test 4 Flashcards
(157 cards)
1
Q
6 functions of urinary system
A
o Filter blood to remove wastes/toxic substances
o Production, storage and elimination of urine
o Regulates fluid and electrolyte balance
o Regulates blood PH
o Regulates blood volume and blood pressure
o Regulates erythropoiesis
2
Q
kidney functions
A
filter blood and produce urine
3
Q
ureter
A
move urine from kidneys to bladder
4
Q
urethra
A
moves urine from bladder to exterior
5
Q
urinary bladder
A
stores urine
6
Q
Kidney location and structure
A
retroperitoneal-outside/behind abdominal cavity
Renal cortex
Renal Medulla
7
Q
kidneys surrounded by three external layer
A
renal fascia
adipose capsule
renal capsule
8
Q
Nephron: definition and structure
A
major functional unit of the kidney. Urine production begins here. Empties into collecting system.
o Renal corpuscle: filters blood
o Renal tubule: collects filtrate
9
Q
Collecting system
A
series of tubules that receive filtrate from nephron and further modify it
10
Q
parts of collecting system
A
Cortical and medullary collecting ducts and papillary collecting ducts and papilla and minor calyx
11
Q
Types of nephrons
A
Cortical nephron and Juxtamedullary nephron
12
Q
what’s the difference between the types of nephrons
A
Cortical nephron: primarily in cortex. Branch into peritubular capillaries. And Juxtamedullary nephron: extend into medulla. Peritubular capillaries connected to long straight capillaries
13
Q
which nephron is more abundant
A
Cortical nephron
14
Q
Urine production
A
eliminates metabolic waste products while minimizing loss of water and nutrients
15
Q
urea
A
most abundant organic waste from protein catabolism
16
Q
creatinine
A
product of creatine phosphate catabolism
17
Q
uric acid
A
product of nucleic acid catabolism
18
Q
renal failure
A
results in buildup of toxic wastes
19
Q
dialysis
A
medical process for those who have lost kidney functions. Machine that filters blood.
20
Q
Filtration
A
kind of transport: passive movement of fluid and solutes direction of movement: blood in glomerular capillaries to filtrate inside renal corpuscle (blood to filtrate). Driven by hydrostatic pressure
21
Q
Reabsorption
A
active or passive movement of water solute from filtrate in renal tubule back to blood in peritubular capillaries
22
Q
Secretion
A
active transport of water and solutes from blood in peritubular capillaries to filtrate in renal tubule
23
Q
Paracellular route
A
substances pass between adjacent tubule cells
24
Q
Transcellular route
A
substances must move through tubules cells
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diffusion and osmosis are examples of
passive transport
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active transport requires
an energy input
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facilitated diffusion and active transport are examples of
carrier-mediated transport and require protein pumps
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Carriers (channels) are specific and can be saturated (what happens if channels get saturated
all binding sites are filled and can start seeing the substance in urine
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transport maximum
maximal blood solute levels that can be transported
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renal threshold
plasma concentration at which a specific compound appears in urine because the TM has been reached
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Renal corpuscle
Glomerular (Bowman’s) capsule and the glomerulus
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What are podocytes
cells that form the visceral layer of the capsule of the renal corpuscle
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what are filtration slits
between podocytes and part of filtration membrane. Must fit in these area in order to filter.
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how filtration works
it is only selective based on size: only small particles filtered (proteins and cells are not filtered)
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Components of filtration membrane
made of pores of fenestrated capillaries, basal lamina, and filtration slits of podocytes
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Hydrostatic pressure
pressure in glomerulus
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GHP and filtration
favors filtration
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CHP and filtration
opposes filtration
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GCOP
osmotic pressure and pulls water into capillaries, so it opposes filtration
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Net filtration pressure equation
= GHP – CHP-GCOP
o 0 or negative =no filtration
o Positive number = filtration
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What is GFR
amount of filtrate produced by both kidneys per minute
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what does GFR depend on
GFR depends on blood pressure (higher BP means higher GFR)
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Autoregulation
ability of neprhons to adjust their own blood flow and GFR
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myogenic
stretch receptors in afferent arteriole detect pressure changes and respond to adjust GFR
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tubuloglomerular mechanisms
the glomerulus receives feedback on the status of downstream tubular fluid and adjusts filtration rate accordingly
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changes in the afferent and efferent arterioles control
blood pressure in the glomerulus and therefore GFR
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BP low/GFP low
= dilate arteriole/constrict efferent arteriole. Goal: high BP and high GFR
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BP high/GFP high
= constrict afferent arteriole/dilate the efferent arteriole. Goal: low BP/low GFR
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JGA
macula densa of DCT + smooth muscle of arterioles
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JGA Hormonal regulation
JGA cells secrete rennin and EPO
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Renin-angiotensin-aldosterone system
renin converts angiotensinogen to angiotensin I and then ACE converts angiotensin I to Angiotensin II
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renin is released in response
low BP (low GFR) and low filtrate concentration in DT
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low BP causes
low GFR, causes release of renin, causes activation of angiotensin II, causes increase in blood volume, causes increase in BP and therefore increase in GFR.
