Anatomy And Physiology Ii Fluid Balance

Front 1

what happens to the level of our body water content as we get older?

Back 1

it declines

Front 2

what factors play a role in how much water our body contains?

Back 2

amount of body fat (lower the better)
amount skeletal muscle (more the better
bone mass (the lower the more water content)

Front 3

water occupies which 2 fluid filled compartments?

Back 3

intracellular fluid (ICF) and extracellular fluid (ECF)

Front 4

describe intracellular fluid

Back 4

about 2 thirds of body water by volume, contained in cells (40% of body weight)

Front 5

describe extracellular fluid

Back 5

consists of 2 major subdivisions
-plasma: fluid portion of the blood (makes up 20% of ECF)
-interstitial fluid: fluid space between the cells (makes up 80% of extracellular fluid)

Front 6

describe the 2 main solute classes

Back 6

-electrolytes: inorganic salts, all acids and bases, and some proteins
-nonelectrolytes: examples include glucose, lipids, creatinine and urea

Front 7

electrolytes have _______ osmotic power than non electrolytes

Back 7

greater

Front 8

what is the "chief cation" of extracellular fluids?

Back 8

sodium

Front 9

what is the "major anion" of extracellular fluids?

Back 9

chloride

Front 10

what is the "chief cation" of intracellular fluids?

Back 10

potassium

Front 11

what is the major anion of intracellular fluids?

Back 11

phosphate

Front 12

sodium and potassium concentrations in extra and intra cellular fluids being nearly opposites reflects what major anatomical concept?

Back 12

activity of cellular ATP-dependent sodium-potassium pumps

Front 13

even though electrolytes are the most abundant solutes, what 4 main compounds make up the bulk of the extra- and intra- cellular fluids?

Back 13

proteins, phospholipids, cholesterol and neutral fats

Front 14

what is compartmental exchange regulated by?

Back 14

osmotic and hydrostatic pressures: 2 way water flow is substantial

Front 15

how do ion fluxes move?

Back 15

selectively by active transport

Front 16

how do nutrients, respiratory gases and wastes move?

Back 16

unidirectionally

Front 17

plasma is the only fluid that what's?

Back 17

circulates throughout the body and links external and internal environemts

Front 18

changes in solute concentrations are quickly followed by what?

Back 18

osmotic changes

Front 19

increases in plasma osmolality trigger what?

Back 19

thirst and release of antidiuretic hormone (ADH)

Front 20

what is the hypothalamic thirst center stimulated by?

Back 20

decreases in plasma volume of 10% and increases of plasma osmolality of 1-2%

Front 21

obligatory water losses include...

Back 21

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

Front 22

obligatory water loss in kidneys reflects the facts that...

Back 22

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

Front 23

define dehydration

Back 23

water loss exceeds water intake and the body is in negative fluid balance

Front 24

what are the causes of dehydration?

Back 24

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

Front 25

what are the signs and symptoms of dehydration?

Back 25

cottonmouth, thirst, dry flushed skin and oliguria

Front 26

what may prolonged dehydration lead to?

Back 26

weight loss, fever, mental confusion, hypovolemic shock and loss of electrolytes

Front 27

what can renal insufficiency or an extraordinary amount of water ingested quickly lead to?

Back 27

cellular overhydration or water intoxication

Front 28

what results when ECF is diluted (sodium content is normal but excess water is present)

Back 28

results in hyponatremia promoting net osmosis into tissue cells, causing swelling
-must be quickly reversed to prevent severe metablic disturbances, particularly in neurons

Front 29

what is an edema?

Back 29

atypical accumulation of fluid in the interstitial space, leading to tissue swelling

Front 30

what causes an edema?

Back 30

anything that increases flow of lfuids out of the bloodstream or hinders their return

Front 31

what are factors that accelerate fluid loss?

Back 31

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

Front 32

what is hypoproteinemia?

Back 32

low levels of plasma proteins

Front 33

what does hypoproteinemia cause?

Back 33

forces fluids out of capillary beds at the arterial ends, fluids fail to return at the venous ends
-blocked (or surgically removed) lymph vessels:
cause leaked proteins to accumulate in interstitial fluid
exert increasing colloid osmotic pressure, which draws fluid from the blood

Front 34

what does hypoproteinemia result from?

Back 34

protein malnutrition, liver disease

Front 35

what are salts important for?

Back 35

-neuromuscular excitability
-secretory activity
-membrane permeability
-controlling fluid movements

Front 36

what are electrolytes?

Back 36

salts, acids and bases by "electrolyte balance" usually refers only to salt balance

Front 37

how does aldosterone affect sodium balance?

Back 37

when aldosterone is high, sodium is actively reabsorbed:
-65% of sodium in filtrate is reabsorbed in the proximal tubules
-25% is reclaimed in the loops of Henle
water follows sodium if tubule premeability has been increased with ADH

Front 38

what triggers the realease of aldosterone and what mediates the response?

Back 38

renin angiotension mechanism triggers release
-this is mediated by the juxtaglomerular appartatus which releases renin
-renin catalyzes the production of angiotensin II which propmpts aldosterone release

Front 39

juxtaglomerular apparatus releases renin in response to what?

Back 39

sympathetic nervous system stimulation
decreased filtrate osmolality
decreased stretch(due to decreased blood pressure)

Front 40

adrenal cortical cells are directly stimulated by the release of what?

Back 40

aldosterone by elevated potassium levels in the ECF

Front 41

what does the Atrial Natriuretic peptide (ANP) do?

