Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

ESA 3- Urinary System > Filtration by the Glomerulus > Flashcards

Filtration by the Glomerulus Flashcards

1
Q

How is blood supplied to the kidney?

A

Via the renal artery

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What divisions does the renal artery undergo?

A

Renal artery -> Segmental arteries -> Interlobar arteries -> Arcuate arteries -> Interlobular arteries -> Afferent arterioles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What do the afferent arterioles each do?

A

Deliver blood to a single nephron

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

How does the diameter of each afferent arteriole differ from the diameter of the associated efferent arteriole?

A

It is slightly greater

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is the result of the diameter difference between the afferent and efferent arteriole?

A

It increases the pressure of the blood in the glomerulus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is the result of the increased pressure of the blood inside the glomerulus

A

The increased hydrostatic pressure helps to force components out of the blood in the glomerular capillaries

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What components are forced out of the blood by the increase in hydrostatic pressure in the glomerulus?

A
  • Most of the water
  • Most/all of the salts
  • Most/all of the glucose
  • Most/all of the urea
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What % of blood delivered to the glomerulus is actually filtered?

A

20%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How does the 80% of delivered blood that isn’t filtered exit?

A

Via the efferent arteriole

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What allows the water, salts, glucose, and urea to be filtered out of the blood inside the glomerulus?

A

They are relatively small particles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What components cannot be filtered out of the blood in the glomerulus as they are too large?

A
  • RBCs
  • Plasma proteins
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the size limit for filtration in the glomerulus?

A

Molecular weight 5,200, or an effective molecular radius of 1.48nm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Other than size, what makes it hard for proteins to be filtered in the glomerulus?

A

The basement membrane and podocytes glycocalyx have negatively charged glycoproteins, which repel protein movement

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What happens to the water and solutes that have been forced out of the glomerular capillaries?

A

They pass into Bowman’s space

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are the water and solutes that pass into the Bowman’s space called?

A

The glomerular filtrate, or the ultrafiltrate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What does the filtration barrier consist of?

A
  • Capillary endothelium
  • Basement membrane
  • Podocyte layer
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What can pass through the capillary endothelium?

A
  • Water
  • Salts
  • Glucose
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Where does filtrate move when passing the capillary endothelium?

A

Between cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is the filtration barrier basement membrane?

A

An acellular gelatinous layer of collagen/glycoproteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is the filtration barrier basement membrane permeable to?

A

Small proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is the purpose of the glycoproteins in the filtration barrier basement membrane?

A

They have a negative charge and so repel protein movement

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What happens in the podocyte layer?

A

Pseudopodia interdigitate to form filtration slits

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Label this diagram

A
  • A - Capillary plasma
  • B - Capillary endothelial cell
  • C - Basement membrane
  • D - Pedicel
  • E - Filtration slit
  • F - Podocyte
  • G - Fenestration
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What physical forces is plasma filration due to?

A
  • Hydrostatic pressure in the capillary (PGC)
  • Hydrostatic pressure in the Bowman’s capsule (PBC)
  • Osmotic pressure difference between the capillary and tubular lumen (πGC)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Which of the physical forces causing plasma filtration can be regulated?

A

Hydrostatic pressure in the capillary

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What is the net filtration pressure?

A

10mmHg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What is the hydrostatic pressure in the plasma?

A

50mmHg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Does the hydrostatic pressure in the plasma favour or oppose filtration?

A

Favour

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What is the hydrostatic pressure in the tubule (Bowman’s capsule)?

A

15mmHg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Does the hydrostatic pressure in the tubule favour or oppose filtration?

A

Oppose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What is the osmotic pressure in the glomerulus?

A

25mmHg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Does the osmotic pressure in the glomerulus favour or oppose filtration?

A

Oppose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

Draw a diagram illustrating how the net filtration pressure is established

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

What is the effect of a molecules negative charge on filtration?

A

Negative charge repels, so more difficult to get through

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

What is the effect of a molecules positive charge on filtration?

A

Allows slightly bigger molecules through

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

What happens to the negative charge on the filtration barrier in many disease processes?

A

It is lost

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

What is the result of the loss of the negative charge on the filtration barrier in disease?

A

Proteins are more readily filtered

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

What is the clinical condition where proteins are more readily filtered?

A

Proteinuria

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

What is the main clinical symptom of proteinuria?

A

Protein in the urine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

What % of the glomerular filtrate leaves the body?

A

~1%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

What happens to the glomerular filtrate that doesn’t leave the body?

A

It is reabsorbed into the blood as it passes through renal tubules

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

What is the process of reabsorbing glomerular filtrate into the blood called?

A

Tubular reabsorption

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

By what mechanisms does tubular reabsorption occur?

A
  • Osmosis
  • Diffusion
  • Active transport
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

Why is tubular reabsorption called reabsorption, not absorption?

A

As these substances have already been absorbed once, particularly in the intestines

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

What is the nature of reabsorption in the PCT?

A

It is isosmotic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

What is reabsorption in the PCT driven by?

A

Sodium uptake

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

What is required to maintain electro-neutrality during reabsorption in the PCT?

