Renal System Histology: Difference between revisions

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* Kidneys, ureters, urinar bladder, urethra
* Kidneys, ureters, urinar bladder, urethra
 
[[File:Gray1126.png|thumb|retroperitoneal kidney]]
'''Anatomy'''
'''Anatomy'''
* retroperitoneal
* retroperitoneal

Revision as of 17:14, 29 August 2011

Introduction

Nephron histology

This section of notes gives an overview mainly of adult renal histology, see also Renal System Development notes. A key structure of the kidney functional unit, the nephron, is the glomerulus (renal corpuscle), which represents the initial vascular/renal interface.

HMsmall.jpg

Page also provides further background information for Medicine phase 1 Health Maintenance B Urinary Tract Histology Practical Virtual Slides. This page content is not part of the HMB practical class.


HMB: Pancreas Histology | Liver Histology | Gall Bladder Histology | Renal System Histology
Renal Links: renal | Lecture - Renal | Lecture Movie | urinary bladder | Stage 13 | Stage 22 | Fetal | Renal Movies | Stage 22 Movie | renal histology | renal abnormalities | Molecular | Category:Renal
Historic Embryology - Renal  
1905 Uriniferous Tubule Development | 1907 Urogenital images | 1911 Cloaca | 1921 Urogenital Development | 1915 Renal Artery | 1917 Urogenital System | 1925 Horseshoe Kidney | 1926 Embryo 22 Somites | 1930 Mesonephros 10 to 12 weeks | 1931 Horseshoe Kidney | 1932 Renal Absence | 1939 Ureteric Bud Agenesis | 1943 Renal Position

Kidney Anatomy

  • Nephron - Functional unit of kidney
  • Humans up to 1 million
  • Filtration of waste from blood
  • Endocrine
  • Blood pressure regulation
Gray1128.jpg

Adult nephron structure

Nephron Histology

  • mean glomerular number shown to level at 36 weeks, increasing from about 15,000 at 15 weeks to 740,000 at 40 weeks.

Glomerulus

Nephron histology 01.jpg Nephron histology 02.jpg
Glomerulus structure Vascular and renal poles
Links: glomerulus structure image | vascular and renal poles image

Nephron Tubules

Nephron histology.jpg

Nephron overview

Nephron histology 03.jpg Nephron histology 04.jpg


Links: Nephron histology image

Ureter Histology

  • The adult ureter is a thick-walled muscular tube, 25 - 30 cm in length, running from the kidney to the urinary bladder.
  • Anatomically can be described in two parts the abdominal part (pars abdominalis) and pelvic part (pars pelvina).
  • The ureter is composed of three layers: outer fibrous layer (tunica adventitia), muscular layer (tunica muscularis) and mucous layer (tunica mucosa).
  • The muscular layer has also been described as being subdivided into 3 fibre layers:
  1. an external longitudinal
  2. a middle circular
  3. an internal longitudinal
Adult bladder.jpg

Ureter histology 001.jpg Ureter histology 002.jpg


Can be described anatomically by its 4 layers from inside outward:
  • Mucosa - (mucus layer) a transitional epithelium layer formed into folds (rugae).
  • Submucosa - connects the muscular layer with the mucous layer.
  • Muscular - the detrusor muscle is the muscle of the urinary bladder wall.
  • Serous - the superior or abdominal surfaces and the lateral" surfaces of the bladder are covered by visceral peritoneum, the serous membrane (serosa) of the abdominal cavity, consisting of mesthelium and elastic fibrous connective tissue.


Detrusor Muscle

  • The adult detrusor muscle consists of three layers of smooth (involuntary) muscle fibres.
    • internal layer - fibres arranged longitudinally
    • middle layer - fibres arranged circularly
    • external layer - fibres arranged longitudinally

Note that while the smooth muscle fibre layer organisation is described as longitudinal or circular, this is only a general organisation of fibre direction, and is better described as a "spiral" organisation.

