Renal Physiology (Part 2) Flashcards Preview

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Flashcards in Renal Physiology (Part 2) Deck (170)
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1

Which ion is the major cation of the ECF?

Na+

2

The reabsorption of Na+ into the ECF after filtration is critically important in maintaining what?

- normal ECF volume
- normal blood volume
- normal blood pressure

3

The kidneys ensure that Na+ _____ exactly equals Na+ ____, a matching process called what?

intake

excretion

Na+ balance

4

If Na+ excretion is less than Na+ intake, then the person is in _____ Na+ balance.

positive

5

What happens if the person is in positive Na+ balance?

Extra Na+ is retained, therefore there is ECF volume expansion which causes blood volume and arterial pressure to increase. This may result in edema.

6

If Na+ excretion is greater than Na+ intake, then the person is in _____ Na+ balance.

negative

7

What happens if the person is in negative Na+ balance?

Excess Na+ is lost from the body, therefore is ECF volume contraction which causes blood volume and arterial pressure to decrease.

8

How can a person have increased Na+ content but normal Na+ concentration?

If water content is increased proportionally

9

In nearly all cases, changes in Na+ concentration are caused by what?

Changes in body water content

*not Na+ content

10

Excretion of Na+ is __% of the filtered load.
Net reabsorption is __% of the filtered load.

1

99

11

Where does the bulk of Na+ reabsorption occur?

In the proximal convoluted tubule

12

__% of the filtered load is reabsorbed in the proximal convoluted tubule.

67

13

What is water reabsorption linked to in the proximal convoluted tubule?

Na+ reabsorption

14

__% of the filtered load is reabsorbed in the thick ascending loop of Henle.

25

15

Is the thick ascending loop of Henle permeable to water?

no

16

__% of the filtered load is reabsorbed in the terminal portions of the nephron (the distal tubule and the collecting ducts).

8

17

__% of the filtered load is reabsorbed in the early distal convoluted tubule.

5

18

__% of the filtered load is reabsorbed in the late distal convoluted tubule and collecting ducts. These structures are ultimately responsible for what?

3

the fine-tuning of Na+ reabsorption which ensures Na+ balance

19

In which part of the nephron are sites of action of the Na+ regulating hormone aldosterone?

the late distal convoluted tubule and collecting ducts

20

As already stated, the entire proximal convoluted tubule reabsorbs 67% of the filtered Na+, it also reabsorbs 67% of the filtered water. This tight coupling between Na+ and water reabsorption is called what?

isosmotic reabsorption

21

The proximal tubule is also the site of what?

glomerulotubular balance

22

What is the first half of the proximal convoluted tubule called?

the early proximal convoluted tubule

23

The early proximal convoluted tubule performs the ______ priority reabsorptive work

highest

24

In the early proximal convoluted tubule, what are the most essential solutes that are reabsorbed?

- glucose
- amino acids
- bicarbonate

25

What are the 2 mechanisms by which solutes are reabsorbed into the proximal convoluted tubule?

- cotransport
- countertransport

26

What are the 5 cotransport mechanisms in the proximal convoluted tubule?

1) Na+ - glucose (SGLT)
2) Na+ - amino acid
3) Na+ - phosphate
4) Na+ - lactate
5) Na+ - citrate

27

Once Na+, glucose, amino acid, phosphate, lactate, and citrate are in the cell how are they extruded from the cell into the blood?

Na+ by way of the Na+ - K+ ATPase

Glucose and the other solutes are extruded by facilitated diffusion

28

What is the only contertransport mechanism in the proximal convoluted tubule?

Na+ - H+ exchange

29

Via the Na+ - H+ exchange system __ is transported into the lumen in exchange for __.

H+

Na+

30

In the early proximal convoluted tubule what anion is reabsorbed with Na+?

bicarbonate