anatomy and histology of the kidney Flashcards
5 segments defined by
non-anastomosing blood supply
5 segments
apical upper middle lower posterior
nerve supply
vasomotor
ie. if you have a transplant you need hormonal control
parasympathetic innervation
vagus increases renal arterial flow
increase in glomerular filtration rate
sympathetic innervation
lesser splanchnics
T10-11 via aorticorenal plexuses
gross renal anatomy
renal lobes = cortex medullary pyramid
cortex
outer tissue with renal column extensions (into medulla)
glomeruli and convoluted tubules (proximal/distal) + medullary rays
medulla
pyramids contain the long tubules of the nephrons
loop of henle and collecting ducts and papilla
medullary pyramid
papilla and pyramidal body and medullary rates (in cortex)
nephron
1 million/kidney
6 major components of a nephron
- bowman’s capsule
- glomerulus
- proximal convoluted tubule
- loop of henle
- distal convoluted tubule
- collecting ducts
process of making urine
filter of the blood - glomerular filtration, BP dependant
reabsorb water salts and glucose
secrete some proteins - notable creatinine
passive mechanisms
counter current flow between peritubular capillaries and tubules
concentration gradient established by selective transporters
osmosis and diffusion
glomerulus
multi layered electro mechanical filter, representing joining of filtration and excretion side of system
filtration side
coiled fenestrated capillary (70-90nm)
3 cell types in the filtration side
mesangial cells
juxtaglomerular cells
macula densa
excretion side
basement membrane and 2 sides of bowman’s capsule cells
parietal - cells of capsule wall
visceral - podocytes and their pedicel extensions
cortical nephrons
short loops of henle
- glomeruli found further away from medulla
- mid cortical is a hybrid of cortical and juxta
juxtaglomerular nephrons
at junction of cortex and medulla
loops of henle descend deeper into medullary pyramid
distal convoluted tubule interacts with afferent arteriole
the deeper into the medullary pyramid
the higher the concentration of salts around the tube become
proximal convoluted tubule
high amount of active transport high surface area = microvilli lots off mitochondria large irregular shaped cells few nuclei in cross section
distal convoluted tubule
no microvilli
more nuclei in tubular cross sections
outer diameter often roughly equal to inner diameter of PCT
less active transport - less machinery in cell
loop of henle
proximal thick segment
distal thick segment
thin segments have simple sqmaous epithelium
collecting ducts
inner diameter roughly equal to out diameter of DTT/DCT
still cuboidal with crisp liminal surface
sensitive to aldosterone
ureter
transitional epithelium
protects against stretch
stratified squamous near extorting opening - distal urethra
layers of the ureter
mucosa
muscular externa - inner circular and out longitudinal
ureter moves urine by
peristalsis
urethra moves urine by
bladder and abdominal pressure
tracing the ureter
passes through retroperitoneal fat
crosses the pelvic brim at bifurcation of common iliac arteries
blood supply of the ureter
upper ureter - branches from renal arteries
lower ureter and bladder - branches from vesicular arteries
nerve supply of the upper ureter
parasympathetic - vagus
sympathetic - least splanchnic
nerve supply of the lower urete r and bladder
parasympathetic - pelvic splanchnics via hypogastric plexus detrusor contraction of smooth muscle carry stretch afferents sympathetic - sacral splanchnic L1/2 spinal nerves - tighten sphincter
micturition reflex
stretch triggers detrusor contraction
felt as an urge to pee, but can be consciously overridden
4 surfaces of the pyramid
2 lateral - against the pubic bones
superior - covered in peritoneum
posterior - receives ureters