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ANP
released in response to high BP and GFR
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high BP causes
ANP/ BNP release, which causes an increase in GFR, which leads to more fluid loss and therefore less blood volume and less blood volume means lower BP.
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recycling urea
helps pull water by osmosis
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the countercurrent exchanger in the vasa recta
blood and filtrate go in opposite directions. Descending vasa recta absorbs NaCl, and the ascending vasa recta absorbs water
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DT and collecting duct secretion
depending on needs substances can be secreted. Potassium, HCO3, and ammonium ions
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DT and collecting duct selective reabsorption
body has a choice (selective based on needs). Na+, Ca2+, HCO3, water, urea. 85% of water and 90% of sodium reabsorbed.
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aldosterone causes
more Na reabsorption and K loss
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ADH causes
more water reabsorption (by increasing the number of aquaporins in membrane of DT and collecting duct
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in collecting duct urine gets?
concentrated and its volume is reduced
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Obligatory water reabsorption
85% in Proximal tubule and loop, through osmosis driven by medullary concentration
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Facultative water reabsorption
(15 %, controlled by ADH, in Distal Tubule and collecting duct and requires aquaporins) more aquaporins means more reabsorption, which produces a smaller amount of concentrated urine. No ADH= no aquaporins, which means no water reabsorption and large amounts of diluted urine.
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slit like opening in ureter
prevents back flow
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rugae
series of ridges produced by folding of the wall the bladder
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detrusor muscle
around the bladder
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urethra is longer in
males
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pH scale
low H+=high PH=basic. High H+=low PH=acidic
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acid
dissociates to release H+
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base
reduces the amount of free hydrogen in solution
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Strong acid
completely dissociates in solution
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Weak acid
does not dissociate completely
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Strong base
dissociates completely
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Weak base
do not dissociate completely
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Volatile acids
can move from liquid to gas
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carbonic acid is a
volatile acid
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Fixed acids
only stay in solution. Remain in body until excreted
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Organic acids
byproducts of metabolism
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Normal range of ECF pH
7.35-7.45
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Sources of H+ gains
from GI tract and metabolism
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Sources of H+ losses
kidneys and lungs
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Chemical Buffer systems
combination of weak acid and its anion. Are the first response, but a temporary solution
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Protein buffer systems
know that amino group accepts H (base) and carboxyl group can donate H (acid) and act as buffer; know that only free or terminal amino acids can do that; know that hemoglobin is a buffer
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Phosphate buffer systems
you only need to know that it’s the major ICF (intracellular fluid) buffer
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Carbonic-acid bicarbonate buffer system
most important ECF buffer
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how does the Carbonic-acid bicarbonate buffer system work?
prevents PH changes caused by fixed and organic acids
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the 2 limitations to the Carbonic-acid bicarbonate buffer system
only works if respiratory system works and need enough bicarbonate
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Carbonic-acid bicarbonate buffer system equation
CO2+H2O --- H2CO3 --- H+ + HCO3-
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what will drive forward reaction? what will drive reverse?
too basic- forward reaction. too acidic= reverse reaction.
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most important factor affecting pH
pCO2
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relationship between H+, pH and pCO2
high pCO2=high H+=low ph. low pCO2=low H+=high Ph
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Acute phase
ph moves rapidly out of normal range/ no compensation
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compensated phase
adjusted back to normal pH but constant compensation
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normal phase
normal pH and no compensation, source of problem is removed
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what happens to ph and pCO2 during Respiratory acidosis
low Ph, high CO2.
