Lec 33 - Kidney

• Kidneys are in the retroperitoneal space. They filter blood - about 25% of the body's blood at one time. They remove excess H2O, salts, and wastes. They return nutrients and chemicals. They produce urine that drains through the ureters to the bladder
• The kidneys are located between T12 ad L3 vertebral levels. Left kidney is about 1.5cm higher than the right. Kidneys can descend during inspiration or changes in posture
• Label the kidney

  A) fibrous capsule

  B) hilum

  C) renal vein

  D) renal artery

  E) renal pelvis

  F) ureter

  
• Label the internal kidney

  A) renal cortex

  B) renal column

  C) renal pyramids

  D) renal papilla

  E) minor calyces

  F) major calyces

  G) renal pelvis

  H) ureter

  
• 1 lobe of the kidneys = 1/2 renal column + renal pyramid + 1/2 renal column
• The arcuate arteries separate the cortex from the medulla
• Urine leaves the collecting system and enters the renal pelvis. The remainder of the urinary system transports, stores, and eliminates urine
• The ureter does peristalsis to move urine down to the bladder
• The nephron is the functional unit of the kidney with approximately 1 million in each kidney. The nephron produces ultrafiltrate from blood, conservation of water, electrolytes, and metabolites, removal of metabolic waste, control of blood pressure
• Label the areas of the kidney that hold the nephron

  A) outer medulla

  B) inner medulla

  C) cortex

  
• What area of the kidney is this? Cortex

  
• The renal cortex produces filtrate of blood. If you see renal corpuscles, you are looking at the renal cortex.
• If the tubules are running in and out of the plane and you are in the cortex - it is a convoluted tubule
• This image is depicting

  A) glomerulus

  
• The renal medulla is responsible for absorption of electrolytes and water
• There are straight tubules in the renal medulla

  A) straight tubules

  B) vasa recta

  
• Multiple collecting ducts merge into papillary ducts that open into the minor calyx
• The ureter consists of transitional epithelium
• Renal lobule is one collecting duct with all of the nephrons associated with it
• Medullary rays are parts of the straight tubules from the medulla that project up into the cortex
• Label the nephron

  A) glomerulus

  B) afferent arteriole

  C) renal corpuscle

  D) proximal convoluted tubule

  E) renal loop

  F) thick descending limb

  G) thin segment

  H) thick ascending limb

  I) distal convoluted tubule

  J) interlobular vessels

  K) arcuate vessels

  L) collecting duct

  
• The vascular pole of the renal corpuscle is the site of the afferent and efferent arterioles
• The efferent arteriole gives rise to the vasa recta
• The urinary pole is the portion of the renal capsule where the filtrate leaves
• Label this portion of the cortex

  A) medullary rays

  B) renal corpuscle

  C) convoluted tubules

  
• Morphogenesis of the renal corpuscle

  • tuft of capillaries forming the developing glomerulus
  • invaginate into the tubule lining epithelial cells
  • causes a visceral and parietal layer of the renal capsule
• The parietal layer of the renal capsule is made up of squamous epithelium and the visceral layer is also squamous but differentiates into podocytes
• Juxtaglomerular cells are specialized smooth muscle cells of the afferent arteriole. They are endocrine cells that produce renin
• Macula dena cells are specialized cells in the distal convoluted tubule
• The space between the parietal and visceral layers of the capsule is called the urinary space
• Label the portions of this glomerulus

  A) vascular pole

  B) urinary pole

  C) distal convoluted tubule

  D) macula densa

  E) juxtaglomerular cells

  F) glomerulus

  G) podocyte

  H) renal capsule

  I) urinary space

  J) proximal convoluted tubule

  
• Filtration occurs between the relationship of the podocytes and endothelial cells. The endothelial cells are fenestrated. They are not large enough for formed elements of the blood to leave but all the soluble things can leave. There is a thick basement membrane of both the podocytes and the endothelial cells that also plays a role of being a selective barrier. The podocytes give off processes that interdigitate and form a specific sized space with a membrane between them ans leads to a second filter
• Molecules are filtered based on size and charge. The fenestrations filter based on size and the negatively charged basement membrane filters based on charge - will repel negatively charged ions
• Mesangial cells are found between capillaries and podocytes and act like glue - they are structural support. They are also responsible for removing trapped residues, immune complexes, and large plasma proteins. They do this by phagocytosis. This is required because the high turnover of the basement membrane. They are endothelial derived

  
• The urinary pole consists of the beginning of the proximal convoluted tubule of the nephron