RENAL PHYSIOLOGY/URINALYSIS Flashcards
The most important function of the kidney is its
ability to maintain the stability of the ECF volume, electrolyte composition and osmolarity
What is the 60-40-15-5 Rule?
60% = water
40% = intracellular fluid
20% = extracellular fluid
–> 15% = interstitial fluid
–> 5% = plasma
Where is the kidney located?
T12-L3
Where is the kidney situated?
retroperitoneum
The kidney is divided into:
- Outer: Renal Cortex
- Inner: Renal Medulla
Fill in the blanks: Formed ____________ the kidney, ____________ the ureter, and is_________________________.
urine exits, through, renal pelvis, stored in the urinary bladder
Functions:
- H2O balance
- osmolarity
- electrolytes
- plasma volume
- Acid-Base
- Eliminating waste products
- Eliminating drugs
- Erythropoietin
- blood pressure through renin production
- Vitamin D to its active form
What is the unit of the kidney?
Nephron
What is the nephron?
structural and functional units
What is nephron made up of?
- vascular component
- tubular component
- combined component
Two major types of Nephrons
- Cortical Nephron
- Juxtamedullary Nephron
Make up 75% of nephrons
Cortical Nephron
Make up 25% of nephrons
Juxtamedullary Nephron
Located in the renal cortex
Cortical Nephron
Located in the corticomedullary junction
Juxtamedullary Nephron
Shorter Loops of Henle
Cortical Nephron
Longer Loops of Henle
Juxtamedullary Nephron
Has peritubular capillaries
Cortical Nephron
Has vasa recta
Juxtamedullary Nephron
Vascular Component consists of
- Afferent arteriole
- Glomerulus
- Efferent arteriole
- Peritubular arteriole
- Vasa Recta
carries blood to the glomerulus
Afferent arteriole
tuft of capillaries that filters plasma into the tubular component
Glomerulus
carries blood away from the glomerulus
Efferent arteriole
involved in the exchange of substances with the fluid in the tubular component
Peritubular capillaries
serves as an osmotic exchanger for the concentration of urine
Vasa recta
Tubular Component consists of
- Bowman’s Capsule
- Proximal Tubule
- Loop of Henle
- Distal Tubule
- Collecting Duct
collects the glomerular filtrate
Bowman’s capsule
Site of reabsorption of 100% of Glucose and amino acids
Proximal Tubule
Establishes the osmolarity of urine
Loop of Henle
Descending limb: permeable to
water
Ascending limb: permeable to
solutes
Reabsorption of Na
Distal Tubule
Variable reabsorption and secretion of K
Distal Tubule
Secretion of H+
Distal Tubule
Site of Macula Densa
Distal Tubule
Site of action of Antidiuretic Hormone
Collecting Duct
____ urine volume & ______ urine concentration
low, high
Combined Component consists of
- Juxtaglomerular Apparatus
Found in the walls of the afferent arterioles
Juxtaglomerular Apparatus
Produces Renin which helps in the maintenance of blood pressure
Juxtaglomerular Apparatus
Basic Steps in Urine Formation
- Glomerular Filtration
- Tubular Reabsorption
- Tubular Secretion
- Excretion
It is the process of expelling urine
Micturition
Initiated by a nervous reflex that causes contraction of the detrusor muscle
Micturition
Is the analysis of urine
Urinalysis
Urinalysis is divided into:
- Physical examination
- Chemical examination
- Microscopic examination
Volume in P.E of urine
0.5-1.5 mL/kg/hour
End product of bilirubin metabolism
Urobilinogen
Urobilinogen is elevated in:
Hemolysis, liver disease, blood dyscrasias
Normal Proteinuria
<150mg/day
Normal Albuminuria
<30mg/day
increased quantity of proteins in the serum
Overflow proteinuria
due to low reabsorption at proximal tubule
Fanconi syndrome
Normal pH of urine
5.5-6.5
If alkaline, the most common cause is
stale or old urine specimens
Presence of blood cells in urine
Hematuria
Caused by renal stones, kidney diseases, or trauma
Hematuria
Product of body fat metabolism
Ketone Bodies
presence of ketone bodies in urine
Ketonuria
Most commonly caused by Hepatocellular (liver) disease
Bilirubinuria
Abnormality where conjugated bilirubin is detected in urine
Bilirubinuria
100% of glucose is reabsorbed in
proximal tubule
TRUE or FALSE: urine should contain glucose
FALSE
caused by untreated Diabetes Mellitus
Glycosuria
increased frequency of urination
polyuria
waking up to urinate more than once per night
nocturia
Usually seen when glucose serum levels exceed
180 mg/dL
Also known as Renal Calculi/Kidney Stones
Urinary Stones
Formed as a result of a crystal or crystalline concentration
Urinary Stones
occurs from supersaturation of a certain solute
Concretion
Most common type
Linked to high consumption of food high in oxalate
Calcium Oxalate
Caused by hyperparathyroidism, renal tubular acidosis or UTI
Calcium Phosphate
Result of certain types of UTI
Struvite
Occur in people who don’t drink enough water or have a diet high in animal protein
Uric Acid
Caused by a genetic disorder called cystinuria –> excessive cystine in urine
Cystine
Are formed from an aggregation of proteins called Tamm-Horsfall proteins
Urinary Casts