Renal Structure and Function

Kidneys Paired Retroperitoneal Partially protected by the 11th and 12th ribs Right slightly lower due to liver Surrounded by renal capsule Adipose capsule Renal fascia

Anatomy Hilum (hilus) Renal artery and vein Cortex Medulla Renal pyramids and renal papillae Major and minor calyces Renal Pelvis Ureters

Ureters connect kidneys to urinary bladder Urethra leads from bladder outside the body

Kidney has two major functions: Kidneys make up 1 % of body mass, but receive about 25% of cardiac output. Kidney has two major functions: 1. Filtration of blood Removes metabolic wastes from the body, esp. those containing nitrogen

2. Regulation: Blood volume and composition Electrolytes Blood pH Blood pressure

How to kidneys work?

Nephrons Functional unit of the kidney 1.25+ million nephrons per kidney Forms urine in the Kidney after blood is filtered

Nephrons Glomerulus – tangled web of capillaries Filter fluid  filtration to start process of forming urine Glomerular capsule aka Bowman’s capsule- cap-like structure which surrounds the glomerulus - receives fluid filtrate from glomerulus

Regulates concentration of urine Proximal convoluted tubule (PCT) Coiled portion of tube leading from glomerular/Bowman’s capsule to nephron loop Reabsorption of water and solutes Nephron loop aka Loop of Henle Portion of tube which straightens and curves back (ascending and descending limbs) Regulates concentration of urine

Nephrons Distal convoluted tubule (DCT)- coiled tube connecting nephron loop and collecting duct (within renal complex) Collecting duct- tube leading away from several nephrons -Take urine through renal papilla opening to calyx

RENAL CIRCULATION