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Flashcards in chapter 27 Deck (39):
1

fluid
-definition
-2 types

-water
-1. extracellular fluid
2. intracellular fluid

2

extracellular fluid

blood plasma, interstitial fluid, other

3

intracellular fluid

cytosol (within cells)

4

eletrolyte
-definition
-most important

inorganic compounds that dissociate in solution to form ions
-sodium

5

electrolyte: sodium
-most abundant where
-function

-in the CSF
-main contributor to osmolarity of blood

6

2 factors that must be controlled

1. fluid balance
2. electrolyte balance

7

fluid balance
-water gained=
-normal blood vol

-water lost
-~5 L

8

electrolyte balance
-electrolytes in =
-normal blood osmolarity

-electrolytes out
-300 mOsm/L

9

how do you gain water?
-lose?

-food, beverage and metabolism
-urine, feces, sweat and breathing

10

application: suppose you eat an extra large jumbo tub of movie popcorn with extra salt and butter
-blood osmolarity will
-blood vol will
-how does the body detect these changes?

-increase
-not change
-osmoreceptors in hypothalamus will sense an increase in blood osmolarity (sense of an increase in the concentration of Na+ of blood)

11

application: suppose you eat an extra large jumbo tub of movie popcorn with extra salt and butter
-how does the body respond to these changes?
-effect

-increasing secretion of antidiuretic hormone
-decrease secretion of aldosterone
-restore osmolarity of blood by increasing retention of H2O and decreasing reabsorption of sodium; kidneys produce small vol of concentrated urine

12

increasing secretion of antidiuretic hormone effects

1. increase thirst (consume liquids)
2. decrease water loss at kidneys

13

decreasing secretion of aldosterone effects

decreases Na+ reabsorption in kidney

14

application: suppose you drink a very large volume of water
-blood osmolarity will
-blood volume will
-how does the body detect these changes

-decrease
-increase
-osmoreceptors detect a decrease in the concentration of Na+ of the blood

15

application: suppose you drink a very large volume of water
-how does the body respond to these changes?

-secretion of ADH will decrease
-secretion of aldosterone will increase
-kidneys produce a large vol of dilute urine

16

decreasing secretion of ADH efects

-decreases water reabsorption in DCT and CD
-decreases thirst

17

increasing secretion of aldosterone effects

increases sodium reabsorption

18

application: suppose you consume a large vol of an isotonic solution
-blood osmolarity will
-blood vol will
-how does the body detect these changes

-not change
-increase
-baroreceptors will detect an increase in BP because of an increase in blood vol

19

application: suppose you consume a large vol of an isotonic solution
-how does the body respond to these changes

secretion of atrial natriuretic peptide will increase

20

increasing secretion of ANP causes
-effects

-ADH secretion to decrease
-aldosterone secretion to decrease
-kidneys will produce increased vol of urine with and increased Na+ content

21

application: suppose you are in a very severe car accident and are suffering from excessive blood loss
-blood osmolarity will
-blood vol will
-how does the body detect these changes

-not change
-decrease
-as blood vol decreases, BP declines

22

application: suppose you are in a very severe car accident and are suffering from excessive blood loss
-how does the body respond to these changes?

1. increase in ADH release
2. increase renin secretion
-both work to return blood vol and pressure to normal

23

increasing renin secretion =

increase in angiotensin II activation

24

angiotensin II activation
-3

-increases aldosterone release which increase Na+ retention in the kidneys because water follows salt and water will be retained
-causes vasocontriction = increased BP
-promotes release of ADH

25

pH
-definition
-formula
-pH of extracellular fluids

-concentration of H+ ions in a solution
- [H+] = 1 x 10 ^ -7 M --> pH = 7
- 7.35 - 7.45

26

2 conditions of pH

1. acidosis
2. alkalosis
-primarily effects CNS and cardiovascular functions

27

acidosis
-pH
-serious?

-below 7.35
-very serious problem

28

alkalosis
-pH
-serious?

-above 7.45
-serious but not as common

29

why is the maintenance of pH a problem?
-H+ gains=
-constantly producing H+ through
-formula
-H+ must be

-H+ loses
-metabolic activities
-Co2 + H2O H+ + HCO3-
-eliminated or "tied up" to maintain pH

30

3 mechanisms of acid-base balance

1. buffer system
2. respiratory system
3. urinary system

31

buffer system
-buffer
-3 major systems

-compound that stabilizes the pH of a solution by providing or removing H+ ions
-1. protein buffer system
2. carbonic acid-bicarbonate buffer system
3. phosphate buffer system

32

protein buffer system
-definition
-type of protein

-AA accepts or releases H+ ions
-hemoglobin

33

how does hemoglobin play a role in the protein buffer system?

by maintaining pH as pCo2 changes

34

carbonic acid-bicarbonate buffer system
-formula
-function
-what happens when equation shifts to the left

-Co2 + H2O (H2Co3) H+ + HCO3-
-can prevent changes in pH after addition of H+ ions
-Co2 is released in lungs

35

phosphate buffer system
-equation
-function

-H2Po4- H+ + HPo4 ^2-
-plays a supporting role in maintaining pH

36

respiratory system
-what do changes in respiratory rate do
-direct effect on
-equation

-stabilizes pH of ECF
-direct effect on carbonic acid/bicarbonate buffer system
-Co2 + H2O H+ + HCO3-

37

respiratory system
-increase in pCo2 =
-decrease in pCo2=

-decrease in pH = increase in respiratory rate = more Co2 lost at lungs = pCo2 and pH returns to normal
-increase in pH= decrease respiratory rate = less Co2 lost at lungs = pCo2 and pH returns to normal

38

urinary system
-definition
-occurs where
-principle of buffering system

-changing the rate of H+ and HCO3- secretion or reabsorption by the kidneys regulates the pH of the ECF
-along the PCT, DCT and CD
- Co2 + H2O (H2CO3) H+ _ HCO3-

39

urinary system
-where does the Co2 come from
-principle of buffering system relies on
-decrease pH of ECF
-increase pH of ECF

-from tubular fluid, blood and tubular cells
-relies on carbonic anhydrase in tubular cells
-H+ is secreted into tubular fluid and HCO3- is released into blood = increase in pH of ECF in blood
-HCO3- is secreted into tubular fluid and rate of H+ secretion declines = decrease in pH of ECF