(04) Urinary System I: Kidney

Question 1

(kidney)

(gross anatomy)

1. is a retro-periotneal organ - what does this mean?
2. thin c.t. capsule - thick in what?
3. What lies adjacent to the capsule? darker or lighter area of freshly sectioned kidney?
4. What is located deep in the kidney? Divided into what? Apex of medulla (renal papilla) projects into what of the unilobar kidney? in multilobar?

Answer 1

1. has no mesentery
2. cat
3. cortex; darker
4. medulla; traingular or pyramidal areas (with striated broad base next to cortex); renal pelvis; minor calyx

Question 2

(Kidney)

(gross - cont)

1. A kidney lobe consists of a what and what?
2. Areas of cortical tissue located between medullary pyramids are called what?
3. Unilobar (unipyramidal) kidney has how many pyramids?

Answer 2

1. medullary pyramid and associated adjacent cortex
2. renal columns
3. single pyramid

Question 3

(Kidney)

1. true unilobar kidneys are found in what?
2. most unilobar kidneys have secondarily fused what and what areas? which began development as what?

(Multilobar (multipyramidal) kidneys are of two types…)

1. cortical parts of lobes are fused or separate? pyramids?
2. What are these like in cattle?

Answer 3

1. rodents
2. cortical and medullary areas; as multilobar structures (small ruminants, dog, horse)
3. fused; separate (pig and human)
4. cortical and medullary parts of lobesa are distinctly separated

Question 4

(General Histological Structure)

just read this part

Question 5

(Renal Blood Supply)

1. what percent of cardiac output at rest?
2. Renal artery enters kidney at the hilus and gives rise to…? located where?
3. What are parallel to the capusle at the cortico-medullary junction? give off? which are found between what?

Answer 5

1. 25%
2. interlobar arteries; between pyramids in renal columns
3. arcuate arteries; interlobular arteries; medullary rays

Question 6

(renal blood supply cont)

1. What supply the glomerular capillary loops of a glomerulus? drained by what?

Answer 6

1. afferent arterioles; efferent arteriole (

Question 7

(renal blood supply cont)

(from the efferent arterioles the route of blood flow depens on the location of the glomerulus)

1. Efferent arterioles of superficial and middle cortical nephrons give rise to what? drained by what? that empty into what?
2. Peritubular capillaries are all what?

Answer 7

1. peritubular capillaries of the cortex; stellate or deep cortical veins; arcuate veins
2. fenestrated

Question 8

(from the efferent arterioles the route of blood flow depens on the location of the glomerulus)

1. Efferent arterioles of juxtamedullary nephrons give rise to what? What are they?
2. The descending vasa recta give rise to what of the medulla? are they fenestrated?

Answer 8

1. vasa recta; long straight vessels which descned into the medulla as arterioles and return as venules to the arcuate veins
2. peritubular capillaries; yes

Question 9

(Renal Blood Supply)

1. afferent arteriole to glomerular capillaries to efferent arteriole constitute what?

Answer 9

1. an arterial portal system

(note that the kidney has minimal provision for collateral circulation)

Question 10

(Histology of the Renal Corpuscle (glomerulus + glomerular capsule)

1. what is the filtering structure of the kidney?

2-4. it has three components - what are they?

Answer 10

1. the renal corpuscle
2. glomerular capsule (indented end of the nephron)
3. glomerulus; a cluster of capillary loops, which “indent” the gomerular capsule
4. mesangial cells (located between the capillary loops)

Question 11

(Histology of Renal Corpuscle)

1. The glomerulus consists of what two things?

(the term glomerulus is often used to encompass all three components of the renal corpuslce and thus a synonym for the renal corpuscle)

2. the capillary loops of the glomerulus are supplied by what and drained by what? This represent what kind of system?
3. Is it a high or low pressure system? drained by what?
4. Are the endothelial cells of glomerular cells fenestrated?

Answer 11

1. cluster of capillary loops and associated cells
2. supplied by an afferent arteriole and drained by an efferent arteriole; an arterial portal system
3. high; efferent arteriole (which is smaller than afferent)
4. yes

Question 12

(Kidney)

1. What is where the arterioles enter and leave the renal corpuscle? This is the location of the what?
2. Where does the glomerular capsule become continuous witht eh tubular part of the nephron?

Answer 12

1. the vascular pole; the juxtaglomerular apparatus
2. the urinary pole (opposite vascular pole)

Question 13

(Kidney)

1. glomerular capsule is double walled with a parietal layer of what?
2. What is between the parietal and visceral layers of glomerular capsule?

