Kidney - structure, blood supply, nerve supply

arterial supply of kidneys and where do they arise from

• renal arteries from abdominal aorta (L1-L2 level)

venous drainage of kidneys

• renal veins into IVC

the 2 common tributeries of left renal vein before it drains int

• left adrenal vein

• left gonadal vein

Describe segmental arteries

• renal artery divided into anterior and posterior branches

• anterior branch further divided into four branches: apical segmental artery (ASA), Upper segmental artery (USA), middle segmental artery (MSA), lower segmental artery (LSA)

• posterior branch continue as posterior segmental artery

  
  

what are nephrons

renal functional units

epithelial lining of glomerulus, BC, thin loop of henle

simple squamous (thin membrane allows filtration)

epithelial lining of PCT, DCT

simple cuboidal epithelium (secretion and absorption of aa, glucose, ions)

epithelial lining of CD

columnar epithelium (free passage of water to and from medulla)

location of glomerulus, PCT, DCT

cortex

location of loops of henle and collecting duct

medulla

Innervation of kidneys

• T10-L1 sympathetic fibres

• preganglionic fibres synapse in aorticorenal ganglia or coeliac ganglia

• postganglionic fibres supply kidneys

• vasomotor in function and also supply juxtaglomerular to stimulate renin release

what does the sympathetic NS regulate in the kidney

• blood flow and renin release

• influencing BP and kidney function

what does renal artery stenosis lead to

• renal ischemia

• negatively impacts kidney function and BP regulation

junction of areas supplied by anterior and posterior divisions of renal artery 

approaches on post surface of kidney situated 2/3 of the way from the hilum to lat margin of kidney

• a relatively avascular plain of the kidney as arteries do not anastamose across these lines

• veins do anastamose ocassionall

• therefore the plain used in surgery 

describe the course of segmental arteries

• each segmental artery supplies the contents of the renal sinus

• divides into lobar arteries (approach apex of renal pyramids)

• each lobar artery divides into interlobar artery (ascends between the 2 renal pyramids)

• interlobar arteries divide into arcuate arteries (form an arch over base of medullary pyramids)

• interlobular arteries arise from arcuate arteries

• interlobular arteries divide into afferent arteriole to glomerulus

• afferent arterioles break up into a capillary plexus in glomerulus and merge into an efferent arteriole

• efferent arteriole breaks up into another capillary plexus (peritubular capillary plexus) - drain into an interlobular vein

• interlobular vein follows same pathway of the artery (interlobar vein, lobar vein, segmental vein, renal vein)

2 parts that make up the nephrons

renal corpuscle (capillaries contained within BC) and renal tubule

Juxtaglomerular apparatus location and function

• where DCT comes into contact w/ afferent arteriole of glomerulus

• regulation of BP

• some of the cells of DCT are modified to form macula densa (sense Na conc in tubule and signal cells of afferent arteriole (juxtaglomerular cells) to produce renin (in response to low BP in afferent arteriole or decreased bl vol in afferent arteriole and in response to signals from macula densa when decreaed Na conc in DCT

RAAS

renin —> angiotensin

collecting part of kidney from minor calyces, major callyces, pelvis of ureter down to urinary bladder and urethra epithelium

transitional epithelium (urothelium)

• type of stratified epithelium w/ more than 2 layers of cells

• upper layer of cells = dome (umbrella) shaoed - strectj when tract stretched with increased urine

• produce uroplakins proteins - forms layer on top of upper layer of cells - impermeable to water and protects cytoplasm and cells from hypoosmotic effect of urine

main cancer of kidney

adenocarcinoma type (arise from cells of kidney tubules -PCT or DCT)

cancer of collecting system

• arising from transitional epithelium cells

• transitional cell carcinoma (ureothelioma)