The kidney filters the blood and produces urine.
Key features:
Fibrous capsule (aka, renal capsule)
- A layer of connective tissue that protects the kidney.
Hilum
- Cleft on concave, medial surface where the renal arteries and veins, nerves, and ureters enter and exit the kidney.
- Continuous with the renal sinus.
Renal sinus
- A space where fat, blood vessels, and structures that drain urine reside.
Renal pyramids
- Contain urine-collecting tubules and ducts, which is what gives them their striated appearance.
- Collectively, the renal pyramids constitute the renal medulla (which is why some authors refer to the renal pyramids as the medullary pyramids).
Renal medulla
- Inner area of the kidney that comprises the renal pyramids.
Renal cortex
- Outer area of the kidney that extends between the pyramids of the medulla as renal columns.
Renal papilla
- Is at the apex of the renal pyramid
Corticomedullary junction
- Is the wide base of the renal pyramid, where it meets the cortex
Renal lobe
- Comprises a single renal pyramid and the renal column and cortex that surround it.
Renal calyces
- Minor and major
- Drain urine from the collecting ducts of the pyramids.
Renal pelvis
- Wide, flattened end of the ureter that receives the urine from the major calyces, and funnels it out of the kidney.
Arterial Supply:
Renal artery
- Enters the kidney at the hilum; recall that the renal artery arises from the descending abdominal aorta.
- Gives rise to segmental arteries.
Segmental arteries
- Branch to form interlobar arteries, which travel between the renal lobes, within the renal columns.
Interlobar arteries
- Give rise to arcuate arteries; notice that these arteries "arc" over the bases of the renal pyramids.
Arcuate arteries
- Give rise to multiple interlobular arteries, which radiate through the cortex (hence, their alternative name, cortical radiate arteries).
Interlobular arteries
- Give rise to afferent arterioles
Afferent arterioles
Efferent arterioles
- Carry filtered blood away from glomerulus
Peritubular capillary beds
- Where gas exchange occurs
- Vasa recta weaves around nephron loop of juxtamedullary nephron.
Nephron Anatomy:
- Nephrons are the functional units of the kidney; they filter the blood to produce urine.
- Two nephron types:
— Cortical (aka, superficial), which reside primarily in the renal cortex
— Juxtamedullary, which travel through the renal pyramids
Features of the Juxtamedullary nephron:
- Renal corpuscle comprises:
— Outer glomerular capsule (aka, Bowman's capsule)
— Inner glomerulus, which is a dense collection of capillaries
- Distal convoluted tubule
- Collecting duct, which drains to the renal papilla
Additional Photos:
Kidney