Renal Flashcards
What are the mechanism of increasing BP by the kidneys?
⬇️Renal blood flow
⬇️GFR
⬆️Renin, which is secreted by the juxta glomerular cells
The renin converts the angiotensinogen (in the liver) to angiotensin 1, which will be converted by the Angiotensin converting enzymes (ACEs) to angiotensin 2 (this is the active form that increases the blood pressure by VC.
Kidney regulate blood pressure by secreting…..firstly
Renin
The substance that causes VC and actually increases BP is….
Angiotensin 2
Where does Angiotensin 2 cause VC?
1-On the blood vessels in general, so increases the BP
2-On the efferent arteriol in the kidney especially, so increase the GFR
Why is captopril and enalapril considered as Hypertension treatments?
Because they are ACEI (Angiotensin converting enzymes inhibitor) so it inhibits the synthesis of angiotensin 2
What is the role of sympathetic system in regulating the BP?
1-It causes VC to the body blood vessels in general, so increases the BP.
2-It causes VC to the Afferent arteriol in the kidney, so in decreases the GFR.
How to differentiate between oliguria and blocked catheter?
Blocked catheter: 80,80,80,0,0,0
Oliguria: 80,70,40,30,20,0
What is (Renal blood flow)?
The amount of blood that passes to both kidneys/minute
1200ml/min=20% of COP
(98% to cortex, 2% to medulla)
What is the first part to get affected by a shock in the kidney?
The medulla, because it has the least blood supply, might lead to papillary necrosis and renal failure
What is the GFR?
Amount of glomerular filter are formed in all nephrons in both kidneys/minute
125ml/min
How is the Renal blood flow measured?
By the PAHA clearance
How is the GFR measured?
By the inulin clearance
What are the differences between PAHA and inulin?
PAHA: is filtered, SECRETED and not reabsorbed.
Inulin: is filtered, NOT SECRETED and not reabsorbed.
What is the site of action and the action of loop diuretics? (As furosemide)
It acts on the thick ascending loop of henle by blocking the NA,K,CL channel at the liminal border
What is the action and site of action of the thiazide diuretic?
It acts on the DCT, by blocking the NA,Cl channel at the luminal border.
What is the action and site of action of the K-sparing diuretics as spironolactone and amiloride?
It acts on the collecting tubules, by blocking the action of the NA,K pump
What is the action and site of action of the vasopressin/ADH?
It acts on the medullary collecting tubules to reabsorb water
Where is the glucose and mannitol absorbed?
ALL the glucose is absorbed in the PCT as the Na-glucose transporter is only found in this segment
What are the substances that are normally not seen in the urine?
RBCs (Large size)
Proteins (Large size and negative charges)
Glucose and Amino acids (they are completely reabsorbed)
What is the mechanism of urine concentration?
The counter current multiplier mechanism
How does the counter current multiplier mechanism work?
It works in the ascending loop of henle as it is impermeable to water but actively transport solutes to the medulla, so the osmolarity of the medulla increase, so down in the medullary collecting tubules, the ADH reabsorbs water to the blood leaving the urine concentrated
What is the urinary sediment in the pre-renal uremia/azotemia and in the Acute tubule necrosis?
Pre renal uremia: Normal or hyaline casts
Acute tubular necrosis: Epithelial cell casts
What is the amount of urine sodium in Pre renal uremia and acute tubular necrosis?
Pre renal uremia: <20 mmol/l
Acute tubular necrosis: >30mmol/l
What is the specific gravity of urine in Pre renal uremia and acute tubular necrosis?
Pre renal uremia: >1020
Acute tubular necrosis: <1010
