Chapter 27 Flashcards
1
Q
body fluid percentage of total body mass
A
female 55%
male 60%
2
Q
About ___ of body fluid is intracellular fluid (ICF) or cytosol, the fluid within cells. The other ___, called extracellular
fluid (ECF), is outside cells and includes all other body fluids. About ___ of the ECF is interstitial fluid, which occupies the microscopic spaces between tissue
cells, and ___ of the ECF is blood plasma, the liquid portion of the
blood
A
2/3
1/3
80%
20%
3
Q
2 general barriers that seperate ICF, interstitial fluid, and blood plasma
A
- plasma membrane
- blood vessel walls (only capillaries allow exchange of water/solutes between plasma/interstitial)
4
Q
Obese people have proportionally less water than leaner people because water comprises less than ___ of the
mass of adipose tissue. Skeletal muscle tissue, by contrast, is about
___ water. Infants have the highest percentage of water, up to ___ of body mass. The percentage of body mass that is water decreases until about 2 years of age. Until puberty, water accounts for about ___ of body mass in boys and girls. In lean adult males, water still accounts for about ___ of body mass. However, lean adult females have more subcutaneous fat than lean adult males. Thus, their
percentage of total body water is ____, accounting for about ___ of body mass
A
20%
65%
75%
60%
60%
lower
55%
5
Q
electrolytes
A
inorganic compounds that dissociate into ions
6
Q
what are most solutes and what does that mean
A
most electrolytes
means fluid balance is closely related to electrolyte balance
7
Q
2 ways body can gain water
A
ingestion
metabolic synthesis
8
Q
The main sources of body water are ingested liquids (about _____ mL) and moist foods (about _____ mL) absorbed from the GI tract, which total about _____ mL/day
A
1600
700
2300
9
Q
metabolic water (def, what reactions, mL/day)
A
produced in the body mainly when electrons are accepted by O2 during aerobic resp and some during dehydration synthesis reactions
200mL per day
10
Q
Each day the kidneys excrete about ____ mL in urine, the skin evaporates about ____ mL (____ mL through insensible perspiration and ____ mL as sweat), the lungs exhale about ____ mL as water vapor, and the GI eliminates about ____ mL in feces
A
1500
600
400
200
300
100
11
Q
When more ATP is produced, ____ water is formed
A
more
12
Q
Body water gain is regulated mainly by the volume of water intake, or how much fluid you drink. An area in the _______ known as the thirst center governs the urge to drink
A
hypothalamus
13
Q
5 stimuli that stimulate thirst center in hypothalamus
A
- increased blood osmolarity (stimulates osmoreceptors in hypoT)
- decreased BV (decreased activity of atrial volume receptors)
- decreased BP (baroreceptors in BV detect)
- decreased BP (increases renin from kidneys-.increases angiotensin II)
- Dry mouth
14
Q
urinary salt (NaCl) loss determines
A
body fluid volume as “water follows solutes” in osmosis and the two main solutes in ECF/urine is sodium and chloride
15
Q
urinary water loss determines
A
body fluid osmolarity
16
Q
ADH produced/stored by and AKA
A
AKA vasopressin
produced by hypothalamus
stored by post pituitary
17
Q
ADH stimulated by
A
increased body fluid osmolarity (mostly)
decrease BV/BP, pain, nausea, stress
18
Q
ADH promotes insertion of what and where
A
aquaporin-2 in apical membrane of principal cells of late distal tubules and collecting ducts
19
Q
wha inhibits ADH secretion
A
alcohol which is why you pee so much
20
Q
The two most important hormones that regulate the extent of renal Na+ reabsorption (and how much is lost in the urine)
A
aldosterone
atrial natriuretic peptide
21
Q
aldosterone vs ANP
A
increase Na+ reabsorption in kidneys
vs
increases excretion of Na+ in urine
22
Q
aldosterone steps in Na+ regulation (start with what stimulates it)
A
decreased BP and/or Na+ deficiency in plasma
-> increased release of renin from kidneys
->increased aldosterone formation
-> increased Na+ reabsorption in late distal tubules/collecting ducts; water reabsorption accompanies Na+ as ADH also released by low BP
->increase Na+, BV, BP (reduce water loss in urine)
23
Q
ANP steps in Na+ regulation (start with what stimulates it)
A
increased BV
-> increased stretch of atria
-> release of ANP
-> natriuresis + water excretion in urine due to osmosis
-> decrease BV/BP
24
Q
increase in osmolarity of ECF (happens when/results in/what happens to fix it)
A
after having salty meal as Na+ and Cl- rise in ECF = water movies from cells to ECF = cells shrink
thirst mechanism/secretion of ADH occurs
25
decrease in osmolarity of ECF (happens when/results in/what happens to fix it)
after drinking large amount of water as Na+ and Cl- levels in ECF decrease = water from ECF to cells = cells swell
ADH secretion inhibited, kidneys excrete large amount dilute urine
26
water intoxication happens because and symptoms
