Flashcards in case 6 anatomy Deck (40):
The kidneys are responsible for the production of urine and excretion of metabolic waste products. They play a major role in the maintenance of water balance and in the control of blood pressure. They are also involved in electrolyte and acid-base balance and in the production of hormones (erythropoietin and calcitriol).
They kidneys are reddish-brown, bean shaped organs that are approximately 10cm long, 5cm wide and 2.5cm thick.
what peroneal covering do the kidneys have
what level do the kidneys lie
The kidneys lie on each side of the vertebral column at the level of T12 -L3 vertebrae
the right kidney is inferior to the left
relations of the kidneys
THe diaphragm seperates the kidneys from the pleural cavity and the twelfth ribs. The 2nd part of the duodenum sits infront of the right kidney. The liver sits infront of the right kidney. The superrenal gland sits on top. the colon is infront of the bottom of the kidneys. The stomach spleen pancreas and jejunum is infront of the left kidney. The kidneys are crossed posteriorly by the subcostal, ilioinguinal and iliohypogastric nerves. The three muscles that lie posterior to the kidneys are the quadratus lumborum, iliopsoas (psoas major) and transversus abdominis.
coverings of the kidneys
The kidneys are protected, supported and held in position by 4 covering layers; capsule, perirenal fat, renal fascia and pararenal fat. Despite being held in place by these layers the kidney is a fairly mobile structure. Movement occurs during respiration and when moving from a supine to an erect position. The kidney may descend up to 3cm on inspiration.
A fibrous covering that is adhered to the outer surface of the kidney.
perirenal (perinephric) fat
A fatty layer that surrounds the kidney and extends into the renal sinus
A fibrous connective tissue layer that surrounds the kidney and suprarenal gland.
pararenal (paranephric) fat
The region of retroperitoneal fat that surrounds the posterior aspect of the kidney.
external structure of the kidney
When viewed externally the kidney presents superior & inferior poles, anterior & posterior surfaces and lateral and medial borders. A vertical crevice, the hilum, is present on the medial border. The renal vessels and ureter can be seen entering/exiting the kidney at the hilum. order enter hilum from front to back-vein artery ureter. The hilum extends into the renal sinus. The sinus contains vessels, nerves, fat and the structures that collect and drain the urine.
The expanded superior end of the ureter
two to three of these structures drain into each major calyx.
Two to three of these structures drain into the renal pelvis.
The apex of the renal pyramid which projects into the minor calyx.
internal structure of the kidney
renal sinus-fat which the structures in the hilum sit on. capsule around the outside. cortex the outer layer. Medulla and medullary pyramids. Renal column in between - renal papilla-minor-major calix-renal pelvis-ureter.
what level do renal arteries aries from the aorta
below the SMA. between L1 and 2
which is the longest renal artery
renal artery divisions into segmental arteries
divides 5 segments, apical, anterosuperior, anteroinferior, inferior and posterior.
Arise from the segmental arteries, each supplies a medullary pyramid.
Arise from the lobar arteries and run on either side of a pyramid to the cortex.
Run between the cortex and medulla arching over the base of the pyramids.
Pass through the cortex towards the glomerulus.
Arise from the interlobular arteries and give rise to the glomerular capillaries.
Exit the glomerular capillaries.
Arise from efferent arterioles and surround the tubules within the cortex.
Arise from efferent arterioles and surround the tubules within the medulla.The peritubular capillaries and vasa recta drain via the interlobular veins into the arcuate veins and then into the interlobar veins. A number of renal veins unite at the hilum to form a single renal vein. The right and left renal veins drain into the inferior vena cava.
lymphatic drainage of the kidneys
Lymph from the kidneys drains into the para-aortic (lumbar) lymph nodes which are located around the renal artery. These nodes drain into the lumbar trunks. unite intestinal trunk to form cisterna chyli, lies anterior to L1 and 2 then drains into the thoracic duct.
innervation of the kidney
Preganglionic sympathetic fibres arise in the lateral horn of grey matter in segments T10-L1 of the spinal cord. They pass in the least splanchnic nerve to the aorticorenal ganglion. Post ganglionic sympathetic fibres supply the renal vasculature of the cortex and the efferent arterioles of the juxtaglomerular nephrons and the vasa recta. Sympathetic stimulation leads to vasoconstriction of these vessels.
