Renal Function and Renal Function Test Flashcards
Functional unit of kidney; maintain body’s essential water & electrolyte balances
Nephron
Consist of coil 8 capillary lobes
Glomerulus
Surrounding glomerulus; starts the forming of tubules
Bowman’s Capsule
Known as Peritubular capillary; surrounds PCT for immediate reabsorption
Distal Convoluted Tubule (DCT)
Located adjacent to the ascending & descending loop of henle
Vasa recta
Renal Function:
(4 points)
Renal Blood Flow
Glomerular Filtration
Tubular Reabsorption
Tubular Secretion
Renal Blood Flow
RENAL ARTERY that supplies blood to kidney
AFFERENT ARTERIOLE (unfiltered)
GLOMERULUS (filtration)
EFFERENT ATERIOLE
PERITUBULAR CAPILLARIES
VASA RECTA (water & salt exchange)
RENAL VEIN
over ____% kidney’s receive large blood flow
25%
Average body size
1.73m^2
Total renal BLOOD flow
1200 mL/min
Total renal PLASMA flow
600-700 mL/min
Served as a sieve or a filter of plasma substances with molecular weight of:
Glomerulus
MW: <70,000
Served as a sieve or a filter of plasma substances with molecular weight of:
Glomerulus
MW: <70,000
Factors that influence the actual filtration process:
(3 points)
• cellular structure of capillary walls & Bowman’s capsule
• hydrostatic & oncotic pressure
• feedback mechanisms of RENINANGIOTENSIN ALDOSTERONE SYSTEM
Cellular layer that contains pores (fenestrated)
Cellular wall membrane
Restriction of large molecules occurs as the filtrate passes
Basement Membrane
thin membranes covering the filtration slits formed by the intertwining foot processes of the podocytes of the inner layer of Bowman’s capsule
Visceral epithelium of 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
Inadequate supply of blood in glomerulus will cause
Vasolidation/Vasoconstriction
BP drops
Dilation of _______ arterioles
Constriction of _______ arterioles
afferent
efferent
Autoregulatory mechanism within the juxtaglomerular apparatus
Hydrostatic Pressure
regulates the flow of blood to and within the glomerulus.
RAAS (Renin Angiotensin Aldosterone System)
This system respond to changes in blood pressure and plasma sodium content
RAAS (Renin Angiotensin Aldosterone System)
Renin Angiotensin Aldosterone System is monitored by
Juxtaglomerular Apparatus
FUNCTIONS OF ANGIOTENSIN II:
- Vasodilation of afferent & vasoconstriction of efferent arteriole.
- Stimulate Sodium reabsorption in the (PCT).
- Release of the Aldosterone from adrenal cortex.
- Release of Antidiuretic hormone from hypothalamus.
TUBULAR REABSORPTION
The body cannot lose _____ of water-containing essential substances every minute
120 mL
Reabsorption Mechanism
- Active Transport
- Passive Transport
Plasma concentration at which active transport stops
Renal Threshold
Exceeding the renal threshold of substances affects the ________ capacity of the tubules, leading to the appearance of the ______ in the urine
Maximal reabsorptive
substance
Location of
Glucose
Amino acids
Salts
Promixal Convoluted Tubule
Location of Sodium
PCT and DCT
Location of
Water
PCT
Descending Loop of Henle
Collecting Duct
Location of Urea
PCT
Ascending Loop of Henle
Location of Sodium
Ascending loop of henle
TUBULAR CONCENTRATION
Water is removed by osmosis in the_______ loop of Henle, and sodium and chloride are reabsorbed in the______ loop
Descending loop of henle
Ascending Loop of Henle
selective reabsorption process; maintain the osmotic gradient of the medulla
Countercurrent mechanism
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
Reabsorption depends on the osmotic gradient in the _____ and the hormone _____
medulla
VASOPRESSIN (ADH)
Reabsorption depends on the osmotic gradient in the _____ and the hormone _____
medulla
VASOPRESSIN (ADH)
Production of vasopressin is determined by the ________.
state of body hydration
Tubular Secretion functions:
- Elimination of waste products not filtered by glomerulus
- Regulation of acid base balance (secretion of hydrogen ions)
standard tests used to measure the filtering capacity of the glomeruli
Clearance Test
STANDARD METHOD for GFR; Demonstrate progression of renal disease or response to therapy
Urea Clearance Test
True or False
Urea Clearance Test
gives reliable estimates of GFR (40% filtered urea is reabsorbed)
False
REFERENCE METHOD for GFR; Not routinely done because of the necessity for
continuous IV infusion
Inulin Clearance Test
Most commonly used; screening method of GFR
Creatinine Clearance Test
Determines the functional capacity of nephrons
Glomerular Filtration Rate
Determines the extent of nephron damage in known cases of renal disease.
Creatinine Clearance
Indirect estimate of GFR; A low molecular weight protease inhibitor
Cystatin C
rise has been shown to be more sensitive indicator of decrease in GFR than creatinine clearance.
Beta 2 Microglobulin
routinely screening patients as part of metabolic profile; to monitor patients already diagnosed with renal disease or at risk for renal diseas
Estimated Glomerular Filtration Rates
