Filtration & Absorption Flashcards
What controls the pressure within the glomerulus?
The afferent and efferent arterioles
What defines the GFR?
Amount of blood filtered by kidney’s glomerulus into the bowman’s capsule per unit of time
Which two forces are battling to maintain the fluid level in the glomerular capillaries?
Hydrostatic (bowman’s capsule) and oncotic (notably albumin)
*hydrostatic varies with BP
What GFR indicates renal failure?
15ml/min or lower
What provides short and long term regulation of BP
Short/fast: (short term) Myogenic response, baroreceptor reflex
Longer/slow: fluid volume, RAAS, Hormones; ANP, aldosterone
What is the normal filtrate produced per minute?
125 ml/min
Name 5 vasoconstrictors and 4 vasodilators
Vasoconstrictors: sympathetic, angiotensin II, endothelin, renin, adenosine (A1AR)
Vasodilators: Prostaglandins, NO, Bradykinin, ANP (atrial natriuretic peptide)
What’s the renal threshold? What defines glycosuria?
Max rate glucose can be resorbed
10mmol/L of glucose in the urine
Where is hydrogen carbonate recovered and through which channel?
90% is filtered and recovered in the PCT via the Na+/H+ antiport
What are the two parts of the Collecting Duct?
The cortical part: similar to DCT
The medullary part: resorption of water
Where is H+ secreted?
In the DCT
What substances would you use to measure the GFR, and what is the formula?
Using inulin in animals or creatinine in muscles as both are neither resorbed or secreted in the nephron.
*consider age, gender and person size
Formula: Conc of substance (creatinine/inulin)) in urine X Volume of urine in 1 min/Conc of substance in plasma
Briefly describe the myogenic response
BP rises - sm muscle contracts (protects GFR)
