Extra Flashcards
Angiotensin II.
What does it do
to PGC, GFR, RBF and FF, Pertitubular oncotic pressure
Causes vasoconstriction of the efferent arteriole
–> Increase PGC–> increase GFR, but decrease RBF
Filtration fraction will thus, increase because the amount of protein in the plasma increases–> increasing your peritubular oncotic pressure
L –> dL
1L= 10dL
L to mL
1L= 1000 mL
Rate of rate of urine (K+) excretion
Ux * V (flow)
TGF goal:
- Maintain a constant GFR
- Maintain constant NaCl delivery to DCT
How does this work>
Adenosine acts on what part of the GC?
Vasoconstriction of the afferent arteriole
How do MESENGIAL CELLS ALTER GFR?
Alter SA of K+
How does constriction of the afferent arteriole alter of FF?
No change
How does constriction of the efferent arteriole alter of FF?
increase
Why do our kidneys use 2x rate of O2 than the brain?
Increase reabsorption of Na+ occurs linearly
What happens when we sweat?
Think of sweat as losing water:
Hyperosmotic volume contraction
When we sweat
- Decrease in ECF volume*
- Increase in ECF osmolarity*
- —creates a concentration gradient: water wants to move from ICF–> ECF—-*
- Decrease in ICF volume*
- Increase in ICF osmolarity*
A child is diagnosed with SIADH. What happens to ECF, ICF and osmolarity.
Same thing as excessive water intake: hypoosmotic volume expansion
— Increase ECF volume—-
Decrease osmolarity of ECF and ICF
—– Increase in ICF volume—–
- Plasma protein levels decrease bc increase in ECF volume.
Hematocri- stays same bc water goes into RBC, increasing volume and offesting dilution
What happens when we have diarreah?
isoosmotic volume contraction
- ECF volume will decrease; no change in osmolarity, so ICF volume does not change.
- Plasma protein levels increase and hemotocrit increase because decrease ECF increases them. RBC do not shrink or swell
- BP will decrease d/t decrease in ECF volume
What happens when lost in a desert?
Sweat
(hyperosmostic volume contraction)
- Decrease in ECF volume: Increase in ECF osmolarity--> water moves from [ICF–> ECF–> decrease in ICF volume–> incrrease in ICF osmolarity
- Plasma protein levels increase
- Hemotocrit: stays the same bc water is moving out
What happens when during adrenal insufficiency
Adrenal insufficiency–> loss of NaCl
-
Hypo-osmotic volume contraction
1. Decrease ECF osmolarity because aldosterone insufficiency, leading to decreased reabsorption and the kidneys excrete more NaCl> water. - ECF volume decrease:
- ICF volume increases
- ICF osmolarity decreases
- Plasma protein concentration increases
- Hematocrit will increase d/t decreased ECF volume and the RBC swell
- BP decreases
What happens during infusion of isotonic NaCl
- Plasma protein concentration
- hematocrit
- BP
isoosmotic volume expansion
- ECF volume decreases; but there is not change in osmarity.
* BECAUSE THERE IS NO CHANGE IN OSMOLARITY, water cannot move bc the NaCl distributed evenly in both. - Plasma protein concentration decreases and hematocrit decreases bc it dilutres. RBCs do not shrink or swell bc no change in osmolarity.
- BP increases
What happens when during excessive NaCl intake
- hyperosmotic volume expansion
- Increase in ECF osmolarity
- Cause water to move from the ICF–> ECF: ECF increases and ICF decreases
- Increase in ICF osmolarity
- plasma protein concentration decreases
- hemotocrit decreases
A 40 y/o Caucasian female presents with a 3 week cc of “weird urine problems” She says the urine is extremely clear and doesn’t seem to be as yellow as she thinks it should be. You decide to perform a test that assesses the bodies ability to concentrate the urine. What is the name of this test?
.
Specific gravity- used to assess the concentrating ability of rthe kidney.
Constriction of the afferent arteriole occurs via _____ and does what
sympathetic
- decrease GFR
- decrease RBF
- no change on filtration fraction
Constriction of efferent artioles occurs via _____ and does what?
Angiotensin II
Increase GFR
Decrease RBF
Incerase filtration fraction
Increase plasam protein does to GFR, RBF, filtration fraction
Decrease GFR
no change in RBF
-decrease FF
Uretal stone does what to GFR, RBF, FF
Decrease GFR d/t increase hydrostatic pressure in BC
- no change in RBF
- decrease FF
-
What is invluded in the renal sinus
Renal pelvis
renal calyces
BV
nerves
fat
Cells in PCT
Simple cuboidal–> simple columnar with alot of microvillus, creating a brush boarder
-has TONs of Na/K ATpases
LoH cells
Thin limb- permeable simple squamous cells
Thick ascending- simple cuboidal epithelium with microvillus, but no BB
Why is the LoH so important?
SUPER important for concentrating the filtrate passing through, creating a HYPEROSMOTIC gradient.
How do we maintain a water concentration gradient in medulla?
Vasa recta take the water away
DCT cells and big player
Cells: simple cuboidal with few microvillus, having a smoother surface than the thick ascending limb
Angiotensin II influences Na+ reabsorption
CD
Cells:
Simple cuboidal–> simple columnar at the end
Job: concentrate urine by reabsorping water
ADH works here via type 2 aquaporin channels
Aldosterone
Types of collecting tubule cells
- Light cells (intercalated)–> H+ and bicarb transport
- Dark cells (principle cells)- aldosterone hits and increases Na+ reabsorption via Enac and K secretion
Remember, the concentration of Na+ in the tubular lumen will be the same as extracellular fluid (145meq). Intracellular Na+ is about 15 meq. This creates a concentration gradient.
The regulation of K/Na in the distal tubule is controlled by _______\_
aldosterone
How does aldosterone back on principle cells in the DCT?
Hold onto Na+, get rid if K.
Increase Na+ reabsorption,
Increase K+ secretion
As we go from CTX–> medulla: osmolarity increases.
What does this allow?
concentrate urine.
Water is freely filtered.
Regulated where?
Distal tubule and collecting ducts
Ascending thick limb reabsorbs Na, 2Cl and K. How does this affect the osmolarity?
Decreases; thus the thick ascending limb will always be hyposmotic and hypotonic.
What does ANP doe
Vasodilate afferent arterioles- and to a lesser extend; vasoconstrict efferent
ANP, overall increases RBF
Vasoconstriction of arteriols
Vasconstriction–> decrease in RBF
Occurs by activating [sympathetic NS and angiotensin II]
- Angiotensin II constricts efferent artioles and increases GFR.
What do ACE-inhibtors do?
dilate efferent arterioles and decrease GFR;
reduce hyperfiltartion
What does vasodilation do?
Increases RBF;
producted by PGE2, PGI2, NO, DA, bradykinin, ANP
Summary of tubulogomerular feedback
increased renal arterial pressure–> increased fluid delivery to macula densa
MD senses and constricts afferent arterioles, increasing resistance to maintain constant BF.
GFR decreases with age, although serum [creatinine] remains _____ because of
decreased muscle mass.
constant
