FUNCTIONAL ANATOMY OF KIDNEYS, URETERS & SUPRARENAL GLANDS By Prof. Saeed Abuel Makarem

Kidneys Its main function is to excrete most of the waste products of metabolism It control the water and electrolyte balance of the body It maintain acid-base balance of the blood The waste products leave the kidneys as urine, which passes down the ureters to the urinary bladder The urine leaves the body through the urethra

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

Kidneys With contraction of the diaphragm during respiration, both kidneys move downward in a vertical direction as much as 2.5 cm On the medial border of each kidney is a vertical slit called the hilum The hilum extends into a large cavity called the renal sinus 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 1- Fibrous capsule: It surrounds the kidney 2- Perirenal fat: It covers the fibrous capsule 3- Renal fascia: it is a condensation of connective tissue that encloses the kidneys and suprarenal glands, it is continuous laterally with the fascia transversalis 4- Pararenal fat: it lies external to the renal fascia, and forms part of the retroperitoneal fat

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

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

ANTERIOR Relations of THE Kidneys RIGHT KIDNEY Suprarenal gland Liver, Second part of the duodenum, Right colic flexure Coils of small intestine LEFT KIDNEY Suprarenal gland, Spleen, Stomach, Pancreas (body), Left colic flexure, Descending colon Coils of jejunum .

Posterior Relations of the Kidneys RIGHT KIDNEY Diaphragm, Costodiaphragmatic recess of the pleura, Twelfth rib & last intercostal space, Psoas major Quadratus lumborum, Transversus abdominis muscle Subcostal nerve (T12) Iliohypogastric nerve (L1) Ilioinguinal nerve (L1) LEFT KIDNEY Same as the right except it is higher it reaches up to the 11th rib.

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

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

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

The two ureters are muscular tubes that extend from the kidneys to the posterior surface of the urinary bladder The urine is propelled along the ureter by peristaltic contractions Each ureter measures about 25 cm long Each ureter has three constrictions along its course, 1- Where the renal pelvis joins the ureter, 2- As it crosses the pelvic brim, 3- Where it pierces the bladder wall ( intra-mural part) Ureters

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

Relations, Right Ureter Anterior: Duodenum, Terminal part of the ileum, Right colic vessels, Iliocolic vessels, Right testicular or ovarian vessels, and the Root of the mesentery. Posterior: Right psoas muscle, Bifurcation of the right common iliac artery

Relations, Left Ureter Anterior: Sigmoid colon, Sigmoid mesocolon, Left colic vessels, Left testicular or ovarian vessels Posterior: Left psoas muscle, Bifurcation of left common iliac artery

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

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

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

Suprarenal Glands The cortex secretes hormones include: Mineral corticoids, which control fluid and electrolyte balance. Glucocorticoids, which control carbohydrates, fats, and proteins. Sex hormones, which probably play a role in the prepubertal development of the sex organs The medulla secretes the catecholamine, epinephrine and norepinephrine

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

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

Blood Supply Arteries: Three arteries supplying each gland, 1- Superior suprarenal artery: from inferior phrenic artery 2- Middle suprarenal from aorta. 3- Inferior suprarenal from renal. Veins: A single vein emerges from the hilum of each gland: The right suprarenal vein drains into the IVC . The left suprarenal vein drains into the left renal

These large glands result from the extensive size of the fetal cortex. The suprarenal glands of the human fetus are 10 to 20 times larger than the adult glands relative to body weight, and are large compared with the kidneys. These large glands result from the extensive size of the fetal cortex. Dr. L. Tchakarov

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