Fluid, Electrolyte, And Acid-Base Balance

Front 1

what are the characteristics of infants that cause them to have a higher body water content? %?

Back 1

low body fat, low bone mass
73%

Front 2

healthy males about__% water; healthy females about __% water

Back 2

60%
50%

Front 3

why do females have lower body water content?

Back 3

higher body fat, smaller amt of skeletal muscle

Front 4

what are the 2 fluid compartments that water occupies in the body?

Back 4

intracellular (ICF) and extracellular (ECF)

Front 5

how much and where is the intracellular fluid contained?

Back 5

about 2/3 of the body water by volume, contained in cells

Front 6

where is the extracellular fluid contained?

Back 6

plasma-the fluid portion of the blood
interstitual fluid(IF)-fluid in spaces between cells

Front 7

so lets say the total body water volume is 60%...what would be the % in intracellular? extracellular?

Back 7

40% intracellular
20% extracellular

Front 8

how about in the extracellular...what % of that takes up the interstitual fluid volume? % in the plasma volume?

Back 8

80% interstitial fluid
20% plasma

Front 9

water is the universal __?

Back 9

solvent

Front 10

solute classes?(2)

Back 10

electrolytes, nonelectrolytes

Front 11

electrolytes include?

Back 11

inorganic salts, all acids and bases, and some proteins

Front 12

nonelectrolytes include?

Back 12

glucose, lipids, creatinine, and urea

Front 13

electrolytes have greater __ __ that nonelectrolytes

Back 13

osmotic power

Front 14

water moves according to what?

Back 14

osmotic gradients

Front 15

extracellular fluids are similar(except for high protein content of plasma) in 2 ways?

Back 15

-sodium is chief cation
-chloride is major anion

Front 16

intracellular fluids have low __ and __. what is the chief cation and anion for them?

Back 16

sodium, chloride
potassium, phosphate

Front 17

sodium and potassium in extra- and intracellular fluids are nearly opposites- this reminds us of what that goes on in the cellular membrane?

Back 17

ATP-dependent sodium-potassium pumps

Front 18

even though __ are the most abundant solutes, what 2 things make up the bulk of extra- and interstitual fluids?

Back 18

electrolytes
-proteins and nonelectrolytes bc they are large molecules

Front 19

proteins, phospholipids, cholesterol, and neutral fats account for:
__% of the mass of solutes in plasma
__% of the mass in interstitual fluid
__% of the mass in the intracellular compartment

Back 19

90%
60%
97%

Front 20

compartmental exchange is regulate by __ &__pressures

Back 20

osmotic and hydrostatic

Front 21

understand how to explain 2-way water flow---IT IS SUBSTANTIAL!!!

Back 21

-basically osmolalities of all body fluids are equal(except during those brief moments of exchange); increasing the ECF solute content can be expected to cause the osmotic and volume chnages in the ICF-namely a shift of water out of the cells; conversely, decreasing ECF osmolality causes water to move into the cells
thus, ICF volume is determined by ECF solute concentration

Front 22

w/in extra-and intracellular fluids: __ __ are restricted and move selectively by active transport

Back 22

ion fluxes

Front 23

__,__,__ move unindirectionally between ICF&ECF

Back 23

nutrients, respiratory gases, and wastes

Front 24

__ is the only fluid that circulates throughout the body and links external and internal environments

Back 24

plasma

Front 25

changes in solute concentrations are quickly followed by __ changes

Back 25

osmotic

Front 26

to remain properly hydrated, water intake must equal what?

Back 26

water output

Front 27

increases in plasma osmolality trigger what?

Back 27

thirst and release of antidiuretic hormone(makes u not pee)

Front 28

the __ thirst center is stimulated by 2 specific things?

Back 28

hypothalamic
-decreases in plasma volue of 10%
-increases in plasma osmolality of 1-2%

Front 29

obligatory water losses include: (3)

Back 29

-insensible water losses from lungs and skin
-water that accompanies undigested food residues in feces
-urine

Front 30

obligatory water loss in kidneys reflects 2 factors?

Back 30

-kidneys excrete solutes to maintain blood homeostasis
-urine solutes must be flushed out of the body in water

Front 31

what are 3 disorders of water balance?

