Brainscape's Knowledge GenomeTM

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


See full index

Renal > Renal Physiology I > Flashcards

Renal Physiology I Flashcards

1
Q

Total body water is distributed between intracellular and extracellular compartments. The majority of total body water exists as

A

Intracellular fluid

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

Shifts between intra- and extracellular water occur as directed by

A

Volume, electrolyte, and protein status

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

Defined as the concentration of solutes in a given weight of H2O

A

Osmolality

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

In the context of physiology, the osmotic state of the extracellular fluid is defined by

A

Iso- hypo- and hyperosmolality

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

In the context of body fluid balance, total osmolality is not always important. Instead, we use the

A

Effective osmolality

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

Effective osmolality is created by

A

Effective solutes

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

Solutes which can not passively diffuse across cell membranes

-Example: Na+

A

Effective solutes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Sets tonicity, that is the relative concentration that determines the direction and extent of H2O diffusion

A

Na+

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

Cell membranes are permeable to ineffective solutes such as

A

Urea

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

Not used to calculate effective osmolality, but IS used to calculate total osmolality

A

Urea (measured as Blood Urea Nitrogen; BUN)

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

An effective solute since it is metabolized within cells and thus does not accumulate within cells

A

Glucose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the main difference between an effective and ineffective solute?

A

An effective solute creates an osmotic gradient, where as an ineffective solute does not

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

What happens if the ECF becomes hyperosmotic due to an increase in effective solute (i.e. Na+) concentration

A

Free H2O will move from plasma down its concentration gradient into the ECF

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

In this case, plasma volume will be

A

Reduced (ECF volume increases)

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

The blood volume that is required for adequate perfusion of the vital organs

  • another way to describe stressed volume
  • Not a static quantity that can be measured
A

Effective Circulating Volume (ECV)

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

The renal system senses changes in body fluid balance via changes in renal blood pressure and attempts to compensate by either

A

Conserving or eliminating Na+ and free H2O

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What 5 things do the Kidneys regulate?

A
  1. ) Plasma volume
  2. ) Blood pressure (BP)
  3. ) Waste excretion
  4. ) Electrolyte balance
  5. ) Plasma pH
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

This regulation is accomplished by a system of structures known as

A

Nephrons

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

A network of tubules, ducts, and microvasculature

A

Nephrons

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

How many nephrons does each kidney contain?

A

Appproximately 1 x 10^6

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

Each kidney is supplied with oxygenated, nutrient-rich blood by the

A

Renal artery

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

Renal circulation receives approximately what percentafe of cardiac output?

A

20%

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

Within the kidney, the constituents of blood plasma are filtered as a result of the interactions between the

A

Afferent arteriole, glomerulus, efferent arteriole, and peritubular capillaries

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Characterized by a relatively high pressure and high compliment of vascular smooth muscle. This it is capable of high resistance

A

Afferent arteriole

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Has a large surface area and is loaded with fenestrations that allow filtration

A

Glomerulus

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

The efferent arterioles and paritubular capillaries are characterized by

A

Low pressure and flow

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

Mediated by 1) internal mechanisms, 2) the extra- and intrarenal endocrine systems (e.g., aldosterone, arginine vasopressin, angiotensin, and atrial natriuretic peptide), and 3) the autonomic nervous system

A

Renal function

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

The kidneys are innervated EXCLUSIVELY by the

A

SNS (NO PNS innervation)

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

Controls vasoconstriction of the renal microcirculation, Na+ reabsorption, and it stimulates secretion of renin

A

SNS activity

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

Which three processes in essence define renal function?

A
  1. ) Filtration
  2. ) Reabsorption
  3. ) Secretion
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

The movement of plasma constituents (i.e. H2O, ions, glucose, urea, and small proteins) from the glomerulus into Bowman’s capsule

A

Filtration

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

The movement of constituents from the tubule lumenal fluid (i.e. forming urine) into the renal intersitium, and/or recycling of these substances back into circulation

A

Reabsorption

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

The movement of constituents from renal circulation, interstitium, and/or tubule epithelium into the forming urine

A

Secretion

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

The adult kidneys filter about 120L of plasma/day. Assuming normal flid input of about 2L per day, the average urine output is approximately

A

0.8-2.0L per day

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

Therefore, it should be apparent that the default mode of renal function is the process of

A

Antidiuresis (reabsorption)

