1. Kidney(for LS 1, LS 4, LS 5 and LS 9 only)

A.B.1.2.3.4.5.6.7.8.*9*

10.*11.*

12.*

13.

14.*15.*16.16a*17.18.

Marrow of the kidney, Medulla rentsCortex of the kidney, Cortex rentsRenal vein, Vena renalisRenal artery, Arteria renalisUreterPelvis of the kidney, Pelvis renalisCalyces of the kidney, Colices renalesRenal papillae, Papillae renalesRenal pyramids, Pyramides renalesCollecting ductContort renal tubule II, Tubulusrenalis contortus IILoop of HenleContort renal tubule I, Tubulusrenalis contortus ICorpuscles of the kidney,Corpuscula rentsInterlobular arteries, Aa.interlobularesAfferent vessel, Vas affirmsEfferent vessel, Vas efferensArcuate arteries, Aa. arcuataeCapillary networkInterlobular veins, Vv. interlobularesArcuate veins, Vv. arcuatae

19. Papillary ducts, Ductus papittares20. Suprarenal gland, Glandula

suprarenalis (for LS 1 only)

* not concerning LS 5 as the finer con-'struction of the kidney is represented onthe models LS 1, LS 4 and LS 9 only.The kidney is a composite tubulous gland.It serves for the excretion of useless sub-stances.

Structure:At the surface it has a tough capsule whichcan be removed easily. Underneath it thecortex of the kidney, Cortex rents (B), is si-tuated; it contains the urine forming or-gans. Next to the cortex is the marrow ofthe kidney, Medulla rents (A); it containsthe urine secreting organs.

Blood-Vessels:The renal artery, Arteria renalis (2), givesoff main branches, which enter into the re-nal substance at the side of the renal pyra-mids, Pyramides renales (7). At the borderbetween medulla and cortex they divideinto the arcuate arteries, Arteriae arcuatae(16); they run parallel to the surface andgive off the interlobular arteries, Arteriaeinterlobulares (13). Out of these arise fineshort lateral branches, the afferent vessels

(14); they dissolve into a vascular bundle,Glomerulus, however, become fused againand form the efferent vessels (15).The efferent vessels flow over a capillarynetwork (16a) into the interlobular veins,Venae interlobulares (17); the latter arebranches of the arcuate veins, Venae arcua-tae (18). The Venae arcuatae are mainbranches of the renal vein, Vena renalis (1).

The Urinary Tract:The urine forming organs of the kidney arethe corpuscles of the kidney (Corpuscula re-nts [12]). A corpuscle of the kidney consistsof:a) a vascular bundle, Glomerulus,b) the glomerular capsule (Bowman's

capsule — Capsula glomeruli).It is a globular, sack-shaped intussuscep-tion of the end part of me uriniferous tu-bule, which encompasses the vascularbundle. The glomerular capsule consists oftwo parts: the inner layer, which rests onthe glomerulus, and the outer layer, whichforms a smooth hollow sphere.These two layers are separated from oneanother up to the neck of the glomerularcapsule by a narrow space.

The uriniferous tubes are the urine secre-ting organs of the kidney. A uriniferous tu-be consists of the following sections:convoluted tubule (11)loop of Henle (10)contort renal tubule (9)collecting duct (8).Numerous junctional tubules flow toge-ther into the collecting duct, which formstogether with other collecting ducts greatcollecting ducts (or: papillary ducts), Duc-tus papillares (19), in the inner zone of themedulla. At the apex of the papilla theyflow into the calyces of the kidney, Cakcesrenales (5). They unite in the pelvis of thekidney, Pehis renalis (4), from where theureter (3) emerges.

The Function:The urinary organs have the task to excretethe urine, that is the liquid and soluble ex-creta (excretions), from the blood and topush it out of the body. The blood, whichflows through the vascular bundles, carriesthe metabolic products of the different or-gans of the body. The products, the nitro-genous substances in particular, diffusethrough the inner layer of the glomerularcapsule into the uriniferous tube. The in-

ner layer thus serves as a filter; in normalconditions it is impermeable to protein orsugar. The metabolic products are trans-formed by the parietal cells of the urinifer-ous tube into the final form of the urine.The urine is accumulated in the collectingducts and in the renal calyces. From the re-nal pelvis it flows into the ureter, which,due to its smooth muscular structure, con-tracts downwards continuously and rhyth-mically spurting each time some drops ofurine into the bladder, which becomes gra-dually filled in by this process.

If too little urine is excreted, as a result of akidney disease, uraemia will arise.

2. Nephron(for LS 6 and LS 9 only)

1. Corpuscle of the kidney withGlomerulus and Bowman's capsule

2. Main sectiona) Pars convoluta, Tubulus renalis

contortus Ib) Pars recta, descending limb (thick

portion) of Henle's loop3. Section of transition: thin portion

of Henle's loop4. Central section

c) Pars recta, ascending limb (thickportion) of Henle's loop

d) Pars convoluta, Tubulus renaliscontortus II, (convoluted tubule)

5. Connecting section and6. Collecting tube are part of the

efferent urinary tract7. Arcuate artery and vein, Arteria et

Vena arcuata8. Interlobular artery and vein, Arteria

et Vena interlobularis9. Afferent vessel, Vas afferens10. Efferent vessel, Vas efferens11. Capillary network

3. Kidney Corpuscle(for LS 7 and LS 9 only)We distinguish the Glomerulus (1) and theBowman's capsule, Capsula glomeruli (2).The corpuscle as a whole is globular. Itstransition into the renal tubules is fre-quently narrower than the remaining con-voluted section, and is, therefore, calledcervical portion, Cottum (3). One distin-guishes between a vascujar pole (5) andurinary pole (4). At the urinary pole tne ur-ine leaves the Bowman's capsule through

the cervical portion of the renal tubule. Atthe vascular pole the Glomerulus is joined tothe capsule; here the vessels enter and goout. The afferent (entering) vessel, Vas af-

ferens (6), as well as the efferent (outgoing)vessel, Vas efferens (7), are arteries and, the-refore, they are called Arteriola afferens andArteriola efferens. The urinary pole liesusually exactly opposite to the vascularpole. The Glomerulus is interposed betweenthe Arteriola afferens and the Arteriola effer-ens as an arterial network. Its loops are capil-laries in their structure. The Arteriola effer-ens merges into the capillary network orthecortex. The Arteriola afferens separates intoa quite great number of branches, formingindependent loops. Later they unite to theVas afferens. The individual entangledloops (8) are separated from each other,thus the Glomerulus shows deep indenta-tions and has the appearance of being lobu-lated. The entire surface of the loops is co-vered with epicytes. These epicytes (9)constitute together the inner lamella of theBowman's capsule. At the vascular pole theinner lamella merges in that of the outerwall: outer lamella (10) of the Bowman'scapsule. In addition to a single-layered pa-vement epithelium the outer lamella con-sists of a tender transparent membrane. To-

wards the urinary pole the pavement cellsbecome taller and taller and form thus agradual transition to the tall cylindricalcells of the convoluted section of the at-tached uriniferous tubule.

1. Glomerulus2. Bowman's capsule, Capsula glomeruli3. Cervical portion, Cottum4. Urinary pole5. Vascular pole6. Afferent vessel, Vas afferens7. Efferent vessel, Vas efferens8. Vascular loops9. Epicytes (inner lamella)

10. Outer lamella