excessive blood loss, sweating, vomiting, diarrhea coupled with water intake
mental confusion, seizures, coma, and possibly death
27
hyponatremia
decreased Na+ concentration of ECF
28
The ions formed when electrolytes dissolve and dissociate serve
four general functions in the body:
1. control the osmosis of water between fluid compartments
2. help maintain the acid–base balance
required for normal cellular activities
3. carry electrical current, which allows production of action potentials and graded potentials
4. serve as cofactors needed for optimal activity of enzymes
29
what is the concentration of ions measured in
milliequivalents per liter (mEq/liter)
30
The chief difference between the two ECFs—blood plasma and interstitial fluid—is that blood plasma contains many ______ ______, in contrast to interstitial fluid, which has _____ ____. Because normal capillary membranes are virtually _________ to proteins, only a few plasma proteins leak out of blood vessels into the interstitial fluid. This difference in protein concentration is largely responsible for the _____ ______ ______ pressure exerted
by blood plasma
protein anions
very few
impermeable
blood colloid osmotic
31
In ECF, the most abundant cation is ___, and the most abundant anion is ___. In ICF, the most abundant cation is ___, and the most abundant anions are ______ and _______ (HPO4 2−). By actively transporting ___ out of cells and ___ into cells, sodium–potassium
pumps (Na+–K+ ATPases) play a major role in maintaining the high intracellular concentration of ___ and high extracellular concentration of ___
Na+
Cl-
K+
proteins
phosphates
Na+
K+
K+
Na+
32
sodium percentage of ECF cations and blood plasma concentration
90%
136-148 mEq/liter
33
sodium function (2)
1. plays a pivotal role in fluid and electrolyte balance as it accounts for almost 1/2 of the osmolarity of ECF
2. flow of Na+ through voltage gated channels in the PM is necessary for the generation and conduction of AP in neurons and MF
34
sodium levels in blood controlled by what hormones (3)
aldosterone: increases renal reabsorption of Na+
ADH: low Na+=ADH release stops=water released in urine=Na+ rises back up
ANP: increases Na+ excretion when Na+ is too high
35
normal blood plasma Cl− concentration is ______ mEq/ liter
95-105
36
chloride functions (2)
1. chloride shift: antiporter exchange
of Cl− for HCO3− maintains the correct balance of anions between ECF and ICF of RBC
2. part of the hydrochloric acid secreted into gastric juice
37
hormone that controls chloride
ADH: regulates Cl- as it controls the rate of water loss in urine
38
normal blood plasma K+ concentration is ______ mEq/liter
3.5-5.0
39
potassium function (3)
1. plays a key role in establishing the resting membrane potential and in the repolarization phase of AP in neurons and MF
2. helps maintain normal
intracellular fluid volume
3. . When K+ moves in/out of cells, it often is exchanged for H+ and thereby helps regulate the pH of body fluids
40
what hormone mainly controls potassium
aldosterone: blood plasma K+ high=aldosterone released= stimulates principal cells of renal collecting ducts to secrete K+
41
Normal blood plasma HCO3− concentration is _____ mEq/liter in systemic arterial blood and ______ mEq/liter in systemic venous blood
22-26
23-27
42
function of bicarbonate ions
the exchange of Cl− for HCO3 − helps maintain the correct balance of anions in ECF and ICF
43
what is the main regulated of bicarbonate ions
intercalated cells of the renal tubule either form HCO3− and release it into the blood when the blood level is low or excrete excess HCO3− in the urine when the level in blood is too high
44
About ___ of the calcium in adults is located in the skeleton and teeth, where it is combined with ______ to form a crystal lattice of mineral salts
98%
phosphates
45
The normal concentration of free or unattached Ca2+ in blood plasma is ______ mEq/liter. About the same amount of Ca2+ is attached to various plasma proteins
4.5-5.5
46
calcium functions (5)
Plays role in
1. hardness of bones/teeth
2. blood clotting
3. neurotransmitter release
4. maintenance of muscle tone
5. excitability of nervous and muscle
tissue
47
Effect of PTH on calcium levels
1. low Ca2+ in blood plasma = release PTH = stimulates osteoclasts to release Ca2+ from bone ECM = increase bone 2. resorption into bloodstream
enhances reabsorption of Ca2+ from glomerular filtrate to blood
3. increases calcitriol production = increase Ca2+ absorption from food
48
Effect of calcitonin on calcium levels
inhibits osteoclasts = accelerates Ca2+ deposition = lowers blood Ca2+ levels
49
About ___ of the phosphate in adults is present as calcium phosphate salts, which are structural components of bone and teeth. The remaining ___ is ionized
85%
15%
50
The normal blood plasma concentration of ionized phosphate is
only _____ mEq/liter.
