Unit 1 Flashcards
(243 cards)
1
Q
What is total body water?
A
Sum of all fluid found in the body
2
Q
Approx how much total body water is in an individual?
A
42 liters or 60% of body weight
*variations due to body size, gender, age, obesity
3
Q
What are the extracellular fluid compartments?
A
Plasma not including blood cells
Interstitial fluid
4
Q
What is the intracellular fluid compartment?
A
Sum of all fluid inside cells
5
Q
What dos the transcellular fluid compartment include?
A
Synovial, peritoneal, pericardial, CSF, intraocular fluid
NOTE: Even though these fluids are outside of cells, they are not included in the extracellular fluid compartment
6
Q
What is considered as output?
A
Kidneys Lungs Feces Sweat Skin
7
Q
Layers of cellular fluid in the body
A
Plasma
Capillary membrane
Interstitial fluid
Cell membrane
Intracellular fluid
8
Q
What is the barrier between the plasma and interstitial fluid compartments?
A
Capillary membrane
9
Q
Where is the capillary membrane important in the kidney?
A
Glomerulus filtration
Peritubular capillaries and vasa recta for reabsorption of substances into the blood stream
10
Q
What is the barrier between the interstitial fluid compartment and intracellular fluid?
A
Cell membrane
11
Q
Where is the cell membrane in the kidney important?
A
Reabsorption and/or secretion of substances through the cells lining the nephron tubules
12
Q
To maintain homeostasis, water intake must:
A
Balance water output
13
Q
What are the 2 sources of water in the body?
A
Ingestion
Synthesis
14
Q
What happens to water when ingested?
A
It is absorbed from the GI tract into the plasma compartment
15
Q
Water synthesis is made how?
A
Oxidation of carbohydrates
Contributes to intracellular fluid
16
Q
What are the two types of water loss?
A
Insensible and sensible water loss
17
Q
What is insensible water loss
A
Evaporation through ventilation and through the skin
does NOT include sweat!
18
Q
What is sensible water loss?
A
Sweat
Feces
Kidneys (excretion of urine)
19
Q
How much sweat is typically lost?
A
Depends on the ambient temperature and physical activity (normally approx 100 ml/day; can increase to 1-2 L per hour with heavy sweating)
20
Q
How much water is lost from feces?
A
Approx 100 ml/day- increases with diarrhea
21
Q
How much water is lost from urine excretion
A
Approx 1400 ml/day
22
Q
The capillary wall is highly permeable to ____ and ____. Therefore:
A
Water
Ions
Ion concentrations are nearly the same
23
Q
What does the Donnan effect state?
A
Because plasma proteins have a net negative charge, there are slightly more cations in the plasma than in the interstitial fluid
24
Q
The capillary wall to practically impermeable to:
A
Proteins
25
The protein concentration of plasma is (HIGHER/LOWER) than interstitial fluid.
What does plasma contain?
Higher
Albumin, lipoproteins, antibodies, etc.
26
The plasma cell membrane (IS/IS NOT) permeable to most ions and protein, therefore:
is NOT
There are many differences between ECF and ICF
27
What is the ECF higher in?
NA+, Cl-, HCO3-
28
What is ICF higher in?
K+, PO4-3, MG+2, organic anions, protein
29
A way to measure patient’s fluid compartments is by using what principle?
Indicator dilution principle
30
What is the indicator dilution principle equation?
Volume B = volume A x [A]/[B]
31
What are the direct measurements of the body fluid compartments?
Total body water (TBW) - 3H2O or 2H2O
Extracellular fluid- Radioactive Na+ or inulin
Plasma volume- I^125 albumin, Evan’s blue die
32
What is inulin
A complex polysaccharide present in the roots of various plants. It is not able to be metabolized in humans
33
What are the indirect measurements in the body fluid compartments
ICF volume = TBW - ECF
Interstitial fluid volume =
ECF volume - plasma volume
Blood volume = Plasma volume / 1-HCT
34
Diffusion of water across a selectively permeable membrane from a region of high H2O to a region of low H2O
Osmosis
35
Moles vs. Osmoles
Mole = 6.022 X 10^23 particles of solute
Osmole = a mole of osmotically active particles of solute
Ex- One mole of NaCl = 2 osmoles of osmotically active particles
36
Osmolality vs. osmolarity
Osmolality = # of moles / kg water
Osmolarity = # of moles / L of water
37
What is the amount of pressure needed to oppose osmosis?
