Renal Physiology (Final Exam) Flashcards
1
Q
What is the role of the kidney in long-term blood pressure regulation?
A
Expansion of blood volume through fluid & electrolyte retention.
2
Q
What is the role of the kidney in long-term pH regulation?
Where is HCO₃⁻ produced?
Why can’t pH be regulated using just the lungs?
A
- Kidneys determine whether to retain HCO₃⁻ or not.
- Kidneys
- CO₂ can be exhaled but H⁺ can’t be disposed of by the pulmonary system.
3
Q
What is the role of the kidney in long-term RBC regulation?
How does this occur?
A
- Hematocrit regulation
- Kidney reacts to internal low deep tissue O₂ levels & secrete Epoietin (Epo) to cause the bone marrow to produce RBCs.
4
Q
What is the role of the kidney in long-term electrolyte regulation?
A
- Kidneys reabsorb filtered ions.
5
Q
How much of our renal plasma flow is filtered?
A
1/5 of RPF (Renal Plasma Flow)
6
Q
How much Renal Blood Flow do we have in a healthy patient?
A
1000mL/min
7
Q
RBF (Renal Blood Flow) is approximately _____% of CO.
A
20%
8
Q
Renal Plasma Flow (RPF) is _____% of RBF.
A
60%
9
Q
What is the role of the kidney in long-term regulation of Vitamin D?
A
- Activation of cholecalciferol through hydroxylation with two -OH groups into 125-Dihydroxycholecalciferol
10
Q
What is the chemical name for Vitamin D?
A
125-Dihydroxycholecalciferol
11
Q
Under normal conditions, what occurs with glucose and the kidneys?
A
- Glucose is filtered and reabsorbed.
12
Q
When chronically hyperglycemic, what occurs with glucose and the kidneys?
A
- Glucose is filtered and the kidneys allow a portion of this glucose to be urinated out rather than be reabsorbed.
13
Q
What metabolic waste products does the kidney dispose of? Which is the most important?
A
- Nitrogenous Waste Products
- Urea
14
Q
How does the renal system regulate blood osmolarity?
A
- Through filtration & reabsorption of electrolytes
15
Q
What three hormones secreted by the kidney (discussed in lecture) regulate osmolarity?
How does each do so?
A
- Aldosterone - H₂O & salt retention
- Angiotensin II - Conserves sodium, H₂O follows.
- ADH - reabsorption or secretion of H₂O alone. No electrolytes involved.
16
Q
What muscle sits right above the kidneys?
What sits on top of the kidneys themselves?
A
- Diaphragm
- Adrenal Glands.
17
Q
What structure is denoted by 1 on the figure below?
A
Renal Artery
18
Q
What structure is denoted by 2 on the figure below?
A
Segmental Arteries
19
Q
What structure is denoted by 3 on the figure below?
A
Interlobar Arteries
20
Q
What structure is denoted by 4 on the figure below?
A
Arcuate Arteries
21
Q
What structure is denoted by 5 on the figure below?
A
Interlobular Arteries
22
Q
Where does blood go to from the interlobular arteries?
A
- Glomerulus (Afferent Arterioles specifically)
23
Q
Describe the blood flow path of the glomerulus.
A
- Afferent Arterioles
- Glomerular Capillaries
- Efferent Arterioles
- Peritubular Capillaries
24
Q
Describe the flow of blood through the kidneys as the blood exits the peritubular capillaries.
A
- Interlobular Veins
- Arcuate Veins
- Interlobar Veins
- Segmental Veins
- Renal Vein
25
Which four components of the cardiovascular system are found in the nephron?
1. Afferent Arterioles
2. Glomerular Capillaries
3. Efferent Arterioles
4. Peritubular Capillaries
26
What controls blood flow into the glomerulus?
Afferent Arteriole
27
What influences pressures in the glomerulus & peritubular capillaries?
Efferent Arteriole
28
Where is 99% of filtrate reabsorbed?
Does filtrate go directly from Loop of Henle into this structure?
- Peritubular Capillaries
- No, fluid goes from nephron lumen → ISF → peritubular cap's.
29
What percentage of nephrons are cortical nephrons?
90-95%
30
What percentage of nephrons are medullary nephrons?
5-10%
31
What is the name for deep peritubular capillaries found in medullary nephrons?
Vasa Recta
32
Differentiate descending vs ascending vasa recta by their purposes. (Besides the obvious that one goes down and one goes up).
- More Ascending Vasa Recta (AVRs) than descending. This helps ↓ blood velocity thus slowing blood leaving the medulla.
33
What quadrants are the kidneys found in?
Right & Left Upper Quadrants
34
Why are renal cancer rates typically lower?