Back 41

reduces blood pressure and blood volume by inhibiting
-events that promote vasoconstriction
-sodium and water retention

Front 42

where is atrial natriuretic peptide released?

Back 42

released in the heart atria as a response to stretch (elevated blood pressure

Front 43

what does atrial natriuretic peptide promote?

Back 43

excretion of sodium and water

Front 44

what can kyperkalemia and hypokalemia do?

Back 44

-disrupt electrical conduction in theheart
-lead to sudden death

Front 45

how does the parathyroid hormone (PTH) help regulate calcium in bones?

Back 45

PTH activates osteoclasts to break down bone matrix

Front 46

what is the hormone involved in regulation of potassium balance?

Back 46

aldosterone

Front 47

how does PTH regulate calcium in the small intestine?

Back 47

PTH enhances intestinal absorption of calcium

Front 48

how does PTH regulate calcium in the kidneys?

Back 48

PTH enhances calcium reabsorption and decreases phsophate reabsorption

Front 49

for where do most hydrogen ions originate from?

Back 49

cellular metablism

Front 50

what are 4 sources of cellular metabolism, therefore becoming sources of hydrogen ions?

Back 50

-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 51

what are the three major chemical buffer systems?

Back 51

-bicarbonate buffer system
-phosphate buffer system
-protein buffer system

Front 52

what do the buffer systems do?

Back 52

resist any drifts in pH; act within a fraction of a second

Front 53

what is an example of a physiological buffering system?

Back 53

the respiratory system regulation of acid-base balance

Front 54

what is the reversible equilibrium equation between dissolved carbon dioxide and water and carbonic acid and thehydrogen and bicarbonate ions?

Back 54

CO2 + H2O yields H2CO3 yields H + HCO3

Front 55

what results when hypercapnia or rising plasma H levels occur?

Back 55

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

Front 56

what does alkalosis cause?

Back 56

slower, more shallow breathing, causing H levels to increase

Front 57

what does respiratory system impairment cause?

Back 57

acid-base imbalance: respiratory acidosis or respiratory alkalosis

Front 58

how do the lungs eliminate carbonic acid?

Back 58

by eliminating carbon dioxide

Front 59

what is the only organ that can rid thebody of metabolic acids (such as phosophoric, uric, and lactic acids and ketones) and prevent metabolic acidosis?

Back 59

kidneys

Front 60

the ultimate acid-base regulatory organs are the what?

Back 60

kidneys

Front 61

what are the 2 most important renal mechanisms for regulating acid-base balance?

Back 61

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

Front 62

why is it said that reabsorption of bicarbonate "takes the scenic route"?

Back 62

because the kidney tubule cells are impermeable to the bicarbonate ion

Front 63

what are the net results of bicarbonate reabsorption?

Back 63

-for each hydrogen ion secreted, a sodium ion and a bicarbonate ion are reabsorbed by the PCT cells
-secreted hydrogen ions form carbonic acid; thus, bicarbonate disappears from filtrate at the same rate that it enters the peritubular capillary blood

Front 64

what are the 2 final steps of bicarbonate reabsorption?

Back 64

-carbonic acid formed in filtrate dissociates to release carbon dioxide and water
-carbon dioxide then diffuses into tubule cells where it acts to trigger bicarbonate ion reabsorption and hydrogen ion secretion

Front 65

what type of cells generate new bicarbonate ions?

Back 65

type A intercalated cells (of collecting ducts)

Front 66

dietary hydrogen ions must be counteracted by what?

Back 66

generating new bicarbonate

Front 67

what are the steps to generating new bicarbonate ions using hydrogen ion excretion?

Back 67

-dietary hydrogen ions must be counteracted by generating new bicarbonate
-the excreted hydrogen ions must bind to buffers in the urine (phosphate buffer system)
-intercalated cells actively secrete hydrogen ions into urine, which is buffered and excreted

Front 68

what happens to the newly generated bicarbonate after using hydrogen ion excretion?

Back 68

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

Front 69

how does generating new bicarbonate ions using hydrogen ion excretion (through type A intercalated cells) respond to acidosis?

Back 69

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

Front 70

when the body is in alkalosis, what do type B intrecalated cells (of collecting ducts) do?

Back 70

-secrete bicarbonate ions
-recalim hydrogen ions and acidify the blood
-this mechanism is OPPOSITE that of the type A intercalated cells and the bicarbonate ion reabsorption process

Front 71

what does respiratory acidosis and alkalosis result from?

Back 71

failure of the respiratory system to balance pH

Front 72

what is the single most important indicator of respiratory inadequacy

Back 72

P co2

Front 73

what are normal levels for P co2

Back 73

-fluctuates between 35 and 45 mm Hg
-values above 45 mmHg signal respiratory acidosis
-values below 35 mm Hg indicate respiratory alkalosis

Front 74

what is the most common cause of acid-base imbalance and when does it occur?

Back 74

respiratory acidosis: occurs when a person breathes too infrequently and/or shallowly, or gas exchange is hampered by diseases such as pneumonia, cystic fibrosis, or emphysema

Front 75

respiratory alkalosis is a common result of what?

Back 75

hyperventilation

Front 76

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

Back 76

metabolic

Front 77

what is the second most common cause of acid-base imbalance? describe what it is

Back 77

metabolic acidosis: excessive loss of bicarbonate ions

Front 78

what indicates metabolic alkalosis?

Back 78

rising blood pH and bicarbonate levels

Front 79

what are typical causes of metabolic alkalosis?

Back 79

-vomiting of the acid contents of the stomach
-intake of excess base (ex: from antacids)

Front 80

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

Back 80

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