Urinary System Flashcards
(106 cards)
1
Q
concave medial border where nerves enter, ureter exits and blood and lymph vessels enter and exit- lateral border is convex covered by a thin fibrous capsule
A
Hilum
2
Q
upper expanded end of the ureter which divides into
A
Renal Pelvis
3
Q
outer darker region with many corpuscle and cross section of tubules
A
Renal Cortex
4
Q
inner layer consisting of 8-12 conical structures called renal pyramids which are separated by extensions the cortex called renal columns
A
Renal Medulla
5
Q
each pyramid plus the cortical tissue at its base and along
A
Renal lobe
6
Q
consist of the central medullary ray and the closely associated cortical tissue on either side of it, extending as far as in interlobular artery. Its many nephrons drain into the collecting tubules of the medullary ray
A
Renal Lobule
7
Q
striations extending from the medulla into the cortex
A
Medullary Rays
8
Q
tip of the renal papilla that projects into a minor calyx that collects urine formed by tubules in the pyramid
A
Renal papilla
9
Q
Consists primarily of fibroblasts and mononuclear cells (probably macrophages).
A
Renal Interstitium
10
Q
In the medulla, they are located along the blood vessels that supply the loops of Henle.
A
Pericytes
11
Q
It is a vasodepressor hormone converted to medullipin II in the liver.
A
Medulllipin I
12
Q
It is a vasodilator that acts to reduce blood pressure
A
Medullipin II
13
Q
Nephrons can be classified according to location of the renal corpuscle:
NEAR THE CORTICOMEDULLARY JUNCTION
A
Juxtamedullary
14
Q
Simple Squamous Epithelium lining Bowman capsule: Podocytes (visceral layer), outer (parietal layer)
A
Renal Corpuscle
15
Q
Simple Cuboidal Epithelium with Brush border: many compartmentalized mitochondria
A
Proximal convoluted tubule
16
Q
Simple Cuboidal Epithelium: compartmentalized mitochondria
A
Loop of Henle; ascending thick limb
17
Q
Lined by simple cuboidal epithelium with brush border
A
Loop of Henle, descending thick limb
18
Q
Simple Squamous Epithelium
A
Loop of Henle, descending thin limb
19
Q
Simple Squamous Epithelium
A
Loop of Henle, ascending thin limb
20
Q
Simple Cuboidal Epithelium
A
JG apparatus macula densa
21
Q
JG cells in the afferent arteriole
A
Modified smooth muscle cells containing renin granules
22
Q
Distal convoluted tubule
A
Simple cuboidal cells: compartmentalized mitochondria
23
Q
Collecting tubules
A
Simple Cuboidal Epithelium; simple columnar epithelium
24
Q
They possess longer loops of Henle than cortical or mid-cortical nephrons and are responsible for establishing the interstitial concentration gradient in the medulla.
A
Juxtamedullary nephrons
25
It consists of the glomerulus and Bowman capsule and is the structure in which the filtration of blood occurs.
Renal corpuscle
26
In a Bowman capsule:
It is the simple squamous epithelium that lines the outer wall of the Bowman capsule.
Parietal layer
27
In a Bowman capsule:
It is the modified simple squamous epithelium composed of podocytes that lines the inner wall of the Bowman capsule and envelops the glomerular capillaries.
Visceral layer (Glomerular epithelium)
28
In a Bowman capsule:
It is the narrow chalice shaped cavity between the visceral and parietal layers into which the ultrafiltrate passes.
Bowman space (also known as capsular space or urinary space)
29
In a Bowman capsule:
It is the site on Bowman capsule where the afferent glomerular arteriole enters and the efferent glomerular arteriole leaves the glomerulus.
Vascular pole
30
In a Bowman capsule:
It is the site on Bowman capsule where the capsular space becomes continuous with the lumen of the proximal convoluted tubule.
