Anatomy and physiology of the kidney

• True/false: the kidneys are outside the peritoneal cavity True

• The kidneys sit at __ to __ vertebral levelT12 to L3

• Why is the right kidney lower that the left?

The liver push on the right kidney

• In relation to the vertebral level, describe where are the hila.

Left hilum is at the upper border of L1 and the right hilum

is at the lower border

• Give the order of structure in the hilum from the frontVein, artery, ureter

• Where do the renal arteries come from and at what vertebra level?

From abdominal aorta at L2

• Where do the renal veins come from?Inferior vena cava

• What level does the sympathetic supply to the kidneys come from? T12 and L1

A. Ureter

B. Renal pelvis

C. Renal vein

D. Renal artery

E. Major calyx

F. Renal capsule

G. Renal pyramid

H. Medulla

I. Minor calyx

A

B

C

D

A. Interlobular artery and vein

B. Interlobar artery and vein

C. Renal artery and vein

D. Arcuate artery and vein (at the corticomedullary junction)

Afferent arteryGlomerulusEfferent artery

Interlobular artery

Interlobular veinPeritubular capillary network

Collecting duct

Vasa recta

9. What is the difference between cortical nephron and juxtamedullary nephron and why is this important?

Function of The Kidney

Regulation of water & electrolyte, volume & osmolarity

• Sodium, chloride, potassium, calcium, phosphate, magnesium

Regulation of acid-base balance

• Hydrogen ions (pH)

Excretion of metabolic waste products and foreign chemicals

• Nitrogen

Removal of foreign chemicals from blood

• drugs, pesticides and food additives

Secretion of hormones:• renin = controls the formation of angiotensin • erythropoietin = stimulates red blood cell production• 1,25-dihydroxy vitamin D3

Glucogenesis = conversion of amino acids to glucose

Filtration

Reabsorption

Secretion

Excretion

How the nephron works

How does each of these structures work?

• High capacity for active & passive reabsorption• 65% H2O & Na+; 50% Cl-; 90%

HCO3-; >90% K+, Nearly all glucose, lactose, amino acid

• Apical cell surface has a border of microvilli

• Na+/K+-ATPase located in basolateral cell membrane

Proximal convoluted tubule

• Highly permeable to water and H2O reabsorbed

• No active Na+ reabsorption

Descending loop of Henle

• Impermeable to water• Reabsorbs 25% of filtered Nacl & K+,

Ca2+ ,HCO3-

• Creates a hypotonic condition in the tubule compared to the interstitial space

Ascending loop of

Henle

• Reabsorption regulated by hormones• Na+ reabsorbtion depends on

aldosterone• H2O reabsorbtion depends on ADH

Distal convoluted tubule

• Macula densa – monitors the content of DCT

• Juxtaglomerular cells in afferent arteriole synthesise renin which converts angiotensinogen to angiotensin I

Macula densa and

juxtaglomerular apparatus