11/28: Urinary System II Flashcards

1
Q

What is the first segment of the renal tubule?

A

Proximal convoluted tubule

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2
Q

Where does the proximal convoluted tubule begin?

A

At the urinary pole of the glomerulus

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3
Q

Where is a majority of the glomerular filtrate reabsorbed?

A

PCT (70%)

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4
Q

What is the loop of henle continuous with?

A

PCT in cortex

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5
Q

Where does the loop of henle travel?

A

Into the medulla, then back to the cortex

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6
Q

Where does the loop of hele empty into?

A

Distal convoluted tubule (DCT)

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7
Q

What does the loop of henle form?

A

A hair-pin structure that dips down into the medulla

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8
Q

What 4 segments are contained in the loop of henle?

A

Pars recta (straight/thick descending limb of proximal tubule)
Thin descending limb
Thin ascending limb
Thick ascending limb

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9
Q

What do the thick and thin segments denote?

A

Epithelial change (cuboidal to squamous) in both the descending and ascending limbs

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10
Q

Where does the turn of the loop of henle occur?

A

In the thin segment within the medulla

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11
Q

Where does the tubule ascend after the turn in the loop of henle?

A

Towards the cortex parallel to the descending limb

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12
Q

What does the end of the loop of henle become?

A

The distal convoluted tubule near its original glomerulus

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13
Q

What is the area in the loop of henle where it runs parallel into capillary loops known as?

A

Vasa recta

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14
Q

What does the loop of henle serve to create?

A

High oscmotic pressure in the renal medulla via the counter-current multiplier system

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15
Q

What is high osmotic pressure important for?

A

Reabsorption of water in the later segments of the renal tubule, helps create hypertonic urine (excretion of excess solutes)

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16
Q

Where does the bulk of the loop of henle extend into?

A

Medulla; variable length

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17
Q

Describe the length of thin limbs

A

Long in juxtamedullary nephrons
Short in cortical nephrons

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18
Q

What kind of epithelium does thin limb have?

A

Simple squamous

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19
Q

What kind of epithelium does thick limb have?

A

Simple cuboidal epithelium

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20
Q

What does the pars recta have?

A

Brush border of apical microvilli (like PCT)

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21
Q

What is the loop of henle surrounded by?

A

Peritubular capillary network, vasa recta

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22
Q

What does the countercurrent multiplier function to generate?

A

High osmotic pressure in ECF of renal medulla via Na-K pumps in thick ascending limb of loop of henle

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23
Q

Where is extracellular Na quantities higher?

A

Medulla combined with water resorption by proximal convoluted tubule in cortex (cortico-medullary interstitial gradient)

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24
Q

What does counter current (exchange) multiple system of urine concentration result in?

A

Production of hypertonic urine

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25
Q

What is the loop of henle’s vascular component?

A

Vasa recta

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26
Q

What does the vasa recta arise from?

A

Efferent arterioles of juxtamedullary nephrons

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27
Q

What surrounds all loops of henle (regardless of whether cortical or juxtamedullary nephrons)?

A

Vasa recta

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28
Q

What has the concentration of the interstitium?

A

Loop of henle

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29
Q

What is a continuation of thick ascending limb of loop of henle; present within cortex?

A

Distal convoluted tubulel

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30
Q

What epithelium is the DCT?

A

Simple cuboidal epithelium with short apical microvilli

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31
Q

What does the DCT lack?

A

Distinct brush border

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32
Q

What is the DCT responsible for?

A

Active resorption of Na and Cl secretion of H & K ions

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33
Q

What two cell types is the DCT controlled by?

A

Principal cells
Intercalated cells

34
Q

What is the function of principal cells?

A

Resorb - Na and water
Secrete - K

35
Q

What is the function of intercalated cells?

A

Resorb- K, Cl
Secrete - H, HCO3-

36
Q

What is important regualtors of acid-base balance?

A

Intercalated cells

37
Q

What is the DCT controlled by?

A

Aldosterone (adrenal mineralcorticoid)

38
Q

What receptors make up the juxtaglomerular appratus (JGA)?

A

Baroreceptor (pressure)
Chemoreceptor (Ion)

39
Q

The JGA (juxtaglomerular apparatus) has specialized areas of?

A

Afferent arteriole and distal convoluted tubule

40
Q

The JGA is used for what?

A

Regulate systemic blood pressure via renin-angiotensin-aldosterone system (RAAS)

41
Q

What are the three components of the JGA?