Urinary Pole
31
They are highly modified epithelial cells that form the visceral layer of Bowman capsule and synthesize glomerular endothelial growth factor, a signaling molecule that facilitates the formation and maintenance of the glomerular endothelial cells.
Podocytes
32
They have complex shapes and possess several primary processes that give rise to many secondary processes called pedicels.
Podocytes
33
It embraces the glomerular capillaries and interdigitate with pedicels arising from other primary processes.
Pedicels
34
Pedicels surfaces facing Bowman space are coated with a protein that is thought to assist in maintaining their organization and shape called:
Podocalyxin
35
Pedicels possess molecules that cause them to adhere to the basal lamina called:
α2β1integrin
36
They are elongated spaces about 40 nm in width between adjacent pedicels.
Filtration slits
37
It bridges each filtration slit and is the principal structure that is the barrier responsible for the filtration of proteins.
Filtration slit diaphragm
38
Each slit diaphragm comprises the extracellular portion of the transmembrane protein of one pedicel that contacts the extracellular portion of that protein from the adjacent pedicel.
Nephrin
39
It is the tuft of capillaries that extends into the Bowman capsule.
Renal Glomerulus
40
- It forms the inner layer of the capillary walls.
- have a thin cytoplasm thicker around the nucleus, where most organelles are located.
- possess large fenestrae (60-90 nm in diameter) but lack the thin diaphragms that typically span the openings in other fenestrated capillaries.
Glomerular endothelial cells
41
It is between the podocytes and the glomerular endothelial cells and is manufactured by both cell populations. It is unusually thick (0.15-0.5 um)
Basal Lamina
42
Three Distinct Zones of Basal Lamina:
It is an electron-lucent zone adjacent to the podocyte epithelium
Lamina rara externa
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Three Distinct Zones of Basal Lamina:
It is a thicker, electron-dense intermediate zone of amorphous material.
Lamina densa
44
Three Distinct Zones of Basal Lamina:
It is an electron-lucent zone adjacent to the capillary endothelium.
Lamina rara interna
45
It is the interstitial tissue between glomerular capillaries. It is composed of mesangial cells and an amorphous extracellular matrix elaborated by these cells.
Mesangium
46
- phagocytose large protein molecules and debris, which may accumulate during filtration or in certain disease states.
- can also contract, thereby decreasing the surface area available for filtration.
- possess receptors for angiotensin II and atrial natriuretic peptide.
- manufacture platelet-derived growth factor, endothelins, inteleukin-1, and prostaglandin E2
Mesangial Cells
47
It is composed of the fenestrated endothelium of the glomerular capillaries, the basal lamina (laminae rarae and lamina densa), and the filtration slit diaphragm bridging the filtration slits between adjacent pedicels filtration slit diaphragm.
Renal filtration barrier
48
It permits passage of water, ions, and small molecules from the bloodstream into the capsular space but prevents passage of large and/or most negatively charged proteins, thus forming an ultrafiltrate of blood plasma in the Bowman space.
Renal Filtration Barrier
49
It contains heparan sulfate
Lamina rarae
50
A polyanionic glycosaminoglycan that restricts the passage of negatively charged proteins into the Bowman space.
Heparan sulfate
51
It contains type IV collagen (composed of a3, a4, and a5 chains rather than the a1 and a.z chains most present, perlacan, lam in in, entactin, and agrin. The negative charges of some of these macromolecules and the filtration slit diaphragm act as a selective macromolecular filter, preventing the passage of large protein molecules (molecular weight greater than 69,000 Da) into the Bowman space
Lamina densa
52
CLINICAL CORRELATION:
1. It is a type of nephritis characterized by inflammation of the glomeruli.
2. It is sometimes marked by the proliferation of podocytes, endothelial cells, and mesangial cells in the glomerular tuft; infiltration of leukocytes is also common.
3. often occurs secondary to a streptococcal infection elsewhere in the body, which is thought to result in the deposition of immune complexes in the glomerular basal lamina. The immune complexes damage the glomerular basal lamina and markedly reduce its filtering ability.
