Kidney I Flashcards


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1

Where are the 3 constriction locations in the urinary tract?

  1. Right outside kidneys
  2. middle of ureter
  3. At entrance to bladder

2

The outside of the bladder is protected by _______________

serous membrane

3

The inner layer of the bladder is lined w/ a mucosal membrane consisting of _____________,_______________, _______________ , and ______________

Surface glycocalyx, basement membrane, lamina propria, and urothelium

4

Which type of cells act as a barrier to ions, water, and solutes?

Umbrella cells

5

The bladder is flexible, but impermeable, because of _______________

Uroplakin plaques

6

What does the pudenal nerve innervate?

External sphincter

7

The ____________ nerve is not fully developed until a child reaches ~3-4 years of age

Pudenal

8

List 8 ways the kidneys maintain the body's internal environment

  1. Excretion of metabolic wastes and foreign substances
  2. Regulation of total water volume in the body and osmolarity
  3. Regulation of ion concentrations in extracellular fluids
  4. Regulation of arterial P
  5. Long-term acid-base balance
  6. Production of erythropoietin and renin
  7. Conversion of vitamin D to its active form
  8. Carrying out gluconeogenesis during prolonged fasting

9

Approximately how much blood is filtered through the kidneys each day?

1728 L

10

How many liters of plasma is filtered per day?

180 L

11

How much plasma enters the glomerular capillaries per minute?

650 mL

12

How many liters of filtrate is reabsorbed per day?

178.5 L

13

How many liters of urine are excreted per day?

1.5 L

14

The outermost layer of the kidney where majority of reabsorption and secretion take place

Cortex

15

Middle layer of the kidney where urine concentration and dilution occur

Medulla

16

The medulla consists of multiple pyramidal tissue masses, called the ___________

renal pyrimids

17

In between renal pyramids are spaces called ___________ through which the blood vessels pass. These structures nourish the kidneys

Renal column

18

The tip of the renal pyramid that points toward the renal pelvis

Papilla

19

Innermost layer of the kidney, which is a collection of channels cushioned on fat tissue

Pelvis

20

Channels through which urine passes to the pelvis

Major and minor calyces

21

Urine passes through the renal papilla into the _____________

Minor calyx

22

2-3 minor calyces merge to form _______________, through which urine passes through the renal pelvis into the ureter

Major calyx

23

Fatty cavity underneath renal pelvis through which blood vessels, nerves and lymphatics pass

Renal sinus

24

Thin membrane sheath covering outer surface of kidney. Consists of tough fibers containing collagen and elastin that protect kidneys from injury and infecton

Fibrous capsule

25

Concave part of the bean-shape where blood vessels and nerves enter and exit the kidney; also the point of exit for the ureter

Renal hilum

26

Urine formation through kidney:

Cortex --> Medulla --> Papilla --> Minor calyx --> major calyx --> Pelvis --> ureter --> urinary bladder

27

What is the functional unit of the kidney?

Nephron

28

Major structures of the nephrons:

Glomerulus and tubules

29

What structure is the primary site for reabsorption?

Proximal convoluted tubule

30

The thin segment of the loop of Henle reabsorbs ________ only

water

31

The thick segment of the loop of Henle reabsorbs ________ only

Na

32

Glomerular capillaries are mostly located where?

Cortex

33

Macula densa has a ______ sensing mechanism

Na+

34

Where do thiazide diuretics work?

Distal convoluted tubule

35

Peritubular capillaries are located in which type of nephron?

Cortical nephron

36

Vasa recta is located in which type of nephron?

Juxtamedullary nephron

37

Which type of nephron has short loops of henle?

Cortical nephron

38

Where is the glomeruli located in Cortical nephrons?

outer cortex

39

Cortical nephrons comprise what percentage of total nephrons?

85%

40

Juxtamedullary nephrons comprise what percentage of total nephrons?

15%

41

Where is the glomeruli located in juxtamedullary nephrons?

deep w/in renal cortex

42

Which type of nephrons have long loops of henle that set up an osmotic gradient by increasing Na reabsorption, promoting water reabsorption?

Juxtamedullary nephron

43

What cell types are found in the Juxtamedullary complex?

  • Macula densa cells
  • Extraglomerular mesangial cells
  • JG cells

44

Cells of the Juxtamedullary complex that respond to changes in the NaCl levels in the distal tubule of the nephron via tubuglomerular feedback (TGF)

Macula densa cells

45

Cells of the Juxtamedullary complex that are located in the jxn b/w afferent and efferent arterioles

Extraglomerular mesangial cells

46

Cells of the Juxtamedullary complex that are specialized cells located on either side of the afferent arteriole; secrete renin

JG cells

47

What is the primary fxn of glomerular mesangial cells?

Remove trapped residues and aggregated ptns from the basement membrane to keep filter unclogged

48

Function of podocytes:

Form filtration barrier (along w/ glomerular capillary endothelial cells and glomerular basement membrane)

49

Autonomic innervation to the kidneys is entirely ___________, with nerves originating from the ________________

Sympathetic; celiac plexus

50

What are the 3 major effects of sympathetic stimulation of the kidneys?

