Test 1 - Renal Physiology Flashcards
1
Q
What are the structures that make up the urinary system?
A
- Kidneys
- Ureters
- Urinary Bladder
- Urethra
2
Q
What components of the urinary system do little to change the volume and composition of urine?
A
Ureters, urinary bladder, and urethra.
Not physiologically interested in these structures.
3
Q
What are the functions of the kidney?
A
- Regulation and maintenance of plasma composition within homeostatic norms. - Trying to make perfect plasma.
- Regulation and maintenance of blood volume and pressure.
- Conversion of 25 hydroxycholecalciferol (exported by the liver) to 1,25 dihydroxycholecalciferol (calcitriol); sometimes referred to as active Vitamin D3) by 1, alpha, hydroxylase
- Catabolism (e.g., of parathyroid hormone)
- Gluconeogenesis
- Synthesis of erythropoietin
- Synthesis of creatine (requires the liver as well)
4
Q
What mechanisms are used to regulate and maintain plasma composition with homeostatic norms?
A
- Filtration
- Secretion
- Reabsorption
- Excretion
5
Q
What are the renal components of volume and pressure homeostasis?
A
- Juxtaglomerular (JG) cells of the afferent arteriole
- Mesangial cells (myofilamentous, phagocytic cells)
- Podocytes (visceral epithelium of Bowman’s Capsule)
- Renin (a circulating enzyme produced by JG cells)
- Macula densa (cells of the distal tubule)
This is a network of communication that influences how much is secreted/reabsorbed.
6
Q
What does renal physiology refer to specifically?
A
ONLY kidney. The majority of the physiology goes on in the kidney. Once the waste product (urine) leaves the kidney, not much is done to change its composition. Since they do not secrete/absorb or change the volume, physiologically we are not interested in them.
7
Q
At what point of the urinary system is fluid considered to outside the body?
What is this fluid?
A
As soon as fluid is pushed through the filter and enters Bowman’s space.
This is filtrate of blood.
8
Q
Kidneys receive close to _____% of total cardiac output even though they constitue only ____% of the total body mass.
A
20%
0.5%
9
Q
In what direction does fluid flow?
A
From high pressure to low pressure. E.g. pressure in bowman’s space is greater than the pressure in the convoluted tubule.
10
Q
What is the flow of blood through renal vasculature?
A
Aorta → Renal Artery → Interlobar Artery → Arcuate Artery → Interlobular Artery → Afferent Arteriole → Glomerulus → Efferent Arteriole → Peritubular Capillaries (cortex) → Vasa Recta (medulla) →
Intralobular Vein → Arcuate Vein → Interlobar Vein → Renal Vein → Caudal Vena Cava
11
Q
What are components of the ductular network?
A
Glomerular Cabsule (Bowman’s Capsule)
Proximal Tubule
Loop of Henle (Descending Limb, Ascending Limb)
Distal Tubule
Collecting duct (Cortical and medullary)
12
Q
How often is fluid being filtered through the kidney?
How often is urine being produced?
A
Blood is always flowing through the kidney, and is therefore, always being filtered.
Urine is being produced all of the time.
13
Q
Explain the process of emptying the bladder.
A
This is a reflex.
The bladder fills and causes stretching
Stretching sends a signal to the spinal cord
Subsequent signal is sent to contract the detrusor m.
Internal and external sphinchters need to be working synergistically.
14
Q
What happens when the urinary sphincters are not working synergistically and how can you treat this?
A
Urine cannot escape.
Treat with medication.
15
Q
What structures alter the composition/volume of urine through reabsorption and secretion?
Where in the urinary system are they found?
A
Proximal Convoluted tubule
Distal Convoluted Tubule
Connecting segment
Loop of Henle
Cortical/medullary ducts
These structures are found in the kidney only!
16
Q
True/False:
Only waste product escapes through the filter.
A
FALSE.
Important substances escape as well such as glucose, ions/electrolytes (sodium, chloride, potassium), organic molecules (amino acids, VFAs) etc. If the filter was designed to keep these substances out, then nothing would get out because of size.
17
Q
Glucose should _______ (always, never, sometimes) be seen in the urine.
A
NEVER.
If glucose is seen in urine, then something is wrong!
18
Q
True/False
Cells NEVER get through the filter under normal conditions.
A
TRUE.
This includes RBCs, WBCs, platelets.
19
Q
What hapens if an organ does not have blood flowing to it?