4. It may also result from immune or autoimmune disorders.
5. It is associated with the production of urine-containing blood (hematuria), protein (proteinuria), or both; in severe cases, decreased urine output (oliguria) is common.
6. It occurs in acute, subacute, and chronic form. The chronic form, in which the destruction of glomeruli continues, leads eventually to renal failure and death.
Glomerulonephritis
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CLINICAL CORRELATION:
1. It can result from a variety of diseases (e.g., diabetes mellitus, hypertension, atherosclerosis) in which blood flow to the kidneys is reduced, causing a decrease in glomerular filtration and tubular ischemia.
2. It is associated with pathological changes (hyalinization) in the glomeruli and atrophy of the tubules, which impair virtually all aspects of renal function.
3. It is marked by acidosis and hyperkalemia because the acid-base balance cannot be maintained, and by uremia because of t e inability to eliminate metabolic wastes.
4. If untreated, it leads to neurological problems, coma, and death
Chronic renal failure
54
It is lined by a single layer of irregularly shaped (cuboidal to columnar) epithelial cells that have microvilli forming a prominent brush border.
Proximal convoluted tubule
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In a proximal convoluted tubule:
They function in protein absorption
Apical canaliculi, vesicles, and vacuoles (endocytic complex)
56
In a proximal convoluted tubule:
They interlock adjacent cells with one another
Prominent interdigitations along their lateral borders
57
In a proximal convoluted tubule:
They supply energy for the active transport of Na + out of the tubule.
Numerous mitochondria compartmentalized in the basal region by extensive infoldings of the basal plasma membrane
58
In a Proximal convoluted tubule:
They endocytose small proteins and peptides that escaped into the ultrafiltrate.
Apically situated occluding junctions that block the paracellular pathway. And the apical cell membrane has glucose transporters, Na+K+ -ATPase pump, and an apically positioned tubulovesicular system
59
It possesses Na +K+ -ATPase pump, and, additionally, the basal cell membrane has glucose and amino acid transporters.
Basolateral cell membrane
60
It functions in monitoring the flow and composition of the ultrafiltrate.
Primary cilium
61
It drains the Bowman space at the urinary pole of the renal corpuscle.
Proximal convoluted tubule
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It resorbs from the glomerular filtrate all of the glucose, amino acids, and small proteins and 60% to 80% of the sodium chloride and water and returns it into the peri tubular capillary system to be distributed from there into the remainder of the body.
Proximal Convoluted Tubule
63
It exchanges H+ in the interstitium for HC03- in the filtrate.
Proximal Convoluted Tubule
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It secretes organic acids (e.g., creatinine) and bases and certain foreign substances into the filtrate.
65
It is also known as the straight portion (pars recta) of the proximal tubule, lined by a simple cuboidal epithelium that has a prominent brush border and its function is to resorb, exchange, and secreted in a manner similar to that of the proximal convoluted tubule.
Descending thick limb of the Henle loop
66
It is composed of a descending segment, a loop, and an ascending segment, all of which are lined by simple squamous epithelial cells possessing a few short microvilli. The nuclei of these cells bulge into the lumen.
Thin limb of the Henle loop
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Cells of the descending thin limb possess many of these cells and makes it permeable to water as well as being somewhat permeable to ions such as sodium and chloride.
Aquaporin l channels
68
Mostly impermeable to water
Henle loop
69
It is almost completely impermeable to water but possesses many sodiums and chloride channels, which permit these ions to enter the cell from the lumen of the tubule and exit the cell into the renal interstitium. Additionally, urea enters the lumen of the ascending thin limb.
Ascending thin limb
70
- It is also known as the straight portion (pars recta) of the distal tubule, lined by cuboidal epithelial cells that possess only a few microvilli, an apical nucleus, and mitochondria compartmentalized within basal plasma membrane infoldings.
- It establishes a gradient of osmolarity in the medulla (see Section V).