  • Catecholamines cause vasoconstriction (mostly α1A, some α1B)
  • Catecholamines enhance Na reabsorption in proximal tubules (α1B)
  • Increased nerve activity dramatically increases renin secretion from JG cells (β1)

51

Renal nerves also include ___________ (afferent/efferent) fibers to conduct chemoreceptor and baroreceptor impulses from the kidney

Afferent

52

Which process of the kidney occurs in the renal corpuscle and produces cell- and ptn-free filtrate?

Glomerular filtration

53

Which process of the kidney occurs in the renal tubules and collecting ducts and selectively moves substances from filtrate into the blood (based on pressures)?

Tubular reabsorption

54

Which process of the kidney occurs in the renal tubules and collecting ducts and selectively moves substances from the blood to the filtrate, utilizing active transport?

Tubular secretion

55

T/F: If a substance is freely filtered, the concentration in the glomerular capsule is equal to the concentration in the urine.

True

56

If only filtration and reabsorption is occurring and 100 molecules of a substance comes to the glomerulus, approximately what volume of the substance would be found in the urine (assuming this substance can be reabsorbed)?

<20

57

List molecules that can be partially absorbed

  • Na
  • Cl
  • Bicarb

58

List molecules that can be completely absorbed

  • Glucose
  • AA

59

If only filtration and secretion is occurring and 100 molecules of a substance comes to the glomerulus, approximately what volume of the substance would be found in the urine (assuming this substance can be secreted)?

>20

60

List molecules that can be partially secreted

  • Creatinine
  • Penicillin

61

List molecules that can be completely secreted

Para-aminohippuric acid (PAH)

62

List molecules that can be partially reabsorbed and secreted

  • K
  • Uric acid

63

T/F: Glomerular filtration is an active process in which hydrostatic P forces fluids and solutes through the filtration membrane

False

64

Where is the filtration membrane located?

B/w the blood and the interior of the glomerular capsule

65

What 3 layers make up the filtration membrane?

  • Fenestrated endothelium of the glomerular capsule
  • Basement membrane
  • Foot processes of podocytes of the glomerular capsule

66

_____________ of the glomerular capillary endothelium filter by size

Fenestrations

67

The basement membrane of the filtration membrane is composed of:

Collagen and proteoglycan

68

T/F: Collagen filters by charge and proteoglycan filters by size

False

69

If albumin is 6.9 nm in diameter, but glomerular membrane pores are 7-8 nm in diameter, why doesn't albumin get through?

Charge on albumin is negative = repelled by negative charge on proteoglycan

70

Defined as the volume of filtrate formed each minute by the glomeruli of the kidneys

GFR

71

Defined as the fraction of the renal plasma flow that is filtered

Filtration fraction

72

How much plasma is filtered every minute?

125 mL

73

About ______% of plasma flowing through the kidney is filtered through the glomerular capillaries

20

74

GFR is directly proportional to:

  • Net filtration P
  • Total surface area available for filtration
  • Filtration membrane permeability

75

Net filtration P =

Outward P - Inward P

76

A vascular P of ~______ mm Hg is needed for filtration to occur

50

77

A vascular P of ~______ mm Hg is needed for reabsorption and secretion to occur

17

78

What kind of pressure is created by the amount of liquid present?

Hydrostatic P

79

Pushing force

Hydrostatic P

80

What kind of pressure is created by the amount of dissolved solute (i.e. albumin)

Osmotic P

81

Pulling force

Osmotic P

82

T/F: Kf cannot be measured directly, so it must be calculated

True

83

The glomerular capillary filtration coefficient (Kf) is calculated by:

hydraulic conductivity x SA of glomerular capillaries

84

T/F: the Kf value for the glomerular capillaries is ~200x higher than the Kf for most other capillary systems i the body

False

85

T/F: Maintenance of GFR is likely due to changes in Kf

False

86

In chronic uncontrolled HTN and DM, thickening of the basement membrane occurs, which ultimately damages the capillaries. How does this affect Kf and GFR?

Decrease both

87

How can obstructions lodged in the urinary tract affect HPcs, NFP, and GFR?

Increase; decrease; decrease

88

Defined as distention and dilation of the renal pelvis and calices

Hydronephrosis

89

Defined as the volume of plasma that is completely cleared of a substance by the kidneys per unit of time

Renal clearance

90

Renal clearance equation:

Cs x Ps = Us x V

91

T/F: If a substance is freely filtered and is not reabsorbed/secreted, then the rate at which the substance is excreted in urine = the filtration rate of the substance by the kidneys.

True

92

T/F: Inulin is freely filtered

True

93

What equation could you use to calculate GFR using inulin?

GFR = (Us x V) / Ps

94

__________ is a byproduct of muscle metabolism

Creatinine

95

T/F: Creatinine is not cleared by the body via glomerular filtration and requires IV infusion to measure

False

96

How would an increase in HPgc affect GFR?

