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What is the function of medullipin II?
What is the function of medullipin II?
What is the name of the structure that surrounds the glomerular capillaries?
What is the name of the structure that surrounds the glomerular capillaries?
What is the name of the structure that separates the urinary space from the bloodstream?
What is the name of the structure that separates the urinary space from the bloodstream?
What is the name of the part of the nephron that collects the filtrate?
What is the name of the part of the nephron that collects the filtrate?
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What is the function of the filtration slit diaphragm?
What is the function of the filtration slit diaphragm?
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What is the name of the cells that line the glomerular capillaries?
What is the name of the cells that line the glomerular capillaries?
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What is the name of the structure that connects the proximal convoluted tubule to the thin descending limb of Henle loop?
What is the name of the structure that connects the proximal convoluted tubule to the thin descending limb of Henle loop?
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What is the name of the three-layered structure that makes up the glomerular filtration barrier?
What is the name of the three-layered structure that makes up the glomerular filtration barrier?
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What is the function of the apical canaliculi, vesicles, and vacuoles in the proximal convoluted tubule?
What is the function of the apical canaliculi, vesicles, and vacuoles in the proximal convoluted tubule?
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What is unique about the lateral borders of proximal convoluted tubule cells?
What is unique about the lateral borders of proximal convoluted tubule cells?
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What is the primary function of the numerous mitochondria in the basal region of proximal convoluted tubule cells?
What is the primary function of the numerous mitochondria in the basal region of proximal convoluted tubule cells?
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What type of epithelial cells line the thin limb of the Henle loop?
What type of epithelial cells line the thin limb of the Henle loop?
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What is a characteristic of the distal convoluted tubule compared to the proximal convoluted tubule?
What is a characteristic of the distal convoluted tubule compared to the proximal convoluted tubule?
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What type of cells are juxtaglomerular cells?
What type of cells are juxtaglomerular cells?
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Where are juxtaglomerular cells primarily located?
Where are juxtaglomerular cells primarily located?
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What is characteristic of macula densa cells?
What is characteristic of macula densa cells?
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What is the approximate number of nephrons in each kidney?
What is the approximate number of nephrons in each kidney?
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What is the location of the cortical collecting tubules?
What is the location of the cortical collecting tubules?
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What is the term for the extensions of cortical tissue between adjacent renal pyramids?
What is the term for the extensions of cortical tissue between adjacent renal pyramids?
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What is the function of principal cells in the collecting tubule?
What is the function of principal cells in the collecting tubule?
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What is the percentage of the cortical volume composed of renal interstitium?
What is the percentage of the cortical volume composed of renal interstitium?
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What is unique about intercalated cells in the collecting tubule?
What is unique about intercalated cells in the collecting tubule?
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What is the term for the pyramidal-shaped structures that compose the bulk of the renal medulla?
What is the term for the pyramidal-shaped structures that compose the bulk of the renal medulla?
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What is the name of the cells located along the blood vessels that supply the loops of Henle?
What is the name of the cells located along the blood vessels that supply the loops of Henle?
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What is the role of the macula densa cells in the juxtaglomerular apparatus?
What is the role of the macula densa cells in the juxtaglomerular apparatus?
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What is the name given to the extraglomerular mesangial cells?
What is the name given to the extraglomerular mesangial cells?
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What is the term for the groups of tubules that extend from the base of each renal pyramid into the cortex?
What is the term for the groups of tubules that extend from the base of each renal pyramid into the cortex?
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What is the function of the gap junctions between the macula densa cells and the juxtaglomerular cells?
What is the function of the gap junctions between the macula densa cells and the juxtaglomerular cells?
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What is the percentage of the medullary volume composed of renal interstitium?
What is the percentage of the medullary volume composed of renal interstitium?
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What is the term for the area at the apex of each renal pyramid that projects into the lumen of a minor calyx?
What is the term for the area at the apex of each renal pyramid that projects into the lumen of a minor calyx?
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What is the primary function of the mesangial cells in the glomerulus?
What is the primary function of the mesangial cells in the glomerulus?
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Which component of the renal filtration barrier contains type IV collagen?
Which component of the renal filtration barrier contains type IV collagen?
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What is the characteristic of the glomerular endothelial cells that allows for efficient filtration?
What is the characteristic of the glomerular endothelial cells that allows for efficient filtration?
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What is the function of the lamina rara externa in the glomerular filtration barrier?
What is the function of the lamina rara externa in the glomerular filtration barrier?
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What is the primary function of the mesangial matrix in the glomerulus?
What is the primary function of the mesangial matrix in the glomerulus?
