FUNCTIONAL ANATOMY OF KIDNEYS URETERS SUPRARENAL GLANDS By

FUNCTIONAL ANATOMY OF KIDNEYS, URETERS & SUPRARENAL GLANDS By: Dr. Mujahid Khan

Kidneys Ø The two kidneys function to excrete most of the waste products of metabolism Ø They control the water and electrolyte balance of the body Ø Maintain acid-base balance of the blood Ø The waste products leave the kidneys as urine, which passes down the ureters to the urinary bladder Ø The urine leaves the body in the urethra

Kidneys Ø Kidneys are reddish brown in color Ø Lie behind the peritoneum high up on the posterior abdominal wall on either side of the vertebral column Ø Are largely under cover of the costal margin Ø The right kidney lies slightly lower than the left due to the large size of right lobe of the liver

Kidneys Ø With contraction of diaphragm during respiration, both kidneys move downward in a vertical direction as much as 2. 5 cm Ø On the medial border of each kidney is a vertical slit called the hilum Ø The hilum extends into a large cavity called the renal sinus Ø The hilum transmits the renal vein, two branches of renal artery, ureter, and the third branch of renal artery from the front backward (V. A. U. A. )

Coverings Ø Fibrous capsule: It surrounds the kidney Ø Perirenal fat: It covers the fibrous capsule Ø Renal fascia: it is a condensation of connective tissue that encloses the kidneys and suprarenal glands, it continuous laterally with the fascia transversalis Ø Pararenal fat: it lies external to the renal fascia, and forms part of the retroperitoneal fat

Renal Structure Ø Each kidney has a dark brown outer cortex and a light brown inner medulla Ø Medulla is composed of about a dozen renal pyramids Ø Each pyramid having its base oriented toward the cortex, and its apex, the renal papilla, projecting medially Ø The cortex extends into the medulla between adjacent pyramids as the renal column

Renal Structure Ø Extending from the bases of the renal pyramids into the cortex are striations known as medullary rays Ø The renal sinus within the hilum, contains the upper expanded end of the ureter, the renal pelvis Ø Renal pelvis divides into two or three major calyces, which divides into two or three minor calyces

Relations of Right Kidney Ø Anteriorly: The suprarenal gland, the liver, the second part of the duodenum, and the right colic flexure Ø Posteriorly: The diaphragm, the costodiaphragmatic recess of the pleura, the twelfth rib, and the psoas, quadratus lumborum, and transversus abdominis muscles, the subcostal (T 12), iliohypogastric and ilioinguinal (L 1) nerves

Relations of Left Kidney Ø Anteriorly: The suprarenal gland, the spleen, the stomach, the pancreas, the left colic flexure, and coils of jejunum Ø Posteriorly: The diaphragm, the costodiaphragmatic recess of the pleura, the 11 th and 12 th ribs, and the psoas, quadratus lumborum, and transversus abdomnis muscles, the subcostal (T 12), iliohypogastric and ilioinguinal (L 1)nerves

Blood Supply Ø The renal artery arises from the aorta at the level of second lumbar vertebra Ø Each renal artery divides into five segmental arteries that enter the hilum of the kidney, four infront and one behind the renal pelvis Ø They are distributed to different segments of the kidney called segmental arteries Ø Lobar artery arise from each segmental artery, one for each renal pyramid

Blood Supply Ø Each lobar artery gives off two or three interlobar arteries Ø The interlobar arteries run toward the cortex on each side of the renal pyramid Ø Interlobar arteries give off the arcuate arteries at the junction of the cortex and medulla Ø The arcuate arteries give off several interlobular arteries Ø Afferent glomerular arterioles arise as branches of interlobular arteries

Veins, Lymph, Nerve Supply Ø Renal vein emerges from the hilum in front of the renal artery and drains into the IVC Ø Lateral aortic lymph nodes around the origin of the renal artery Ø Renal sympathetic plexus, the afferent fibers that travel through the renal plexus enter the spinal cord in the 10 th, 11 th, and 12 th thoracic nerves

Ureter Ø The two ureters are muscular tubes that extend from the kidneys to the posterior surface of the urinary bladder Ø The urine is propelled along the ureter by peristaltic contractions Ø Each ureter measures about 25 cm long Ø Have three constrictions along its course, where the renal pelvis joins the ureter, where it is kinked as it crosses the pelvic brim, and where it pierces the bladder wall

Ureter Ø The renal pelvis is the funnel-shaped expanded upper end of the ureter Ø It lies within the hilum of the kidney and receives the major calyces Ø It enters the pelvis by crossing the bifurcation of the common iliac artery in front of the sacroiliac joint Ø It runs down the lateral wall of the pelvis and turns forward to enter the lateral angle of the bladder

Relations, Right Ureter Ø Anterior: The duodenum, the terminal part of the ilium, the right colic and iliocolic vessels, the right testicular or ovarian vessels, and the root of the mesentery of the small intestine Ø Posterior: The right psoas muscle, and the bifurcation of the right common iliac artery

Relations, Left Ureter Ø Anterior: The sigmoid colon and sigmoid mesocolon, the left colic vessels, the left testicular or ovarian vessels Ø Posterior: The left psoas muscle, and the bifurcation of the left common iliac artery

Blood Supply Ø Upper end is supplied by the renal artery Ø Middle portion is supplied by testicular or ovarian artery Ø In the pelvis is supplied by the superior vesical artery Ø The lymph drains to the lateral aortic nodes and the iliac nodes

Nerve Supply Ø Renal, testicular (or ovarian), and hypogastric plexus (in the pelvis) Ø Afferent fibers travel with the sympathetic nerves and enter the spinal cord in the first and second lumbar segments

Suprarenal Glands Ø The two suprarenal glands are yellowish retroperitoneal organs that lie on the upper poles of the kidneys Ø They are surrounded by renal fascia Ø Separated from the kidneys by the perirenal fat Ø Each gland has a yellow cortex and a dark brown medulla

Suprarenal Glands Ø The cortex secretes hormones include mineral corticoids, which is concerned with the control of fluid and electrolyte balance Ø Glucocorticoids, concerned with the control of carbohydrates, fats, and proteins Ø Sex hormones, which probably play a role in the prepubertal development of the sex organs Ø The medulla secretes the catecholamines epinephrine and norepinephrine

Right Suprarenal Glands Ø The right suprarenal gland is pyramid shaped and caps the upper pole of the right kidney Ø It lies behind the right lobe of the liver and extends medially behind the IVC Ø It rests posteriorly on the diaphragm

Left Suprarenal Glands Ø The left suprarenal gland is crescentic in shape Ø Extends along the medial border of the left kidney from the upper pole of the hilus Ø Lies behind the pancreas, the lesser sac, and the stomach Ø It rests posteriorly on the diaphragm

Blood Supply Ø Arteries: The arteries supplying each gland are three in number: inferior phrenic artery, aorta, and renal artery Ø Veins: A single vein emerges from the hilum of each gland drains into the IVC on the right and into the renal vein on the left

Nerve Supply and Lymph Ø Preganglionic sympathetic fibers derived from the splanchnic nerves supply the glands Ø Most of the nerves end in the medulla of the gland Ø The lymph drains into the lateral aortic nodes