Osmotic pressure
38
Osmotic pressure (IS/IS NOT) related to osmolarity
Is
39
What is van’t Hoff’s law?
Pi = CRT
Pi= osmotic pressure
C = concentration of solutes (Osm/L)
T= temperature (K)
40
1 mOsm/L gradient across a membrane exerts an osmotic pressure of:
19.3 Hg
41
What is the osmolarity of ICF?
Approx 282 mOsm/L
42
If a cell is placed in pure water, there would be an osmotic pressure of:
5400 mm Hg
43
What happens to a cell when the solution is isotonic (isosmotic)?
Nothing- no change
44
What happens to the cell when it’s environment is hypotonic (hypo-osmotic)?
The cell swells
45
What happens to a cell when it’s environment is hypertonic (hyperosmotic)?
It shrinks
46
What happens to ECF volume when..
Isotonic solution added?
Hypertonic?
Hypotonic?
They all increase the ECF volume
47
What happens to the ECF osmolarity when..
Isotonic solution added:
Hypertonic:
Hypotonic:
Stays the same
Increases
Decreases
48
What happens to the ICF volume when..
Isotonic solution is added:
Hypertonic:
Hypotonic:
Stays the same
Decreases
Increases
49
What happens to the ICF osmolarity when..
Isotonic solution is added:
Hypertonic:
Hypotonic:
Stays the same
Increases
Decreases
50
What is the most hydrated ion?
Na+- typically with 4 or 6 water molecules in the first layer, depending on the environment
51
Na+ has a (WEAK/STRONG) bind to water. The hydration shell is (WEAK/STABLE), so this makes them:
Strong
Stable
Move together with the cation
52
Any Na+ movement (_____,____) is followed by:
Retention, excretion
H2O movement
53
The more salt in the ECF, the more ______, the higher:
Water
Volume and blood pressure
54
Potassium is (SMALLER/LARGER) than Na+, It has _____ ___ electrons shielding positively charged nucleus, so K+ makes _____ associations with water rather than:
Larger
8 more
Transient
A discrete hydration layer
55
Which has a higher permeability across the cell membrane- K+ or Na+?
K+
56
What is an indicator of plasma osmolarity?
Plasma sodium concentration
57
Two examples of hyponatremia
Hypo-osmotic dehydration (Na+ loss)
Hypo-osmotic overhydration (H2O gain)
58
Symptoms of hypo-osmotic dehydration
Diarrhea or vomiting
Diuretic overuse
Decreased aldosterone (Addison’s disease)
59
Hypo-osmotic overhydration results in increased ______ secretion
ADH
60
Examples of hypernatremia
Hyperosmotic dehydration (H2O loss)
Hyperosmotic overhydration (Na+ gain)
61
Hyperosmotic dehydration results in decreased ______
And increased ______
ADH (diabetes insipidis)
Sweating (>water intake)
62
Hyperosmotic overhydration results in increased _________
Aldosterone
63
Intracellular edema can be due to...
Hyponatremia (low ECF sodium)
Depressed tissue metabolism
Lack of cell nutrition
**The latter two of the above are often due to inadequate blood supply. The cells are subsequently unable to maintain ion pumps that keep sodium out. Therefore the increased intracellular sodium attracts water into the cell**
64
Extracellular edema can be due to..
Failure of the lymph system to return fluid (lymphedema)
Increased capillary leakage (most common)
65
Potential causes of lymphedema
Filaria worms
Cancer
Surgery
66
Increased capillary leakage can be due to..
