Renal - Anatomy, Embryology, Histology

Front 1

Which kidney is superior? Where are they located?

Back 1

The left kidney is superior to the right kidney and is situated anterior to the 11th and 12th ribs.
The right kidney is situated anterior to the 12th rib.

Front 2

What muscles are the kidneys in contact with?

Back 2

Diaphragm and transversus abdominis, quadratus lumborum, and the psoas major muscles.

Front 3

In the hilus, which structure is anterior to the other?

Back 3

At the hilus, the renal vein is anterior to the renal artery.
The renal artery is anterior to the renal pelvis.

Front 4

At what level do the renal arteries arise from?

Back 4

Renal arteries arise from the abdominal aorta at the level of the upper part of the L2 vertebra.
The right renal artery passes posterior to the IVC and the left renal artery passes anterior to the abdominal aorta just inferior to the origin of the SMA.

Front 5

What do the renal arteries branch into?

Back 5

Renal arteries give rise to interlobar arteries that branch into arcuate arteries at the juncture between the medulla and the cortex; arcuate arteries give rise to interlobular arteries. The interlobular arteries give rise to the afferent arterioles of the glomerulus.

Front 6

What might an aberrant renal artery, arising inferior to the renal artery, compress?

Back 6

The proximal part of the ureter may be compressed by an aberrant renal artery. This may cause hydronephrosis of the renal pelvis.

Front 7

When might a varicocele occur?

Back 7

Compression of the left renal vein by an aneurysm of the superior mesenteric artery near the origin of the artery from the abdominal aorta.

Front 8

What nerves innervate the kidneys?

Back 8

Preganglionic sympathetic axons in the lower thoracic or lumbar splanchic nervers from the T11 to L2 segments, which synapse mainly in aorticorenal ganglia.

Front 9

Where do the ureters arise from?

Back 9

Ureters arise from the renal pelvis of each kidney at about the level of the L2 vertebra.

Front 10

What does the intermediate mesoderm form?

Back 10

The intermediate mesoderm forms a longitudinal elevation along the dorsal body wall called the urogenital ridge.

Front 11

What does the urogenital ridge form?

Back 11

A portion of the urogenital ridge forms the nephrogenic cord, which gives rise to the urinary system.

Front 12

What are the nephric structures? What forms them?

Back 12

The nephrogenic cord develops into three sets of nephric structures: the pronephros, mesonephros, and metanephros.

Front 13

What is the fate of the pronephros?

Back 13

Pronephros develops to form pronephric tubules and pronephric duct. It is a transitory structure that regresses completely by week 5. It is not functional in humans.

Front 14

What is the fate of the mesonephros?

Back 14

The mesonephros forms the mesonephric tubules and the mesonephric duct (Wolffian duct). The mesonephros is the middle nephric structure and is partially transitory. Most of the mesonephric tubules regress, but the mesonephric duct persists and opens into the urogenital sinus. The mesonephros is functional for a short period.

Front 15

Where does the metanephros form from? What is the fate of the metanephros?

Back 15

The metanephros develops from an outgrowth of the mesonephric duct (ureteric bud) and from the mesoderm within the nephrogenic cord. The metanephros is the caudalmost nephric structure. The metanephros begins to form at week 5 and is functional in the fetus at about week 10. The metanephros develops into the definitive adult kidney.

Front 16

What gives rise to the collecting system of the kidneys? What structures does this include?

Back 16

The ureteric bud, which is an outgrowth of the mesonephric duct.
The ureteric bud initially penetrates the metanephric mesoderm and then undergoes repeated branching to form the ureters, renal pelvis, major calyces, minor calyces, and collecting ducts.

Front 17

What regulates the formation of the collecting system?

Back 17

The outgrowth of the mesonephric duct, the ureteric bud, is regulated by WT-1 (an antioncogene), GDNF (glial cell line-derived neurotrophic factor), and c-Ret (a tyrosine kinase receptor).

Front 18

What gives rise to the nephron?

