What is the primary determinant of the osmolality of the extracellular fluid (ECF)?
body water
What do you call the disorders in which there is a deficiency of body water relative to body solute?
HYPERosmolar disorders
What do you call the disorders in which there is an EXCESS of body water relative to body solute?
HYPO-osmolar disorders
What is the main constituent of plasma osmolality?
Sodium
The upper pole of each kidney lies opposite what vertebra?
T12
The lower pole of each kidney lies opposite what vertebra?
L3
Which kidney is usually lower in position?
The right kidney (because of the liver)
True accessory renal arteries arise from where?
the abdominal aorta
The apical segmental or lobar arterial branch of the kidney usually arises from:
a. the anterior division (upper, middle, lower segments)
b. the posterior division(posterior, lower segments)
The anterior division
On the tip of each renal papilla are 10 to 25 small openings that represent the distal ends of what?
The collecting ducts (of Bellini) (These openings form the area cribrosa.)
In humans, the renal cortex is about 1cm thick and forms a cap over the base of each pyramid, and extends downward between the individual pyramids to form what?
The renal columns of Bertin
These longitudinal elements extend into the cortex from the base of the renal pyramid at the corticomedullary junction.
Medullary rays of Ferrein
Despite their name, these longitudinal elements that extend from the base of the renal pyramid at the corticomedullary junction to the renal cortex, are actually considered part of the cortex and are formed by the collecting ducts and the straight segments of the proximal and distal tubules.
Medullary rays of Ferrein
The renal pelvis is lined by what kind of epithelium?
Transitional epithelium
What is the functional unit of the kidney?
The nephron
Each human kidney contains approximately how many nephrons?
0.6 to 1.4 x 106
This term pertains to the glomerulus and Bowman's capsule
renal or malpighian corpuscle
Embryologic origin of the nephron
the metanephric blastema
Embryologic origin of the connecting tubule
the metanephric blastema
Embryologic origin of the collecting duct system
the ureteric bud
This is where the afferent arteriole enters and the efferent arteriole exits the glomerulus. This is also where the visceral epithelium is continuous with the parietal epithelium.
vascular pole
This is where the parietal epithelium of the Bowman's capsule continues into the epithelium of the proximal tubule.
Urinary pole
TRUE/FALSE: The endothelial cell nucleus usually lies adjacent to the mesangium, away from the urinary space.
TRUE
Their surface is negatively charged because of the presence of a glycocalyx (surface coat) that is rich in polyanionic GAGs and glycoproteins. They synthesize both nitric oxide (vasodilator) and endothelin-1 (vasoconstrictor). They also express endothelial nitric oxide synthase (eNOS). What are they?
Glomerular endothelial cells
These are the largest cells in the glomerulus. They are also called podocytes.
visceral epithelial cells
This is the protein that is defective or lacking in familial steroid-resistant nephrotic syndrome. This protein is an integral membrane protein that is expressed in the foot process membrane at the site of insertion of the slit diaphragm.
Podocin
This protein is the product of the gene that is mutated in congenital nephrotic syndrome of the Finnish type (NPHS1).
Nephrin (Nephrin is a transmembrane protein that belongs to the immunoglobulin family of adhesion molecules. It is expressed in the visceral epithelial cells in the glomerulus, where it is located exclusively in the slit diaphragm.)
This is an adapter molecule that binds to the cytoplasmic domain of nephrin and is believed to connect nephrin to the cytoskeleton.
CD2AP (Deletion of CD2AP is associated with congenital nephrotic syndrome and morphologically with effacement or fusion of foot processes.)
This is the principal sialoprotein on the urinary surface of the podocytes.
podocalyxin
What do you call the gap between adjacent foot processes?
Filtration slit or slit pore
What do you call the thin membrane that bridges the gap between adjacent foot processes?
Filtration slit membrane or slit diaphragm
This cell in the glomerulus may represent a specialized pericyte and possesses many functional properties of smooth muscle cells.
Mesangial cell
Functions:
1. provides structural support for the glomerular capillary loops
2. has contractile properties (believed to play a role in regulation of glomerular filtration)
3. has phagocytic properties (participate in clearance of macromolecules from the mesangium)
4. involved in the generation and metabolism of the extracellular mesangial matrix
5. participates in various forms of glomerular injury (can influence cell proliferation and the production of cytokines including PDGF, IL-1, and epithelial growth factor)
6. produces prostaglandins (counteracts the effects of vasoconstrictors)
The local generation of autacoids (e.g. PGE2) by this cell may provide a counterregulatory mechanism to oppose the effect of the vasoconstrictors.
mesangial cell
What are the 3 layers of the glomerular basement membrane?