A
- It will not receive the nutrients/oxygen to perform its job
- It will collect waste and die from toxicity
20
Q
True/False.
Renal perfusion varies with cardiac output. That is, if cardiac output increases, they receive more blood and if it decreases they receive less blood proportionally.
A
FALSE.
Kidneys want 20% of the NORMAL cardiac output. If cardiac output increases/decreases, they will receive 20% of the original amount. Or at least try their hardest to. This is because the kidneys have a lot of work to do ALL OF THE TIME and needs to do it aerobically. It does increase, but the autoregulation of the kidney blunts the effects.
21
Q
Since the kidney is receiving 20% of CO, what does this say about the functions of the kidney?
A
This means that the functions of the kidney require a lot of energy. However, not all of the functions require the same amount of energy.
22
Q
A dog gets hit by a car and is hemorrhaging. What happens to
- Blood Pressure
- Cardiac Output
- Oxygen/nutrient delivery to tissues
- Waste at tissues
What are the measures of compensation?
A
- Decreases
- Decreases
- Decreases
- Increases
Compensation
- clot begins
- Stimulation of erythropoiesis
- increase thirst to increase blood volume through Angiotensin II
- ADH release - water retention
23
Q
What happens during renal shutdown?
A
No urine is being produced. This is ALWAYS alarming. Once urine starts to be produced, then the blood volume and blood pressure have increased.
24
Q
What are components of Blood Pressure?
A
Heart Rate
Contractility
Tone of the Vessels
Blood Volume - if there is no blood, there is no pressure.
**These vary to maintain homeostasis. If all are correct then there is normal blood pressure.
25
Why do we need to urinate?
Remove waste
Maintain Blood Pressure - too much water is waste
26
What happens during drowning?
Urine output is mostly water because there is too much.
It still has waste molecules in it - there is the same rate of waste removal except for water.
Signals tell the kidney to alter the reabsoption of water.
27
True/False
Filtration requires energy.
FALSE.
Only creation of the filter and reabsorption require energy.
28
The rate of waste excretion should be ______ (more, less, the same) as the rate of waste production.
The Same
29
The kidney's role in water balance and urine production are ________ (fixed/variable).
Variable.
It adjusts with the needs of the body (waste, blood pressure, hydration status etc)
30
Describe the plasma entering the afferent arteriole vs. what is leaving through the efferent arteriole.
* Volume has decreased
* Not all of the fluid going to Bowman's space
* It is still carrying waste, which can be secreted into the lumen while important substances are reabsorbed.
* The plasma leaving will eventually go to the peritubular capillaries to provide oxygen and nutrients to the endothelial cells of the tubes.
31
Which of the following processes require energy?
Filtration
Secretion
Reabsorption
Secretion
Reabsorption
32
True/False
All blood that enters glomerular capillaries gets filtered.
FALSE.
Only 1/5-1/3 gets filtered. If all of it got filtered, it would be sludge.
33
What needs to occur before water will move down it's concentration gradient? What is the most important solute during osmosis?
Through the movement of solutes first, which requires energy. The most important solute in this process is Sodium because it is the most abundant.
34
Blood volume ________ (always, never, sometimes) decreases after it reaches the kidney.
ALWAYS.
This is because waste needs to be removed and it is carried by water.
35
What part of the autonomic innervation does the kidney receive?
Mostly SNS. Virtually no PSNS.
36
How many times is plasma filtered?
Plasma is filtered twice.
At the glomeurulus and at the peritubular capillaries through secretion/reabsorption
37
Reabsorption vs. Secretion
During each, transporters are taking substances within the cell and moving across to the other membrane.
Reabsorption: Take things from the filtrate and put it back into the interstitium
Secretion: Take waste from the interstitium and place it into the filtrate.
38
What kind of control is the kidney under? Give examples of each.
1. Hormonal: Cortisol, ADH, Aldosterone, ANP, Angiotensin II
2. Nervous system/Neurotransmitters - Autonomic (NE), virtually no PSNS and reflex. alpha1 on arteriolar smooth muscle; beta1 on JG cells
39
The ______________ is the longest section of the nephron. This means that it does the most work.
Proximal tubule
40
What are the two types of capillaries found in the kidney?
Glomerular Capillaries
Peritubular capillaries
Vasa Recta (subset of peritubular capillaries that go around the loop of Henle)
41
True/False
Plasma composition is always changing because the kidney is taking out waste.
