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Flashcards in Renal Overview Deck (88):
1

Where are nephrons located in the kidney?

Renal pyramids

2

What are the two specific ways that the kidneys regulate water/electrolyte balance?

1. Regulate ECF
2. Plasma osmolality

3

How, generally, do the kidneys function to regulate BP? (2)

1. Volume control
2. Renin-angiotensin system

4

What are the four major chemicals that the kidneys excrete?

Urea
Uric acid
Creatinine
Urobilins

5

What is the main source of erythropoietin?

Kidneys

6

Where does the last step of Vit D synthesis take place?

Kidneys

7

When do to the kidneys participate in gluconeogenesis?

Late fast

8

What is the lumen of the nephron?

Renal pelvis

9

What is the luminal side of the tubular cells?

The side that faces the lumen of the tubule

10

What is the apical side of the tubular cell?

The side opposite that of the lumen

11

What is on the basolateral side of the tubular cells?

Tight junctions

12

Where is ADH stored in the kidney?

1.

13

What is the branching names of the renal artery?

Interlobar to arcuate to afferent arterioles to efferent

14

What is the functional difference between the cortical nephrons and the juxtamedullary nephrons?

Cortical can dilute urine, but cannot concentrate

Juxtamedullary can concentrate and dilute urine

15

What are the two places that you can find nephrons? How are these named? (2)

In the cortex (superficial)

Medulla (juxtamedullary nephrons)

16

What is the functional unit of the kidney?

Nephron

17

What is the name of the artery that extends into Bowman's capsule?

Afferent

18

What is the name of the artery that extends out of Bowman's capsule?

Efferent

19

What is the structural difference between juxtamedullary and cortical nephrons?

Juxtamedullary has thin descending and ascending

Cortical has small thin descending. (remainder is thick)

20

What are the two components of the renal corpuscle?

Glomerulus and Bowman's capsule

21

True or false: any freely filtered substance will be at the same concentration in the filtrate as it is in the plasma in the afferent arteriole

True

22

What controls filtration in the glomerulus?

Starling's forces

23

What part of the glomerulus filters?

Glomerular capillaries

24

What part of the glomerulus reabsorb filtrate? What allows for this?

Peritubular capillaries

High protein [c]

25

What is the dilated, blind end of the nephron tubule that is invaginated by a tuft of of capillaries?

Bowman's capsule

26

What are the three components of the Bowman's capsule that allows for filtration of the blood?

1. Capillary endothelium
2. Basement membrane
3. Specialized epithelium of capsule (podocytes)

27

What are the cells that act as phagocytes and removed trapped material from the basement membrane of the glomerulus?

Mesangial cells

28

What are the two epithelial layers of Bowman's capsule?

1. the visceral layer which surrounds the capillaries
2. the parietal layer which is the outer part of the capsule.

29

Bowman's capsule empties into what?

The proximal convoluted tubule

30

What is the general term used when substances move from lumen of tubule into interstitial fluid (and then into blood vessels)?

Reabsorption

31

What is the general term used when substance moves from blood vessel into tubular fluid?

Secretion

32

What are the macroscopic areas of the kidney that produce urine? What are the structures that the urine passes to from here to the ureters?

Renal pyramids to minor calyx to major calyx to renal pelvis

33

What are peritubular capillaries? Are they found on all nephrons?

Capillaries next to the tubules. These are always found with nephrons

34

Where is plasma filtered in the nephron?

At the glomerular capillaries into Bowman's space

35

Where does the filtrate flow from Bowman's space?

To the proximal tubule

36

Where are the cells of the macula densa? What is their function?

In the distal convoluted tubule In contact with the afferent arteriole

Monitors NaCl delivery to the distal tubule

37

Is the pressure in Bowman's capsule always the same?

Normally narrow range, but can vary in disease

38

What prevents proteins from flowing from the capillaries into Bowman's space?

Negative charges on endothelial cells/podocytes and the presence of a BM

39

What is the protein concentration of the efferent arterioles relative to the afferent? What is the consequence of this?

Higher d/t loss of plasma

This allows for easier reuptake later for the peritubular capillaries

40

From the blood to Bowman's space, how many layers does filtrate have to go through? What are these?

Three-- Endothelium, BM, podocytes

41

What is the structural feature of the capillary endothelial cells that allows for high rates of filtration?

Fenestrated

42

What are the cells that sit on the capillaries in Bowman's capsule that aid in filtration, and have many interdigitating extension?

Podocytes

43

What are the four processes that take place in the nephron?

1. Filtration
2. Reabsorption
3. Secretion
4. Excretion

44

Urinary excretion rate = what?

