List of abbreviations
of micros-
specialist terms
explained in
English +

Every attempt was made to provide correct information and labelling, however any liability for eventual errors or incompleteness is rejected!

dieser Seite

Dr. med.
H. Jastrow

of use
Overview kidney (Ren):
Pages with explanations are linked to the text below the images if available! (Labelling is in German)
overview (rat)
glomerular capillary
loops (monkey)
endothelial cell of a
glomurular capillary (rat)
glomerulum detail
glomerulum detail 2
glomerulum detail 3
cells of the parietal part of
Bowmann's capsule (monkey)
Bowmann's capsule
+ glomerulum (monkey)
urinalry pole change
of epithelium (monkey)
urinary pole 1
urinary pole 2
glomerulum and
distal tubule (monkey)
fenestrated endothelium +
podocyte processes (monkey)
podocytes, filtration barrier
glomerulum (monkey)
pseudopodea of a
podocyte 1 (monkey)
pseudopods of a
podocyte 2 (monkey)
basement membrane in
flat section (monkey)
podocyte, filtration
mikrovilli on epithelial cells of the
proximal renal tubule (monkey)
tubule 2 (monkey)
proximal renal tubule
3 (monkey)
proximal renal tubule in
coss-section (monkey)
basale striping of aproxi-
mal tubule cell (monkey)
basal striping 2
proximal tubule (monkey)
different tubuli and
blood vessels 1 (monkey)
different tubules + blood
vessels 2 (monkey)
different tubules + blood
vessels 3 (monkey)
different tubules + blood
vessels 4 (monkey)
filtration barrier
basal mitochondrial stripes proxi-
mal tubulus epithelial cell (rat)
Henle's loop in cross-
section (monkey)
Henle's loop in longi-
tudinal section 1 (monkey)
Henle's loop in longi-
tudinal section 2 (monkey)
distal convolut 1
distal renal tubule 1
basal stripes of mito-
chondria (rat)
distal tubule + blood
vessels (monkey)
distal convolut 2
distal convolut 3
distal renal tubule 2
collecting duct

The kidney (Terminologia histologica: Ren, Nephros) has a weight of 120 - 200 g and serves in filtration of urine from blood. Thus it is the initial organ of the urinary system (Terminologia histologica: Systema urinarium) that also comprises the draining ureter which reaches the bladder (Vesica urinaria) and then continues into the urethra.
The kidney is covered and protected by a perirenal fat capsule (perinephric fat; Terminologia histologica: Capsula adiposa) consisting of a usually some centimetres wide construction fat of unilocular fat tissue cells. However, at the beginning, i.e. in newborns and babies and then dramatically decreasing in number multilocular fat cells are present here as well. The organ proper is ensheated by a fibrous capsule (Terminologia histologica: Capsula fibrosa) build of woven connective tissue. One human kidney has 6 to 9 lobes (Renculi; Terminologia histologica: Lobi renales) which usually are not visible as it is the case in many animals (e.g., cows). Human kidneys with a clearly visible lobulation are called renculus kidneys and present in ~ 7% of adults. During development humans have 14 single kidney premordia thus a maximum of 14 lobes is possible for each side. The lobes can be recognised in kidney sections by their calyces into which they release their urine. Renal columns (Bertini columns; Terminologia histologica: Columnae renales) are present in the regions where the lobes border each other they reach downwards from the renal cortex and are in fact parts of the renal cortex which to the exterior borders the renal capsule. In the other direction the renal cortex borders the renal medulla which ends in the calyces that collect the urine and lead it into the renal pelvis. The functional unit of the kidney is the Nephron, which consists of the renal corpuscles  and the non branched segments of the tubules, that together with 11 other such tubules terminate in one collecting duct. About 150 to 180 Litres of primary urine are filtered from blood in the renal corpuscles located only in the renal cortex. This urine flows through initial proximal tubules that reach down into the medulla then make a turn in Henle's loop ascend as distal tubules pass a chloride ion sensor, the macula and continue to connecting tubules turn downwards again and via collecting ducts descend to papillary ducts ending at the tip of the papilla of the medulla. Here the final urine is released into the renal calices. While passing the nephron about 99% of the water and lots of ions are regained from the primary urine. Further, other substances are secreted here. This results in 1.5 Litres of final urine. These processes happen either transcellularly, i.e. through the epithelial cells with help of transport proteins in apical and basal cell membranes or, restricted to some sections of the tubules, paracellularly (for small ions and substances) through the pores of the tight junctions of the junctional complex between the cells via the intercellular space. Additionally, the kidney releases the following hormones: renin and erythropoëtin.

Detailed information and many more images are only available in the professional version of this atlas.

--> blood-urine barrier, ureter, urinary bladder, prostate, seminal gland, epithelium, microvilli
--> Electron microscopic atlas Overview
--> Homepage of the workshop

Many images were kindly provided by Prof. H. Wartenberg; other images, page & copyright H. Jastrow.