- It returns to the renal corpuscle of origin, where it is in close association with the afferent and efferent glomerular arterioles.
- In this region, the wall of the tubule is modified, forming the macula densa, which is part of the juxtaglomerular apparatus (JG apparatus).
Ascending thick limb of the Henle loop
71
A glycoprotein that reduces the ability of the kidney to form kidney stones and, in some fashion, reduces the possibility of urinary tract infections. It also modulate the mechanism of urine concentration.
Uromodulin (Tamm-Horsfall glycoprotein)
72
It is located at the vascular pole of the renal corpuscle
JG apparatus (juxtaglomerular apparatus)
73
They are modified smooth muscle cells that exhibit some characteristics of protein secreting cells.
JG cells (juxtaglomerular cells)
74
They are located primarily in the wall of the afferent arteriole, but a few may also be present in the wall of the efferent arteriole
JG cells (juxtaglomerular cells)
75
From JG cells (juxtaglomerular cells):
It is a proteolytic enzyme and store in secretory granules.
Renin
76
They are tall, narrow, closely packed epithelial cells of the distal tubule, have elongated, closely packed nuclei that appear as a dense spot (macula densa) by light microscopy.
Macula Densa Cells
77
It may monitor the osmolarity and volume of the fluid in the distal tubule and transmit this information to JG cells via the gap junctions between the two cell types. When the sodium concentration or the volume of the ultrafiltrate is reduced, these cells direct the JG cells to release their renin.
Macula Densa Cells
78
They lie between the afferent and efferent glomerular arterioles, but their functions are not understood.
Polkissen (pole cushion) or lacis cells
79
The JG apparatus maintains blood pressure by the following mechanism:
1. It is detected by the macula densa as decreased ultrafiltrate volume
2. Detected at the afferent glomerular arteriole,
3. Stimulates JG cells to release renin into the bloodstream.
Stimuli:
1. A decrease in extracellular fluid volume
2. A decrease in blood pressure
3. A decrease in the sodium concentration of the ultrafiltrate
79
The JG apparatus maintains blood pressure by the following mechanism:
1. It is detected by the macula densa as decreased ultrafiltrate volume
2. Detected at the afferent glomerular arteriole,
3. Stimulates JG cells to release renin into the bloodstream.
Stimuli:
1. A decrease in extracellular fluid volume
2. A decrease in blood pressure
3. A decrease in the sodium concentration of the ultrafiltrate
80
It acts as on angiotensinogen in the plasma.
Renin
81
A large protein manufactured by liver hepatocytes
Angiotensinogen
82
Renin cleaves the first 10 amino acids from angiotensinogen, converting it to:
Decapeptide angiotensin I
83
In capillaries of the lung and elsewhere, angiotensin-converting enzyme cleaves two amino acids from angiotensin I, converting it to :
Angiotensin II
84
It is a potent vasoconstrictor that stimulates the release of aldosterone in the adrenal cortex and the release of antidiuretic hormone (ADH) by neurohypophysis.
Angiotensin II
85
It stimulates the epithelial cells of the distal convoluted tubule to remove Na + and cr. Water follows the ions, thereby increasing the fluid volume in the extracellular compartment, which increases blood pressure.
Aldosterone
86
It causes the epithelial cells (mainly the principal cells) of the collecting tubule to add aquaporin 2 (AOP-2) channels (as well as AQP-3 and AQP-4 channels) to their cell membrane and thus become permeable to water, releasing H20 into the renal interstitium. As with the aldosterone mechanism discussed above, the increased extracellular fluid volume leads to elevation of the blood pressure.
ADH
87
It is continuous with the macula densa and histologically similar to the ascending thick limb of the Henle loop.
* It is much shorter, has a wider lumen than the proximal convoluted tubule, and lacks a brush border.
FUNCTION: resorbs Na+ from the filtrate and actively transports it into the renal interstitium; this process is stimulated by aldosterone. It also transfers K+, NH4 +, and H+ into the filtrate from the interstitium.
