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Renal Physiology - Anatomy & Physiology

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Termini in questo insieme (29)

  • Primary functions of the kidney
    Excretion of wastes and foreign chemicals, and regulation of body fluid volume and electrolyte composition.
  • Role of ADH in water regulation
    ADH increases aquaporin insertion in collecting ducts, enhancing water reabsorption and producing concentrated urine during dehydration.
  • Countercurrent multiplier mechanism
    Loop of Henle recaptures NaCl and urea via opposite flow in limbs, creating a medullary osmotic gradient for urine concentration.
  • Countercurrent exchanger function
    Vasa recta capillaries exchange water and salts to maintain medullary osmolarity while removing reabsorbed water.
  • Range of urine osmolarity
    Collecting duct can produce urine from 50 mOsm/L (dilute) to 1,200 mOsm/L (concentrated) depending on hydration.
  • Extracellular fluid volume control
    Regulated mainly by kidney control of sodium and water input/output, influenced by GFR and tubular sodium reabsorption.
  • Renal mechanisms for acid-base balance
    Secretion of H+, reabsorption of filtered HCO3−, and production of new HCO3− to maintain blood pH.
  • Sites of H+ secretion and HCO3− reabsorption
    Occurs mainly in proximal tubule (80-90%), thick ascending limb (10%), and distal tubules/collecting ducts.
  • Process of H+ secretion in tubules
    Na+-H+ exchanger secretes H+ into lumen; H+ combines with HCO3− forming CO2 and water, which diffuse back into cells.
  • Role of Type A intercalated cells
    Actively secrete H+ in late distal tubules and collecting ducts to acidify urine and excrete acid.
  • Phosphate buffer system in urine
    H+ combines with HPO42− to form H2PO4−, which is excreted, aiding acid excretion and new HCO3− formation.
  • Ammonia buffer system
    Glutamine metabolism produces NH4+ and new HCO3−; NH4+ is secreted in exchange for Na+ and excreted, aiding acid removal.
  • Micturition process
    Urinary bladder empties via rise in wall tension and micturition reflex involving detrusor contraction and sphincter relaxation.
  • Innervation of the urinary bladder
    Parasympathetic pelvic nerves stimulate detrusor; pudendal nerve controls external sphincter; sympathetic hypogastric nerves modulate sensation.
  • Micturition reflex pathway
    Stretch receptors send afferent signals to spinal cord; efferent parasympathetic fibers cause detrusor contraction and sphincter relaxation.
  • Higher brain centers' role in micturition
    Inhibit or facilitate reflex; maintain external sphincter tone; allow voluntary control of urination.
  • Acute kidney injury (AKI) categories
    Prerenal (blood flow issues), intrarenal (kidney tissue damage), and postrenal (urinary tract obstruction).
  • Causes of prerenal AKI
    Heart problems or low blood volume causing reduced renal blood flow and possible reversible oliguria.
  • Intrarenal AKI causes
    Damage to glomeruli, renal tubules (e.g., tubular necrosis), or interstitium from ischemia, toxins, or infections.
  • Postrenal AKI causes
    Obstruction in urinary tract such as renal stones, clots, bladder or urethral blockage.
  • Physiological effects of AKI
    Retention of water, wastes, electrolytes; edema; hyperkalemia; metabolic acidosis; possible fatal anuria.
  • Chronic kidney disease (CKD) definition
    Progressive loss of kidney function over 3+ months with nephron loss and risk of end-stage renal disease.
  • Common causes of CKD
    Diabetes mellitus, hypertension, glomerulonephritis, polycystic kidney disease, and vascular diseases.
  • Nephrotic syndrome
    Proteinuria due to increased glomerular permeability, often linked to chronic glomerulonephritis or amyloidosis.
  • Renal function tests by clearance
    Measurement of glomerular filtration rate (GFR) and renal plasma flow (RPF) using clearance of substances.
  • Urinalysis components
    Physical, microscopic, and chemical examination to detect abnormalities like proteinuria, hematuria, infection.
  • Blood tests for kidney function
    Plasma protein levels, urea, uric acid, and creatinine concentrations indicate renal health.
  • Principle of renal dialysis
    Blood passes through membranes allowing diffusion of wastes into dialysate, removing toxins and excess substances.
  • Dialyzing fluid composition
    Adjusted to remove urea, creatinine, and other wastes while maintaining electrolyte balance during dialysis.