels result in lower blood volume due to inhibition of ADH secretion. Explain this.
Low salt levels ----> Low osm ----> ADH secretion DECREASED -----> less water absorbed in collecting ducts/ more water exerted in urine ---> blood volume lowered
166
When dealing with the regulation of renin secretion, what is low blood volume detected by? How do they respond?
1. Granular cells that act as baroreceptors
| 2. Respond by secreting renin
167
Besides low blood volume, what is another way granular cells are stimulated?
sympathetic innervation from the baroreceptor reflex
168
What is the macula densa?
Part of the distal tubule that forms the juxtaglomerular apparatus
169
What is the macula densa a sensor for?
Sensor for tubuloglomerular feedback needed for regulation of glomerular filtration rate
170
Review:
1. When there is more Na+ and H2O in the filtrate what does the macula densa do?
2. What type of regulation of GFR is this? (be specific)
3. Negative or positive feedback? Explain how. (hint: why is this happening)
1. Sends signal to the afferent arteriole to constrict, which limits filtration rate
2. Intrinsic Control: Renal autoregulation: Tubuloglomerular feedback
3. Negative (need to keep GFR the same even if BP goes up in this case, or down)
171
The macula densa sends signal to the afferent arteriole to constrict, which limits filtration rate.
1. How does this affect Na+ reabsorption?
2. How does this affect Na+ levels in blood?
1. This results in less reabsorption of Na+, allowing more to be excreted
2. This helps lower Na+ levels in the blood
172
When is release of Atrial Natriuretic Peptide/Hormone increased? What senses this?
- Increases in blood volume also increase the release of atrial natriuretic peptide hormone
- Atria of the heart when atrial walls are stretched
173
What does release of atrial natriuretic peptide hormone cause?
Kidneys to excrete more salt, thus lowering blood volume
174
Reabsorption of Na+ (Na+ going back into blood) stimulates the secretion of other ____ ____.
positive ions
175
Reabsorption of Na+ stimulates the secretion of other positive ions. What competes?
K+ and H+ compete
176
Acidosis stimulates the secretion of and excretion of ___ and inhibits the secretion of __ ions.
1. H+
| 2. K+
177
Acidosis can lead to what?
hyperkalemia
178
Alkalosis stimulates the secretion and excretion of more__.
K+
179
Kidneys maintain blood pH by reabsorbing ______ and secreting ___. This means urine is _____.
1. bicarbonate
2. H+
3. acidic
180
_____ ____ uses Na+/H+ pumps to exchange Na+ out and H+ in.
Proximal tubule
181
Proximal tubule uses Na+/H+ pumps to exchange Na+ ___ and H+ __.
1. out
| 2. in
182
What is some of the H+ brought in the tubules used for, while the rest is extruded?
Some of the H+ brought in is used for the reabsorption of bicarbonate
183
How does H+ in the tubule cells aid in the reabsorption of bicarbonate? (5 steps)
1. Bicarbonate is in the filtrate and cannot cross the inner tubule membrane but CO2 can
2. Must be converted to cabonic acid by reacting with H+
3. Carbonic acids turns into CO2 and H2O using carbonic anhydrase.
4. When CO2 crosses the inner membrane and is inside the sell the reaction reverses and it is now bicarbonate
5. Bicarbonate diffuses into the interstitial space
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Why do we need some H+ in the filtrate tubule cells for the reabsorption of bicarbonate?
Bicarbonate cannot cross the inner tubule membrane but CO2 can and we need H+ to change it back and forth
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Before bicarbonate is reabsorbed, where is it located? Where is H+ located? What happens with H+ in the tubular cells as bicarbonate is reacting back and forth?
1. Filtrate
| 2. Filtrate (produced in the tubular cells when the reverse rxn takes place)
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Nephrons cannot produce urine with a pH below ___.
4.5
187
Since nephrons cannot produce urine with a pH below 4.5, what must happen to increase H+ secretion, without making the pH too acidic?
To increase H+ secretion, urine must be buffered
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What buffers the urine?
Phosphates and ammonia buffer the urine.
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How does phosphate enter the urine? How does ammonia enter?
1. Filtration
| 2. Deamination of amino acids
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What are diuretics clinically used for?
Used clinically to control blood pressure and relieve edema
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What is edema?
fluid accumulation
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How do diuretics effect:
1. Urine volume
2. Blood volume
3. Interstitial volume
1. Increase
2. Decrease
3. Decrease
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What do potassium-sparing diuretics do?
Aldosterone antagonist; block reabsorption of Na+ and secretion of K+
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What happens with acute renal failure?
Ability of kidneys to regulate blood volume, pH, and solute concentrations crashes in a matter of hours/days
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What is acute renal failure due to?
Usually due to decreased blood flow through kidneys
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Acute renal failure is usually due to decreased blood flow through kidneys, which can be due to what 3 things?
1. Atherosclerosis of renal arteries
2. Inflammation of renal tubules
3. Use of certain drugs (NSAIDs)
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What is glomerulonephritis?
Inflammation of the glomerulus
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What type of disease is glomerulonephritis?
autoimmune disease
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What can result from glomerulonephritis?
Many glomeruli are destroyed, and others are become more permeable to proteins. The loss of proteins from blood reduces blood osmotic pressure and leads to EDEMA
200
Renal Insufficiency is what?
Any reduction in renal activity
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What 4 things can cause renal insufficiency?
1. glomerulonephritis
2. diabetes
3. atherosclerosis
4. blockage by kidney stones
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What can renal insufficiency lead to?
1. High blood pressure
2. High blood K+ and H+
3. Uremia (urea in blood)
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What is uremia?
urea in blood
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How are patients with uremia treated?
placed on a dialysis machine to clear blood of these solutes
