Gross Anatomy of the Kidneys

Where are the kidneys located?

• retroperitoneal

• between T12 and L3 vertebrae

• right is lower due to liver

What are the boarders of the kidney

• convex lateral

• concave medial

What are the layers of the kidney going from inner to outermost?

• renal capsule

• perirenal fat

• renal fascia

• pararenal fat

Renal Capsule

• thin , fibrous capsule that tightly adheres to renal surface

Perirenal Fat

• cushioning layer

Renal Fascia

• encloses kidney and adrenal glands

Pararenal fat

• outermost layer

• additional cushioning and insulation

What are the 2 main divisions of the kidney?

• cortex

• medulla

What is the renal cortex

• outermost layer beneath renal capsule

• main site of filtration

• houses renal corpuscles anc convoluted tubules 

what is the renal medulla

• main function is urine concentration by reabsorption and secretion 

• organized by renal pyramids

Renal Pyramids

• cone shaped (8-18 per kidney)

• apex points inward 

• forms the renal papilla

• projects into minor calyces 

Renal Columns

• extensions of cortical tissue between pyramids

• provide structural support 

• contain interlobular arteries and veins

Renal calcyces

• urine collection chambers

• serve as passageways funneling rine toward the renal pelvis

Minor calyces

• cup shaped structures

• 8-18 per kidney 

• receive urine from the papillae of renal pyramids 

Major Calyces

• formed by convergence of 2-3 minor calyces

Renal Pelvis

• collects urine from major calyces

• funnel shaped upper end of ureter

Lobes

• each kidney has 8-18 

• renal pyramid + overlaying cortex + renal columns on either side 

How much cardiac output does the kidney receive?

• 20-25% of cardiac output 

Arterial Supply of the Kideny

renal artery → segmental arteries → interlobar arteries → arcuate arteries → interlobar (cortical) arteries → afferent arterioles → glomeruli 

What do the efferent arterioles that exit the glomeruli form?

• peritubular capillaries

• vasa recta 

Peritubular capillaries

• around the cortical nephrons

Vasa recta

• straight vessels along juxtamedullary nephrons

How does blood flow out

arcuate veins → interlobar veins → segmental veins→ renal vein