Final Exam Lecture 5 Flashcards
What exactly does the Macula Densa do?
Looks at Quantity of Na+ and Cl- that goes by it in a certain amount of time
How is Creatinine concentration as we get further into the PT?
It is increased, as we filter more H2O
What 2 substances have a VERY LOW to 0 CL?
Glucose and Amino Acids
True or False: SGLT Tx of Glucose and Na+ is Primary Active Tx?
False; 2nd Active Transport relying on the Na+ CG
What transporter sends glucose into the renal interstitium?
GLUT
What is Hyperfiltration?
*What Pt population is this seen in a lot
The MD hyperfiltrates Na+ as it sees the #’s are lower, despite what the cause may be
*This happens a lot in diabetic Pts
What is the Amino Acid and Na+ ratio in the transporters located in the cell?
1:1
What is the tubular side of the cell called?
Apical Side
What is the Interstitital Side of the Cell called?
Basolateral Side
Where is the S1 segment of the PT?
*What 2 transporters are located here: Ratio and %
*Describe efficiency and affinity
Early proximal tubule
*SGLT 2 Transporters [90%]; 1:1
*GLUT-2
*High efficient but low affinity
Where is the S2,3 segment of the PT?
*What 2 transporters are located here: Ratio and %
*Describe efficiency and affinity
*Why this Na+ to glucose ratio?
Late Proximal Tubule
*SGLT1 [10%]; very few in S3: 2 Na+ to 1 Glucose
*GLUT-1
*Lower efficiency but high affinity
*2 Na+ b/c harder to pump out glucose in a lower concentrated environment
What is the glucose threshold to not seeing glucose in the urine?
200 mg/dL
What is the Transport Maximum of Glucose?
*How does the graph look after the transport maximum
*What does this mean
300 mg/dL
*1:1 linear line for concentration and excretion in urine
*After 300 mg/dL, every glucose molecule in the blood will show up in the urine
What is Filtered Load?
*What 2 things is it dependent on
How much stuff has been filtered
*Plasma Concentration and GFR
What is the normal Filtered Load of Glucose?
*Math
GFR = 1.25 dL/min x 100 mg/dL = 125 mg/min of glucose to be filtered
What cells release Renin?
*What does this activate and where do they work?
JG cells
*Activates Angiotensin 2, which constricts the Efferent Arteriole
When Angiotensin 2 is released, what exactly does it do?
Constricts EA and increases NaCl reabsorption to increase BP and GFR
What compensatory mechanism do the kidneys do in response to decreased arterial pressure?
Decreased renal blood flow, decreased GFR = constriction of EA and dilation of AA
How do vessels look in chronic HTN and DM
Stiff and Calcified
In Chronic HTN and DM, what happens to AR in the kidneys?
*PCap of GC?
*Podocytes, Fenestrations, Slit Pores?
*Dysfunction of what vessel is mostly effected?
AR is less effective as the vessels are stiff and calcified, so cannot dilate or constrict as well
*PCap of GC will be >60, which will lead to GC destruction
*Podoyctes damaged, Fenestrations and Slit pores widen and scar
*Dysfunction in the AA
What is most damaged in the kidney from Chronic HTN, which leads to renal failure and other long-term kidney injuries?
Glomerular Capillary Beds, as the PCap is constantly higher than normal
If the Macula Densa recognizes a filtration deficiency, what happens?
Renin is released from JG cells to activate Angiotensin 2 and constrict the EA
If the Macula Densa recognizes a filtration increase, what happens?
Less renin will be released to slow down activation of Angiotensin 2 and dilate the EA
In the kidneys, where do drugs normal effect in terms of AA vs EA?
Mostly AA
Out of AA and EA, where does Angiotensin 2 mostly effect?
EA
What would the GFR be if we had a MAP of 200 in severe HTN?
*Math
*New NFP and old
40 mmHg [NFP] x 12.5 [Kf] = 500 ml/min
*New NFP would be about 40 mmHg, when normal is 10 mmHg