Afferent information from the kidney enters the spinal cord at the levels of T10-L1. Pain is the therefore transferred to the T10- L1 dermatomes.
dermatomes for pain
felt in T10 area. T10 by your belly button T4 by your nipples.
muscular tubes that extend from the kidney to the urinary bladder; they are approximately 25cm long and 1.25cm in diameter. They pass through both the abdominal and pelvic cavities and are retroperitoneal throughout their course.
course of ureter
descends from the apex of the renal pelvis at the hilum of the kidney. Passes down the anterior surface of the psoas major. Crosses the bifurcation of the common iliac artery anterior to the sacroiliac joint. Runs down the lateral wall of the pelvis to the level of the ischial spine. turns forward to enter the bladder. There are three regions where the ureter narrows along its course. This has clinical implications as these regions are sites where renal calculi may get lodged.
which three regions are sites where the ureter is narrowed
At the junction between the renal pelvis and ureter. As the ureter crosses the pelvic brim and as the ureter enter the bladder.
neurovascular supply to the ureters
Arterial supply to the ureters is provided by a number of vessels in the abdomen and pelvis; renal, gonadal, abdominal aorta, common iliac, internal iliac and ovarian. These vessels give rise to small ureteric vessels which form anastomoses along the length of the ureter. However the anastomoses don't really provide an effective collateral pathway and disruption to the vessels during surgery may lead to ischaemia.
The veins draining the ureters drain into renal, gonadal, common iliac and internal iliac viens.
Lymph from different levels of the ureter drains to different nodes. upper part drains to the paraortic nodes, middle to the common iliac and inferior part to the common external and internal iliac nodes. The ureters receive autonomic innervation from the renal, aortic and hypogastric plexuses.
Afferent pain from the ureters is referred to the ipsilateral lower quadrant of the abdomen.
paired retroperitoneal (lying posterior to the peritoneum) endocrine glands situated over the medial aspects of the upper poles of each kidney.They secrete steroid and catecholamine hormones directly into the blood.The adrenal glands lie in the posterior abdomen, situated between the superomedial kidney and the diaphragm. They cover part of the anterior surface of each kidney. The right gland is pyramidal in shape, contrasting with the semi-lunar shape of the left gland.
Perinephric (or renal) fascia encloses the adrenal glands and the kidneys. This fascia attaches the glands to the crura of the diaphragm. They are separated from the kidneys by the perirenal fat.The renal fascia surrounds the suprarenal gland and attaches it to the crus of the diaphragm
relations of the suprarenal glands
The right suprarenal gland is in contact with the liver and the inferior vena cava.The left suprarenal gland is in contact with the spleen, stomach and pancreas.
structure of the suprarenal gland
the adrenal glands consist of an outer connective tissue capsule, a cortex and a medulla. Veins and lymphatics leave each gland via the hilum, but arteries and nerves enter the glands at numerous sites.
The outer cortex and inner medulla are the functional portions of the gland. They are actually two separate endocrine glands, with different embryological origins:
Cortex – derived from the embryonic mesoderm.
Medulla – derived from the ectodemal neural crest cells.
Each is responsible for different secretions.
cortex of the suprarenal gland
yellowish in colour. It secretes two cholesterol derived hormones – corticosteroids and androgens. Functionally, the cortex can be divided into three regions which are (from superficial to deep):
Zona glomerulosa – produces and secretes mineralcorticoids such as aldosterone.
Zona fasciculata – produces and secretes corticosteroids such as cortisol. It also secretes a small amount of androgens.
Zona reticularis – produces and secretes androgens such as dehydroepiandrosterone (DHES). It also secretes a small amount of corticosteroids.
medulla of the suprarenal gland
The medulla lies in the centre of the gland, and is dark brown in colour. It contains chromaffin cells, which secrete catecholamines (such as adrenaline) into the bloodstream in response to stress. These hormones produce a ‘flight-or-fight‘ response.
Chromaffin cells also secrete enkephalins which function in pain control.
neurovascular and lymphatic supply of the adrenal glands
The adrenal glands have a rich blood supply, which is supplied via three arteries:
Superior adrenal artery – arises from the inferior phrenic artery
Middle adrenal artery – arises from the abdominal aorta.
Inferior adrenal artery – arises from the renal arteries.
Right and left adrenal veins drain the glands. The right adrenal vein drains into the inferior vena cava, whereas the left adrenal vein drains into the left renal vein.
Lymph drainage is to the lumbar lymph nodes by adrenal lymphatic vessels. These vessels originate from two lympathic plexuses – one deep to the capsule, and the other in the medulla.
The adrenal glands are innervated by the celiac plexus and abdominopelvic splanchnic nerves. Sympathetic innervation to the adrenal medulla is via myelinated pre-synaptic fibres, mainly from the T10 to L1 spinal cord segments.