The urinary system part 1

The kidneys are bean-shaped organs that lie retroperitoneal in the superior lumbar region.
•The medial surface is concave and has a renal hilus that leads into a renal sinus, where the blood vessels, nerves, and lymphatics lie.
•The kidneys are surrounded by an outer renal fascia that anchors the kidney and adrenal gland to surrounding structures, a perirenal fat pad that surrounds and cushions the kidney, and a fibrous capsule that prevents surrounding infections from reaching the kidney.
•Internal Anatomy
oThere are three distinct regions of the kidney: the cortex, the medulla, and the renal pelvis.
oMajor and minor calyces collect urine and empty it into the renal pelvis.
2
Trace the blood supply through the kidney.
•Blood supply into and out of the kidneys progresses to the cortex through renal arteries to segmental, lobar, interlobar, arcuate, and cortical radiate arteries, and back to renal veins from cortical radiate, arcuate, and interlobar veins.

•The renal plexus regulates renal blood flow by adjusting the diameter of renal arterioles and influencing the urine-forming role of the nephrons.
3
Describe the anatomy of a nephron.
•Each nephron consists of a renal corpuscle composed of a tuft of capillaries (the glomerulus) surrounded by a glomerular capsule (Bowman’s capsule).

•The renal tubule begins at the glomerular capsule as the proximal convoluted tubule, continues through a hairpin loop, the loop of Henle, and turns into a distal convoluted tubule before emptying into a collecting duct.
• The collecting ducts collect filtrate from many nephrons, and extend through the renal pyramid to the renal papilla, where they empty into a minor calyx.

•There are two types of nephrons: 85% are cortical nephrons, which are located almost entirely within the cortex; 15% are juxtamedullary nephrons, located near the cortex-medulla junction.

•The peritubular capillaries arise from efferent arterioles draining the glomerulus, and absorb solutes and water from the tubules.