Back 31

dehydration, hypotonic hydration, and edema

Front 32

what are some causes of dehydration?

Back 32

hemorrhage, severe burns, prolonged vomiting or diarrhea, profuse sweating, water deprivation, diuretic abuse, diabetes mellitus or diabetes insipidus

Front 33

what are the s&s for dehydration?

Back 33

cottonmouth, thirst, dry flushed skin, oliguria(decreased urine output)

Front 34

what can prolonged dehydration lead to?

Back 34

weight loss, fever, and mental confusion
other consequences--hypovolemic(inadequate blood volume to maintain normal circulation) shock and loss of electrolytes

Front 35

what is hypotonic hydration?

Back 35

renal insufficiency or an extraordinary amt of water ingested quickly can lead to cellular overhydration, or water intoxication

Front 36

in hypotonic hydration, __ is diluted-meaning what?

Back 36

ECF-sodium content is normal but excess water is present

Front 37

resulting __(low ECF Na+) -promotes net osmosis into tissue cells causing what symptom?

Back 37

hyponatremia
-swelling

Front 38

hypotonic hydration must be quickly reversed to prevent what?

Back 38

severe metabolic disturbances ,particularly in neurons(cerebral edema)

Front 39

what is edema?

Back 39

atypical accumulation of fluid in teh interstitual space, leading to tissue swelling

Front 40

cause of edema?

Back 40

anything that increases flow of fluids out of the bloodstream or hinders there return

Front 41

factors that accelerate fluid loss?

Back 41

increased blood pressure, capillary permeability
incompetent venous valves, localized blood vessel blockage
hypertension, high blood volume
chronic inflammation

Front 42

edema: what is hypoproteinemia?

Back 42

low levels of plasma proteins

Front 43

what are 2 things that happen with edema?

Back 43

-forces fluids out of capillary beds at the arterial ends
-fluids fail to return at the venous ends

Front 44

hypoproteinemia can result from?(2)

Back 44

protein malnutrition, liver disease

Front 45

hypoproteinemia could also result from __ __ being surgically removed. what are 2 factors that would result from this causing hypoproteinemia?

Back 45

lymph vessels
-cause leaked proteins to accumulate in interstitual fluid
-exert increasing colloid osmotic pressure, which draws fluid from the blood

Front 46

elecrolyte balance refers to __ balance

Back 46

salt

Front 47

salts are important for what 4 things?

Back 47

neuromuscular excitability
secretory activity
membrane permeability
controlling fluid movements

Front 48

salts enter the body by ingestion and are lost via what 3 things?

Back 48

perspiration, feces, and urine

Front 49

what hormone regulates sodium balance?

Back 49

aldosterone

Front 50

sodium reabsorption: __% of sodium in filtrate is reabsorbed in the __ __
-__% is reclaimed in the __ of __

Back 50

65%, proximal tubules
25% loops of Henle

Front 51

when aldosterone levels are high, all remaining Na+ is what?

Back 51

actively reabsorbed

Front 52

water follows sodium if what has been increased with ADH?

Back 52

tubule permeability

Front 53

what mechanism triggers the release of aldosterone?

Back 53

the renin-angiotensin mechanism

Front 54

what is the renin-angiotensin mechanism mediated by?

Back 54

the juxtaglomerular apparatus

Front 55

the juxtaglomerular apparatus releases renin in response to what 3 possible things?

Back 55

-sympathetic nervous system stimulation
-decreased filtrate osmolarity
-decreased stretch (due to decreased b.p.)

Front 56

renin catalyzed the production of __, which prompts?

Back 56

angiotensin II
aldosterone release

Front 57

__ __ cells are directly stimulated to release aldosterone not only by the renin-angiotensin mechanism but by elevated _ levels in the ECF

Back 57

adrenal cortical
K+

Front 58

aldosterone brings about its effects? SLOWLY

Back 58

dimished uring output and increased blood volume

Front 59

look at slide 21

Back 59

ok

Front 60

what does the atrial natriuretic peptide(ANP) do?