Distal convoluted tubule
88
It is a short segment between the distal convoluted tubule and the collecting tubule into which it drains.
Connecting tubule
89
Connecting tubule is lined by the following two types of epithelial cells:
They have many infoldings of the basal plasma membrane. These cells remove Na+ from the filtrate and secrete K+ into it.
Principal Cells
90
Connecting tubule is lined by the following two types of epithelial cells:
They have many apical vesicles and mitochondria. These cells remove K+ from the filtrate and secrete H+ into it.
Intercalated cells
91
They have an embryological origin different from that of nephrons. They have segments in both the cortex and the medulla and converge to form larger and larger tubules.
Collecting tubules
92
They are located primarily within medullary rays, although a few are interspersed among the convoluted tubules in the cortex (cortical labyrinth).
- They are lined by a simple epithelium containing two types of cuboidal cells.
Cortical collecting tubules
93
These cells possess a round central nucleus and a single primary cilium. It is these cells that are responsible for the ability of the collecting tubules to concentrate urine.
Principal (light) cells
94
These cells are less numerous than principal cells and possess microplicae (folds) on their apical surface and numerous apical cytoplasmic vesicles.
Intercalated (dark) cells
95
There are two types of intercalated cells:
Cells that have the ability to release H + ions into the tubular lumen and reabsorb HCO3, thus acidifying urine via H+ and H+/K+ exchanger
* possess hydrogen pumps
a-interca lated cells
96
There are two types of intercalated cells:
Cells have the ability to release HC03- ions into the tubular lumen and reabsorb acid, thus causing the urine to be more alkaline. a-Intercalated cells,
* HC03- pumps to fulfill their function.
β-intercalated cells
97
Medullary collecting tubules are similar in structure to cortical collecting tubules and contain both principal and intercalated cells in their lining epithelium.
In the outer medulla
98
The collecting tubules are lined only by principal cells.
In the inner medulla
99
They are large collecting tubules (200-300 Jlm in diameter) formed from converging smaller tubules.
- They are lined by a simple epithelium composed of columnar cells with a single primary cilium.
- They empty at the area cribrosa, a region at the apex of each renal pyramid that has 10 to 25 openings through which the urine exits into a minor calyx
Papillary collecting tubules (ducts of Bellini)
100
It includes the minor and major calyces and the renal pelvis, located within each kidney, and the ureters, urinary bladder, and urethra, located outside the kidneys.
The excretory passages
101
Excretory passages generally possess a three-layer wall composed of:
(except in the urethra) lying on a lamina propria of connective tissue, a muscularis (smooth muscle), and an adventitia.
A mucosa of transitional epithelium
102
It conveys urine from the renal pelvis of each kidney to the urinary bladder.
It has a transitional epithelium that is thicker and contains more cell layers than that of renal calyces.
It possesses a two-layer muscularis (an inner longitudinal and outer circular layer of smooth muscle) in its upper two-thirds. The lowest third possesses an additional outer longitudinal layer of smooth muscle.
It contracts its muscle layers, producing peristaltic waves that propel the urine so that it enters the bladder in spurts.
Ureter
103
It has transitional epithelium with a morphology that differs in the relaxed (empty) and distended states. It also has a * thin lamina propria of fibroelastic connective tissue, and a three-layer muscularis.
Urinary bladder
104
It is five to six cell layers thick and has rounded, superficial dome-shaped cells that bulge into the lumen.
- These cells contain unique plaques (having a highly ordered substructure) in their thick luminal plasma membrane and flattened elliptical vesicles in their cytoplasm.
Epithelium of the relaxed urinary bladder
105
- It only has three to four cell layers thick.
- has squamous superficial cells.
- has much thinner and has a larger luminal surface than the relaxed bladder due to the insertion of the elliptical vesicles into the luminal plasma membrane of the surface cells.
Epithelium of the distended urinary bladder