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

Blood enters the nephron via the

A

Afferent arteriole

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

Filtration (due to starling forces) occurs within the

-Filters approximately 180 L per day

A

Glomerulus

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

However, typically only about 1-1.5L of urine are excreted per day. Thus the vast majority of the glomerular filtrate is

A

Reabsorbed by the nephrons

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

Upon filtration, the filtrate flows from the collecting reservoir known as the Bowman’s Capsule throughout the

A

Renal tubule network

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

Within the tubule system, the forming urine is concentrated by the diffusion and/or transport of

A

H2O, ions, and urea

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

The osmolality of urine is dictated by plasma volume, which in turn depends upon the

A

Interstitial (ECF) osmolality

42
Q

Urine osmolality is ultimately orchestrated by hormonal mechanisms that modulate H2O and Na+ reabsorption within the

A

Nephron and collecting duct

43
Q

The early stages of renal disease are silent and can only be detected by lab analysis measuring the

A

Glomerular filtration rate (GFR) uring blood creatine and/or creatine clearance measurements

44
Q

Hypertension, anemia, malnutrition, bone disease, neuropathy, and renal failure are some complications that stem from

A

Impaired renal function

45
Q

Defined as the volume of blood that can be 100% cleared of a solute per unit time

-units are mL/min

A

Renal Clearance (C)

46
Q

The rate at which filtrate is filtered from the glomerulus into Bowman’s capsule

A

Glomerular Filtration Rate (GFR)

47
Q

The standard marker for determining renal function

A

GFR

48
Q

Any changes in intrarenal BP that influence flow (renal perfusion) and/or the biochemical characteristics and/or ultrastructure of the glomerulus will affect

A

GFR

49
Q

In a very general sense, as glomerular BP increases, what happens to GFR?

A

It will rise accordingly (and decrease in renal BP = decreased GFR)

50
Q

In general, ions, glucose, H2O, and very small proteins can traverse the glomerular fenestrations fairly

A

Easily

51
Q

What three things affect how readily substances can be filtered from the glomerulus?

A

MW, radius, and charge

52
Q

Why do cations tend to cross the glomerular filtration barrier with less resistance than anions?

A

Because the glomerular filtration barrier has a negative charge

53
Q

More complicated than GFR because it can be influenced by filtration, reabsorption, and secretion

A

Renal Clearance (C)

54
Q

Clearance can be summarized into the following relationship

A

Arterial input = venous output + urine output

55
Q

A direct measurement of renal function and is hence the best index of renal function

A

GFR

56
Q

GFR is in fact the product of

A

Single nephron GFR x N (where N = total number of nephrons)

57
Q

Interestingly, during the earliest phases of some kidney diseases (i.e. diabetic kidney disease), a compensatory increase in single nephron GFR (hyperfiltration) can mask a loss in

A

Nephron number

58
Q

Will decrease prior to the onset of symptoms of renal disease

A

GFR

59
Q

GFR decreases in direct correlation with the pathologic severity of

A

Kidney disease

60
Q

These include kidney disease, pregnancy, reduced kidney perfusion, marked changes in extracellular fluid volume, non-steroidal anti-inflammatory drug (NSAID) use, acute/habitual elevated protein ingestion, blood glucose, and arterial BP

A

Pathophysiologic factors that will affect GFR

61
Q

Glomerular function is measured using clearance as an indicator of

A

GFR

62
Q

The process of renal autoregulation assists to control

A

GFR

63
Q

Self governing glomerular regulation of intraglomerular pressure

A

Renal autoregulation

64
Q

In general, increased systemic BP induces a myogenic response within the

A

Afferent arterioles

65
Q

The resultant vasoconstriction of the afferent arterioles prevents potentially damaging increases in

A

Glomerular pressure (thus sustaining GFR)

66
Q

On the other hand, very low BP is sensed within the

kidney, and in response, hormonal mechanisms are mobilized to induce vasoconstriction within the

A

Efferent arterioles

67
Q

What is the normal GFR for

  1. ) Young men
  2. ) Young women
A
  1. ) GFR ≈ 130 ml/min/1.73 m^2

2. ) GFR ≈ 120 ml/min/1.73 m^2

68
Q

After age 35, GFR generally decreases by about

A

1mL per year of age

69
Q

Associated with a HIGH risk for the development of cardiovascular disease

A

GFR less than 60

70
Q

At GFR less than 60, mortality from CV disease actually exceeds the risk of progression to

