M1

• The Kidney is Retroperitoneal organ that weighs 150 grams and is 12.5 x 6 x 2.5 cm
• How long is the URETER?

  25 cm
• If 150 mL of urine is accumulated in the bladder, a nerve reflex is initiated
• URETHRA

  • women: 4cm men: 24 cm 
• FLUID biopsy of the kidney is urine, the biopsy of the kidney is nephron
• NEPHRON

  • Regulates the selective clearance of waste from the blood by the kidneys while concurrently managing crucial water and electrolyte balances within the body
• There are 1 to 1.5 million nephrons per kidney
• Responsible for the removal of waste products and reabsorption of nutrients is the Cortical nephron
• JUXTAMEDULLARY nephron: Primary function is the concentration of urine
• • The kidney receives 25% of the total cardiac output
• Total Renal Blood Flow: 1200 mL/min 
• Total Renal Plasma Flow: 600-700 mL/min
• Vasa Recta is where the arteries and veins meet and where major exchange of water and salt take place
• 1. Collecting Duct → where final concentration of urine takes place
• Glomerulus is a Non-selective filter of plasma substances with MW of < 70,000 Daltons
• • Albumin, despite having a molecular weight of 69,000 Da is repelled because of its negative charge
• • 1st function to be affected in renal disease ?

  Tubular Reabsorption
• Body cannot lose 120 mL of water containing essential substances every minute.
• Renal Threshold

  is the plasma concentration at which active transport stops
• Renal threshold of glucose?

  160 to 180 mg/dL
• Active PCT ?

  Glucose, amino acids, salts
• ASCENDING LH

  ACTIVE TRANSPORT?

  Chloride
• PCT AND DCT

  ACTIVE TRANSPORT

  Sodium
• PCT, Descending LH, CD

  PASSIVE TRANSPORT?

  Water
• PCT, ASCENDING LH

  PASSIVE TRANSPORT?

  Urea
• Ascending LH

  PASSIVE TRANSPORT?

  Sodium
• • Urea: 40% is absorbed, 60% is secreted in urine
• • regulates water reabsorption in the DCT and CD?

  Antidiuretic hormone or Vasopressin
• vasopressin is secreted in the posterior pituitary gland!
• Aldosterone: regulates sodium reabsorption
• • ADH deficiency → Diabetes insipidus
• • High ADH → SIADH (Syndrome of Inappropriate Antidiuretic Hormone Secretion)
• Renin-Angiotensin-Aldosterone System (RAAS)

  • regulates the flow of blood to and within the glomerulus
• TUBULAR SECRETION

  • Regulation of acid-base balance in the body through secretion of Hydrogen ions (in the form of NH4 and H2PO4)
• • Elimination of waste products not filtered by glomerulus?

  Tubular secretion
• • The major site for removal of these non filtered substances is the proximal convoluted tubule (PCT)
• RENAL TUBULAR ACIDOSIS (RTA): Failure to produce (H+)
• PCT? (TS)

  H+ , NH3, weak acid and bases
• LOH? (TS)

  Urea
• DCT (TS)

  H+, NH3, K, Uric acid (some drugs)