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What is the characteristic of the podocyte epithelium in the glomerulus?
What is the characteristic of the podocyte epithelium in the glomerulus?
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What is the role of heparan sulfate in the renal filtration barrier?
What is the role of heparan sulfate in the renal filtration barrier?
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What is the characteristic of the proximal convoluted tubule cells?
What is the characteristic of the proximal convoluted tubule cells?
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Study Notes
Kidney Structure
- The kidney is a paired, bean-shaped organ enveloped by a thin capsule of connective tissue
- Each kidney is divided into an outer cortex and an inner medulla
- Each kidney contains about 2 million nephrons, each with its own microstructure plus renal interstitium
Renal Cortex
- The renal cortex contains renal corpuscles and convoluted tubules
- Renal columns of Bertin are extensions of cortical tissue between adjacent renal pyramids
- Medullary rays are groups of tubules that extend from the base of each renal pyramid into the cortex
Renal Medulla
- The renal medulla is divided into pyramidal-shaped structures called renal pyramids
- Each pyramid has a base that establishes the corticomedullary junction and an apex that forms the deepest portion of the medulla
- Each kidney contains 10 to 18 renal pyramids
- Each pyramid contains thin limbs of loops of Henle, blood vessels, and collecting tubules
Renal Interstitium
- The renal interstitium is a scanty connective tissue compartment that makes up less than 10% of the cortical volume and 20% of the medullary volume
- It contains fibroblasts and mononuclear cells, as well as pericytes and interstitial cells in the medulla
- Interstitial cells manufacture medullipin I, which is converted to medullipin II in the liver and acts as a vasodilator
Uriniferous Tubule
- A uriniferous tubule consists of a nephron and a collecting tubule
- A nephron is composed of a renal corpuscle, proximal tubule, thin descending limb of Henle loop, thin ascending limb of Henle loop, and distal tubule
Renal Corpuscle
- A renal corpuscle consists of a glomerulus and a Bowman capsule
- The Bowman capsule has a parietal layer, a visceral layer composed of podocytes, and a urinary space
- Podocytes possess primary and secondary processes that encircle glomerular capillaries and interdigitate with pedicels from other primary processes
Glomerular Filtration Barrier
- The glomerular filtration barrier consists of fenestrated endothelium, basal lamina, and filtration slits
- It permits passage of water, ions, and small molecules from the bloodstream into the capsular space but prevents passage of large and most negatively charged proteins
Glomerulus
- A glomerulus consists of glomerular endothelial cells, basal lamina, and mesangium
- Glomerular endothelial cells possess large fenestrae but lack thin diaphragms
- The basal lamina contains type IV collagen and helps support glomerular capillaries
- Mesangial cells phagocytose large protein molecules and debris, contract to decrease the surface area available for filtration, and manufacture platelet-derived growth factor and endothelins
Proximal Convoluted Tubule
- The proximal convoluted tubule is lined by cuboidal to columnar cells with microvilli forming a prominent brush border
- Cells possess apical canaliculi, vesicles, and vacuoles that function in protein absorption
- Cells have prominent interdigitations along their lateral borders that interlock adjacent cells
- Cells have numerous mitochondria compartmentalized in the basal region that supply energy for active transport of Na+ out of the tubule
Thin Limb of the Henle Loop
- The thin limb of the Henle loop is composed of a descending segment, a loop, and an ascending segment
- It is lined by simple squamous epithelial cells with short microvilli
Distal Convoluted Tubule
- The distal convoluted tubule is shorter and has a wider lumen than the proximal tubule
- Cells are smaller and less acidophilic, and lack a brush border
Juxtaglomerular Apparatus
- The juxtaglomerular apparatus is located at the vascular pole of the renal corpuscle
- It consists of juxtaglomerular cells, macula densa cells, and extraglomerular mesangial cells
- Juxtaglomerular cells are modified smooth muscle cells that synthesize renin
- Macula densa cells are tall, narrow, closely packed epithelial cells that monitor the osmolarity and volume of the fluid in the distal tubule and transmit this information to juxtaglomerular cells via gap junctions
Collecting Tubule
- The collecting tubule is lined by simple epithelium containing two types of cuboidal cells: principal cells and intercalated cells
- Principal cells possess a round central nucleus and a single primary cilium and are responsible for urine concentration
- Intercalated cells are less numerous than principal cells and possess microplicae on their apical surface and numerous apical cytoplasmic vesicles
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Description
Learn about the structure and components of the kidney, including the renal cortex, medulla, interstitium, and nephrons. Understand the roles of podocytes, glomerular filtration, and the juxtaglomerular apparatus.