(INCREASED/DECREASED) capillary pressure (____)
(HIGH/LOW) venous pressure (___)
(INCREASED/DECREASED) arteriolar resistance (___)
(INCREASED/DECREASED) plasma proteins (___)
Increased (kidney fluid retention, excess aldosterone)
High (heart failure, venous obstruction)
Decreased (vasodilation)
Decreased (nephrotic syndrome, burns, wounds, liver disease, protein malnutrition)
67
Type of edema seen with intracellular fluid accumulation or due to extracellular fluid clotting
Non-pitting/lymphedema
68
Congenital Non-pitting lymphedema caused by
Defect in the lymph system development
69
What leads to acquired non-pitting edema?
Trauma to lymph system (i.e. surgery)
Infection
Myxedema seen in hypothyroidism
70
Type of edema seen where there is free extracellular fluid that is able to move with pressure and when released, flows back
Pitting
71
Localized edema
Inflammation due to local injury or infection
72
Generalized pitting edema is due to..
Cardiac failure or volume overload
73
View slide 18 for assessment of pitting edema **just kidding, we don’t need to know this!**
Slide 18
74
What is peripheral edema
Edema in somatic structures (non-visceral)
75
What is dependent edema?
Swelling accumulating in areas due to effects of gravity
76
What is effusion
Fluid accumulation in “potential spaces”
77
Peritoneal cavity
Ascites
78
Pleural cavity
Pleural effusion
79
Severe generalized edema
Anasarca
80
Prevention ways of edema
Low compliance of interstitium in negative pressure range
Ability to increase lymph flow
“Wash down” effect
81
Main functions of the kidneys
Rid the body of waste products
Control the volume and composition of body fluids
82
Other functions of the kidneys
Regulation of arterial pressure (renin, pressure diuresis and natriuresis)
Regulation of erythrocytes production (EPO)
Activation of vitamin D (1,25-dihydroxyvitamin D3)
Gluconeogenesis (along with the liver) during fasting
83
Waste products the kidneys get rid of
Metabolic wastes- Urea, creatinine, uric acid, urobilinogen, hormone metabolites
Foreign chemicals- drugs, pesticides, food additives
84
How does the kidney control volume and composition of body fluids
Water and electrolyte balance and osmolarity (balance intake with output)
Regulation of acid/base balance
85
Position of the kidneys
Retroperitoneal on the post abdominal wall
Between T12-L3 vertebrae
The right kidney is typically 1-2 cm inferior to the left
86
The hilum of the kidney serves as an entrance/exit point for:
Renal artery
Renal vein
Ureter
Renal nerve plexus (mainly SNS)
87
There are approx ________ nephrons per kidney
1 million
88
What makes up the renal corpuscle
Glomerulus
Bowman’s capsule
89
What is inside a nephron
Renal corpuscle
Proximal convoluted tubule
Loop of henle
Distal convoluted tubule
Collecting tubule/duct
90
What makes up the loop of henle
Short loops in cortical nephrons
Long loops in juxtamedullary nephrons
91
Review slide 26 for renal blood supply
Slide 26
92
Basic nephron function:
Excretion =
Filtration - reabsorption + secretion
93
Renal handling patterns and examples:
1- Filtration only (metabolic wastes like creatine)
2- Filtration and partial reabsorption (electrolytes such as Na+ and Cl-)
3- Filtration and complete reabsorption (amino acids and glucose)
4- Filtration and secretion (organic acids and bases such as bile salts, caracholamines, drugs, toxins)
94
What are the 3 layers of the glomerular capillary structure?
Endothelium with fenestrae
Basement membrane, negative charge
Podocytes epithelium with slit pores, negative charge
95
Glomerular capillaries prevent filtration of ____ and ____ ___ under high filtration pressures
Protein
Blood cells
96
Filterability in the glomerular capillary is based on:
Size and charge of the solute
97
Glomerular filtration rate (GFR) equation
GFR = Kf X Net filtration pressure
Kf = glomerular capillary filtration coefficient (product of surface area and permeability)
Net filtration pressure = sum of Starling’s forces.
98
What are the 4 Starling’s forces?