- Less cell neogenesis occurs in the kidneys thus less chance of cancer cell formation.
35
What is denoted by 1 in the figure below?
What about 2?
- 1 = Renal Pelvis
- 2 = Right Ureter
36
What surface region is indicated by 1 below?
Left Suprarenal Gland (Left Adrenal Gland)
37
What surface region is indicated by 2 below?
Left Renal **Gastric Surface**
38
What surface region is indicated by 3 below?
Left Renal **Splenic Surface**
39
What surface region is indicated by 4 below?
Left Renal **Pancreatic Surface**
40
What surface region is indicated by 5 below?
Left Renal **Descending Colic Surface**
41
What surface region is indicated by 10 below?
Right Renal **Colic Flexure Surface**
42
What surface region is indicated by 12 below?
Right Renal **Hepatic Surface**
43
What surface region is indicated by 13 below?
Right Suprarenal Gland (Adrenal Gland)
44
Why are points of organ contact pertinent in regards to the kidneys?
Points of contact are important because of cancer transference.
45
What are kidneys stones composed of?
Where is pain from kidney stones usually felt?
- "Aggregated salts"
- Lower back due to dermatome affected.
46
Between males & females, who typically has a larger bladder capacity?
Males
47
Where is the "chokepoint" in the male urinary tract system?
What have most men developed by age 70 in relation to this organ?
- Prostate
- BPH
48
Which spinal nerves regulate the emptying & closing of both the rectum and the external sphincter of the urinary tract?
What occur if these spinal nerves are messed with?
- S2 - S4
- Incontinence
49
What structure is indicated by 1 on the figure below?
Bowman's Capsule
50
What structure is indicated by 2 on the figure below?
Proximal Convoluted Tubule
51
What structure is indicated by 3 on the figure below?
Proximal Straight Tubule
52
What structure is indicated by 4 on the figure below?
Descending Thin Limb of the Loop of Henle
53
What structure is indicated by 5 on the figure below?
Ascending Thin Limb of the Loop of Henle
54
What structure is indicated by 6 on the figure below?
Thick Ascending Limb of the Loop of Henle
55
What structure is indicated by 7 on the figure below?
Distal Convoluted Tubule
56
What structure is indicated by 9 on the figure below?
Initial Portion of the Cortical Collecting Duct
57
What structure is indicated by 10 on the figure below?
Cortical Collecting Duct
58
What structure is indicated by 11 on the figure below?
Medullary Collecting Duct
59
Where is Glomerular Filtration Rate (GFR) determined?
- Juxtaglomerular Apparatus
60
Where is the Macula Densa located?
- End of the TAL of the loop of Henle; Beginning of the DCT.
61
What determines efferent arteriole dilation/constriction?
- Filtrate running through urinary lumen at the Macula Densa. (specifically quantity of Na⁺ & Cl⁻ @ the MD)
*verify*
62
How much reabsorption of filtrate occurs in the PCT?
2/3rds
63
How many nephrons does a healthy human (who has never lost any) have?
2 million (1million per kidney)
64
What percentage of Filtrate is reabsorbed? How much becomes urine?
- 98-99% reabsorption
- 1-2% → urine
65
What two structures are the primary determinants of filtration?
- Afferent & Efferent Arterioles
66
What is a healthy GFR?
125cc/min or 1.25dL/min
67
How is secretion different than filtration?
Secretion is the **active pumping** of ions/drugs/stuff out of blood & into tubular system.
68
What is the PCAP of the Glomerulus?
60mmHg
69
What is the πCAP of the glomerulus?
32mmHg
70
What is PTUBE?
This is the pressure exerted by the filtrate in Bowman's Capsule.
71
What is the PTUBE of the glomerulus?
18mmHg
72
What is the πTUBE of the glomerulus? Why is this?
- 0 mmHg
- No proteins are filtered into filtrate.
73
How is NFP of the Glomerulus calculated?
NFP = PCAP - PTUBE - πCAP
74
Would πCAP increase or decrease after filtration occurs at the glomerulus? Why?
- πCAP would increase due to an increased proportion of the fluid being composed of unfiltered proteins.
75
What would one expect for πCAP increase to be closer to the afferent arteriole?
What about closer to the efferent arteriole?
What causes this change?
- Afferent ~ 28mmHg
- Efferent ~ 36 mmHg
- Increased due to higher protein concentration from fluid being filtered out.
*card needs verification*
76
Renal Blood Flow (RBF) is controlled by ______ ______ tone.
Afferent Arteriole
77
During hypertension what occurs to the afferent arterioles?
AA **constrict** to decrease RBF.
78
During hypotension what occurs to the afferent arterioles?
AA **dilate** to increase RBF.