FALSE.
Plasma composition is maintained within homeostatic limits. Waste, amongst other things, are being removed at the same rate they are being added. Therefore, the kidney is trying to make plasma perfect.
42
What is the molecule that plants create that is similar to cholesterol? Is it edible?
Ergosterol. Yes.
43
Describe the pathway to the creation of Calcitriol.
1. Cholesterol/Ergosterol is converted to an intermediate through a wavelength of light that is found in sunlight.
2. This is put into the blood stream where the liver has an enzyme that recognizes it.
3. This enzymes adds a -OH group to create
_1,25 dihydroxycholecalciferol_
4. This intermediate enters the bloodstream until it reaches the kidney where another -OH group is added. Now it is a the triol known as calcitriol.
5. Calcitriol is not always mdae. PTH needs to stimulate the kidney to convert the intermediate into calcitriol. if not an impotent molecule is created.
44
What is erythropoietin and decribe its synthesis. What is the main organ that produces it and how much do other organs produce EPO?
EPO is a protein hormone that stimulates RBC production.
Receptors are found in the bone marrow
Other organs produce EPO but the amount is relative to the kidney.
Fibroblasts in the cortex produce EPO in response to insufficient oxygen reaching the proximal tubule.
Kidney damage causes compromise in RBC production, lower hematocrit, which leads to anemia.
45
What is the intermediate in the creation of calcitriol?
Vitamin D. It has no function on its own.
46
What is the function of calcitriol?
Calcitriol is a steriod hormone involved in the regulation of calcium.
PTH is produced when there is not enough Calcium. It signals the kidney to produce calcitriol, which in turn alters the reabsorption of calcium. It can pass throuh the bilayer and get into all cells.
47
What is the functon of PTH?
Increase calcium by activating osteoclasts, turning off osteoblasts, signaling the kidney to produce calcitriol, and telling the kidney to reabsorb more calcium.
48
What can happen in regards to PTH signalling if the kidneys get sick?
What is another scenario that this can happen?
When there is not sufficient uptake of calcium because the kidney is sick, there will be increased PTH production, which increases bone degradation. This can also happen if the parathyroid is overproducing PTH.
49
What are the two cells that perform Gluconeogenesis?
Hepatocytes
Proximal Tubular cells
"When glucose levels decrease, who you gonna call? THE LIVER AND THE KIDNEY!"
50
Where is the only place that filtration occurs and why?
In the cortex of the kidney because that is the only place that glomeurlus are located.
51
Cortical perfusion is ______ (\<, \>, =) medullary perfusion.
Greater than.
That is why the kidney is 2 toned.
52
What is the most important function of the kidney?
Filtration
53
The ovaries produce ______ (more, less, the same) EPO as the testes.
Less than. This is why males have higher hematocrit/O2 content in the blood.
54
The kidney performs \_\_\_\_% of the total gluconeogenesis while the liver performs \_\_\_% of the total gluconeogenesis.
10%
90%
55
Creatine
Tripeptide important in energy metabolism of skeletal and cardiac muscle.
Creatine is broken down into creatinine, which has no use.
Creatinine is waste and every molecule is excreted at the same rate it is produced.
Liver and the kidney continue synthesizing creatinine.
If Creatinine levels are rising, differential diagnosis is kidney disease.
56
How does the rate of reabsorption/filtration glomerular capillaries differ than other systemic capillaries?
All capillaries undergo reabsorption and filtration. However, at the glomerular capillary, there needs to be a much higher rate of filtration than reabsorption. Reabsorption at the glomerular capillary would mean that waste would get reabsorbed.
57
What accounts for the difference in the magnitude of filtration at glomerular capillaries?
Starling pressures are different.
Capillary hydrostatic pressure is much higher than any other systemic capillary along the entire length of the capillary.
The volume of plasma exiting the glomerular decreases much more.
Protein concentration keeps increasing until it leaves through the efferent arteriole. This very high plasma oncotic pressure pulls more water in at the peritubular capillaries.
58
What are the layers of the filter at glomerular capillaries?
1. Endothelial cells
2. Basement membrane (macromolecules, collagen): provides support and contributes to filtration and is negatively charged.
3. Pedicels of podocytes.
59
Water reabsorption occurs mainly at the \_\_\_\_\_\_\_.
peritubular capillaries.
This is due to the higher protein concentration.