Capillary hydrostatic Pressure (Pc)
Interstitial fluid hydrostatic pressure (Pif)
Plasma colloid osmotic pressure (Pip)
Interstitial colloid osmotic pressure (Piif)
99
Starling’s forces together determine:
The rate of fluid movement into/out of systemic capillaries (AKA Bulk Flow)
100
Glomerular filtration rate
Movement of fluid from the glomerulus to the renal interstitium
101
GFR equation (broken down w/ starling’s forces)
GFR = Kf X (Pg-Pb-PiG+PiB)
Pg = Glomerular hydrostatic pressure
Pb = Bowman’s capsule hydrostatic pressure
PiG = glomerular colloid osmotic pressure
PiB = Bowman’s capsule colloid osmotic pressure (normally = 0)
102
Review picture in slide 35
Slide 35
103
Kf in GFR (IS/IS NOT) used for regulation
Is not
| But diseases can effect Kf
104
What diseases can effect Kf
Diabetes
Chronic hypertension
(Kidney diseases generally decrease Kf)
105
Pb in GFR (IS/IS NOT) used for regulation
Is not
But diseases can effect it
106
What diseases can effect PB of GFR?
Urinary tract obstruction
107
In a healthy state, PiB of GFR equals _____. why?
0
Proteins do not filer into the Bowman’s Capsule.
However, disease can alter PiB
108
Diseases that can alter PiB in GFR
Proteinurea / albuminurea
109
What factors influence PiG in GFR
Arterial plasma colloid osmotic pressure (PiC)
Filtration fraction = the proportion of the plasma that enters (filters) into the glomerulus
110
Filtration fraction =
GFR / Renal plasma flow
111
What happens as plasma flow increases?
Decreases?
Filtration fraction decreases, PiG decreases, GFR increases
Filtration fraction increases, PiG increases, GFR decreases
(even w/ no change in hydrostatic pressure, changing renal plasma flow effect GFR)
112
The glomerulus (IS/IS NOT) normally permeable to proteins
Is NOT
113
The primary means by which GFR is regulated by changing what?
Pg (glomerular hydrostatic pressure)
114
What happens to GFR when Pg increases?
Decreases?
Increases
Decreases
115
Glomerular hydrostatic pressure (Pg) is determined by what?
Arterial hydrostatic pressure
Afferent arteriolar resistance
Efferent arteriolar resistance
116
What parts of Pg fix kidney filtration rate?
Afferent arteriolar resistance
Efferent arteriolar resistance
117
What helps keep a fairly even glomerular pressure?
Arterial pressure
118
What happens to GFR when there is an increase in....
Arterial pressure?
Afferent arterial resistance (constriction)?
Efferent arteriolar resistance?
Increases
Decreases
Increases
119
What does the biphasic response state?
At large increases in efferent arteriole resistance, some of the effect on GFR is lost due to the reduction of renal blood flow
120
What is the sympathetic effect on GFR?
Causes vasoconstriction of renal arterioles and decreases renal blood flow, thereby decreasing GFR
**Effects are very minimal at normal levels of sympathetic tone, but during acute severe increases in sympathetic activity, GFR can decrease significantly**
121
Norepinephrine and epinephrine (from adrenal medulla) (VASOCONSTRICT/CONSTRICT) renal arterioles causes (INCREASED/DECREASED) GFR and renal blood flow
Constrict
Decreased
(Only in acute severe conditions is there much affect)
122
What is a vasoactive peptide released when there is damaged vessels and causes vasoconstriction?
It may contribute to:
Endothelin
Kidney failure in disease states where endothelin is secreted
123
Angiotensin II constricts:
It is a:
It is secreted locally by:
Efferent arterioles
Circulating hormone
Kidneys (autocoid)
124
Angiotensin II is generally produced when there is:
Reduced BP, or decreased blood volume
125
Constricting efferent arterioles (INCREASES/DECREASES) glomerular pressure, maintaining:
Increases
Kidney function
126
Angiotensin II also (SLOWS/SPEEDS UP) blood flow in the peritubular capillaries, which (INCREASES/DECREASES) reabsorption of Na and water
Slows
Increases
127
What is Endothelial Derived relaxing factor (NO)?