79
Good RBF regulation results in good ____ regulation.
GFR.
80
What is the formula for clearance?
**C = (V · U) / P**
C = Clearance
V = Urinary Flow Rate
U = Urine Concentration
P = Plasma Concentration
81
How is Filtration Fraction (FF) calculated?
GFR/RPF = FF
(125/600) = 20%
82
What percentage of RBF is red blood cells?
Approximately how many mL's is this?
- 40%
- 400mL
83
What will systemic vasodilatory drugs do to the GFR and UO?
Why is this?
- ↑GFR & ↑UO
- AA dilation thus ↑flow
84
What is the best compound for determination of renal function?
Why is it not used?
What is second best and why is it used more?
- Inulin (not used due to being exogenous)
- Creatinine (endogenous and thus more convenient to use)
85
What is secretion?
- Physical removal of substance into urinary lumen via pumping (drugs, K⁺, etc.)
86
What should renal clearance of glucose be in a healthy person?
0 (glucose reabsorbed)
87
What is the GFR of someone who is healthy?
125mL/min or 1.25dL/min
88
What capillary bed specializes in bulk reabsorption?
How much fluid is reabsorbed per minute?
- Peritubular Capillary Bed
- 124 mL/min
89
Dilation of the efferent arteriole will ________ hydrostatic pressure in the glomerulus.
decrease
90
Dilation of the afferent arteriole will ______
hydrostatic pressure at the glomerulus.
increase
91
Constriction of the afferent arteriole will ______
hydrostatic pressure at the glomerulus.
decrease
92
Constriction of the efferent arteriole will ______
hydrostatic pressure at the glomerulus.
increase
93
Efferent constriction will decrease renal blood flow. T/F?
What would this do to filtration?
- True
- Increase Filtration
94
What would the beginning pressure of the efferent arteriole be?
What would the pressure be at the end of the efferent arteriole?
- Beginning = 60 mmHg
- End = 13 mmHg
95
Constriction of the efferent arteriole would _______ intravascular pressure downstream.
decrease
96
What two factors will lead to an increased filtration fraction?
- ↑GFR
- ↓RPF
97
What two factors will will lead to an decreased filtration fraction?
- ↓GFR
- ↑RPF
98
An increased filtration fraction would be associated with what change in downstream colloid concentration?
- ↑ colloid concentration
99
What would a normal, healthy adult's serum creatinine levels be?
How would this concentration change for the fluid in Bowman's capsule?
- 1mg/dL
- It wouldn't change (1mg/dL) no fluid reabsorbed yet.
100
Why is creatinine easily filtered at the glomerulus?
- Creatinine is a small molecule.
101
What would the nephron's response to hypochloremia & hyponatremia seen at the macula densa be?
↑ GFR by:
- Dilating afferent arteriole
- Constrict efferent arteriole
102
What would the macula densa see, in terms of chloride & sodium concentrations, with an increased GFR?
How would the nephron respond to this?
- ↑ serum Na⁺ & Cl⁻
- ↓GFR by constricting afferent arteriole & dilating efferent arteriole.
103
What are the layers of the glomerulus?
1. Endothelium
2. Basement Membrane
3. Epithelium
104
What anatomical feature, unique to the glomerulus, helps provide structure needed to withstand the elevated hydrostatic pressures?
- Epithelial/Podocyte Layer
105
What two anatomical features does the glomerulus have that promote filtration?
- Endothelium **fenestrations**.
- Epithelial **slit pores**.
106
What characteristic of the glomerulus prevents protein filtration?
- Glomerulus (each layer) is negatively charged.
107
How would chronic hypertension or infection affect the glomerulus?
- Open up slit pores & fenestrations so much that proteins leak through.
108
How would chronic leaking of proteins affect the nephron?
- Proteins chronically in the nephron will damage it by getting stuck in the tubule.
109
Large molecules will _______ filterability.
decrease
110
_________ charges will lower filterability.
negative
111
_________ charges will increase filterability.
positive
112
What forces favor reabsorption in the peritubular capillaries?
- PISF = 6 mmHg
- πCAP = 32 mmHg
113
What forces disfavor reabsorption in the peritubular capillaries?
- PCAP = 13 mmHg
- πISF = 15 mmHg
114
How is NRP (Net Reabsorption Pressure) calculated?
- NRP = PISF + πCAP - PCAP - πISF.
115
How much of a pressure loss occurs from the glomerulus to the peritubular capillaries?
What is the cause of this pressure loss?
- 47 mmHg (60mmHg - 13 mmHg)
- Efferent arteriole
116
What does PAH stand for?
What is its significance?
- Para-aminohippurate
- PAH is heavily secreted & PAH clearance will = RPF.
