Renal Review Flashcards
What are the renal functions?
Filtration Secretion Reabsorption Endocrine Metabolic
What renal functions are associated with maintenance of body composition?
Filtration
Secretion
Reabsorption
What renal functions are associated with excretion of toxins and metabolic end products?
Filtration
Secretion
Reabsorption
What is the order of renal arteries to veins?
Renal artery Afferent arterioles Glomerulus Efferent arteriole Peritubular capillaries Venules Renal vein
What kind if movement is glomerular filtration?
Passive diffusion
What molecular properties affect their ability to be filtered?
Size
Charge
What direction is solute movement involved in tubular reabsorption?
Lumen to blood
What are the major solutes involved in tubular reabsorption?
Na Cl HCO3 Glucose AA Protein Phosphates Ca Mg Urea Uric acid
Where does tubular reabsorption occur?
Proximal tubule
Loop of Henle
Distal tubule and collecting duct
Where is the bulk of filtrate absorbed?
Proximal tubule
What is the direction of solute movement in tubular secretion?
Blood to lumen
Where does tubular secretion occur?
Proximal tubule
Distal tubule and collecting duct
What are the major solutes involved in tubular secretion?
H
K
NH4
Organic acids and bases
What is produced in the endocrine system?
Renin
Erythropoietin
Prostaglandins and kinins
Where is renin produced and released from?
Granular cells in the wall of renal afferent arterioles
When is erythropoietin produced and secreted?
Oxygen tension in the blood decreases
What are prostaglandins and kinins used for?
Production and metablism
What is the metabolic function of the kidney?
Activation of vitamin D3
Gluconeogensis
Metabolism of endogenous compounds
How does sodium absorption occur?
Active transport via Na-K-ATPase transport
Na out, K into cells
Where is the Na, K, 2Cl-cotransport located?
Thick ascending limb of LoH
What drugs work on the Na, K, 2Cl-cotransporter?
Furosemide
Bumetinide
Torsemide
Where is the Na/Cl cotransport located?
Distal tubule
What drugs affect the Na/Cl-cotransporter?
HCTZ
Where is the Na channel located?
Collecting duct
What drugs work on the Na channel?
Amiloride
Triamterene
How does the sympathetic nervous system affect regulation of NaCl excretion?
- Increased renal tone = Increased salt reabsorption and decreased renal blood flow
- Increased sympathetic outflow -> promotes activation of RAAS
How does RAAS affect regulation of NaCl excretion?
- Decreased arterial pressure = increased renin production
- Increased renin -> increased angiotensin II -> vasoconstriction of efferent arteriole -> increased GFR
- Angiotensin II -> Increased Na and H2O reabsorption and Increased aldosterone production and release
How does ANP affect regulation of NaCl excretion
Increased ANP -> Decreased Na absorption and Increased GFR -> increased Na excretion
ANP stands for
Atrial naturetic peptide
What systems help to regulate NaCl excretion?
Sympathetic nervous system
RAAS
ANP
Vasopressin
How does vasopressin affect regulation of NaCl excretion?
ADH
Regulated primarily by body fluid osmolarity
Promotes water retention
What is the concentration and dilution of urine dependent on?
ADH production
Hyperosmotic medullary interstitium
What is the primary intracellular electrolyte?
Potassium
How does aldosterone affect potassium regulation?
Increased secretion
How does decreased H concentration affect potassium regulation?
Increased secretion
How does dietary intake affect potassium regulation?
Increased dietary intake = Increased secretion
Decreased dietary intake = decreased secretion (increased absorption)
How does tubular flow rate affect potassium regulation?
Increased flow = increased secretion
Decreased flow = decreased secretion (increased absorption)
What are the 3 mechanisms of regulating acid-base homeostasis?
Extracellular buffering
Respiratory regulation
Renal regulation
What is normal plasma ph?
7.35 - 7.45
Which organ compensates for primary respiratory abnormalities?
Kidneys
What organ compensates for primary renal abnormalities?
Lungs
What is the only means of renal H elimination?
H secretion
What type of process is H secretion?
Passive (dependent on gradient b/n blood and urine)
Below what urine pH does H secretion stop?
< 4.5
Where is HCO3 reabsorbed?
Proximal tubules
What type of transproter is used with HCO3 absorption?
Counter-transport with H secretion
What type of transport is used for glucose absorption?
Co-transport protein carrying Na and glucose
What is the maximal capacity of the Na/Glucose co-transporter?
Plasma glucose of 200
What type of transport is used for amino acid absorption?
Co-transport protein carrying Na and amino acids
How do we evaluate GFR?
Inulin SCr BUN Cockroft-Gault MDRD4 CKD-EPI Timed urine collection
What is the most accurate measure of GFR?
Inulin
Where is SCr produced?
Creatine produced in liver -> stored in muscle as creatine phosphate -> released as creatinine -> kidney
How much of SCr is secreted?
10%
How can SCr vary?
Age
Gender
Body mass
Where is BUN produced?
Liver
What is BUN production dependent on?
Dietary protein and hepatic function
What percent of urea is reabsorbed?
50%
Where is urea reabsorbed?
Proximal tubule
What BUN:SCr ratio is indicative of prerenal cause?
> /= 20:1
What BUN:SCr ratio is indicative of renal (intrinsic) cause?
< 20:1
What is the primary use of MDRD4?
Stage patients with CKD
When can MDRD4 be used?
Stable renal function only
When can CKD-EPI be used?
Stable renal function
What is the primary use of CKD-EPI?
Stage patients with CKD
What are the different parts of a UA?
Macroscopic analysis
Microscopic analysis
Chemical analysis
What are the parts of a microscopic analysis?
Cells
Casts
Crystals (uric acid)
What cells are observed in a microscopic analysis?
Epithelial
Microorganisms
RBC
WBC
What are hyaline casts?
Clear, not indicative of renal disease
What are cellular casts?
WBC
RBC
Tubular epithelial cells
Seen with intrinsic renal disease
What are granular casts?
Seen with ischemic renal damage or toxic insults
What are the parts of chemical analysis?
pH Specific gravity Bilirubin/urobilinogen Blood/Hgb Leukocytes Nitrites Glucose Ketones Protein
Other renal tests
KUB
CT scan
Ultrasound
Biopsy