Increase

97

How would an increase in HPcs affect GFR?

Decrease

98

How would a decrease in OPgc affect GFR?

Increase

99

How would a decrease in Kf affect GFR?

Decrease

100

How would an increase in arterial P affect HPgc ?

Increase (only small effect)

101

How would an increase in efferent arteriolar resistance affect HPgc ?

Increase

102

How would a decrease in afferent arteriolar resistance affect HPgc ?

Increase

103

T/F: severe increases in efferent resistance causes decrease in renal BF.

True

104

Ang II ______________(increases/decreases) efferent arteriole resistance

Increase

105

T/F: A decrease in afferent arteriolar resistance will restrict renal BF and decrease HPgc

False

106

_________ cells causes contraction of basement membrane of glomerular capillaries, leading to decreased SA and decreased GFR

Mesangial

107

RBF is determined by:

P gradient across the renal vasculature divided by total vascular resistance

108

List mechanisms for intrinsic control of GFR:

  • Myogenic response
  • Tubuloglomerular feedback
  • Intrarenal baroreceptor pathway

109

List mechanisms for extrinsic control of GFR:

  • Neural
  • Hormonal

110

How does the myogenic response regulate HP and GFR if there is an increase in systemic BP?

--> ↑stretch of vasc. SMC; ↑Ca --> constriction of afferent arterioles --> ↓ renal BF to glomerulus --> ↓ HP ↓GFR

111

How does the myogenic response regulate HP and GFR if there is a decrease in systemic BP?

--> ↓stretch of vasc. SMC; no Ca accumulation --> relaxation of afferent arterioles --> ↑ renal BF to glomerulus --> ↑ HP ↑GFR

112

Which type of regulation is flow-dependent and directed by cells of the macula densa?

Tubularglomerular feedback

113

How is the [Na] in the tubule affected if there is high GFR?

Less time for Na reabsorption = high [Na] in tubule

114

T/F: If there is high [Na] in tubule, there will be vasodilation of the afferent arteriole in order to increase the amount of water coming into the tuble

False

115

How is the [Na] in the tubule affected if there is low GFR?

more time for Na reabsorption = low [Na] in tubule

116

If there is high [Na] in tubule, what will happen to the afferent arteriole?

Vasoconstriction

117

Describe the overall tubularglomerular feedback mechanism when BP is high

  1. ↑ BP and RBF
  2. ↑ GFR
  3. ↑ speed of filtrate flow through tubules
  4. ↓ contact time b/w filtrate and tubule cells
  5. ↑ apical Na entry into macula densa cells via NKCC
  6. ↑ Na transport across basolateral via Na/K atpase
  7. ↑ATP to AD conversion and A1 receptor binding
  8. ↑ Ca in SMC and ↑ Ca in JG cells
  9. Afferent arteriole constriction and ↓ RBF and ↓ renin secretion, ↓BP

118

Describe the overall tubularglomerular feedback mechanism when BP is low

  1. ↓ BP and RBF
  2. ↓ GFR
  3. ↓ speed of filtrate flow through tubules
  4. ↑ contact time b/w filtrate and tubule cells
  5. ↓ apical Na entry into macula densa cells via NKCC
  6. ↓ Na transport across basolateral via Na/K atpase
  7. ↑ NO and PG production
  8. ↑ NO action in SMC and ↑ PG action in JG cells
  9. Afferent arteriole dilation, ↑ RBF and ↑ renin secretion, ↑BP

119

Describe the inrarenal baroreceptor pathway if renal P is high in afferent arterioles

↓ prostaglandins --> ↓ renin release

120

Describe the inrarenal baroreceptor pathway if renal P is low in afferent arterioles

↑ prostaglandins --> ↑ renin release

121

When would neuronal control take over extrinsic control?

Extreme circumstances (low extracel. fluid / hypovolemic shock from severe hemorrhage)

122

What are the effects of neural control?

  • Constriction of efferent and afferent arterioles causing a reduction in RBF and GFR
  • ↑ secretion of renin via tubuloglomerular feedback
  • Stimulation of β1 on juxtaglomerular cells leading to additional renin secretion

123

What 3 mechanisms can stimulate renin release?

  • Baroreceptor
  • Sympathetic nerve
  • Macula densa

124

Which of the 3 mechanisms that stimulate renin release utilize prostaglandin?

  • Baroreceptor
  • Macula densa

125

How does the intrarenal baroreceptor mechanism release renin when stimulated?

↓ in renal perfusion in afferent arteriole stimulates synthesis and release of prostaglandins = renin release

126

How does the sympathetic nerve mechanism release renin when stimulated?

↑ activity of SNS = release NE and/or E = stimulates β1 on JG cells = renin release

127

How does the macula densa mechanism release renin when stimulated?

↓ in Na reaching MD = MD synthesizes and releases prostaglandins = renin release from JG cells