Reading: RR&K, Chapter 19
SLIDE 76d kidney, monkey (H&E)
(RR&K p585, Fig. 1,2; p587, Fig. 1,2; p589, Fig. 1,2,3,4; p.591, Fig. 1,2)
The large, ovoid piece of tissue on this slide is a longitudinal section through the unilobar kidney of the monkey. You should examine this section in detail before examining the smaller pieces of tissue on this slide. With the aid of an atlas, orient yourself on this large section first with the naked eye and then with a reversed ocular. Locate the connective tissue capsule, cortex, medulla, and the renal calyx.
Using the high power objective, identify the structures of the cortex. Identify the arcuate vessels which lie between the cortex and the medulla and the interlobular vessels which divide the cortex into lobules. Distinguish between the cortical labyrinths and the medullary rays. In the cortical labyrinth locate: renal corpuscles, proximal convoluted tubules, and distal convoluted tubules. Study the renal corpuscle and identify: the parietal layer of Bowman's capsule, the urinary space, and the glomerulus containing podocytes (visceral layer of Bowman's capsule), endothelial cells and mesangial cells. In addition, locate the urinary and vascular poles of the renal corpuscles. The urinary pole is continuous with the proximal convoluted tubule. The vascular pole has associated with it arterioles (afferent and efferent) and a macula densa. Cells of the macula densa are located in the wall of distal convoluted tubule adjacent to the vascular pole. Proximal convoluted tubules have simple cuboidal epithelia with brush borders. The epithelial cell nucleus is centralized. Distal convoluted tubules have cuboidal epithelial cells that lack brush borders and have their nuclei situated near its apical surface. Which tubules are longer (and thus more numerous)? The medullary ray consists of three types of straight tubules running parallel to one another. Within the medullary ray locate: straight (descending) proximal tubules, straight (ascending) distal tubules, and collecting ducts. The straight proximal and distal tubules have a morphology like their convoluted counterparts observed in the cortical labyrinth. The collecting duct has a simple cuboidal epithelium. The epithelial cells lack microvilli and have a centralized nucleus. These cells are smaller than those in the proximal tubule and thus, there are more nuclei in a given segment of the collecting duct. In addition, unlike the proximal and distal tubules, the boundaries between cells are clearly evident. What is the relationship of the medullary rays to the lobules of the kidney? Using the high power objective continue your study of the medulla. In the monkey the medulla consists of a single renal pyramid, with its base next to the cortex and its apex forming a papilla that projects toward the calyx. Locate and study the following structures: Henle's loop, including the thick descending limb (similar in appearance to the proximal convoluted tubule and proximal straight tubule), the thin segment (lined by a simple squamous epithelium) and the thick ascending limb (similar in appearance to the distal convoluted tubule and distal straight tubule). Compare the distribution of the tubules as one proceeds from the base of the pyramid (near the cortex of the kidney) to the apex of the pyramid (projects toward the calyx). Identify collecting ducts (cuboidal epithelium with prominent cell borders). Note the large ducts at the tip of the papilla. The morphology of thin segments and vasa recta is similar. However, some segments of the vasa recta can be identified by the presence of red blood cells. The vasa recta are bundles of straight blood vessels that supply and drain the medulla.
Examine the wall of the minor calyx. Note epithelium present and the nature of the muscle found there.
After studying the large piece of tissue on this slide, examine the smaller pieces of kidney on the right half of the slide and try to identify the structures described above. These smaller sections should be cross- and longitudinal-section through the cortex and medulla. Identify the cortical labyrinths and medullary rays in cross section.
Check list for SLIDE 76d:
SLIDE 75a kidney, human (H&E)
(RR&K p585, Fig. 1,2; p587, Fig. 1,2; p589, Fig. 1,2,3,4; p.591, Fig. 1,2)
With the aid of a low power objective, locate the capsule, cortex, medulla, (renal columns and renal pyramids), and minor calyx.
As you did in the previous slide, examine and identify the tubules within the cortical labyrinth, medullary ray, and medulla. What are the structural differences between the cortex and the renal column? Locate the renal corpuscles, proximal convoluted tubules, distal convoluted tubules, straight (descending) proximal tubules, straight (ascending) distal tubules, thin segments, and collecting ducts. Trace the flow of urine through these tubules. Which of these tubules are found in the medullary rays? Which of these tubules are found exclusively in the medulla? Examine, the renal corpuscle and identify: the parietal layer of Bowman's capsule, urinary space, the glomerulus containing podocytes (visceral layer of Bowman's capsule), endothelial cells and mesangial cells, the urinary pole of the renal corpuscle, and the vascular pole. Examine the wall of the minor calyx and note its epithelial lining.
Finally, identify the interlobular arteries and veins, arcuate arteries and veins, and vasa recta. Are there any other large vessels present? If so, name them.
Check list for SLIDE 75a:
SLIDE 75e kidney, human (PAS) (RR&K p585, Fig. 1,2; p587, Fig. 1,2; p589, Fig. 1,2,3,4; p.591, Fig. 1,2)
This large section of the human kidney is stained with PAS. Orient yourself on this large section, first with the naked eye and then with a reversed ocular. Using low magnification objective, locate the following structures: capsule, cortex, medulla, and minor calyx. Using low and high power objectives, once again identify the structures of the nephron and the collecting duct. Note the dense staining of the renal corpuscle. The glomerular basement membrane (GBM) is best seen in this slide. The mesangial cells are also easy to identify on this slide, since the mesangial matrix stains well with PAS. The brush border and basement membrane of the epithelial cells of the tubules are well stained with magenta. Why?
Check list for SLIDE 75e:
SLIDE 75d kidney, monkey (H&E)
(RR&K p585, Fig. 1,2; p587, Fig. 1,2; p589, Fig. 1,2,3,4; p.591, Fig. 1,2)
This thin plastic slide was prepared to better visualize the capillary network around the nephron. Using low and high power objectives, once again identify the structures of the nephron and the collecting duct. Note that the morphology of the proximal tubules is quite different than that seen in SLIDE 76d. Identify the interlobular arteries and veins, the arcuate arteries and veins, the peritubular capillaries and the vasa recta. You can readily distinguish the vasa recta from the thin loops of Henle, by the presence of red blood cells.
Check list for SLIDE 75d: 
SLIDE 77a urinary bladder, monkey (H&E)
(RR&K p595, Fig. 1,2,3)
Locate the mucosa (epithelium and underlining connective tissue), muscularis externa, and serosa. Using the low magnification, classify the epithelium and compare its appearance along the highly folded surface. Classify the tissue immediately under the epithelium. The dense connective tissue layer of the mucosa is somewhat disrupted on some slides. Observe ill-defined muscularis mucosa, which indicates that your section of the urinary bladder was taken from the part developed from the cloaca. The trigone of the bladder, which developed by the incorporation of both mesonephric ducts, does not have muscularis mucosa. In the muscularis layer, distinguish smooth muscle from dense irregular connective tissue. The three layers of the muscle coat are difficult to recognize. Finally, examine the serosa and mesothelium.
Check list for SLIDE 77a:
FIGURE 09 kidney, glomerulus (EM)
(RR&K p564, Fig. 19.6; p565, Fig. 19.7; p567, Fig. 19.9; p.569, Fig. 19.1)
This is a electron micrograph of a normal glomerulus. Locate the capillary and urinary space. The capillary is lined by endothelial cells, while the urinary space is lined by the podocytes. The podocytes can be identified by their unique foot processes. Using the reverse ocular, examine the basal lamina which is referred to in the clinic as glomerular basement membrane (GBM). GBM is shared by both endothelial cells and podocytes. Are mesangial cells present?
Check list for FIGURE 09: 
FIGURE 10 Kidney, membranous glomerulonephritis (EM) (RR&K p564, Fig. 19.6; p565, Fig. 19.7; p567, Fig. 19.9; p.569, Fig. 19.1)
Membranous gromerulonephritis is the major cause of nephrotic syndrome (massive proteinuria, hypoalbuminemia, generalized edema and hyperlipidemia) in adults. It is characterized by the presence of irregular, electron-dense, immunoglobulin-containing deposits within the glomerular basement membrane (GBM) shared by the endothelial cell and podocytes. The foot processes of podocytes are lost. Newly synthesized collagen IV is distributed between these pathological deposits, which appears as irregular spikes protruding from the GBM. As the disease progresses, these spikes produce dome-like protrusions and finally will close the entire deposit within a unusually thick and irregular GBM of the renal glomerular capillary. This specimen comes from a previously healthy 45-year-old male, who complained of edema on the face, and on the extremities. He had never seen doctor before. Study this EM and identify the capillary, podocyte, endothelial cell and basal lamina. Observe the immunoglobulin-containing deposits embedded within the GBM. Compare this basement membrane to the previous FIGURE 09 of a normal glomerulus.
Check list for FIGURE 10: 
The urinary system is important in filtering the blood of potentially damaging substances as well as any other substance present in excess (resulting in homeostasis). The urinary system consists of the kidneys, ureters, bladder, and the urethra.