Case 6 Anatomy Flashcards
what hormones does the kidney produce?
erythropoietin and calcitriol
what are the dimensions of the kidney?
approximately
- 10cm long
- 5cm wide
- 2.5cm thick
are kidneys primary or secondary retroperitoneal?
primary
which organs/structures are primary retroperitoneal?
- suprarenal glands
- aorta
- ureters
- kidneys
- oesophagus
- rectum
retroperitoneal organs developed and remain outside of the parietal peritoneum
which organs/structures are secondary retroperitoneal?
- duodenum (except 1st segment)
- pancreas (except tail)
- ascending colon
- descending colon
secondarily retroperitoneal organs were initially intraperitoneal, suspended by mesentery – through the course of embryogenesis, they became retroperitoneal as their mesentery fused with the posterior abdominal wall – thus, in adults, only their anterior surface is covered with peritoneum
where do the kidneys lie?
on each side of the vertebral column at the level of T12 – L3 vertebrae
which kidney tends to be slightly inferior?
right kidney
what separates the kidneys from the pleural cavity and the 12th ribs?
diaphragm
what lies anterior to the right kidney?
second part of the duodenum (also in front of IVC)
what are the kidneys crossed posteriorly by?
- subcostal
- ilioinguinal
- iliohypogastric
nerves
which muscles lie posterior to the kidneys?
- quadratus lumborum
- iliopsoas
- transversus abdominis
what are the coverings of the kidneys?
- capsule
- perirenal fat
- renal fascia
- pararenal fat
(protection, support and holding in position)
what is the capsule?
fibrous covering that is adhered to the outer surface of the kidney
what is the perirenal (perinephric) fat?
a fatty layer that surrounds the kidney and extends into the renal sinus
what is the renal fascia?
a fibrous connective tissue layer that surrounds the kidney and suprarenal gland
what is the pararenal (paranephric) fat?
the region of retroperitoneal fat that surrounds the posterior aspect of the kidney
how mobile are the kidneys? what does movement occur? how much?
- 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
what is 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
what can be seen entering/exiting the kidney at the hilum?
- The renal vessels and ureter can be seen entering/exiting the kidney at the hilum
- Front to back:
• Renal vein
• Renal artery
• Ureter
what does the renal hilum extend into?
the renal sinus (the renal hilum is the entrance to the renal sinus)
what does the sinus contain?
- vessels
- nerves
- fat
- structures that collect and drain the urine
what are the structures that collect and drain the urine?
- renal papilla
- minor calyx
- major calyx
- renal pelvis
what is the renal papilla?
the apex of the renal pyramid which projects into the minor calyx
what is the minor calyx?
two to three of these structures drain into each major calyx
what is the major calyx?
two to three of these structures drain into the renal pelvis
what is the renal pelvis?
the expanded superior end of the ureter (the funnel-like dilated part of the ureter) (the pelvis is almost completely enclosed in the sinus)
describe the internal structure of the kidney
- Capsule
- Cortex
- Renal column
- Medulla
- Medullary pyramid
- Renal sinus
- Minor calix
- Major calix
- Renal pelvis
- Ureter
what is the renal column?
is a medullary extension of the renal cortex in between the renal pyramids – it allows the cortex to be better anchored – each column consists of lines of blood vessels and urinary tubes and a fibrous material
how many pyramids in each kidney?
7-18
what is the blood supply of the kidneys?
renal arteries
where do the renal arteries most comonly arise from the aorta?
at the level of the intervertebral disc between L1 and L2
which renal artery is longer?
right
what is the route of the right renal artery?
passes posterior to the IVC
what does each renal artery divide into?
five segmental arteries which are distributed to specific segments of the kidney
what are the 5 segmental arteries?
- Apical (superior)
- Anterosuperior (splits of from anteroinferior)
- Anteroinferior (splits of from anterosuperior)
- Inferior
- Posterior
what do the segmental vessels give rise to?
a complex vascular network
- lobar arteries
- interlobar arteries
- arcuate arteries
- interlobular arteries
- afferent arterioles
- efferent arterioles
- peritubular capillaries/vasa rectae
what do the lobar arteries arise from? what does each supply?
arise from the segmental arteries, each supplies a medullary pyramid
what do the interlobar arteries arise from? where are they?
arise from the lobar arteries and run on either side of a pyramid to the cortex
where do the arcuate arteries run?
run between the cortex and medulla arching over the base of the pyramids
where are the interlobular arteries?
pass through the cortex towards the glomerulus
what do the afferent arterioles arise from? what do they give rise to?
arise from the interlobular arteries and give rise to the glomerular capillaries
what do the efferent arterioles arise from?
exit the glomerular capillaries
what do the peritubular capillaries arise from? where are they?
arise from efferent arterioles and surround the tubules within the cortex
what do the vasa rectae arise from? where are they?
arise from efferent arterioles and surround the tubules within the medulla
what do the peritubular capillaries and vasa recta drain via?
via the interlobular veins into the arcuate veins and then into the interlobar veins
what forms a single renal vein and where?
a number of renal veins unite at the hilum to form a single renal vein
what do the right and left renal veins drain into?
the IVC
what is the renal lobe?
portion of a kidney consisting of a renal pyramid and the renal cortex above it – located between renal columns with peripheral limits within medulla being the interlobar arteries
what is a renal lobule?
part of a renal lobe – consists of the nephrons grouped around a single medullary (refers to destination not location) ray and draining into a single collecting duct
what does lymph from the kidneys drain into?
the para-aortic (lumbar) lymph nodes which are located around the renal artery
what do these para-aortic nodes drain into?
lumbar trunks
what forms the cisterna chyli?
lumbar trunks unite with the intestinal trunks to form an elongated sac-like structure called the cisterna chyli
where is the cisterna chyli?
lies anterior to the bodies of L1 and L2
which fibres innervate the kidney? where do they arise?
preganglionic sympathetic fibres arise in the lateral horn of grey matter in segments T10-L1 of the spinal horn (not part of the gut)
what do the pre-ganglionic fibres pass in and go to which ganglion?