Answer 13

1. simple squamous cells
2. capsule or urinary space

Question 14

(Kidney)

1. the visceral layer of the glomerular capsule is comprised of what?
2. Podocytes stabilze glomerular architecture by doing what? also maintain a large filtration surface thorugh what? In this regard they are responsible for 40% of what?

Answer 14

1. podocytes (with elaborate, long branching processes that closely enwrap glomerular capillaries)
2. counteracting distensions of the glomerular basement membrane; the slit diaphragms; the hydraulic resistance of the filtration barrier

Question 15

(kidney)

1. A thick basal lamina between podocytes and endothelial cells is composed of what and what? produced by what? The basal lamina is how much thicker than ordinary basal lamina?
2. The filtration slit membrane spans the distance between tertiary processes of what? It is similar in diaphragm of what?

Answer 15

1. collagen and glycosaminoglycans (negatively charged); podocytes; 3X
2. the adjacent podocytes; capillary fenestrations

Question 16

(kidney)

(filtration)

1. Is there higher hyrdostatic and osmotic pressure in glomerular capillaries or the urinary space?
2. Water, ions, and small proteins pass through the filtration barrier (basal lamina) by what route? Cells are held back by what? Which thing are slowed or excluded by the negatively charged basal lamina?

Answer 16

1. glomerular capillaries
2. an entirely extracellular route; the endothelium; large or negatively charged molecules

Question 17

(Kidney)

1. mesangial cells are inside (intraglomerular) or outside (extraglomerular) the glomerulus?
2. What is a cluster of mesangial cells located between capillary loops of the glomerulus?

Answer 17

1. both
2. intraglomerular mesangium

Question 18

(Kidney)

1. Mesangial and endothelial cells are located on the same or different sides of the basal lamina?
2. What are located in the center of the glomerulus? contain what? connected by what? have long what?

Answer 18

1. same (same basal lamina compartment)
2. mesangial cells; microfilaments; gap junctions; processes

Question 19

(Kidney)

1-2. What are the two functions of mesangial cells?

3-4. They may also provide what and produce what?

Answer 19

1. phagocytize worn out basal lamina and other debris
2. regulate filtration (flow) rate

(mesangial cells thus have phagocytic and contractile properties)

3. structural support
4. vasoactive agents

Question 20

1. the intraglomerular mesangial cells are continuous with what which forms part of what?

Answer 20

1. extraglomerular mesangium which forms part of the juxtaglomerular apparatus

Question 21

(Histology of the nephron tubule and collecting duct)

1-3. Nephron (renal) loop (of Henle) consists of what three things?

Answer 21

1. thick descedning limb (of proximal tubule), both convoluted and staight
2. thin segment (descending and ascending parts)
3. thick ascending limb (of distal tubule)

Question 22

1. In most domestic mammals the majority of nephron loops are short or long?
2. Long loops from juxtamedullary nephrons extend far into medulla and produce what?
3. Which species have both types? Which only have long loops?

Answer 22

1. short (don’t extend far into medulla)
2. hypertonic urine
3. most species; dogs and cats

Question 23

1. What is the longest part of the nephron filling most of the cortex? The lumen may be obscured by what?

Answer 23

1. the proximal tubule; fixation artefact (tissue disintegration or collapse of tubule)

Question 24

(proximal tubule)

1. consists of what segments? histology similar or different?
2. Apical borders fo the lining cells have long what? this brush border gives what appearance?
3. there are apical junctional complexes (terminal bars) joining the cells - but these tend to be what?

Answer 24

1. convoluted and straight segments; similar
2. microvilli; apical striated appearance
3. leaky

Question 25

(Proximal tubule - cont) 1. Pinocytic and endocytic vesicles form between what? take up what from lumen of the tubule? What percentrage of protein is removed by endocytosis? 2. Many basally arranged mitochondria result in what kind of stain? Cells appear packed with what? The mitochondira provide the energy source (ATP) needed to drive what?

Answer 25

1. the bases of the microvili; protein; 100% (degraded in lysosomes) 2. an intesnse acidophilic stain (and basal straition of the proximal tubule cells); organelles; the active transporters (glucose, AA, and Na)

Question 26

(Proximal Tubule - cont 2) 1. Complex basal and lateral infoldings and projections of plasma membrane make the lateral cell boundaries what? This specialization to increase surface area is a characteristic of what? 2. The straight segment of the proximal tubule = ?; found where? They are morphologically similar to what?