A

Other ions accompany sodium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

What ions accompany sodium during reabsorption in the PCT to maintain electro-neutrality

A
  • Chloride
  • Bicarbonate
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

What % of filtered water is reabsorbed?

A

99%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

What % of filtered sodium is reabsorbed?

A

99.5%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

What % of filtered glucose is reabsorped?

A

100%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

What % of filtered urea is reabsorbed?

A

50%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q

Where do solutes move from the tubular lumen?

A

To the interstitum, then to the capillaries

54
Q

What are the possible types of reabsorption?

A
  • Transcellular
    Paracellular
55
Q

What is meant by paracellular reabsorption?

A

Around cells through tight junctions

56
Q

Describe the process of tubular reabsorption of Na+

A
  1. Na+ is pumped out of tubular cells across the basolateral membrane by 3Na-2K-ATPase
  2. Na+ moves across the apical (luminal) membrane down its concentration gradient.
  3. Water moves down the osmotic gradient created by reabsorption of Na+
57
Q

What does the movement of Na+ across the apical membrane utilise?

A

A membrane transporter or channel on the apical membrane

58
Q

Draw a diagram illustrating the tubular reabsorption of Na+

A
59
Q

What does secretion in the kidney provide?

A

A second route, other than glomerular filtration, for solutes to enter the tubular fluid

60
Q

Why is secretion in the kidney useful?

A

As only 20% of the plasma is filtered each time the blood passes through the kidney

61
Q

What does secretion in the kidney help maintain?

A

The blood pH

62
Q

What is the range of normal blood pH?

A

7.38-7.42

63
Q

What substances are secreted into tubular fluid?

A
  • Protons (H+)
  • Potassium (K+)
  • Ammonium ions (NH4+)
  • Creatinine
  • Urea
  • Some hormones
  • Some drugs
64
Q

Give an example of a drug that is secreted into the tubular fluid

A

Penicillin

65
Q

What is the model for organic cation (OC+) secretion in the PCT?

A
  1. Entry by passive carrier - Mediated diffusion across the basolateral membrane down favourable concentration and electrical gradients, created by the 3Na-2K-ATPase pump
  2. Secretion into the lumen - H+-OC+ exchanger that is driven by the H+ gradient created by the Na+-H+-Antiporter
66
Q

Draw a diagram illustrating the model for organic cation secretion in the PCT

A
67
Q

What do different segments of the tubule have?

A

Different types of Na+ transporters and channels in the apical membrane

68
Q

What does the different types of Na+ transporters and channels in different segments of the tubule allow?

A

Na+ to be the driving force for reabsorption, using the concentration gradient set up by 3Na-2K-ATPase (active transport)

69
Q

What Na+ transporters/channels are found in the proximal tubule?

A
  • Na-H antiporter
  • Na-Glucose symporter (SGLUT)
70
Q

What Na+ transporters/channels are found in the Loop of Henle?

A

Na-K 2Cl symporter

71
Q

What Na+ transporters/channels are found in the early distal tubule?

A

Na-Cl symporter

72
Q

What Na+ transporters/channels are found in the later distal tubule and collecting duct?

A

ENaC (epithelial Na-Cl)

73
Q

Label this diagram

A
  • A - Interlobular arteries
  • B - Afferent arterioles
  • C - Glomerular capillaries
  • D - Efferent arterioles
  • E - Glomerular capsule
  • F - Rest of renal tubule
  • G - Peritubular capillaries
  • H - To interlobular veins
  • I - Urine
74
Q

In what direction does Na+ travel down its concentration gradient in the kidney?

A

From the tubule lumen into the intersticium

75
Q

What sets up the Na+ concentration gradient between the tubule and the intersticium?

A

3Na-3K-ATPase

76
Q

What does the transport of Na+ down its concentration gradient from the tubule lumen into the intersticium often occur with the help of?

A

A symporter

77
Q

What is the importance of the mechanism by which Na+ travels from the tubule lumen into the intersticium?

A

It is the mechanism by which the body reabsorbs glucose, amino acids, water soluble vitamins (B & C), lactate acetate, ketones, and other Krebs cycle intermediates

78
Q

What happens one glucose, amino acids, water soluble vitamins (B & C), lactate acetate, ketones, and other Krebs cycle intermediates have been reabsorbed?

A

They then move on through cells via diffusion and/or active transport

79
Q

How is glucose reabsorbed in the PCT?

A

Using the Na-glucose symporter, SGLUT

80
Q

What does SGLUT do?

A

Moves glucose against its concentration gradient into the tubule cells

81
Q

What happens once SGLUT has moved glucose into the tubule cells?

A

Glucose moves out of the tubule cell on the basolateral side by facilitated diffusion

82
Q

How much glucose is normally reabsorbed?

A

100%

83
Q

What limits the amount of glucose that can be reabsobed?

A

The system has a maximum capacity, or transport maximum (Tm)

84
Q

What happens if the plasma concentration of glucose exceeds the Tm?

A

The rest spills over into the urine

85
Q

What happens if excess glucose spills over into the urine?

A

Water follows into the urine, causing frequent urination

86
Q

What is the clinical symptom of frequent urination called?