60
The filter is built in order to keep out \_\_\_\_\_\_\_. How is this done?
Protein.
Proteins are kept out because of their size, charge (filter is negative and thus repels negative proteins).
61
What protein is positively charged yet cannot get through the filter? Why can it not be filtered?
Immunoglobulins (antibodies) have a net positive charge.
They are the largest proteins.
62
The larger and more negative the protein, the _____ (more/less) likely it is to get through.
Less.
However, amino acids, small dipeptides, tripeptides, and creatinine can get through.
63
What causes the peritubular capillaries to be very good at water reabsorption?
The high plasma colloid oncotic pressure - it is very high because of the filtration that occured at the glomerular capillary.
64
What alter's an ions ability to get through the filter? E.g. calcium.
Its affinity to protein. About 40%-50% of calcium floats in plasma and cannot get through because it is bound to protein.
65
What does a molecule's affinity to protein affect?
Its length of time in the bloodstream. The tighter a molecule is bound to a protein, the longer it will remain in the bloodstream. This is not an accident, it is a property of the molecule that has been molded by natural selection because it is supposed to act longer to contribute to homeostasis.
66
If a molecule circulates 40% bound to protein, then \_\_\_\_\_% can be filtered when it arrives at the glomerulus..
60%
67
\_\_\_\_\_ is the hormone with the highest protein affinity.
Thyroid hormone
68
Filterability is based on what molecule?
Water. It is the most freely filterability. If it is not getting through, neither is waste.
69
If a molecule's filterability is equal to that of water, what can you say about it's concentration in plasma vs. Bowman's space? Give examples.
What about if it is less than water? Give examples.
A freely filterable molecule's concentration is equal in plasma and in bowman's space. Freely filterable means that it's filterability is the same as water. This includes sodium, chloride, potassium, urea, glucose.
Molecules that are not filtered as easily as water include Myoglobin, hemoglobin, albumin.
70
How is urea put into the blood? How is it removed?
BY THE LIVER ONLY.
The kidney removes it.
71
Urea
Major nitrogen waste product.
To turn amino acids into energy you have to get trid of the amino group. If it is removed alone, that is ammonia, which is TOXIC. The liver, puts 2 amino groups with a bicarbonate and this is urea.
72
Who you gonna call if urea increases?
LIVER AND KIDNEY.
Liver puts it in, kidney takes it out.
Either
1. the liver is over producing it and the kidney cant keep up
OR
2. Liver is putting it into the bloodstream at the same rate and there is something wrong with the kidney.
73
What are the possibilities when there is an increase in plasma waste (such as urea and creatinine)?
1. Kidney disease- filters are being lost. There are about 500K filters in the kidney & 8-10 capillaries at each filter. Losing filters means there is less filtration occuring.
2. The starling pressures have been disrupted. E.g. weakening heart decreases the starling pressures favoring filtration.
74
When would glucose be seen in urine?
* Diabetes: excessive glucose and it becomes waste
* Hemorrhage, neoplasia, trauma. Blood would be seen in the urine, which has glucose.
75
Inulin
Used an inidcator molecule to calculate GFR. It is almost freely filterable. Compare inulin in plasma and urine.
76
TRUE/FALSE.
Just because there is urine production, that does not mean the filtration/reabsorption are occuring properly.
TRUE.
That is why GFR is calculated. Both tubular and glomerular diseases can occur and therefore want to narrow down where it is occurring.
77
Hemoglobin
Found in plasma when RBCs lyse. WBCs destroy RBCs and consume hemoglobin in the spleen, normally. Some may die in blood, so there would not be a lot of hemoglobin found unless there is pathogenesis. 20% gets sent to kidney.
Hemoglobin's filterability is 0.03, and therefore gets filtered.
If hemoglobin increased in blood, 3% of the increased concentration gets through the filter. This may be due to hemorrhage in the urinary tract or RBCs dying in the blood.
78
What accounts for a product's concentration in Bowman's space?
A molecule's concentration in plasma and its filterability.
79
Myoglobin
Protein abundantly found in muscle to hold on to O2. Found in plasma due to secretion by muscle cells. IN plasma, it does not have a function. It was secreted because of dying muslcle cells. It's 1/3 - 1/4 the size of hemoglobin. Increased concentration in blood is due to muscle damage. It is damaging to the nephron.
80
Filterability of myoglobin is ________ (\<, \>, =) hemoglobin.