A

Macula densa
juxtaglomerular cells
Extraglomerular mesangial cells

42
Q

What is a thickened region on one side of the distal convoluted tubule?

A

Macula densa

43
Q

What kind of epithelial cells does the macula densa contain?

A

Densely packed cuboidal to columnar epithelial cells

44
Q

What kind of receptor does the macula densa contain?

A

Chemoreceptor sensitive to changes in [Na] in filtrate

45
Q

What does a decrease in systemic BP cause?

A

Decrease in filtrate -> decrease [Na]

46
Q

What are modified smooth mm cells in wall of afferent arteriole?

A

Juxtaglomerula cells

47
Q

What do juxtaglomerular cells act as?

A

Baroreceptors; detect changes in blood pressure

48
Q

What do juxtaglomerular cells produce?

A

Renin in response to decrease in blood pressure

49
Q

What do juxtaglomerular cells convert?

A

Angiotensinogen to angiotensin I

50
Q

What are flattened cells surrounding afferent and efferent arterioles?

A

Extraglomerular mesangial cells (lacis or polkissen cells)

51
Q

What is the function of Extraglomerular mesangial cells (lacis or polkissen cells)?

A

Exact function is unclear; provide structural support & phagocytosis

52
Q

What kind of feedback can extraglomerular mesangial cells assist in?

A

Tubular glomerular feedback (by transmitting signals from cells of macula densa to intraglomerular mesangial cells) whose contraction/relaxation may change glomerular filtration rate

53
Q

What does the macula densa act as?

A

Sensor, regulating juxtaglomerular
function by monitoring Na+ &
Cl- levels in the DCT

54
Q

A decrease in blood volume/pressure elicits…

A

secretion of renin by JG cells

55
Q

Angiotensinogen ->

A

Active angiotensin

56
Q

What does angiotensin cause?

A

Suprarenal glands to secrete aldosterone

57
Q

What inhibitors are used for the treatment of hypertension (high bp)?

A

Angiotensin-convertinge nzyme (ACE) inhibitors

58
Q

What pathway do Angiotensin-convertinge nzyme (ACE) inhibitors take to treat chronic hypertension?

A

Prohibit angiotensin I from converting to angiotensin II

59
Q

What and where do collecting tubules receive liquid from?

A

Isotonic urine from DCT

60
Q

What and where do collecting ducts receive liquid from?

A

Isotonic urine from collecting tubules

61
Q

Where do collecting ducts leave the cortex?

A

In medullary rays and enter medulla

62
Q

Where do collecting ducts open at?

A

papilla into minor calyx

63
Q

What do collecting ducts play an important role in?

A

Final concentration of urine (interstitium and vasa recta)

64
Q

What do lining cells in collecting tubules/ducts have?

A

Distinct intercellular borders

65
Q

What shape are lining cells?

A

Cuboidal (smaller tubules) to columnar (larger ducts)

66
Q

What is responsibe to antidiuretic hormone (ADH,vasopressin) and what is it released by?

A

Epithelium; posterior pituitary

67
Q

What do epithelial cells contain?

A

Awuaporin 2 (AQP-2) transmembrane proteins

68
Q

What regulates collecting ducts?

A

ADH

69
Q

What are mutations in AQP-2 (do not respond to ADH) linked to?

A

Congenital nephrogenic diabetes inspidius

70
Q

What causes hypertonic urine?

A

ADH - water lost from collecting ducts

71
Q

What causes iso-/hypotonic urine?

A

Without ADH - ducts remain impermeable to water

72
Q

What are collecting ducts/tubules lined by?

A

Cuboidal epithelium, cells have distinct borders and stain poorly

73
Q

Describe the 4 steps towards the ureter?

A

Minor calyces -> major calyces -> renal pelvis -> ureter

74
Q

What is the structure of the ureter?

A

Hollow tube with muscular walls

75
Q

What is the ureter lined by?

A

Transitional epithelium

76
Q

What is the ureter designed to be?

A

Distensible; withstand contact with fluid containing toxic substances

77
Q

What does the ureter wall consist of?

A

Mucosa (epithelium and underlying CT)
Muscularis
Adventitia

78
Q

What is the urinary bladder lined by?

A

Stratified urothelium

79
Q

What is the surface layer of balloon cells linked by?

A

Desmosomes and tight junctions

80
Q

What does the surface area of balloon cells have?

A

Deep clefts and vesicles that may increase surface area with distention

81
Q
A