RENAL FUNCTION Flashcards
memorization
Basic structural & functional unit of the kidney
Nephron
there are approximately __ to ____ nephrons per kidney
1 to 1.5 million nephrons per kidney
2 types of nephrons
Cortical nephrons
Juxtamedullary nephrons
Order of urine formation
- Glomerulus
- Proximal convoluted tubule (PCT)
- Loop of Henle (LH)
- Distal convoluted tubule (DCT)
- ## Collecting ducts (CD)
- Calyx
- Renal pelvis –> Ureter –> Bladder –> Urethra
The kidneys receive ___% of the total cardiac output
25% of the total cardiac output
Total Renal Blood Flow:
1,200 mL/minute
Total Renal Plasma Flow:
600 - 700 mL/minute
Renal Blood Flow order:
- Renal artery (blood in)
- Afferent arteriole
- Glomerulus (sieve)
- Efferent arteriole
- peritubular capilliaries
- vasa recta
- Renal vein (blood out)
The working portion of the kidney; resembles a sieve; coil of approximately 8 capillary lobes located within the Bowman’s capsule:
Glomerulus
The glomerulus is a non-selective filter of plasma substances with MW of __________
<70,000 Da
it repels negatively charged substances even if they are small enough to pass
Shield of negativity
First function to be affected in renal disease
Tubular reabsorption
Renal threshold for glucose:
160-180 mg/dL
substances that are reabsorbed in the PCT via active transport
Glucose
Amino acids
Salts
substance/s that are/is reabsorbed in the PCT and DCT via active transport
Sodium
substance/s that are/is reabsorbed in the Ascending LH via active transport
Chloride
substance/s that are/is reabsorbed in the PCT, descending LH, CD via passive transport
Water
substance/s that are/is reabsorbed in the PCT, ascending LH via passive transport
Urea
substance/s that are/is reabsorbed in the Ascending LH via passive transport
Sodium
3 glomerular filtration barrier:
- capillary endothelium
- trilayer basement membrane
- filtration diaphragm
glomerular filtration barrier that has large open pores:
Capillary endothelium
glomerular filtration barrier that consist of the lamina rara interna, lamina densa, and lamina raraexterna
Trilayer basement membrane
glomerular filtration barrier that is found between the podocytes of the bowman’s capsule
filtration diaphragm
the RAAS system is activated when there is ____ blood pressure
low blood pressure
the RAAS system ______ the blood pressure
increases the blood pressure
In cases of Diabetes Insipidus, ADH is:
Deficient
In cases of Syndrome of inappropriate ADH secretion (SIADH), ADH is:
Excess/Increased
Body hydration increased
ADH decreased
Urine volume = ?
Increased
Body hydration decreased
ADH increased
Urine volume =?
Decreased
Aldosterone regulates ____ reabsorption in the DCT
Sodium (Na) reabsorption
Major functions of tubular secretion:
- Regulation of the acid-base balance in the body through secretion of hydrogen ions
- Elimination of waste products not filtered by the glomerulus
Major site for removal of non-filtered substances
PCT
Failure to produce acid urine due to the inability to secrete hydrogen ions
Renal Tubular Acidosis
In RTA, urine pH is _______
alkaline
to maintain the normal blood pH, what ion is secreted into the urine?
Hydrogen ion (H+)
In renal tubular acidosis, the blood pH is:
Acidic
used to evaluate glomerular filtration; measures the rate at which the kidneys are able to remove a filterable substance from the blood
Clearance test
most common clearance test:
Creatinine clearance test
Gold standard/reference method clearance test
Inulin
Creatinine clearance formula:
Ccr (mL/min) = UV/P x 1.73m^2/A
In the creatinine clearance formula, the ‘U’ represents:
U = urine creatinine (mg/dL)
In the creatinine clearance formula, the ‘A’ represents:
A = Body surface area
In the creatinine clearance formula, the ‘P’ represents:
Plasma creatinine
Reference range or creatinine clearance test:
Male:
Female:
Male: 107 - 139 mL/min
Female: 87 - 107 mL/min
What are the variables included in the Estimated GFR formula developed by COCKGROFT & GAULT
Variables:
1. Age
2. Sex
3. Body weight in kg
What are the variables included in the Modification of Diet in Renal Disease (MDRD) system formula?
Variables:
1. Ethnicity
2. BUN
3. Serum albumin
Used to evaluate tubular reabsorption:
Concentration test
concentration test where the patient is deprived of fluid for up to 24 hours
Fishberg test (obsolete)
concentration test where the patient maintains a normal diet and fluid intake, and compares day & night urine in terms of volume & Specific gravity
Mosenthal test (obsolete)
Influenced by the number & density of particles in a solution
Specific gravity
Influenced by the number of particles in a solution; more accurate and preferred than S.G. determination
Osmolality
Most commonly used test and the reference method for tubular secretion & renal blood flow:
p-aminohippuric acid (PAH) test
test for tubular secretion & renal blood flow; obsolete test; results are hard to interpret
Phenolsulfonphthalein (PSP) test