Lamina rara externa
Lamina densa (electron dense)
Lamina rara interna
The layered configuration of the GBM results in part from the fusion of endothelial and epithelial basement membranes during development.
This is the major constituent of the glomerular basement membrane (GBM).
Collagen IV
The glomerular basement membrane (GBM) contains specific components not found in other basement membranes, which most likely reflect its specialized function as part of the glomerular filtration barrier. The specific components include the following, except:
A. entactin/nidogen
B. agrin
C. perlecan
D. laminin 11
ENTACTIN/NIDOGEN
Specific to GBM: laminin 11, distinct collagen IV alpha chains (alpha 1-5), proteoglycans agrin and perlecan
Common to all basement membranes: collagen IV, laminin, entactin/nidogen, sulfated proteoglycans
Alport syndrome is a hereditary basement membrane disorder associated with progressive glomerulopathy. Mutations in the genes encoding what kind of collagen cause Alport syndrome?
alpha3,4,5 (type IV) collagen chains
To cross the glomerular capillary wall, a molecule must pass SEQUENTIALLY through these 3 layers.
1. the fenestrated endothelium (which has a negatively charged glycocalyx)
2. the GBM
3. the epithelial slit diaphragm
In rapidly progressive glomerulonephritis (RPGN), these cells proliferate to contribute to the formation of crescents. They are squamous in character, but abruptly transform into taller cuboidal cells of the proximal tubule at the urinary pole.
parietal epithelial cells (they form the outer wall of the Bowman's capsule)
These cells are located at the origin of the glomerular tuft in the Bowman's space and is interposed between the visceral and parietal epithelial cells. They contain multiple membrane-bound electron-dense granules and are separated from the afferent arteriole only by the basement membrane of the Bowman's capsule. They are believed to be a component of the juxtaglomerular apparatus.
peripolar cells
The juxtaglomerular apparatus is located here, where a portion of the distal nephron comes into contact with its parent glomerulus:
A. vascular pole
B. urinary pole
A. VASCULAR POLE
The vascular component of the juxtaglomerular apparatus (JGA) is composed of these (3).
1. the terminal portion of the afferent arteriole
2. the initial portion of the efferent arteriole
3. the extraglomerular mesangial region
The tubule component of the juxtaglomerular apparatus (JGA) is composed of this.
The macula densa (which is the portion of the thick ascending limb that is in contact with the vascular component)
The extraglomerular mesangial region (of the JGA) is also known as...?
the polar cushion (polkissen) or the lacis
The extraglomerular mesangial region (of the JGA) is bounded by these 3.
1. cells of the macula densa
2. specialized regions of the afferent and efferent glomerular arterioles
3. mesangial cells of the glomerular tuft (the intraglomerular mesangial cells)
There are 2 distinct cell types in the vascular component of the juxtaglomerular apparatus (JGA). What are they?
1. the juxtaglomerular granular cells (epithelioid or myoepithelial cells)
2. the agranular extraglomerular mesangial cells (lacis cells or pseudo-meissnerian cells of Goormaghtigh)
These cells of the juxtaglomerular apparatus produce renin.
The juxtaglomerular granular cells (epithelioid or myoepithelial cells) - they are located primarily in the walls of the afferent and efferent arterioles, but are also present in the extraglomerular mesangial region.
These cells lack the lateral cell processes and interdigitations that are characteristic of the thick ascending limb. They are low columnar cells with an apically placed nucleus.
Macula densa
The absence of this protein in the macula densa has prompted some investigators to suggest that the macula densa may be relatively permeable to water (in contrast to the thick ascending limb which is impermeable to water).
Tamm-Horsfall protein
Tubular injury is the hallmark of ATN and is most severe in what part of the nephron?
Outer medulla - involving the pars recta (S3 segment) of the proximal tubule and the medullary thick ascending limb (mTAL) of the distal nephron
Cisplatin is a highly nephrotoxic chemotherapeutic agent that damages cells in what segment of the proximal tubule?
S3 segment of the proximal tubule
These are proapoptotic members of the Bcl-2 family, whose consistent activation has been noted in studies in human renal allografts.