A

Renal failure

71
Q

Indicates renal failure and would require replacement via dialysis or kidney transplant

A

GFR less than 15 mL/min/1.73 m^2

72
Q

In order for GFR to be measured without very invasive approaches, GFR must equal

A

Clearance (C)

73
Q

A fructose polymer that meets the criteria for measuring GFR where by GFR = C

A

Insulin

74
Q

Isulin is not routinely used anymore because it is not cost effective and it is not endogenous so it must be injected to be measured. However, for all intents and purposes we can say that

A

C(insulin) = GFR

75
Q

In clinical reality, we measure GFR by measuring

A

Creatinine

76
Q

A metabolic by product of the muscle creatine phosphate reaction

A

Creatinine (Cr)

77
Q

Measured in drawn blood

A

Serum creatinine (SCr or PCr for plasma creatinine)

78
Q

SCr will vary between men and women with a greater value seen in

A

Men

79
Q

Greater muscle mass will increase

A

PCr

80
Q

Thus, assuming stready state conditions, basal SCr will generally fall within a standard range of

A

0.4-1.5 mg/dL

81
Q

How much creatinine is excreted per day in

  1. ) Men
  2. ) Women
A
  1. ) 20-25 mg per day

2. ) 15-20 mg per day

82
Q

The following relationships will exist in a healthy patient:

1.) Increased GFR will induce a decrease in

A

SCr

83
Q

The following relationships will exist in a healthy patient:

2.) Decreased GFR will cause

A

Increased SCr and Blood Urea Nitrogen (BUN)

84
Q

Blood Urea Nitrogen (BUN) is a product of

A

Protein metabolism

85
Q

Although plasma creatinine levels remain relatively constant, BUN levels can fluctuate dramatically with changes in

A

Diet (high protein), metabolism, and importantly volume status

86
Q

Make note that a high protein diet and volume depletion will each raise BUN, with the latter due to the increased renal tubule reabsorption of urea that accompanies

A

Na+ and H2O reabsorption

87
Q

Thus, an elevation in BUN without an accompanying rise in creatinine is not a reliable indicator of

A

GFR

88
Q

Two of the many equations that are used for the estimation of GFR based upon the relationship between SCr and CCr are the

A

CDK-Epi and Modification of Diet in Renal Disease (MDRD) equations

89
Q

Can also be determined via the “24 hour urine”, a method that relies upon the total urine collection by the patient in a 24 hour period

A

Creatinine clearance (GFR)

90
Q

All currently used methods used to estimate GFR have limitations. Thus screening for kidney disease requires the use of

A

Multiple markers of renal function

91
Q

The amount of solute filtered into Bowman’s capsule per unit time

A

Filtered load

92
Q

The ratio of solute excreted to that of the filtered load (in other words, how much of what gets filtered actually ends up in excreted urine)

A

Fractional Excretion (FE)

93
Q

What are the forces within the afferent arteriole and the glomerular capillary that favor ultrafiltration?

A

Pcap and π-Bowman’s

I.e capillary hydrostatic pressure and Bowman’s colloid osmotic pressure

94
Q

Within the afferent arteriole, and especially the glomerular capillary, the hydraulic forces (Pcap + π-Bowman’s) that favor ultrafiltration win-out; hence

A

Filtration occurs

95
Q

As plasma enters the efferent arteriole, the opposing

forces (PBowman’s + πcap) increase concomitant with a decrease in the hydraulic forces; these forces oppose

A

Ultrafiltration

96
Q

Which 4 things regulate input to the nepbhron?

A
  1. ) Systemic BP
  2. ) Blood flow within afferent arteriole
  3. ) Glomerulr P which dictates GFR
  4. ) Vasomotion within afferent and efferent arterioles
97
Q

The key here is at the level of the

A

Afferent Arteriole

98
Q

The greatest pressure drop in the renal system occurs between the

A

Afferent arteriole and glomerulus

-essentially no pressure drop occurs between afferent and efferent ends of glomerulus

99
Q

This means that vasoconstriction and vasodilation of the afferent arteriole has a major impact on

A

Renal perfusion and GFR

100
Q

In a simple model loss of blood pressure in the afferent arteriole means

A

Decreased GFR

Renal (10 decks)

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