Renal system micro-anatomy Flashcards
list the parts of the renal system
1) Renal corpuscle ( bowman capsule + glomerulus )
2) PCT (cortex)
3) Loop of henle
4) DCT (cortex)
what does the blind ending nephron mean ?
1) PCT = expanded spherical portion which is the closed end
2) developing glomerulus pushed into this blind ending tubule
3)Leads to 2 epitheliums = parietal , and visceral epithelium around the glomerulus
= hence blind ending nephron
outline the structure of the kidney
Multi lobular each lobe is divided into 3 parts:
1) Outer cortex
2) Inner medulla (pyramid looking)
3) Papilla = apex
the papillae = cups which drain into the calyces
1-minor calyces
2-Major calyces
3-Renal pelvis
4-Ureter
describe the renal corpuscle
-afferent arteriole = larger diameter
-Efferetn arteriole = smaller diameter = higher pressure ! High pressure causes blood to back log = filters for longer
Like is there is only one door open in a classroom , there will be a backlog
-JH complex ( MD cells, Jg cells, Lacis cells)
-Parietal epithelium
-Viscerla epithelium
-Capsular space in between the epitheliums
what does the Juxtaglomerular apparatus consist of ?
Function is to monitor and adjust BP
- Macula dense cell = chemoreceptors
- Lacis cells ( unknown)
- JG cells = specialised smooth muscle of the media , afferent arteriole –>Secrete RENIN
what is the blood supply to the nephron RM in Arcades Can Really Act Good especially playing V -
Renal artery from abdominal aorta
- Interblobular artery
- Arcuate artery ( in corticomedullary region )
- Cortical radial artery
- Afferent arterioles
- Glomeruli
- Efferent arterioles
- Peritubular capillaries ( wrapped around nephron, takes up reabsorbed nutrients )
- venous return ( parallel to arterial flow) or vasa recta–>blood to medulla
what does the blood-filtration barrier consist of ?
3
1- fenestrated endothelium of glomerular capillaries
2-Fused basal laminae
3-Pedicles ( fingers) of the podocytes in visceral epithelium
Structure of the PCT
epithelium , lumen , reabsorption and blood supply
1) simple cuboidal epithelium with long microvilli which makes the lumen look cloudy
2) 70% of glomerular filtrate is reabsorbed here !
3) reabsorbed ions return via the peritubular capillaries
Outline the Loop of henle
- thick and thin portion epithelium
- vessels
- permeability ?***
1) Thin portion = simple squamous
Thick portion = simple cuboidal
2) Vasa recta = straight vessels which run parrallel to Loop of henle = branches from efferent arterioles
3)counter current flow ***
Describe the distal convoluted tubule
- cells
- special cells
- twisted ?
- vessles?
1- cuboidal cells + no microvilli = so they don’t appear cloudy
2-less twisted than PCT
3-regulates : K+,Na+,Ca2+, pH
4-Macula densa cells = chemoreceptor cells which allow activation of JG cells –>RAAS
5- Peritubular capillaries
Describe the microanatomy of the collecting ducts
3
1) Collecting tubules –>Collecting ducts —>Ducts of Bellini ***
2) This delivers filtrate to the Papillae –>minor calyx
( not part of nephron )
Microanatomy of the renal calyces + pelvis
-epithelium
1) epithelium = transitional
2) well developed smooth muscle but the layers are ill defined
3) Peristalitic movements help ti empty the tubules into the calyces
Microanatomy of the ureter ?
3
1-Transports urine to bladder via peristalsis
2- Transitional epithelium + lamina propria ( elastic fibres)
3- Star shaped lumen
Microanatomy of the bladder?
1-Resevoir for storage and expulsion into urerthra
2-Transitional epithelium ( urothelium , because there are umbrella cells )
3-Underlying lamina proprietor + BV + Fibroelastic CT
4-Smooth muscle = 3 layers in INDISTINCT layers