Autocoid that decreases renal vascular resistance.
128
Endothelial derived relaxing factor is secreted ______ to help maintain:
Tonically
Normal level of vasodilation
129
What is the purpose of regulating renal blood flow?
To maintain a relatively normal GFR, even when systemic blood pressure changes
130
Normal GFR occurs in MAP ranges from :
75-160 mm Hg
131
In normal BP..
If MAP = 100 mm Hg, then...
GFR =
Reabsorption =
Excretion =
180 L/day
178. 5 L/day
1. 5 L/day
132
If MAP = 125 mm Hg, then...
GFR =
Reabsorption =
Excretion =
225 L/day
178. 5 L/day
46. 5 L/day
(This can’t be possible to survive... there is a mechanism to prevent massive fluid losses)
133
Autoregularion in the kidney is called:
Tubuloglomerular feedback
134
Juxtaglomerular complex/apparatus:
Macula densa
135
The macula densa is located in the ____ ____. It senses ______ concentration
Distal tubule
NaCl
136
Juxtaglomerular cells are located where?
They are involved in:
The afferent and efferent arterioles
Vasomotion and renin secretion
137
Slowed GFR would (SLOW/SPEED UP) fluid flow in the proximal tubule giving it (MORE/LESS) time to reabsorb (SMALLER/LARGER) amounts of NaCl, which then drops in the:
Slow
More
Larger
Nephron tubule
138
What does the macula dense sense?
Lower NaCl
139
What does the macula densa do when it senses lower NaCl?
What happens next?
It triggers the juxtaglomerular cells to change arteriole resistance and renin secretion as shown
This then increases Pg and GFR back towards normal
140
What are the two pathways through tubular epithelium?
Transcellular (carrier mediated)
Paracellular (“tight” junctions)
141
What are the transport mechanisms in tubular reabsorption ?
Active transport
Secondary active transport
Passive transport
Osmosis
Bulk flow (starling’s forces)
142
Sodium potassium ATPase (active transport) is located where?
On the basolateral membranes of tubular epithelial cells
143
Sodium potassium creates:
A Na+ gradient (low intracellular sodium)
A negative membrane potential
144
Na+ diffuses in the tubule how?
Passively- either transcellulaly or peri-cellularly due to gradients.
145
What are some other primary active transport carriers?
Hydrogen ATPase
Hydrogen-Potassium ATPase
Calcium ATPase
146
What drives the coupled secondary active transport?
Na+ gradient caused by the ATPase (Na+ with another solute)
Ex- Na+/glucose carrier
Na+/amino acid carriers
147
Review pic in slide 52
Slide 52
148
What is 2ndary active secretion in tubular processing?
The 2ndary active transport of a substance in the opposite direction (antiport)
149
H+ can be secreted using what mechanism?
Secondary active secretion
150
What is the only mechanism that causes reabsorption of water?
Osmosis
151
Osmotic gradient is created principally by the:
Primary and 2ndary active reabsorption of solutes such as Na+
152
Water moves by osmosis either _______ly or _______ly.
Transcellularly
Or pericellularly
(Assuming that part of the nephron is permeable to water)
153
What is solvent drag?
Rapid H2O reabsorption that brings other solutes with it
154
Bulk flow, AKA:
It is governed by:
Ultrafiltration, starling’s forces
Hydrostatic and colloid osmotic pressures
155
Due to the active reabsorption of Na. And the subsequent osmosis of water, other solutes become:
Therefore, these solutes:
Concentrated in the tubule lumen.
Solutes are reabsorbed
(Ex.- Urea and Cl-)
156
Review pic in slide 55
Slide 55
157
Filtration, reabsorption and excretion of..
Glucose
Filtration: 180 g/day
Reab: 180
Ex: 0
158
Filtration, reabsorption and excretion of..
Bicarbonate
Filtration: 4320 mEq/day
Reab: 4318
Ex: 2
159
Filtration, reabsorption and excretion of..
Sodium
Filtration: 25,560 mEq/day
Reab: 25,410
Ex: 150
160
Filtration, reabsorption and excretion of..
