Overview of Renal Structure and Function - Wall Flashcards Preview

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Flashcards in Overview of Renal Structure and Function - Wall Deck (39):
1

What is the major extracellular cation?

Sodium

2

What does total body Na determine?

Size of total body water

3

What is the major intracellular cation?

Potassium

4

What are the major extracellular anions?

Chloride
Bicarbonate

5

What is bicarbonate's role in ECF?

Major ECFV buffer
Key factor in acid-base balance

6

What are the kidney's endocrine functions?

Erythropoietin
1-alpha hydroxylase produce calcitriol
Renin

7

What are the kidney's paracrine/autocrine functions?

Bradykinin (vasodilatory, natriuretic)
Prostaglandin (mostly vasodilatory)
Nitric oxide (vasodilatory)
Endothelin (potent vasoconstrictor)

8

What does angiotensin II do?

Vasoconstrict

9

What does aldosterone do?

Promote Na reabsorption

10

Name two accessory functions of the kidney.

Small peptide catabolism (ie insulin)
Gluconeogenesis during fasting (25-33%)

11

Define neutral, positive, and negative balance.

Neutral - Intake + Production = Excretion
Positive - Intake + Production > Excretion
Negative - Intake + Production < Excretion

12

What is the best index of kidney function?

GFR

13

What vertebral segments do the kidneys span?

T12 to L3

14

What percent of total blood flow to the kidney does the cortex receive?

90%

15

What does the hilum contain?

Renal artery, vein, nerves, pelvis, ureter, and lymphatics

16

What does the medulla contain?

Loops of Henle
Collecting ducts
Vasa recta

17

What are sites of potential obstruction within the ureter?

Pelvic ureteral junction
Crossover of pelvic brim
Urinary trigone

18

What is the most common spot for urethral obstruction in males?

Prostatic urethra

19

Which type of nephrons have a higher pressure in the glomerular capillaries?

Juxtamedullary > Cortical

20

Are nephrons working at full capacity under normal conditions?

Cortical - No (basis for reserve capacity)
Juxtamedullary - Yes

21

What layers are between the mesangium and circulation?

Endothelial cells (with large fenestrations)

22

Is urine volume a good index of kidney function?

No (urine flow rate / volume is not autoregulated)

23

What does clearance represent?

Volume of plasma cleared of the substance

24

What is the equation for clearance?

Cx = U * V / P

25

What is the equation for clearance ratio?

Cx / GFR

26

What does a clearance ratio 1 imply?

< 1 - filtered and reabsorbed
= 1 - filtered
> 1 - filtered and secreted

27

What is the clearance of PAH equivalent to?

Renal Plasma Flow

28

What is a normal filtration fraction?

~20% of RPF becomes glomerular filtrate

29

What does decreased cardiac output or volume depletion result in?

RAS - increased FF

30

What can the autoregulatory response in a hypovolemic state be disturbed by?

Decreased AT II production
ACE-inhibitors, AT receptor blockers, renin inhibitors
Prevent production of vasodilatory prostaglandins (NSAIDS)

31

Describe the proximal and distal tubule in terms of resistance and capacity.

Proximal tubule - High capacity, Low resistance
Distal tubule - Low capacity, high resistance

32

What is the major difference between carriers and channels?

Channels are not saturable

33

What is the tonicity of the bulk reabsorption in the PCT?

Isotonically

34

How much of the filtered load is reabsorbed by the PCT?

50-55%

35

What is the tonicity of fluid that enters the LOH?

Isotonic

36

What is reabsorbed in the thin descending limb?

Passive water and urea

37

What is reabsorbed in the thin ascending limb?

Passive sodium / chloride

38

What is reabsorbed in the thick ascending limb?

Active NaCl
Ca, Mg

39

What is reabsorbed in the DCT?

NaCl
Calcium