Back 18

The inductive influence of the collecting ducts causes the metanephric mesoderm to differentiate into metanephric vesicles. The metanephric vesicles give rise to primitive S-shaped renal tubules, which differentiate into the connecting tubule, distal convoluted tubule, loop of Henle, proximal convoluted tubule, and Bowman's capsule. Nephron formation is complete at birth, but functional maturation of nephrons continues throughout infancy.

Front 19

What happens during the "ascent" of the kidneys?

Back 19

The kidneys rotate 90 degrees, causing the hilum, which initially faced ventrally, to finally face medially.

Front 20

What is the urinary bladder formed from?

Back 20

The urogenital sinus, which is continuous with the allantois. The lower ends of the mesonephric ducts become incorporated into the posterior wall of the bladder to form the trigone of the bladder. The mesonephric ducts eventually open into the urogenital sinus below the bladder. The transitional epithelium lining the urinary bladder is derived from endoderm because of its etiology from the urogenital sinus and gut tube.

Front 21

What forms the urethra?

Back 21

Lower portion of the urogenital sinus.

Front 22

What are the components of the renal glomerulus?

Back 22

Mesangium: extracellular matrix between capillaries
Mesangial cells: Phagocytic and contractile function; have receptors for angiotensin II and atrial natriuretic peptide.
Juxtaglomerular (JG) cells: modified smooth muscle cells of the afferent arteriole that secrete renin.

Front 23

What composes the Bowman's capsule?

Back 23

Simple squamous epithelium (Parietal layer)
Podocytes (Visceral layer)

Front 24

What composes the proximal convoluted tubule? What is the PCT sensitive to?

Back 24

Proximal convoluted tubule (PCT) consists of simple cuboidal epithelium with a brush border (microvilli), apical endocytic vesicles, lateral interdigitations, and basal infoldings (with numerous mitochondria and Na--K ATPase). The PCT is atrial natriuretic peptide sensitive.

Front 25

What parts of the loop of Henle consist of simple squamous epithelium?

Back 25

Descending thin limb and ascending thin limb

Front 26

What composes the distal convoluted tubule? What about thick ascending limb?

Back 26

DCT consists of simple cuboidal epithelium with basal infoldings (with numerous mitochondria and Na-K ATPase).

Thick ascending limb is similar in morphology to the DCT. In the region of the afferent and efferent arterioles, it contains specialized macular densa cells.

Front 27

What does the collecting duct consist of? What are the different collecting ducts sensitive to?

Back 27

The collecting duct consists of principal cells and intercalated cells.
Cortical CDs are ADH and aldosterone sensitive.
Medullary CDs are ADH and ANP sensitive.

Front 28

What are the components of the glomerular filtration barrier?

Back 28

a) Glomerular capillary endothelium
b) Basal lamina
c) Filtration slits of podocytes

Front 29

What are the components of the basal lamina in the glomerular filtration barrier?

Back 29

Basal lamina contains fibronectin, laminin, type IV collagen, and heparin sulfate (important in maintaining the negative charge).

Front 30

What are the components of the juxtaglomerular complex?

Back 30

a) JG cells: modified smooth muscle cells of the afferent arteriole and secrete renin
b) Extraglomerular mesangial cells (Lacis cells): located between the afferent and efferent arterioles and have receptors for angiotensin II and ANP.
c) Macula densa (MD) cells: located in the wall of the distal straight tubule and monitor a decrease in Na+ in the DST fluid.

Front 31

How is Wilms' tumor characterized histologically?

Back 31

Wilms' tumor has three components that attempt to recapitulate embryonic development of the kidney:
1) metanephric blastema elements
2) stromal elements
3) epithelial elements (tubules or glomeruli)

Front 32

How is Rapidly Progressive Glomerulonephritis characterized histologically?

Back 32

RPGN is characterized histologically by the accumulation of cells in the urinary space in the form of "crescents". The crescents are formed by proliferation of the parietal layer (simple squamous epithelium) of Bowman's capsule and by monocytes, macrophages, neutrophils, and lymphocytes.

Front 33

How is Diabetic glomerulosclerosis characterized histologically?

Back 33

Basement membrane thickening, a diffuse increase in mesangial matrix, and Kimmelstiel-Wilson nodules (hyaline masses situated at the periphery of the glomerulus)