Urinary System Flashcards
The kidneys are large, reddish, bean-shaped organs located in the retroperitoneal
space. The kidney surface is covered by a connective tissue capsule.
The parenchimal part of kidney can be divided into two distinct regions:
a) cortex, the outer reddish brown part
b) medulla, the much lighter-colored inner part
On this slide you can see a semi-thin section of the glomerulus (0,5 μm) and cellular
elements which compose him:
1. glomerular endothelium with underlying glomerular basement membrane
2. specialized cells of the visceral layer of Bowman’s capsule called podocytes
3. and mesangial cells.
The same cytological structure we can find in a slide stained with a PAS staining
technique.
Podocytes are usually located superficially and they are in a close connection with the
endothelial cells of capillaries, while mesangial cells are located in the central part of
the glomerulus and usually they are with more stained cytoplasm.
It consists of the glomerulus, a tuft of capillaries composed of 10 to 20 capillary
loops, surrounded by a double-layered epithelial cup, the renal or Bowman’s capsule
and Bowman’s space between them.
While in the cortex we can found renal corpuscles (corpusculum renis), convoluted
and straight tubules of the nephron, and the beginning of the collecting ducts.
They are lined with a simple cuboidal epithelium.
In the medullar part of the kidney we can recognize 8-15 pyramids (piramides renales) with the bases of the pyramids face the cortex and apices face the renal sinus.
From bases of the pyramids starts medullary rays of Ferrein (striae medullares).
The adventitia of the bladder is made of loose connective tissue with vascular and
nerve elements.
The muscular layer is dominant.
The ureter is a tubular organ that propels urine from the kidney to the urinary
bladder.
In the wall of the ureter three layers are described:
I. mucosa (tunica mucosa),
II. muscular layer (tunica muscularis) and,
III. adventitia (tunica adventitia).
The muscular layer is made of smooth muscle cells organized into three poorly
delineated sublayer:
- inner longitudinal
- middle circular
- and outer longitudinal
The medulla is dominantly composed of collecting ducts.
Around the renal corpuscle is present numerous tubules which can be differentiated
according to the cytoplasmic characteristics.
Proximal convoluted and straight tubules have a dark-colored cytoplasm, while distal
convoluted and straight tubulespossess a light-colored cytoplasm.
The wall of the bladder consists of four layers:
I. Mucosa (tunica mucosa)
II. Submucosa (tunica submucosa)
III. Muscular layer (tunica muscularis)
IV. Adventitia or serosa (tunica adventitia et serosa)
The site where the afferent and efferent arterioles penetrate and exit from the
parietal layer of Bowman’s capsule is called the vascular pole.
The representative picture with of all three layers.
Proximal and distal tubule represents histological elements of recent mentioned
medullary rays of Ferrein (striae medullares). They are lined with a simple cuboidal
epithelium.
Opposite to vascular pole is the urinary pole of the renal corpuscle, where the
proximal convoluted tubule begins. On this slide, you can see a special PAS staining
technique.
The renal corpuscle (corpusculum renis) represents the beginning of the nephron.
The urinary bladder is a tubular organ serving to collect and temporarily store urine.
Tunica mucosa of urinary bladder is made of:
a) lamina epithelialis mucosae - transitional epithelium, urothelium which lei on
basal membrane,
b) lamina propria mucosae - loose connective tissue with lood vessels and nerves,
c) and discontinuous lamina muscularis mucosae
The mucosa (tunica mucosa), of the ureter, is made of:
- lamina epithelialis mucosae, which represent transitional epithelium – urothelium
which lei on the basal membrane, and
- lamina propria mucosae, or lamina propria, made of loose connective tissue
containing blood vessels and nerves.
Tunica muscularis or muscular layer, is made of smooth muscle cells organized in a
form of:
- inner longitudinal sublayer
- outer circular sublayer
- outer longitudinal sublayer.
Tunica adventitia or the adventitia of ureter is made of loose connective tissue.
