compendium 7

• Describe the gross anatomy of the renal system

  2 kidneys- formation of urine

  
  

  2 ureters- passage of urine

  
  

  urinary bladder- storage of urine

  
  

  urthera- passage of urine
• Describe the location of the kidneys

  Posterior to the parietal peritoneium, on the posterior abdominal wall, lateral to the spine

  
  

  partially protected by lumbar vertebrae and ribs
• Which kidney is larger and why

  Left due to the position of the liver on the right
• Renal capsule


  Connective tissue surrounding each kidney
• Adipose tissue

  Surrounds the outside of the capsule for protection
• Renal fascia

  Thin layer of CT surrounds the adipose tissue; anchor kidneys to abdominal wall
• Hilum


  On the concave (medial) side, renal artery and nerves enter, renal vein, ureter, lymphatics exit
• Which structure opens into the renal sinus

  Hilum
• Renal sinus


  Filled with fat and loose CT
• What are two major regions the kidneys are organised into

  Outer cortex (outer area consists of renal columns)

  
  

  inner medulla (area closest to surroundings)
• Renal pyramids

  Bases project into cortex. Cone shaped. The base is the boundary between cortex and medulla
• Renal columns

  Extensions of cortical tissue into the medulla
• What are the kidney internal anatomy

  Renal Hilum and sinus

  
  

  ureter (connects to bladder)

  
  

  renal cortex (outer layer)

  
  

  renal columns
• Renal papilla


  Apex of pyramid. Papillae extend into minor calyces which are funnel shaped chambers
• Minor calyces


  Funnel into larger chamber called major calyces
• Renal pelvis


  A single large funnel-shaped chamber. Embedded in the renal sinus. At the Hilum it narrows forming the ureter
• Nephron


  Functional unit of kidney.

  
  

  blood enters the nephron form filteration
• What are the 4 regions of the nephron

  Renal corpuscle

  
  

  proximal convoluted tubule

  
  

  loop of henle

  
  

  distal convoluted tubule
• What is the urine flow in the KIDNEYS

  nephron->papillary

  ducts ->minor calyces->major

  calyces-> renal pelvis ->ureter
• juxtamedullary nephrons


  Renal corpuscle is deep in the cortex near the medulla.

  
  

  long loop of henle extending deep into the medulla.

  
  

  15% of nephrons.
• Cortical nephrons

  Renal corpuscles located near the periphery/cortex.

  
  

  shorter loop of henle.

  
  

  85% of nephrons
• Renal corpuscle

  Filteration portion of the nephron

  
  

  consists of the glomerulus and bowman's capsule
• Glomerulus

  Network/ball of capillaries
• Bowman's capsule

  Enlarged end of the nephron double walled chamber. Filters blood/fluid which then enters the proximal convoluted tubule
• Where does blood enter the glomerulus

  Afferent arteriole
• Where does filtered blood exit in the glomerulus

  Efferent arteriole
• What are the two layers in the bowman's capsule

  Parietal layer: Outer layer. Simple squamous epithelium.

  Becomes cuboidal in the PCT

  
  

  Visceral layer: Inner layer. Constructed of specialised cells

  called podocytes, which wrap around the

  glomerular capillaries
• Fenestrae

  The glomerular capillaries are highly permeable. Fenestrae are little windows
• Basement membrane


  Sandwiched between the endothelial cells of the glomerular capillaries and podocytes
• Filtration slits


  Gaps between the cell processes of the podocytes
• What specialisations does the filteration membrane contain

  Fenestrae

  
  

  basement membrane

  
  

  filteration slits
• What apparatus can you sue to see podocytes

  SEM: high magnification
• What are the renal tubules

  Proximal convoluted tubule

  
  

  loop of henle

  
  

  distal convoluted tubule

  
  

  collecting duct
• Proximal convoluted tubule FUNCTION

  Filtrate drains into here from bowman's capsule
• Proximal convoluted tubule HISTOLOGY


  Simple cuboidal epithelium with many microvilli (reabsorption), mitochondria (active reabsorption), active reabsorption of Na+, k+ and Cl-
• Loop of henle FUNCTION

  Has a descending and ascending limb
• Loop of henle histology

  Thick parts -

  simple cuboidal epithelium.

  
  

  Thin parts - simple squamous

  epithelium - for

  osmosis/diffusion.
• Distal convoluted tubule FUNCTION

  Shorter than PCT
• Distal convoluted tubule HISTOLOGY


  Simple cuboidal epithelium, and

  very few microvilli. Numerous

  mitochondria. Active reabsorption
• Collecting duct FUNCTION

  several DCTs

  connect to a single collecting duct.

  Large diameter. Extends through

  medulla towards renal papilla to

  ureter