Bladder histology.jpg

Urethra Histology

Images

External Links

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Practical Overview

  • Kidneys, ureters, urinar bladder, urethra
retroperitoneal kidney

Anatomy

  • retroperitoneal
  • kidney - bean shaped
  • rich blood supply

Kidney Function

  • elimination of foreign substances
  • regulation of the amount of water in the body
  • control of the concentration of most compounds in the extracellular fluid
  • filtration - glomeruli of the kidney
  • selective resorption and excretion - tubular system of the kidney
Capsule
  • outer layer - dense CT (fibroblasts and collagen
  • inner layer - myofibroblasts
Cortex
  • outer renal corpuscles
  • medullary rays
    • only straight tubules + straight collecting tubules
    • 400-500 project medulla to cortex
  • between medullary rays - convoluted tubules of nephrons
Medulla
  • medullary pyramids (together with associated cortical region = renal lobe)
    • base at cortioco-medullary border
    • apex at renal papilla (surrounded by minor calyx)
  • minor calyces converge to form major calyces then renal pelvis

Blood Supply

  • renal artery
  • interlobar arteries (across medulla thru renal columns)
  • arcuate arteries (cortico-medullary junction)
  • interlobular arteries
  • afferent glomerular arterioles
  • glomerular capillary network
  • efferent glomerular arterioles

Vasa Recta

  • descending arterioles (arteriole rectae) + ascending venules (venulae rectae)

Glomerulus

  • glomerulus - round (~0.2 mm in diameter) blind beginning of the nephron
  • vascular pole - invaginated by a tuft of capillaries
  • urinary pole - substances leave the capillaries enter the renal tubule
  • Bowman's capsule - anatomical glomerulus is enclosed by two layers of epithelium.
    • outer or parietal layer of Bowman's capsule form a simple squamous epithelium.
    • inner layer, podocytes in the visceral layer, are extremely complex in shape.
  • Mesangial cells in the glomerulus form the connective tissue that gives structural support to podocytes and vessels (Podocytes, mesangial cells, glomerular capillaries)
  • Juxtaglomerular cells - smooth muscle cells afferent glomerular arteriole (epithelial-like cells)
  • Macular Densa
    • distal convoluted tubule near vascular pole (narrower and taller than rest of DCT)

Tubules

Proximal Convoluted Tubules

  • brush border
  • star-shaped
  • larger outside diameter

Distal Convoluted Tubules

  • clean lumen surface
  • apical nuclei

Collecting Tubules

  • larger lumen than DCT (about size of PCT)
  • cuboidal cells and smaller than DCT

Renal Pyramids

  • medullary straight tubules, ducts and vasa recta
  • apical renal papilla - simple cuboidal/columnar epithelia
  • calyx - lined by transitional epithelia

Note the urinary system transitional epithelium is also known as urothelium.

Ureters

  • epithelium - transitional epithelia
  • lamina propria - mainly of dense connective tissue, with many bundles of coarse collagenous fibres
  • muscularis - consists of an inner longitudinal and outer circular layer of smooth muscle cells
    • In lower parts of the ureter and the bladder an additional outer longitudinal layer of muscles is added to the first two.

Bladder

  • epithelium - transitional epithelia
    • apical plaques - thickened domain allows great changes in surface area.
  • lamina propria - mainly of dense connective tissue, with many bundles of coarse collagenous fibres
  • muscularis - consists of an inner longitudinal and outer circular layer of smooth muscle cells
    • In the bladder (and lower parts of the ureter) an additional outer longitudinal layer of muscles is added to the first two.

Urethra

  • penile urethra within corpus spongiosum
  • pseudostratified columnar epithelia
  • distal end - stratified squamous
  • continuous with outer skin


Glossary Links

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Cite this page: Hill, M.A. (2024, March 29) Embryology Renal System Histology. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Renal_System_Histology

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© Dr Mark Hill 2024, UNSW Embryology ISBN: 978 0 7334 2609 4 - UNSW CRICOS Provider Code No. 00098G