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causes of respiratory acidosis
respiratory problems, emphysema, CNS injury, heart failure
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compensation for acidosis
respiratory compensation- increase RR; renal compensation- excretion of H+; reabsorption of HCO3-
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what happens to ph during metabolic acidosis
low ph
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causes of metabolic acidosis
diarrhea, loss in bicarbonate, unable to get rid of acid, producing too much acid
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what happens to Ph and CO2 during respiratory alkalosis
high Ph and low CO2
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causes of respiratory alkalosis
hyperventilation, pain, anxiety
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compensation for alkalosis
decreased RR, excretion of HCO3-; reabsorption of H+
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what happens to Ph during metabolic alkalosis
high ph
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causes of metabolic alkalosis
vomiting, diuretics, too much bicarbonate
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compensation for metabolic alkalosis
decreased RR, excretion of HCO3-; reabsorption of H+
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what fluids make up the ECF
fluid outside cells. Includes plasma of blood, interstitial fluid, and other body fluids
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ICF
intracellular fluid (cytosol)
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how ECF and ICF are different
more than half fluid is inside cells and ICF contains more water
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Major ICF ions
potassium, magnesium, proteins, sulfate, hydrogen phosphate
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major ECF ions
sodium, chloride, calcium, bicarbonate
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basic principles of regulation
o All receptors in ECF not ICF
o Receptors monitor plasma volume and osmotic concentration
o Cells cannot move water by active transport only passively by osmosis – water follows salt
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Main sources of water gains
from drinking, eating, and metabolism
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water losses
urine, feces, exhaled air, insensible and sensible perspiration
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fluid shifts
rapid movement of water between ECF and ICF
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hypertonic ECF
(low fluid, high concentration), shift is out of cells (from ICF to ECF)
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hypotonic ECF
(high fluid, low concentration), shift is into cells (from ECF to ICF)
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Osmoreceptors
in the hypothalamus respond to angiotensin 2 and rise in osmolarity of ECF. Regulates thirst and urination sensation
119
ADH
secreted by posterior pituitary upon stimulation from osmoreceptors. Stimulates you to drink more/excrete less
120
Aldosterone
secreted by adrenal cortex in response to too much potassium or not enough sodium or in presence of Ang 2. Stimulates to drink more/excrete less
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Angiotensin II
Activated after renin is released by kidneys in response to low BP and blood volume. Stimulates us to drink more/excrete less
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ANP/BNP
secreted by cardiac muscle excreted in response to high BP and increased volume. drink less/excrete more
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how to get Dehydration
Sweating too much, diarrhea, vomiting, diabetes, too many diuretics
124
Dehydration results in
hypertonic ECF (hypernatremia), low plasma volume and low BP
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Response mechanisms to dehydration
water shift out of cells (from ICF to ECF); roles of renin-angiotensin, ADH, aldosterone: increase volume (increase thirst and decrease excretion)
126
What is the difference between hypovolemia and dehydration
hypovolemia is loosing water and solute (bleeding) no fluid shift because no change in concentration and dehydration is only losing is water. Concentration goes up.
127
causes of overhydration
Renal failure, too much IV fluid, too much water, low or no ADH
128
over hydration results in
hypotonic ECF (hyponatremia), increased plasma volume and BP
129
Response mechanisms to overhydration
water shift into cells (from ECF to ICF); role of ANP/BNP (decrease thirst and increase excretion)
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What is the difference between hypervolemia and over hydration
hypervolemia is both water and electrolytes gained. Results in edema. No fluid shift because no change in concentration and overhydration is water gain and concentration change
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difference between total amount and the concentration of an ion
o Total amount of ions= how much solute
| o Concentration of ions = total amount/ amount dissolved in
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o fluid balance is critical factor that determines
electrolyte balance
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Sodium imbalance is, while potassium imbalance is
sodium balance is more common while potassium balance is more dangerous
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sources of Na gains
absorption though GI tract
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sources of Na losses
excretion by kidneys and perspiration
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water follows
salt
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fluid loss and gain affects the concentration of electrolytes
fluid gains lower concentration and fluid losses increases concentration
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Hypernatremia
higher than normal concentration of sodium. caused by fluid loss. Detected by osmoreceptors stimulates same mechanisms as response to dehydration
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Hyponatremia
lower than normal concentration of sodium caused by overhydration or rapid loss of sodium. Detected by osmoreceptors in brain and stimulates same mechanisms as response to overhydration.
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sources of K gains
absorption through GI
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sources of K losses
excretion by kidneys
142
Hyperkalemia
lower than normal potassium concentration. caused by- inadequate intake, diuretics causes more negative resting membrane potential, which leaves cells less responsive to stimuli
143
Hypokalemia
higher than normal potassium levels caused by pH or ECF, renal failure, burns. Results in more positive resting membrane potential or excitable cells, such as cardiac arrhythmias.
144
Calcium balance. what is it important for and what hormones do you need to stay in balance?
important for muscle contractions. PTH and Vit. D are important for balance
145
what causes hypercalcemia
higher than normal calcium concentration. caused by hyperparathyroidism, excess vitamin D, bone disorders, and renal failure
146
hypocalcemia
lower than normal calcium concentration. caused by Ca and Vitamin D dietary deficiency, PTH deficiency, chronic renal failure
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where is the JGA located
between the renal corpuscle and the afferent/efferent arteriole
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what does the JGA do?
regulates blood flow to the glomerulus and secretes EPO and renin
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effects of low level neural stimulation
causes increase in GFR
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effects of high level neural stimulation
causes constriction of afferent arterioles and decrease in GFR. Ex: warm weather and exercise
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parts of renal tubule
proximal tubule, nephron loop, and distal tubule
152
what happens to the filtrate as it travels through the tubule?
the filtrate changes as it travels through the tubule.
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proximal tubule function
some secretion but mainly reabsorption.
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what is reabsorbed in the proximal tubule
sodium, potassium, Cl-, PO4-, HCO3-
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difference between thick and thin nephron loop
thick: reabsorption of ions: sodium chloride, calcium, and magnesium. thin: reabsorption of water
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during Medullary concentration gradient concentration is higher in
medulla, because of countercurrent mechanisms and urea
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what needs to be present for urine concentration at the collecting duct
ADH