A

Polyuria

87
Q

What is the renal threshold for glucose?

A

200mg/100ml

88
Q

What is meant by clearance?

A

The volume of plasma from which a substance can be completely cleared to urine per unit time

89
Q

What is the input to the kidney?

A

The renal artery

90
Q

What are the possible outputs from the kidney?

A
  • The renal vein
  • The ureter
91
Q

What must happen if a substance is not metabolised or synthesised in the kidney?

A

An equal amount must leave in the urine and the renal venous blood

92
Q

How can clearance be calculated?

A

Clearance = (Amount in urine x Urine flow rate) / Arterial Plasma Concentration

93
Q

What is meant by glomerular filtration rate (GFR)?

A

The volume of plasma from which any substance is completely removed by the kidney in a given amount of time (usually 1 minute)

94
Q

What is GFR a measure of?

A

The kidney’s ability to filter a substance, thus overall function

95
Q

What is GFR an indication of?

A

How well the kidney works

96
Q

What does a fall in GFR generally mean?

A

Kidney disease is progressing

97
Q

What must happen to measure GFR?

A

A substance must be freely filtered across the glomerulus

98
Q

What is meant by a substance being freely filtered across the glomerulus?

A

It must pass directly into the urine- it must not be reabsorbed, secreted, or metabolised by the cells of the nephron

99
Q

Give two examples of substances that can be used to calculate GFR

A
  • Creatinine
  • Inulin
100
Q

What equation is used to calculated GFR?

A

(Amount in urine x urine flow rate) / Arterial plasma concentration

101
Q

What is the normal GFR for males?

A

115-125ml/min

102
Q

What is the normal GFR for women?

A

90-100ml/min

103
Q

How much blood does the kidney recieve a minute?

A

About 1.1L

104
Q

What % of the blood the kidney receives is RBCs, and what % is plasma?

A
  • 45% RBCs
  • 55% plasma
105
Q

What is renal plasma flow to the kidney?

A

605ml/min of plasma

(55% of 1.1L)

106
Q

What is meant by filtration fraction?

A

The proportion of a substance that is actually filtered

107
Q

How is filtration fraction calculated?

A

Filtration fraction = Glomerular filtration rate / renal plasma flow

108
Q

What is the normal filtration fraction in healthy adults?

A

About 20%

109
Q

How is the normal filtration fraction of 20% worked out?

A

If renal plasma blow is 605ml/min, and 20% of all plasma is filtered, 125ml is filtered through into Bowman’s space- this is the normal GFR, and 480ml passes through into peritubular capillaries

125/605=20.8%

110
Q

What is the purpose of autoregulation of renal blood flow?

A

Auto-regulatory mechanisms keep the GFR within normal limits when arterial BP is within physiological limits

111
Q

What is the result of the myogenic response to rises in arterial BP?

A

Afferent arteriole constriction

112
Q

What is the result of the myogenic response to falls in arterial BP?

A

Afferent arteriole dilation

113
Q

Draw a graph showing the relationship between renal blood flow and glomerular filtration rate

A
114
Q

What can changes in GFR result in?

A

Changes in tubular flow rate

115
Q

What is the result of changes in tubular flow rate?

A

Change in the amount of NaCl that reaches the distal tubule

116
Q

What responds to changes in the amount of NaCl reaching the distal tubule?

A

Macula densa cells

117
Q

What response is needed if NaCl reaching the distal tubule increases?

A

GFR needs to decrease

118
Q

What response is initiated if NaCl reaching the distal tubule increases?

A

Adenosine is released, causing vasoconstriction of afferent arteriole

119
Q

What response is needed if NaCl reaching distal tubule decreases?

A

GFR needs to increase

120
Q

What response is initiated if NaCl reaching distal tubule decreases?

A

Prostaglandins released, causing vasodilation of afferent arteriole

121
Q

Draw a diagram illustrating the potential ways to modify the resistance in the glomerular capillay

A
122
Q

What is meant by general overflow aminoaciduria?

A

All amino acids are present in the urine

123
Q

What is general overflow aminoaciduria normally due to?

A

Inadequate deamination in the liver, or increased GFR

124
Q

When is general overflow aminoaciduria often seen?

A

In early pregnancy

125
Q

What is meant by specific overflow aminoaciduria?

A

Only a specific AA is present in the urine

126
Q

What is specific overflow aminoaciduria usually due to?

A

Genetic inability to break down one AA

127
Q

Give an example of a condition where the patient has a genetic inability to break down one AA

A

PKU

128
Q

What happens in PKU?

A

There is a lack of phenylalanine hydroxylase, so phenylalanine can’t be broken down

129
Q

What is renal aminoaciduria mainly confined to?

A

The dibasic acid

130
Q

What is renal aminoaciduria due to?

A

A genetically determined lack of the specific transport protein(s)

131
Q

Why is cysteine of importance when considering renal aminoaciduria?

A

It is an abnormally insoluble amino acid, especially in acidic urine

132
Q

What may cystinuria be associated with?

A

Stone formation

ESA 3- Urinary System (13 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions