Urology Flashcards
Functions of the kidney?
Excretion
Homeostasis
Blood pressure regulation
Hormone secretion
From interlobular artery to interlobular vein?
IL artery to afferent arteriolar to glomerular capillaries to efferent arteriolar to peritubular capillaries to IL vein
Detrusor muscle?
Contracts to build pressure in urinary bladder to support urination
Trigone?
Stretching of this triangular region to its limit signals to the brain for need to urinate.
Internal sphincter?
Involuntary control to prevent urination
External sphincter?
Voluntary control to prevent urination
Bulbourethral gland?
Produces thick lubricant which is added to watery semen to promote sperm survival
From glomerulus to collecting duct?
Glomerulus to bowman’s capsule, to proximal convoluted tubule, to thin descending then thin ascending LOH, to thick LOH, to distal convoluted tubule, to collecting duct.
Superficial vs juxtamedullary nephrons?
Superficial glomeruli in outer cortex, shorter LOH
juxtamedullary have glomeruli near corticomedullary border, longer LOH and larger glomeruli so higher GFR
Juxtaglomerullar apparatus constituents?
Macula densa, extra glomerular mesangial cells, juxtaglomerular cells
Juxtaglomerullar apparatus function?
GFR regulation and renin secretion
Why is glomerular filtration a passive process?
Fluid driven through semipermeable glomerular capillaries into Bowman’s capsule space by hydrostatic pressure of the heart
Filtration barrier in glomerular filtration?
Highly permeable to fluids and small solutes, impermeable to cells and proteins.
Hydrostatic vs oncotic pressure?
Hydrostatic - fluid exerts this pressure, solute and fluid shoved out.
Oncotic - pulling, solute exerts this, fluid drawn in.
Net ultrafiltration pressure?
Puf = HPgc - HPbw - Pigc
Net ultrafiltration pressure = hydrostatic pressure in glomerular capillaries - hydrostatic pressure in bowman’s capsule - oncotic pressure of plasma proteins in glomerular capillaries.
Glomerular filtration rate?
GFR = Puf x Kf
GFR = net ultrafiltration pressure x ultrafiltration coefficient
Ultrafiltration coefficient?
Membrane permeability and SA available for filtration. Changes = GFR imbalances.
Myotonic mechanism for GFR regulation?
Arterial pressure increases
Afferent arteriole stretches
Arteriole contracts
Vessel resistance rises
Blood flow reduces
GFR stays same
Tubulo-glomerular feedback mechanism?
Increase/decrease in GFR
Increase/decrease NaCl in LOH
Change detected by macula densa
Increased/decreased ATP + adenosine discharged
Afferent arteriole contracts/dilates
GFR stabalises
Renal clearance?
C = U x V / P (mL/min)
U is concentration of substance in urine, V is rate of urine production, P is concentration of substance in plasma.
Most commonly and ideal molecule used to calculate renal clearance?
Ideal = insulin (freely filtered and neither absorbed nor reabsorbed, so filtered = amount secreted.
Commonly used = creatinine - decrease clearance = increased plasma creatinine = renal failure.
Not perfect, some secreted so overestimates GFR.
PAH?
Para aminohippurate - all removed from plasma passing through kidney through filtration and secretion. Renal clearance of PAH = renal plasma flow.
RPF?
Renal plasma flow - volume of blood reaching the kidney per unit of time.
Filtration fraction?
FF = GFR/RPF
ratio of amount of plasma filtered and plasma which reaches afferent arteriole.
Reabsorption in early proximal convoluted tubule?
100% glucose and amino acids, 80% HCO3, 67% Na, Cl and H2O, 50% urea.
Na-H antiporter, Na-K ATPase, Na-HCO3 symporter.
Na-glucose symporter (SGLT2), GLUT2.
Reabsorption in LOH?
25% Na + Cl, 15% H2O.
passive reabsorption in thin, active in thick
Reabsorption in early distal convoluted tubule?
Na, Cl and Ca reabsorbed.
Late distal convoluted tubule and collecting duct reabsorption?
Aldosterone regulates Na, AVP regulates water reabsorption.
Intercalated cells?
Alpha - pumps H+ into tubular fluid, reabsorbes bicarbonate.
Beta - secretes bicarbonate into tubular lumen, reabsorbes H+.
Kidney dysfunction consequences?
Filtration failure
Hypertension, water retention
Metabolic acidosis
Anaemia
Vitamin D deficiency
Different types of urinary disorders?
Inflammatory
Obstructive
Developmental/genetic
Examples of inflammatory?
Infection - cystitis
Non-infective:
- metabolic - diabetic nephropathy
- immunological - nephritic syndrome and nephrotic syndrome
Examples of obstructive disorders?
Stones
Benign prostatic hypertrophy
Examples of developmental/genetic disorders?
Polycystic kidneys, horseshoe kidney.
UTI
Urine dipstick test, cloudy urine, blood in urine, increase leukocytes.
Antibiotics, hydration, pain control.
Usually e.coli
Nephritic syndrome presentation?
Haematuria, proteinuria, hypertension, reduced urine output, increased urea and creatinine.
Caused by IgA nephropathy (most common cause of glomerulonephritis)
Diabetic nephropathy?
Metabolic cause, microalbuminuria, proteinuria, associated with diabetic retinopathy and neuropathy.
Thickened glomerular.basement membrane.
Nephrotic syndrome?
Immunological cause, peripheral and periorbital oedema, severe proteinuria, low serum albumin, hyperlipidaemia.
Corticosteroids, diuretics and anti coagulation.
Stones presentation?
Pain, haematuria, UTI, tenderness of loin and lower abdomen.
Supportive or specific treatment
Specific treatments for stones?
Shockwave lithotripsy
Ureteroscopy
Percutaneous nephrolithotomy
Polycystic kidney disease?
Neonatal - autosomal recessive, vs adult onset - autosomal dominant.
Loss of kidney function, pain, bleeding into renal cysts, infection of renal cysts.
Replacement therapy, Tolvaptan (vasopressin receptor 2 agonist), treat hypertension or infection.
Horseshoe kidney?
Increased risk of obstruction, stones and infection. Imaging of abdomen/pelvis.
