Renal function Flashcards
Kidney’s function
- Maintaining homeostasis
- Excretion of waste products
- Concerned with the maintenance
of blood pressure and
erythropoiesis
Renal function:
A. Renal Blood Flow
B. Glomerular Filtration
C. Tubular Reabsorption
D. Tubular Secretion
Contains pores and are referred to as fenestrated
Capillary wall membrane
Consists of coil approximately 8 capillary lobes referred to as a capillary tuft
Glomerular filtration
Thin membrane podocytes
Visceral layer of bowman’s capsule
Endothelial capillaries
capillary wall membrane
supplies blood to the
kidney.
renal artery
Total renal blood flow
1200 ml/min
Total renal plasma flow
600-700 ml/min
glomerular function located within the
bowman’s capsule
Necessary to overcome the opposition of pressure from the fluid from the bowman’s capsule and the oncotic pressure of unfiltered plasma protein
Hydrostatic pressure
caused by size of afferent and efferent arteriole
presence of hydrostatic
Dilation of the afferent arterioles and construction of the efferent arterioles
BP drops
Caused by size afferent and efferent arteriole
Presence of hydrostatic pressure
restriction of large molecules occurs as the filtrate passes
Basement membrane (basal lamina)
regulates the flow of blood to and within the glomerulus.
RAAS (Renin-Angiotensin-Aldosterone System)
Renin-Angiotensin-Aldosterone System is controlled by
JUXTAGLOMERULAR APPARATUS
FUNCTIONS OF ANGIOTENSIN II
- Vasodilation of afferent & vasoconstriction of efferent arteriole.
- Stimulate Sodium reabsorption in the Proximal Convoluted Tubule (PCT).
- Release of the hormone Aldosterone from adrenal cortex.
- Release of Antidiuretic hormone from hypothalamus
Substance to be reabsorbed must combine to a carrier protein contained in
the membranes of the renal tubular cells
active transport
plasma concentration at which active transport stops
renal threshold
The body cannot lose 120 mL of water-containing essential substances every minute
tubular reabsorption
movement of molecules across membrane as a result of
differences in their concentration or electrical potential.
passive transport
location of Glucose
Amino acids
Salts
Proximal Convoluted
Tubule
location of Sodium
Proximal and distal convoluted tubule
The final concentration of the filtrate
through the reabsorption of water begins
in the late distal convoluted tubule and
continues in the collecting duct.
collecting duct concentration
determined
by the state of body hydration.
vasopressin
2 MAJOR FUNCTIONS OF TUBULAR SECRETION
-Elimination of waste products not filtered by the
glomerulus
-Regulation of acid- base balance
ACTS AS BUFFER TO THE BLOOD
MAINTAINING NORMAL pH
Bicarbonate
The standard tests used to measure the filtering capacity of the glomeruli
clearance test
Not routinely done because of the necessity for continuous IV infusion
INULIN CLEARANCE TEST
STANDARD METHOD for GFR
Urea clearance
specific test example
- fishberg test
- mosenthal test
Patients were deprived of fluids for 24 hours prior to measuring specific
gravity
fishberg test
Compare the volume and specific gravity of urine of day and night urine
samples
mosenthal test
PRINCIPLES OF FREEZING POINT OSMOMETERS
Measurement of freezing
point depression
PRINCIPLES OF VAPOR PRESSURE OSMOMETERS
Measurement of dew point
Tests to measure tubular secretion of nonfiltered substances and renal blood
flow
TUBULAR SECRETION & RENAL BLOOD
FLOW TEST
This condition may result from impaired tubular secretion of hydrogen ions associated with the
proximal convoluted tubule
RENAL TUBULAR ACIDOSIS
Process of renal blood flow
RENAL ARTERY > AFFERENT ARTERIOLE > GLOMERULUS > EFFERENT ARTERIOLE > PERITUBULAR CAPILLARIES > VASA RECTA > RENAL VEIN
Factors influence the actual filtration process
- cellular structutr of capillary walls
- hydrostatic and oncotic pressure
- feedback mechanisms of the reninangiotensin aldosterone system
This system respond to changes in blood pressure and plasma sodium content
RAAS
