Renal anatomy Flashcards
Inner blood supply to kidney
Renal artery -> Interlobar arteries (between medullary pyramids)
- > Arcuate arteries (along cortico-medullary junction)
- > Interlobular arteries (into cortex)
- > Afferent arterioles, glomerular capillaries
Venous drainage the same
- veins thinner walls, larger lumen
Renal cortex
Darker, granular
Dense peritubular capillary network surrounding tubules in any spare space
Renal corpuscle includes glomeruli + Bowman’s capsule
Proximal vs distal convoluted tubules in renal cortex
Proximal tubules - no clear lumen, brush border, dark pink
Distal tubules - wider limen, pale purple (as less mitochondria)
More proximal than distal visible, as more convoluted and longer
Renal medulla
Paler, parallel striations
Collecting ducts lined by columnar epithelium
Descending think limb lined by squamous epithelium
Ascending thick limb of loop of Henle lined by cuboidal epithelium
Vasa recta capillaries contain RBCs
Medullary rays
Medullary tissue that perforates renal cortex
Between interlobular arteries and veins
Contains collecting tubules and loops of Henle
To drain fluid from the most superficial, subcapsular nephrons
(rays reaching into granular tissue)
Renal pelvis
Simple columnar epithelium at papilla
Transitional epithelium at pelvis -> ureter
Ureter histology
Ragged outer connective tissue (torn, as retroperitoneal in extraction)
Longitudinal inner and circular outer smooth muscle
Muscular tube that moves urine by peristalsis
Accomodates lumen size to volume of urine conveyed - transitional epithelium can be relaxed or stretched
Urothelium create watertight boundary, impermeable to water and urine
Transtitional epithelium
Lines renal pelvis, ureter and bladder
3-6 cell layers, stratified
Basal - cuboidal, dividing cells
Intermediate - columnar cells
Surface - umbrella cells, large ovoid cells
Umbrella cells
Large ovoid cells projecting into lumen
Form watertight barrier - luminal membranes are thick, with high lipid content, and desmosomes (fibrils to hold cells together for unified contraction) and tight junctions
Adapted to enable stretch of urothelium - luminal membranes have accordion-like, pleated capability so that cells can lengthen quickly when flow of urine increases and lumen is distended - also allows small calculi (stones) to pass without damaging lining
Bladder histology
Sac-like, expandable store
Propels urine out - no peristalsis but single unified contraction
Outer connective tissue Smooth muscle, elastic fibres Delicate muscularis mucosa Lamina propria Transitional epithelia
Structure of kidney
Superior and inferior poles
Renal hilum has renal vein, renal artery and pelvis (AP)
Lymph drains to para-aortic nodes, lumbar
Function of excretion and electrolyte balance
Capsules of kidney
Fibrous capsule - adherent to kidney surface
Perinephric fat - solid, protective adipose tissue
Renal fascia - extraperitoneal fascia
Pararenal fat
Posterior relations of kidney
Psoas major, transversus abdominus, quadratus lumborum, diaphragm 12th rib (and 11th on left) Subcostal, iliohypogastric, ilioinguinal nerves
Anterior relations of kidney
RIGHT
Adrenal gland, liver, duodenum, right colic flexure
LEFT
Spleen, stomach, jejunum, pancreas, left colic flexure
Adrenal glands relations
Right - posterior to liver
Left - posterior to stomach and pancreas
Lie within coverings of perinephric fat and renal fascia