Chloride
Filtration: 19,440 mEq/day
Reab: 19,260
Ex: 180
161
Filtration, reabsorption and excretion of..
Potassium
Filtration: 756 mEq/day
Reab: 664
Ex: 92
162
Filtration, reabsorption and excretion of..
Urea
Filtration: 46.8 g/day
Reab: 23.4
Ex: 23.4
163
Filtration, reabsorption and excretion of..
Creatinine:
Filtration: 1.8 g.day
Reab: 0
Ex: 1.8
164
What is the transport maximum?
The maximum rate by which some substances can be reabsorbed.
This is due to saturation of transport carriers with excessive tubular (filtered) loads
165
What is the result of transport maxiumum?
Increased excretion of the specific substance
Ex- glucose reabsorption in uncontrolled diabetes mellitus
166
Histology of Proximal convoluted tubule—-
Cells have a lot of mitochondria
Brush border on apical (luminal) side
Basal channels (on basolateral side)
167
What is excreted into the proximal convoluted tubule?
H+
Organic acids,
Bases
168
What is reabsorbed from the proximal tubules?
Na+
Cl-
HCO3-
K+
H2O
Glucose
Amino acids
169
Transports in the early proximal tubule
Na+/K+ pump
2ndary cotransport of organic solutions
(Na+/glucose symport— 100% reabsorption)
(Na+/amino acids symport — 100% reabsorption)
Na+/H+ antiport (H+ secretion)
HCO3- absorption
Aquaporin I- water reabsorption via osmosis
170
Transports in the late proximal tubule
Continued Na+ / K+ pump
Passive transport Cl-
Aquaporin 1
171
What else is seen in the late proximal tubule?
Active secretion of organic acids and bases (I.e. waste products such as bile salts, oxalate, urate, catacholamines)
Active secretin of drugs and toxins
172
By the time the filtrate reaches the end of the proximal tubule, ___% ofH2O, Na+, Cl-, K+ are reabsorbed, ___% of bicarbonate, and ____% of glucose and amino acids
65%
85%
100%
*also, secretion of H ions and metabolic and drug wastes occur in large amounts
173
The proximal tubule lumen is _______ relative to outside the tubule (plasma).
This is due to:
Isosmotic
Passive reabsorption of water through aquaporin 1
174
Histology of loop to henle
Thick descending limb
Thin descending limb
Thin ascending limb
Thick ascending limb
175
Pathway from Bowman’s capsule to the bladder
Bowman’s capsule
Proximal tubule
Descending limb of loop
Loop of henle
Ascending limb
Distal tubule
Collecting duct
To bladder
176
Which part of the loop of henle is very permeable to H2O?
Thin descending limb
177
The think descending limp of loop of henle has some permeability to ______.
Here, there (IS/IS NOT) active reabsorption .
Solutes
Is not
178
The think ascending limb of loop of Henle is impermeable to ____.
There is so significant:
H2O
Reabsorption nor secretion occurs here.
179
What is reabsorbed from the thick ascending limb of loop of henle?
What is excreted into it?
Na+, Cl-, K+, Ca++, HCO3-, Mg++
H+
180
The thick ascending limp of loop of henle is (PERMEABLE/IMPERMEABLE) to H2O
Impermeable
181
What is found in the thick ascending limb of loop of henle?
Na+/K+ pump
Na+/H+ antiport (H+ secretion)
1 Na+, 2-Cl-, 1K+ co-transporter (reabsorption of these 3 ions) (target for loop diuretics)
Paracellular reabsorption of Mg+2, Ca+2, Na+, and K+ occurs (due to electrochemical gradient)
182
The thick ascending limb lumen is ____.
Hypo-osmotic
183
What are the thick ascending limb diuretics?
Furosemide
Ethacrynic acid
Bumetanide
184
The early distal tubule’s characteristic is similar to:
It contains:
Thick ascending loop of henle
A Na+/Cl- co-transporter
185
What is reabsorbed from the early distal tubule?
Na+, Cl-, Ca++, Mg++
186
What are the early distal tubule diuretics?
