Nephrology
Kidney, ureters, bladder, urethra
Embryology
Metanephric blastema: nephrons
Mesonephric duct (Wolffian duct): epidid, vas, seminal ves, Ureteric bud (collecting ducts)
Paramesonephric duct (Müllerian duct):
Aorta > renal a. (25% of cardiac output) > segmental a. > Lobar a. > Interlobar a. > arcuate a. (between med/cort)> interlobular a. > afferent a. > glomerulus >
efferent a. > peritubular c. (cortical) / vasa recta (Juxtamed) > interlobular v. > arcuate v. interloper v. > renal v. > IVC
Autonomic > celiac plexus (SNS: least thoracic and 1st lumbar splanchnic) + PNS > Renal plexus
5 Segments (ant inf, ant sup, sup, pos, inf)
Renal cortex: light and granular
Renal medulla/medullary pyramids: red (apex = papilla v base) stripy (c.f. collecting ducts)
Renal columns: separate pyramids and carry blood supply to cortex. One pyramid and surrounding cortex = lobe (~8)
Minor calyx: drains a papilla, start of smooth muscle
Major calyx: drains minor calyx (~3)
Renal pelvis: drains major calyx, continuous with ureter
Renal hilum:
Renal sinus:
Kidney superior lumbar, T12>L3, left lower than right (liver)
1 million nephrons, 150g, 12x6x3cm (bar of soap)
filtering 200L of blood of (99% resorbed)
- cortical (85%) nephrons LOH in medulla but close to cortex
- juxtamedullary (15%) nephrons corpuscle close to medulla, LOH deep in medulla with longer thin segments (role in concentrating)
Corpuscle
tubule (includes Bowman's) = 3cm, squamous in capsule and thin loop otherwise cuboidal
drain into collecting duct (many tubules per duct) > merge to papillary ducts > minor calyces
Therefore filtrate goes from cortex > medulla > cortex > medulla on way to urine
Pyelonephritis
Embryology
Metanephric blastema: nephrons
Mesonephric duct (Wolffian duct): epidid, vas, seminal ves, Ureteric bud (collecting ducts)
Paramesonephric duct (Müllerian duct):
Aorta > renal a. (25% of cardiac output) > segmental a. > Lobar a. > Interlobar a. > arcuate a. (between med/cort)> interlobular a. > afferent a. > glomerulus >
efferent a. > peritubular c. (cortical) / vasa recta (Juxtamed) > interlobular v. > arcuate v. interloper v. > renal v. > IVC
- high resistance in afferent arterioles protects the kidney from variations in systemic blood pressure
- higher resistance (↓ diameter) in eff v aff = high BP in glom driving filtration.
- renal ptosis (kidney's drop from normal position with extreme emaciation i.e. loss of adipose capsule) can cause ureters to kink > obstruction > hydronephrosis
Autonomic > celiac plexus (SNS: least thoracic and 1st lumbar splanchnic) + PNS > Renal plexus
5 Segments (ant inf, ant sup, sup, pos, inf)
Renal cortex: light and granular
Renal medulla/medullary pyramids: red (apex = papilla v base) stripy (c.f. collecting ducts)
Renal columns: separate pyramids and carry blood supply to cortex. One pyramid and surrounding cortex = lobe (~8)
Minor calyx: drains a papilla, start of smooth muscle
Major calyx: drains minor calyx (~3)
Renal pelvis: drains major calyx, continuous with ureter
Renal hilum:
Renal sinus:
Kidney superior lumbar, T12>L3, left lower than right (liver)
1 million nephrons, 150g, 12x6x3cm (bar of soap)
filtering 200L of blood of (99% resorbed)
- metabolic waste
- toxins: drugs,
- ions: salt and acid/base balance
- Gluconeogenesis
- Endocrine: Renin, erythropoietin
- Metabolism: Vit D to active Vit D
- cortical (85%) nephrons LOH in medulla but close to cortex
- juxtamedullary (15%) nephrons corpuscle close to medulla, LOH deep in medulla with longer thin segments (role in concentrating)
Corpuscle
- glomerulus (fenestrated epithelium) (glom = ball of yarn): only capillary bed drained by arterioles.
- basement membrane separating the fenestrated capillary bed and podocytes
- bowman capsule: collects the filtrate (visceral layer epithelium = podocytes, octopus like feet intertwined creating filtration slits. parietal = simp squam)
tubule (includes Bowman's) = 3cm, squamous in capsule and thin loop otherwise cuboidal
- Bowman's capsule (see above)
- prox CT (cortex): cuboid epi. only part with microvilli (fuzzy on microscope) most of resorption : 100% glucose/AAs, 80% PO4, Citrate, 75% H2O/Na, 65% K,
- pro ST (cortex> outer med)
- LOH (inner med): descending thick > descending thin > ascending thin > ascending thick)
- dis CT: cuboid: secretion. initial part of DCT passes close to aft a. forming the juntaglomerular apparatus. flate in the DCT (aka connecting tubule) 2 cells. intercalated cells (α and b) with microvilli control acid base. Principle cells control Na and H2O.
drain into collecting duct (many tubules per duct) > merge to papillary ducts > minor calyces
Therefore filtrate goes from cortex > medulla > cortex > medulla on way to urine
Pyelonephritis
- enter from urinary tract or seed from haematogenous spread.