Back 60

reduces blood pressure and blood volume

Front 61

it reduces b.p. and volume by doing what 2 things?

Back 61

events that promote vasoconstriction
Na+ and water retention

Front 62

ANP is release where?? in response to stretch(elevated bp)

Back 62

heart atria

Front 63

ANP has potent ___ and __ effects

Back 63

natriuretic and diuretic effects
-promotes excretion of sodium and water

Front 64

see slide 23

Back 64

lk

Front 65

regulation of potassium balance: hyperkalemia an hypokalemia can:

Back 65

disrupt electrical conduction in the heart, lead to sudden death

Front 66

regulation of calcium is done by what hormone?

Back 66

parathyroid hormone

Front 67

PTH does what with bones?

Back 67

activates osteoclasts to break down bone matrix

Front 68

PTH does what with small intestine?

Back 68

enhances intestinal absorption of calcium

Front 69

PTH does what with kidneys

Back 69

enhances calcium reabsorption and decreases phosphate reabsorption

Front 70

most hydrogen ions originate from where?

Back 70

cellular metabolism

Front 71

give 4 ex of cellular metabolism where H+ would be produced?

Back 71

Breakdown of phosphorus-containing proteins releases phosphoric acid into the ECF
Anaerobic respiration of glucose produces lactic acid
Fat metabolism yields organic acids and ketone bodies
Transporting carbon dioxide as bicarbonate releases hydrogen ions

Front 72

what are 3 major chemical buffer systems?

Back 72

bicarbonate buffer system
phosphate buffer system
protein buffer system

Front 73

any drifts in __ are resisted by the entire chemical buffering system--act w/in a fraction of a second to resist __ changes

Back 73

pH; pH

Front 74

what is a chemical buffer?

Back 74

a system of one or more compounds that acts to resist changes in pH when a strong acid or base is added

Front 75

how do they work?

Back 75

they do this by binding to H+ whenever the pH drops and releasing them when pH rises

Front 76

the respiratory system regulation of acid-base balance provides a ___ buffering system.

Back 76

physiological

Front 77

there is a reversible equilibrium between??

Back 77

dissolved CO2 and H2O
carbonic acid and the hydrogen and bicarbonate ions

CO2 + H2O <-> H2CO3 <-> H+ + HCO3-

Front 78

when hypercapnia(high CO2 levels in the blood) or rising plasma H+ occurs, what happens?

Back 78

deeper and more rapid breathing expels more carbon dioxide
hydrogen ion concentration is reduced

Front 79

alkalosis(state of abnormally low H+ concentration in the ECF) causes what?

Back 79

slower more shallow breathing, causing H+ to increase

Front 80

respiratory system impairment causes?

Back 80

acid-base imbalance (respiratory acidosis or respiratory alkalosis)

Front 81

the ultimate acid-base regulatory organs are the what?

Back 81

kidneys

Front 82

chemical buffers can tie up excess acids or bases, but they cannot?

Back 82

eliminate them from the body

Front 83

the lungs can eliminate __ __ by eliminating carbon dioxide

Back 83

carbonic acid

Front 84

only the __ can rid the body of metabolic acids(??) and prevent __ __

Back 84

kidneys
(phosphoric, uric, and lactic acids and ketones)
metabolic acidosis

Front 85

the most important renal mechanisms for regulating acid-base balance are:?(2)

Back 85

-conserving(reabsorbing) or generating new bicarbonate ions (Important to combat acidosis)
-excreting bicarbonate ions(Important to combat alkalosis)

Front 86

reabsorption of bicarbonate: kidney tubule cells impermeable to bicarbonate ion, so reabsorption of bicarbonate "takes the scenic route"

Back 86

ok

Front 87

explain the steps to this "scenic route"

Back 87

1) CO2 combining w/ water w/in the tubule cell, forming H2CO3
2) H2CO3 is quickly split, forming H+ and HCO3-
3) For each H+ secreted into the filtrate, a bicarbonate ion(HCO3-) enters the peritubular capillary blood by cotransport(either via symport w/ Na+ or via antiport with Cl-)
4) Secreted H+ combines w/ HCO3- present in the tubular filtrate, forming carbonic acid(H2CO3). Thus, HCO3- disappears from the filtrate at the same rate the that HCO3-(formed w/in the tubule cell) enters the peritubular capillary blood.
5) The H2CO3 formed in the filtrate dissociates to release carbon dioxide and water
6) Carbon dioxide then diffuses into the tubule cell, where it acts to trigger further H+ secretion