1.7-2.6
51
PTH effect on HPO4 2-
1. PTH stimulates bone ECM by osteoclasts = release phosphate into the bloodstream
2. inhibits reabsorption of phosphate ions by renal tubular cells
Both together = increase urinary excretion of phosphate and lowers blood phosphate levels
52
calcitriol effect on phosphates
promotes absorption of phosphates and Ca2+ from the GI tract
53
Fibroblast growth factor 23 regulation of HPO4 2-
decreases HPO4 2− blood levels by increasing HPO4 2− excretion by the kidneys and decreasing absorption of HPO4 2− by the GI tract
54
In adults, about ___ of the total body magnesium is part of bone matrix as magnesium salts. The remaining ___ occurs as magnesium ions (Mg2+) in ICF (___) and ECF (___).
54%
46%
45%
1%
55
Normal blood plasma Mg2+ concentration is ______ mEq/liter
1.3-2.1
56
magnesium functions (3)
1. cofactor for certain enzymes needed for the metabolism of carbohydrates and proteins and for the sodium–
potassium pump
2. essential for normal neuromuscular activity,
synaptic transmission, and myocardial functioning
3. secretion of parathyroid hormone (PTH) depends on Mg 2+
57
Hyponatremia (what, causes, symptoms)
low Na+
causes: decreased sodium intake; increased sodium loss through vomiting, diarrhea, aldosterone deficiency, or taking certain diuretics; and excessive water intake
symp: Muscular weakness; dizziness, headache, and hypotension; tachycardia and shock; mental confusion, stupor, and coma.
58
hypernatremia (what, causes, symptoms)
high Na+
causes: dehydration, water deprivation, or excessive sodium in diet or IV fluids; causes hypertonicity of ECF, which pulls water out of body cells into ECF, causing cellular dehydration
symp: Intense thirst, hypertension,
edema, agitation, and convulsions
59
hypochloremia (what, causes, symptoms)
low chloride
causes: excessive vomiting, overhydration, aldosterone deficiency, congestive heart failure, and therapy with certain diuretics
symp: Muscle spasms, metabolic alkalosis, shallow respirations, hypotension, and tetany
60
hyperchloremia (what, causes, symptoms)
high chloride
causes: dehydration; excessive chloride intake; or severe renal failure, hyperaldosteronism, certain types of acidosis, and some drugs
symp: Lethargy, weakness, metabolic acidosis, and rapid, deep breathing
61
hypokalemia (what, causes, symptoms)
low potassium (K+)
causes: vomiting or diarrhea, decreased potassium intake, hyperaldosteronism, kidney disease, and therapy with some diuretics
symp: Muscle fatigue, flaccid paralysis, mental confusion, increased urine output, shallow respirations, and changes in electrocardiogram (flattening of T wave).
62
hyperkalemia (what, causes, symptoms)
high potassium (K+)
causes: excessive potassium intake, renal failure, aldosterone deficiency, crushing injuries to body tissues, or transfusion of hemolyzed blood.
symp: Irritability, nausea, vomiting, diarrhea, muscular weakness; can cause death by ventricular fibrillation.
63
hypocalcemia (what, causes, symptoms)
low Ca 2+
causes: increased calcium loss, reduced calcium intake, elevated phosphate levels, hypoparathyroidism
symp: Numbness and tingling of fingers; hyperactive reflexes, muscle cramps, tetany, and convulsions; bone fractures; spasms of laryngeal muscles that can cause death by asphyxiation
64
hypercalcemia (what, causes, symptoms)
high Ca 2+
causes: hyperparathyroidism, some cancers, excessive intake of vitamin D, and Paget’s disease of bone
symp: Lethargy, weakness, anorexia, nausea, vomiting, polyuria, itching, bone pain, depression, confusion, paresthesia, stupor, and coma
65
hypophosphatemia (what, causes, symptoms)
low HPO4 2-
causes: increased urinary losses, decreased intestinal absorption, or increased utilization
symp: confusion, seizures, coma, chest and muscle pain, numbness and tingling of fingers, decreased coordination, memory loss, and lethargy.