Thiazide
187
What are the actions of the principal cells in the late distal tubule?
Na+/K+ pump
Sodium reabsorption (passive)
Potassium secretion (passive)
Sensitive to K+ sparing diuretics
With ADH is permeable to water (reabsorption)
188
Sodium reabsorption and potassium secretion (both passive) in the late distal tubule are both sensitive to ____.
Aldosterone
189
What is found in the late distal tubule?
Principal cells
Intercalated cells
190
What is reabsorbed from the late distal tubule?
What is excreted?
NA+, Cl-
(+ADH)H2O
HCO3-
K+
K+a
H+
191
What are the aldosterone antagonists in the late distal tubule?
Spironolactone
Eplerenone
192
What are the Na+ channel blockers for the late distal tubule?
Amiloride
Triamterene
193
Late distal tubule is also known as the
Cortical collecting duct
194
Type A intercalated cells secrete:
They reabsorb:
Hydrogen (H+ ATPase, H+/K+ ATPase)
Reabsorbs bicarbonate and potassium
195
Type B intercalated cells reabsorb:
They secrete:
Hydrogen (H+ ATPase, H+/K+ ATPase)
Bicarbonate and potassium
196
Reabsorption in the medullary collecting duct
Small amount of H2O and Na+
Passive reabsorption of Cl-
197
The medullary collecting duct is sensitive to:
It is permeable to _____.
It also has:
ADH
Urea (some reabsorption)
An H+ ATPase (secretion)
198
Review chart in slide 69
Slide 69
199
What does the glomerotubular balance refer to?
The balance between GFR and reabsorption
- as GFR goes up, so does reabsorption
200
What is the first like of defense against large changed in GFR?
2nd line of defense?
1st- “tubuloglomerular feedback”, aka “renal autoregulation”
2nd- Glomerulotubular balance
201
Glomerulotubular balance is governed by what?
Hydrostatic and colloid osmotic forces of the IF and peritubular capillaries
202
Peritubular capillary reabsorption equation
Kf x net reabsorption force
203
Net movement of fluid is into the:
Peritubular capillaries
204
Note which starling’s force goes into the peritubular capillary vs leaves the peritubular capillary
Pc:
Pif:
PiC:
PiIf:
Pc: leaves
Pif: Enters
PiC: enters
Piif: leaves
205
What influences Pc (peritubular capillary hydrostatic pressure)?
MAP increased, Pc increased, reabsorption decreased
Afferent art. Resistance increase, Pc decreased, reabsorption increased
Efferent art resistance increases, Pc decreases, reabsorption increases
206
What influences PiC? (peritubular capillary colloid osmotic pressure)
Increased plasma protein, increased PiC, Increase reabsorption
Increased filtration fraction, increases PiC, Increases reabsorption
207
What influences Kf (filtration of coefficient)?
Normally doesn’t change, but...
Increased Kf -> increased reabsorption
208
What influences Pif (interstitial fluid hydrostatic pressure)?
Anything that decreases peritubular reabsorption; more fluid stays in the interstitium therefore increasing Pif
Increasing Pc and decreasing PiC
With a higher Pif, More “backleak” occurs into the tubular lumen with
209
What influences Piif (interstitial fluid colloid pressure)?
Anything that decreases peritubular reabsorption; more fluid in the interstitium dilutes any protein in the IF, therefore decreasing Piif
Less colloid means less attraction of water to the IF, and more backleak occurs
210
Aldosterone is secreted by:
Zona glomerulosa cells of the adrenal cortex
211
Aldosterone promotes:
It’s target:
Na+ reabsorption and K+ secretion
Principal cells of the cortical collecting tubules
212
Mechanism of aldosterone:
Stimulates Na+/K+ pump on basolateral membrane
Increases Na+ permeability of luminal membrane
213
Angiotensin II is secreted by liver as _____
Converted by renin into _____,
Then to angiotensin II by ____ in the ____.