Answer 26

1. indistinct; **transport epithelia** 2. **thick descending limb**; the medullary ray and outer stripe of medulla; proximal convoluted tubules

Question 27

**(Thin Segment (of Henle's loop))** 1. simple squamous or low cuboidal epithelium - may resemble what? 2. However, the thin segment has a larger diameter than most capillaries and thus has what? 3. The nuclei tend to bulge into lumen and appear round on enface view. 4. What forms a thing rim around the tubule?

Answer 27

1. capillaries 2. more cells around periphery 3. a pale eosinophilic cytoplasm

Question 28

1. The distal tubule also consists of what segments? 2. The straight segment returns to what?

Answer 28

1. **convoluted and straight segments** 2. renal corpuscle from which the nephron arose

Question 29

(In comparison to proximal tubule the distal tubule has...) 1. wider or thinner lumen? 2. Surrounded by cuboidal cells with more or less distinct lateral boders? 3. smaller cells so more or less in tubule cross section? 4. smaller or larger overall tubule diameter? 5. nuclei which may bulge into tubule lumen 6. lighter or darker acidophilic stain of cytoplasm? 7. apical tight junctions - impermeable to what? 8. Like the proximal tubule, the distal tubule has basal striations due to plasma membrane infoldings and aligned mitochondria driving Na or Cl pumps 9. straight segment of distal tubule = ?

Answer 29

1. wider 2. more distinct 3. more 4. smaller 6. lighter 7. water **9. thick ascending limb**

Question 30

1. Collecting ducts consist of what two segments? 2. several arched collecting ducts join to from what? 3. lining cells have distinct boders and bulge into lumen 4. cells are joined by what?

Answer 30

1. straight and arched segments 2. a straight collecting duct 4. apical tight junctions

Question 31

(Collecting ducts) 1-2. What two cells are found in collecting ducts?

Answer 31

1. light or principal cells 2. dark or intercalated cells

Question 32

(cell types in collecting ducts) (light or principal cells) 1. cuboidal and stain how? 2. function in what two things?

Answer 32

1. pale eosinophilic 2. Na/K transport, H2O resorption

Question 33

(cell types in collecting ducts) (dark or intercalated cells) 1. contain many what? 2. may be what?

Answer 33

1. mitochondria (for acid production) 2. columnar

Question 34

1. several **collecting ducts** join to form what? 2. papillary ducts are of larger or smaller diameter than collecting? what type of epithelium; how does cytoplasm stain?

Answer 34

1. a **papillary duct** 2. larger; columnar; light staining (near the renal papilla the epithelium may be transitional like that of the papilla and renal pelvis)

Question 35

1. What is located at the point where the distal straight tubule is adjacent to vascular pole of the renal corpuscle from which the nephron arose? 2-4. Juxtaglomerular (JG) Apparatus consists of what three structures not separated by a complete basal lamina?

Answer 35

1. **Juxtaglomerular (JG) Apparatus** (adjacent afferent arteriole is part of the JG apparatus) 2. macula densa 3. juxtaglomerular cells 4. extraglomerular mesangium

Question 36

(Three strutrucres of the Juxtaglomerular apparatus) (Macula Densa) 1. in distabl tubule wall is an area of narrow tall colmunar cells with nuclei that appear crowded or overlapping 2. Is part of system for sensing what?

Answer 36

2. Na and Cl concentrations

Question 37

(Juxtaglomerular cells of JG) 1. located in the wall of hwat? adjacent to what? 2. modified smooth muscle cells with round nuclei 3. a few filaments and membrane bound granules containing what? 4. function as baroreceptors which are stimulated to release renin by what? 5. May also be stimulated how?

Answer 37

1. afferent arteriole (possibly efferent as well); macula densa 3. **renin** (enzyme) 4. a fall in luminal pressure 5. sympathetic innervation or indirectly via the macula densa and extracellular mesangium in reponse to and increase in distal tubule Na and Cl concentrations

Question 38

(Extraglomerular Mesangium of JG) 1. Continous with what? composed of what? 2. It is located at vascular pole or renal corpuscle between what and what? 3. The mesangial cells transmit info to what concerning what?

Answer 38

1. intraglomerular mesangium; similar cells 2. afferent and efferent arterioles and distal tubule 3. Na and Cl concentrations to the JG cells (via gap junctions)

Question 39

(Clinical) 1. A thickened basal lamina in disease (eg diabetes) results in what? 2. When filtration is blocked by immune complexes, the result is what?

Answer 39

1. reduced kidney function 2. glomerulonephritis (occurs in many diseases)