The rate at which the substance is filtered - the reabsorption rate + the rate at which it is secreted from the peritubular capillary blood into tubules

45

Looking at a nephron, how do you determine whether or not it is a cortical or a juxtamedullary one?

Where the glomerulus is

46

What are the cortical medullary rays?

The part of the cortex that contains the straight proximal tubules, cortical thick ascending limbs, and cortical collecting ducts

47

What are the structures through which filtrate passes on its way to the collecting duct (starting with Bowman's capsule, 6)

1. Bowmans capsule
2. Proximal tubule
3. Thin descending limb
4. Thin ascending limb (if juxtamedullary)
5. Thick ascending limb
5. Distal tubule

48

How many cell layers make up the walls of the distal/proximal convoluted tubule?

One

49

The tight junctions between the cells that surround the tubule lumen separate what two parts of the nephron?

The lumen membrane and the basolateral membrane

50

What is the Na/K pump located in the nephron?

The cells of the proximal tubule

51

Where does most Na reabsorption occur in the nephron?

Proximal tubule

52

What is the chemical driving force for Na from the the lumen side of the tubule: into or out of the renal tubule cells?

Into

53

Thick or thin cells surrounding the proximal tubule?

Thick

54

Thick or thin cells surrounding the descending loop of henle ?

Thin

55

Thick or thin cells surrounding the ascending loop of henle?

Thick

56

Thick or thin cells surrounding the early and late distal tubules?

Thick

57

What is the direction of flow for Na, Cl, K, H2O, glucose, and aa in the proximal tubule? H+?

Out of for all except H+

58

What is direction of flow for Na, Cl H2O, and urea in the descending loop of henle?

All into except for H2O

59

What is the direction of flow for Na, Cl, K, Ca, HCO3, H+, and Mg in the thick ascending loop of Henle?

all out of the tubule lumen and into the capillaries except for H+

60

What are the two chemical that pass out of the lumen from the early distal tubule?

Na and Cl

61

What is the flow of Na, K, H2O, HCO3, and H+ in the late distal tubule?

Out of lumen: Na, H2O, HCO3

Into lumen: H+ and K+

62

How is Na reabsorbed from the lumen of the tubule?

Na/K pump into cell, and out towards capillaries

63

How is glucose reabsorbed from the lumen of the tubule?

Synport

64

Where is most of the Na reabsorbed? How?

Proximal tubule

Via Na proton antiporter

65

How is HCO3 reabsorbed?

Na/H transporters

66

What is absorbed in the first half of the proximal tubule?

Na with glucose, amino acids, lactate

67

How is glucose reabsorbed from the tubule?

Na symporters

68

What is the major driving force of water out of the tubule? How can it diffuse so readily?

Reabsorption of solutes

Aquaporins

69

Approximately what % of the filtered water Na+, Cl- , K+ have been reabsorbed by the end of the proximal tubule?

67%

70

What is the main way that substances are moved from the tubule of a nephron back into capillaries?

Na symport

71

What is isosmotic reabsorption of water?

Water moves with dissolved solutes

72

What can pass through tight junctions of the tubules?

Na and Cl

73

What are the two pumps on the capillary side of the renal tubule cell? Which way do the ions flow?

Na/K pump -Na in, K out

K/Cl pump -both out

74

A small amount of proteins are filtered each day. How are these reabsorbed?

Peptidases on the luminal surface breakdown to AAs. Reabsorbed like other AAs

Endocytosis for larger proteins

75

True or false: • Normally virtually all filtered protein is reabsorbed so little or no protein in urine.

True

76

How does proteinuria come about?

since endocytosis/digestion mechanism easily saturated an increase in filtered protein can cause proteinuria

77

What is the significance of the limited number of transporters in the distal tubule?

Saturable, and shared by many things

78

What is the major process occuring in the thick ascending limb of a nephron?

NaCl is pumped out but water cannot follow

79

Where does countercurrent exchange take place?

In the loop of henle

80

Where is the macula densa located within a nephron?

The final portion of the thick ascending limb

81

What is significant about the thick loop of henle, and plays a major role in secretion? What is the significance of this?

Impermeable to water

Thus can dilute filtrate here

82

Where can the body change the water concentration of the filtrate?

Collecting duct

83

What is the diluting segment of a nephron?

Thick ascending tubule

84

What part of the nephron is responsible for isosmotic reabsorption?

Descending limb

85

True or false: there are receptors that directly control water balance, and adjust excretion accordingly

False

86

Where is osmolality of the blood monitored?

Hypothalamus

87

Where is ADH synthesized?

Hypothalamus

88

What are the changes that osmoreceptors experience that cause a change in ADH secretion?

Swelling/shrinkage