Greater than
This is because of its smaller size.
81
Albumin
Most abundant protein in plasma and in Bowman's space.
Constitutes 40-50% of all plasma protein.
Most important osmolyte.
Highest molecular weight and least filterability (\<0.01).
~7 grams of albumin is filtered daily.
82
Who puts albumin in the plasma? How often?
LIVER ONLY.
It is making it all of the time because it is being lost all of the time. If it was not being put into plasma all the time, then there would be generalized edema. It is _NEVER_ overproduced by the liver. It recognizes low albumin levels.
83
What happens when albumin is filtered? What are albumin concentrations in urine?
Proximal tubule takes up albumin through endocytosis and breaks it down into amino acids. This happens with hemoglobin and myoglobin. Albumin is the most abundant protein and the proximal tubule cannot take up all of it.
Treat albumin in urine as ZERO. If there is concern for renal disease, then it would be appropriate to test for albumin using specialized tests. Standard tests cannot measure albumin concentrations in urine. even if it doubles, it would still be undetectable. It may be found in the urine if the proximal tubule is sick and cannot endocytose it. If it is being lost at a higher rate because of disease, then generalized edema would be seen.
84
What is the only plasma protein found in urine?
Albumin.
85
What is the second most abundant plasma protein?
What are it's concentrations in the urine.
Fibrinogen.
Concentration in urine is ZERO. it does not get filtered.
86
What are the sources of the measureable protein in urine?
What can be causes of increased protein and what is this called?
* Cell turnover
* Secreted protein
* Uromodulin: secreted by loop of Henle - like bacteria velcro.
* Mucin: protective and getting produced all of the time.
* Causes of increased protein (proteinurea):
* mucin can be overproduced due to UTI.
* Increased cell death
* Kidney or tract disease will cause more protein in urine.
* bleeding into urinary tract
* Protein is not getting reabsorbed
87
What does Up: Uc indicate?
What do you think when it is really high?
It is a ratio of protein/creatining. It tells you if too much protein has gotten through. If there is an increase, it is due to protein.
High values may indicate glomerulopathy.
88
What does UNa: Uc indicate?
This will tell you if sodium is being reabsorbed as it should.
89
Specific Gravity of Urine
What are the values of Specific Gravity of H2O, Blood, Bowman's Space and Urine?
Measure of density in relation to water. It is the ratio of density of a volume to the density of an identical volume of water. It is a function of the ionic/molecular of solutes in a solution. The more particles in a solution, the higher the specific gravity.
Looking at SG in light of an animal's hydration status and kidney's ability to reabsorb water.
SG of H2O = 1.0
SG of Blood = 1.6
SG in Bowman's space = 1.008-1.0012
SG of Urine = 1.018
90
What could be the case if specific gravity of urine increases?
This does not necessarily mean that the kidney is doing a better job at concentrating the urine. It may be that more protein got through. you would have to look at Up/Ucr to see if that is normal and tell if the ability of the kidney is working and the increase is not because of extra protein.
91
What is the urine specific gravity of cats?
1.030 -1.035
92
When is the liver excreting urea into plasma?
As long as it is performing gluconeogenesis (utilizing amino acids) or oxidizing amino acids, or removing NH3 from plasma.
93
What species suffers the most from high BP?
Cats
94
What happens to pressure when blood reaches arterioles?
Arterioles are a resistance vessels because they have a small radius and there are not many of them, in comparison to arteries and decreased radius of lumen.
"Blood pressure goes into arterioles like a lion and comes out like a lamb."
If blood pressure was not reduced, vessels would pop
95
Describe the pressure profile at the kidney.
What happens when pressure is increased?
When the afferent arteriole is constricted vs. dilated?
The pressure begins at about 100mmHg.
Once it reaches the afferent arteriole, it decreases drastically to a little more than 40 mmHg.
The pressure stays the same at the entire length of the capillary.
Once it leaves through the efferent arteriole, it drops to about 20 mmHg and then continues to decrease.
Isolated Kidney:
If the pressure is increased, then pressure is the same by the time it gets to the glomerulus.
If the afferent arteriole is constricted, then causes decreased pressure at the glomerular capillary. While vasodilation would cause increased pressure at the glomerular capillary. The efferent arteriole has the same effect by acting in the opposite manner.
96
Autoregulation is performed by the kidney in order to ensure that.....
Renal blood flow and consequently, GFR remain constant.