Angiotensinogen
Angiotensin I
ACE
Lungs
214
Effects of angiotensin II
Increases aldosterone secretion
Constricts efferent arterioles; decreasing Pc of peritubular capillaries therefore increasing reabsorption
Stimulates Na+/K+ pump and Na+/H+ exchanger, AND Na+/HCO3- cotransport therefore a lot of Na+ is reabsorbed.
215
What receptor attaches to angiotensin II?
AT1
216
ADH, aka
Arginine vasopressin- AVP
217
ADH is secreted by ____ ____ ____.
It increases:
It’s mechanism:
Posterior pituitary gland
Water permeability of distal tubules
Causes insertion of aquaporin-2 into tubular membrane
218
Atrial natriuretic peptide is secreted by:
It decreases:
Distended atria
Na+ and water reabsorption
219
PTH increases:
Reabsorption of Ca+2 in the distal tubules
220
Site of action and effects of...
Aldosterone
SOA: Collecting Duct
Effects: Increased NaCl, H2O reabsorption
Increased K+ and H+ secretion
221
What is the definition of renal clearance?
The volume of plasma that is completely cleared of a substance by the kidneys per minute
—This is a theoretical value, as it is impossible to completely clear a substance from a given volume of plasma
222
Site of action and effects of...
Angiotensin II
SOA: Proximal tubule, thick ascending loop, distal tubule, collecting duct
Effects: Increased NaCl, H2O reabsorption
Increased H+ secretion
223
Site of action and effects of...
ADH (AVP, Vasopressin)
SOA: Distal tubule, collecting duct
Effects: Increased H2O reabsorption
224
Site of action and effects of...
Atrial natriuretic peptide
SOA: Distal tubule
Collecting duct
Effects: Decreased NaCl reabsorption
225
Site of action and effects of...
Parathyroid hormone
SOA: Proximal Tubule
Thick ascending loop
Distal tubule
Effects: Decreased PO4- reabsorption
Increased Ca+2 reabsorption
226
What is the measurement of for the amount of substance that moves from plasma into the tubules?
Cs X Ps = the amount of substance that moves from the plasma into the tubules (mg/min)
Cs = clearance rate of substance (ml/min)
Ps = Plasma [s] (mg/ml)
227
Equation for rate of movement of substance from the tube into urine/excretion rate (mg/min)
Us X V = rate of movement of substance from the tube into urine/excretion rate (mg/min)
Us = Urine [substance] (Mg/ml)
V = urine flow rate (ml/min)
228
Equation that states a substance is freely filtered, but not reabsorbed nor secreted
Cs X Ps = Us X V
(Says that the mg/min of clearance of a substance from the plasma into the tubules is the same as the mg/min of the substance showing up in the urine (excretion))
229
Equation measuring renal clearance (Cs)
What does this mean for GFR?
-Give an example
Cs = Us X V/Ps
(Since Cs is essentially GFR, you can replace it with GFR)
Ex- Inulin clearance
230
What can also be used in renal clearance?
Creatinine
231
What is the drawback of creatinine being used?
It is secreting in small amounts in the kidney tubules
232
What is the “happy coincidence” of creatinine in renal clearance?
The lab measurement of Pcreatinine overestimates the concentration by about the amount it is secreted, so they offset each other.
233
What is the funnel-shaped expansion of the superior end of the ureter?
Renal pelvis
234
The renal pelvis receives ____ major calices.
Each major calyx receives ____ minor calices
2-3
2-3
235
What is located in the renal medulla?
Renal pyramids
Papilla
Renal columns
236
The renal pyramids contain:
Collecting tubules and loops
237
What is the apex of the renal pyramids?
Papilla
238
The renal columns separates the ______ and contain:
Pyramids
Blood vessels and nerves
239
Where will you find the renal corpuscles?
Renal cortex
240
If the clearance of a substance is equal to inulin, the:
The substance is filtered, but not reabsorbed or secreted
241
If the clearance of a substance is less than inulin, then:
The substance is reabsorbed
242
If the clearance of a substance is greater than inulin, then:
The substance is secreted
243
How is the relationship between a substance and inulin expressed?
Clearance ratio
Cs/Cinulin
