Renal System

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Renal System
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• Gross structure of the kidneys cortex, medulla
  (inner and outer zones of outer medulla and
  papilla or inner medulla), pyramids, renal
  calyxes and pelvis, ureter.
• Gross size and weight (300400 g) of kidneys
  (about 0.5 of body weight)
• in humans

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Anatomy of the Kidney
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• The nephron is the basic unit of renal structure
• and functions.
• It has a malpigian corpuscle with a vascular
  glomerulus within a matrix formed by mesangial
  cells and an epithelial Bowmans capsule.
• The capsule joins a series of tubules starting
  with the proximal tubule and followed by the loop
  of Henle the distal tubule.

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• Nephron
• Glomerulus
• Bowmans Capsule
• Proximal Convoluted Tubule
• Loop of Henle
• I. Proximal straight tubule
• ii. Descending Thin Limb
• iii. Ascending Thin Limb
• iv. Distal Straight Tubule
• Distal Convoluted Tubule

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branch of renal artery
glomerulus
Bowmans capsule
DCT
PCT
collecting duct
branch of renal vein
capillaries
loop
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branch of renal artery
glomerulus
Bowmans capsule
DCT
PCT
collecting duct
branch of renal vein
capillaries
loop
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Anatomy of the Kidney
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Formation of Urine

• The initial step is the formation of a plasma
  ultrafiltrate (plasma without cells or proteins)
  at Bowmans space through the action of
  hydrostatic pressure in the glomerular
  capillaries.
• The ultrafiltrate flows along the tubules and is
  modified by reabsorption (sodium salts, glucose,
  amino acids) and most water from the when of the
  tubules back into the pennt? Capsule.
• The luminal fluild is also modified by secretion
  of solutes from the peritubular (tubule cells)
  into the lumen.

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Tubular Secretion and Reabsorption
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Function of Collecting ducts

• The collecting ducts make the final fine
  adjustments in composition of the urine through
  anti-diuretic hormone stimulated water and urea
  reabsorption, and aldosterone stimulated Na, K
  and H transport.

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Tubular Reabsorption

• Returns materials from filtrate to blood
• 99 of filtrate reclaimed
• Lose 1.5 2 L/day as urine
• Mechanisms of reabsorption
• Osmosis, Solvent drag, Pinocytosis, Active
  transport Diffusion
• Amounts reabsorbed depends on
• Need for substance Concentration gradient

• Proximal convoluted tubule
• Always permeable to water, reabsorbs 80 of water
  passing through
• Active Transport
• Ions-Na, Cl, K, HCO3
• Nutrients
• Passive Transport
• Urea, Lipid-soluble solutes

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Role of kidney

• Apart from urine formation
• Blood pressure from Renin production
• RBC production from Erythropoietin

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Kidney Structure

• Arteriole Small artery
• Bowman capsule A cup-shaped capsule surrounding
  each glomerulus
• Calyx Cup-like collecting region of the renal
  pelvis
• Catheter A tube for injecting or removing
  fluids
• Cortex Outer region the renal cortex is the
  outer region of the kidney
• Creatine A waste product of muscle metabolism
• Electrolyte A chemical that carries an
  electrical charge on solution
• Filtration Process whereby some substances but
  not all,
• pass through a filter or
  other material
• Glomerulus Tiny ball of capillaries in cortex
  of kidney

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Kidney Structure

• Hilum Depression or pit in that part of an
  organ where blood vessels and nerves enter and
  leave
• Kidney One of two bean-shaped organs located
  behind the abdominal
• cavity on either side of the backbone in
  the lumbar region
• Meatus opening or canal
• Medulla Inner region the renal medulla is the
  inner region of the kidney
• Nitrogenous wastes Substances containing
  nitrogen and excreted
• in urine
• Renal artery carries blood to the kidney

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Kidney Structure

• Renal pelvis - Central blood away from the
  kidney.
• Renal tubules - Microscopic tubes in the kidney
• Renal vein - Carries blood away from the kidney
• Rennin - A hormone synthesized, stored and
  secreted by the kidney
• Sodium (Na) - A salt (electrolyte) regulated in
  the blood and urine by the kidneys
• Trigone - Triangular area in the bladder where
  the ureters enter and the urethra exits
• Urea - Major nitrogenous waste product excreted
  in urine
• Ureter - Tube leading from each kidney to the
  bladder
• Urethra - Tube leading from the bladder to the
  outside of the body
• Uric acid - Nitrogenous waste excreted in the
  urine
• Urinary bladder Sac that holds urine
• Voiding Expelling urine (micturation)
• Glomerulonephritis - Inflammation of the kidney
  glomerulus (Bright disease)

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Kidney Structure

• Interstitial nephritis - Inflammation of the
  renal interstitium
• Nephrolithiasis - Kidney stones (renal calculi)
• Nephrotic syndrome - A group of symptoms caused
  by
• excessive protein loss in the urine (also called
  nephrosis)
• Polycystic kidneys - Multiple fluid-filled sacs
  (cysts) within and upon the kidney
• Pyelonephritis - Inflammation of the renal pelvis
  and renal medulla
• Renal cell carcinoma - Cancerous tumor of the
  kidney in adulthood
• Renal failure - Failure of the kidney to excrete
  urine
• Renal hypertension - High blood pressure
  resulting from kidney disease
• Wilms tumor Malignant tumor of the kidney
  occurring in childhood
• Diabetes insipidus - Inadequate secretion or
  resistance of the kidney to the action of
  antidiuretic hormone (ADH)
• Diabetes mellitus - Inadequate secretion or
  improper utilization of insulin

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• Azot (nitrogenous)
• Dips
• Noct (night)
• Olig (few)
• Tripsy (crushing)
• BUN (blood urea nitrogen)
• IVP
• KUB (kidney, ureter, bladder)
• ADH (anti-diuretic hormone)
• UTI (urinary tract infection)
• CRF (chronic renal failure?, corticotropin
  releasing factor?)
• ARF (acute renal failure?)