97
What are the mechanisms of autoregulation?
1- Myogenic response: The afferent arteriole acts like a baroreceptor except it is is not a neuron. The more it stretches, the more Ca2+ enters the cell, which causes contraction.
2-Humoral response: aka tubuloglomerular feedback. Macula densa (at the beginning of the DCT) has ports for reabsorption, which senses Na+, K+ and Cl-. Increased solutes suggests increased water. Macula densa release vasoactive substances in the the interstitium to act on efferent and afferent arterioles.
98
What are the factors which influence GFR?
1. Renal Blood Flow (increase, increases GFR)
2. CHP, which is a function of
1. Systemic pressure (increase, increases GFR)
2. Afferent arteriolar tone (increase tone, decreases GFR)
3. Efferent arteriolar tone (increase tone, increases GFR)
3. Bowman's space Hydrostatic Pressure (increases, Increases GFR): Edema, obstruction)
4. Kf (increase - increases GFR) - permeability, length. This is the filtration coefficient, which is representative of the number of filters.
5. PCOP: Increase, decreases GFR
6. Bowman's Space Colloid Oncotic Pressure (increase, increases GFR)
99
What are the messages that are contradicting the kidney's autoregulation during dehydration?
1. ADH: Ultimate goal is to reduce water loss. Decrease filtration, increase reabsorption. Vasocontrict afferent arterioles.
2. Angiotensin II: vasoconstrict and increase reabsorption
3. Epinephrine/NE: vasoconstrict and increase reabsorption.
All these messages are risking GFR. Therefore, kidney needs to constantly emit vasoactive substances.
100
TRUE/FALSE.
You NEVER want to decrease prostaglandin production in the kidney.
TRUE.
They are cytoprotective.
101
What are prostaglandins?
20 carbon fatty acids
they are eicosanoic acids.
Precursor is arachidonic acid found in the internal monolayer of the cell membrane of ALL cells.
102
Arachidonic acids are converted to ______ and \_\_\_\_\_\_\_.
prostaglandins
leukotrienes
103
\_\_\_\_\_\_\_ is the enzyme that liberates arachadonic acid from the cell membrane.
Phospholipase A2.
104
Leukotrienes
potent bronchostrictor
105
What are some products from PGG2 and PGH2?
* Leukotrienes
* Thromboxane A2 - message for clotting produced by platelets.
* Prostacyclin - prevents platelets from clotting
* PGE (vasodilate)
* PG - Inflammation by Neutrophils
106
\_\_\_\_\_\_\_\_ blocks phospholipase A2 from freeing arachidonic acid naturally and further inhibits prostaglandin production.
Cortisol
107
What happens when you use a drug such as aspirin to block prostaglandin production?
It will cause bleeding ulcers in GI and decreased blood flow to the kidney.
108
\_\_\_\_\_\_\_ is the enzyme that acts on PGG to produce vasodilatory prostaglandins, while ______ acts on PGG to produce inflammatory prostaglandins.
COX-1
COX-2
109
When a kidney is removed, the overall GFR _______ and SNGFR \_\_\_\_\_\_\_.
(Increases/decreases)
Decreases
Increases
110
TRUE/FALSE.
The characteristics of the filter change to allow increased filtration once a kidney is removed or significant nephron loss has occurred.
FALSE.
Increased profusion results in increased filtration to account for the damage.
111
At what point is nephron loss noticeable via plasma creatinine concentration?
Once there are only 25% of the remaining nephrons.
112
If there is a an increase in plasma creatinine from 1.2 to 1.5 mg/dL in a week, what could the possibilities be?
The animal could be dehydrated.
There is no reason to believe that there is kidney disease if there are no other clinical signs.
113
What molecule works as a better an indicator for nephron loss?
SMDA
114
Two dogs are injected with the same amont of iohexol. Dog A has a lower concentration at Time X than Dog B. Which dog has greater GFR?
Dog A.
115
What are the requirements of a substance to be able to calculate GFR?
1. Freely filtered
2. No secreted
3. Not reabsorbed
4. Not metabolized
116
Creatinine is produced and placed into plasma by ________ and removed from plasma largely by the \_\_\_\_\_\_\_\_.
Skeletal and cardiac muscle
kidney (filtration and some secretion)
117
Plasma creatinine increases as GFR \_\_\_\_\_\_\_.
(Increases, decreases)
Decreases