Front 88

Net Effects for the Reabsorption of Bicarbonate:
for each hydrogen ion secreted, a __ and a __ ion are reabsorbed by the PCT cells

Back 88

sodium and bicarbonate

Front 89

secreted H+ form __; thus, __ disappears from filtrate at the same rate that it enters the peritubular capillary

Back 89

carbonic acid
bicarbonate ions

Front 90

carbonic acid formed in filtrate dissociates to release what?

Back 90

carbon dioxide and water

Front 91

carbon dioxide then diffuses into tubule cells, where it acts to trigger what?

Back 91

bicarbonate ion reabsortion and H+ secretion

Front 92

what generate new bicarbonate ions?

Back 92

type A intercalated cells(of collecting ducts)

Front 93

what is one way of generating new bicarbonate ions?

Back 93

using the hydrogen ion excretion

Front 94

so basically what happens in using hydrogen ion excretion?

Back 94

H+ from the dissociation of H2CO3 is actively secreted by a H+ ATPase pump and combines with phosphate buffer in the lumen. HCO3- generated at the same time leaves the basolateral membrane via an antiport carrier in a HCO3- -Cl- exchange process

Front 95

dietary hydrogen ions must be counteracted by generating new?

Back 95

bicarbonate

Front 96

the excreted hydrogen ions must bind to what in the urine?

Back 96

buffers in the phosphate buffer system

Front 97

intercalated cells actively secrete __ into urine, which is buffered and excreted.

Back 97

H+

Front 98

bicarbonate generated is: ?

Back 98

-moved into the interstitial space via a cotransport system
-passively moved into the peritubular capillary blood

Front 99

in response to acidosis:
what 2 things happen?(just went over this)

Back 99

kidneys generate bicarbonate ions and add them to the blood
an equal amt of hydrogen ions are added to the urine

Front 100

when the body is in alkalosis(state of abnormally low H+ concentration in the extracellular fluid), type _ intercalated cells(of the collecting ducts): do what 2 things?

Back 100

secrete bicarbonate ions
reclaim hydrogen ions and acidify the blood

Front 101

the mechanism is the opposite of what?

Back 101

type A intercalated cells and the bicarbonate ion reabsorption process

Front 102

respiratory acidosis and alkalosis result from what?

Back 102

failure of the respiratory system to balance pH

Front 103

what is the single most important indicator of respiratory inadequacy?

Back 103

CO2 in the Plasma (PCO2)

Front 104

what is the normal PCO2?

Back 104

between 35 and 45 mm Hg

Front 105

values above 45 Hg signal what?

Back 105

respiratory acidosis

Front 106

values below 35 mm Hg indicate?

Back 106

respiratory alkalosis

Front 107

respiratory __ is the most common cause of acid-base imbalance

Back 107

acidosis

Front 108

when would this occur?

Back 108

when a person breathes too infrequently an/or shallowly, or gas exchange is hampered by diseases such as pneumonia, cystic fibrosis, or emphysema

Front 109

respiratory alkalosis is a common result of what?

Back 109

hyperventilation

Front 110

all pH imbalances except those caused by abnormal blood carbon dioxide levels are __

Back 110

metabolic

Front 111

__ acidosis is the 2nd most common cause of acid-base imbalance. what happens?

Back 111

metabolic
excessive loss of bicarbonate ions

Front 112

what indicates metabolic alkalosis?

Back 112

rising blood pH and bicarbonate levels

Front 113

typical causes for metabolic alkalosis?

Back 113

-vomiting of the acid contents of the stomach
-intake of excess base(e.g., from antacids)

Front 114

acid-base imbalance due to inadequacy of a physiological buffer system is compensated for by the other system:2?

Back 114

-the respiratory system will attempt to correct metabolic acid-base imbalances
-the kidneys will work to correct imbalances caused by respiratory disease