- pass in the least splanchnic nerve
- to the aorticorenal ganglion
what do the post-ganglionic sympathetic fibres supply?
the renal vasculature of the cortex and the efferent arterioles of the juxtaglomerular nephrons and the vasa recta
what does sympathetic stimulation lead to?
vasoconstriction of these vessels
where does afferent information from the kdineys enter the spinal cord?
at the levels of T10-L1
which dermatomes is pain from the kidneys transferred to?
T10-L1 dermatomes
what is a juxtamedullary nephron?
a nephron whose renal corpuscle is near the medulla and whose proximal convoluted tubule and its associated loop of Henle occur deeper in the medulla than cortical nephrons
how long are ureters? what is their diameter?
approximately 25cm long and 1.25cm in diameter
what do the ureters pass through? are they intra or retroperitoneal?
- pass through both the abdominal and pelvic cavities
- retroperitoneal throughout their course
what is the course of the ureters?
- 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
what are the three regions where the ureter narrows along its course? what are the clinical implications?
- Three regions:
• At the junction between the renal pelvis and ureter
• As the ureter crosses the pelvic brim
• As the ureter enters the bladder - This has clinical implications as these regions are sites where renal calculi (kidney stones) may get lodged
what is the arterial supply to the ureters provided by?
a number of vessels in the abdomen and pelvis:
- renal
- gonadal
- abdominal aorta
- common iliac
- internal iliac
- ovarian
what do these vessels that supply the ureters give rise to?
small ureteric vessels which form anastomoses along the length of the ureter
what is the problem with these anastomoses?
they 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 what?
- renal
- gonadal
- common iliac
- internal iliac
veins
lymph from different levels of the ureter drains into which lymph nodes?
- upper part of ureter = paraortic (lumbar) nodes
- middle part of ureter = common iliac nodes
- inferior part of ureter = common, external or internal iliac nodes
what type of innervation do the ureters receive? and where from?
autonomic innervation from the:
- renal plexus
- aortic plexus
- hypogastric plexuses
where is afferent pain from the ureters referred to?
the ipsilateral lower quadrant of the abdomen
what surrounds the suprarenal gland and what does this do?
- renal fascia
- attaches it to the crus of the diaphragm
what shape are the suprarenal glands?
the right gland is pyramidal in shape, contrasting with the semi-lunar shape of the left gland
what is the right suprarenal gland in contact with?
- liver
- IVC
what is the left suprarenal gland in contact with?
- spleen
- stomach
- pancreas
where do arteries, veins, lymphatics and nerves enter/leave the suprarenal gland?
- veins and lymphatics leave gland at hilum
- arteries and nerves enter glands at numerous sites
what does the suprarenal gland consist of?
outer cortex and inner medulla
cortex of suprarenal gland
- what is it derived from
- what colour
- what secrete
- Derived from the mesoderm
- Yellow in colour
- Secretes androgens (male sex hormones mainly DHEA and testosterone)
- Secretes glucocorticoids (predominantly cortisol) (class of corticosteroid)
- Secretes mineralocorticoids (aldosterone most important) (class of corticosteroid)
medulla of suprarenal gland
- what derived from
- colour
- what does it contain
- what may be considered as and why
- what secrete
- when activated
- Derived from neural crest cells (arise from ectoderm cell layer)
- Brown in colour
- Contains chromaffin cells
- May be considered as a sympathetic ganglion (fibres terminate by synapsing with chromaffin cells)
- Secretes catecholamines (e.g. dopamine, norepinephrine, epinephrine) (chromaffin cells secrete transmitter)
- Activated in the fight or flight response
what is the arterial supply for the suprarenal gland?
suprarenal arteries branch into 50-60 branches which enter the gland by penetrating the capsule
how many groups of suprarenal arteries exist? what does each arise from?
Three groups of suprarenal arteries exist; superior, middle and inferior:
• Superior group arises from the inferior phrenic artery
• Middle group arises form the abdominal aorta
• Inferior group arises from the renal artery
what is the venous drainage of the suprarenal gland?
only one large suprarenal vein drains each gland
what does the right suprarenal vein drain into?
IVC
what does the left suprarenal vein drain into?
the left renal vein
what is the lymphatic drainage of the suprarenal gland? how does it get back to IVC?
- Two lymphatic plexuses drain lymph from the suprarenal glands; one lies under the capsule and the other in the medulla
- They drain into the lumbar nodes
what fibres innervate the suprarenal gland and where do they arise from? where do these fibres terminate?
- Preganglionic sympathetic fibres to the suprarenal gland arise in the lateral horn of grey matter in spinal segments T10-L1 (same as kidney)
- These fibres terminate by synapsing with the chromaffin cells in the suprarenal medulla