66
hyperphosphatemia (what, causes, symptoms)
low HPO 2-
causes: kidneys fail to excrete excess phosphate, as in renal failure; can also result from increased intake of phosphates or destruction of body cells=releases phosphates into blood
symp: Anorexia, nausea, vomiting, muscular weakness, hyperactive reflexes, tetany, and tachycardia
67
hypomagnesemia (what, causes, symptoms)
low Mg 2+
causes: inadequate intake or excessive loss in urine or feces; also occurs in alcoholism, malnutrition, diabetes mellitus, and diuretic therapy
symp: Weakness, irritability, tetany, delirium, convulsions, confusion, anorexia, nausea, vomiting, paresthesia, and cardiac arrhythmias
68
hypermagnesemia (what, causes, symptoms)
high Mg 2+
causes: occurs in renal failure or due to increased intake of Mg2+, such as Mg2+- containing antacids; also occurs in aldosterone deficiency and hypothyroidism
symp: Hypotension, muscular weakness or paralysis, nausea, vomiting, and altered mental functioning
69
normal pH of systemic arterial blood
7.35-7.45
70
The removal of H+ from body fluids and its subsequent elimination from the body depend on the following three major mechanisms:
1. buffer systems: temporarily bind H+ = raises pH but doesn't excrete it
2. exhalation of carbon dioxide: reduces carbonic acid in blood = raises pH
3. kidney excretion of H+: slowest, remove in urine
71
what is the most abundant buffer in intracellular fluid and blood plasma
the protein buffer system
72
protein ______ is an especially good buffer within RBCs, and ______ is the main protein buffer in blood plasma
hemoglobin
albumin
73
what buffer system cannot protect against pH changes due to respiratory problems in which there is an excess or shortage of CO2
carbonic acid-bicarbonate buffer system
74
Because the concentration of phosphates is highest in ___ , the phosphate buffer system is an important regulator of pH in the ______. It also acts to a smaller degree in ___ and buffers acids in _____.
ICF
cytosol
ECF
urine
75
whats a volatile acid
an acid that can be expelled as a gas through the lungs
ex. carbonic acid
76
Doubling the breathing increases pH by about ____ units, from 7.4 to ____. When CO2 levels increase, the reaction is driven to the ____, the H+ concentration _______, and blood pH ______. Reducing ventilation to one-quarter of normal lowers the pH by ____ units, from 7.4 to ____
0.23
7.63
right
increases
decreases
0.4
7.0
77
show the negative feedback loop of a decreased pH (increased H+)
receptors: central chemoreceptors in medulla oblongata; peripheral chemoreceptors in aortic/carotid bodies
CC: dorsal resp group in medulla O
effectors: diaphragm, (contract forcefully/more frequently=decrease CO2)
response: less H2CO3 forms and fewer H+ present=increase pH
78
metabolic reactions produce and how to remove it
nonvolatile acids
remove H+ in urine
79
cells in both the ____ and the _______ _____ of the kidneys secrete hydrogen ions into the _______ fluid. In the PCT, Na+–H+ antiporters secrete ____ as they reabsorb ____
PCT
collecting ducts
tubular
H+
Na+
80
The _____ membranes of some intercalated cells include proton pumps (H+ ATPases) that secrete ___ into the _____ fluid. Intercalated cells can secrete H+ against a concentration gradient so effectively that urine can be up to _____ times (3 pH units) more acidic than blood. HCO3− produced by
dissociation of H2CO3 inside intercalated cells crosses the ________ membrane by means of Cl−–HCO3
− antiporters and then diffuses
into _______ capillaries. The HCO3 − that enters the blood in this way is ____ ______. For this reason, blood leaving the kidney in the renal vein may have a higher HCO3− concentration than blood entering the kidney in the renal artery.
apical
H+
tubular
1000
basolateral
peritublular
not filtered
81
a second type of intercalated cell has proton pumps in its _______ membrane and Cl−–HCO3− antiporters in its _____
membrane. These intercalated cells secrete _____ and reabsorb _____.
basolateral
apical
HCO3-
H+
82
2 other buffers in collecting duct that combine with H+ (start with most plentiful, what they form when combines with H+, how they are excreted)
HPO4 2− (monohydrogen phosphate ion): combines with H+ to make
H2PO 4− (dihydrogen phosphate ion)
NH3 (ammonia): combines with H+ to make NH4+ (ammonium ion)
cannot diffuse back into tubule cells=excretes in urine
83
84
respiratory acidosis (def, causes, compensatory mechanism)
def: Increased PCO2 (above 45 mmHg) and decreased pH (below 7.35) if no compensation
causes: Hypoventilation due to emphysema, pulmonary edema, trauma to respiratory center, airway obstructions, or dysfunction of muscles of respiration
mechanism: renal: increased excretion of H+/increased reabsorption of HCO3-
= pH normal but PCO2 high
85
respiratory alkalosis
def: Decreased PCO2 (below 35 mmHg) and increased pH (above 7.45) if no compensation
causes: Hyperventilation due to oxygen deficiency, pulmonary disease, cerebrovascular accident (CVA), or severe anxiety
mechanism: decreased excretion of H+; decreased reabsorption of HCO3− = pH normal but PCO2 low
86
metabolic acidosis
def: Decreased HCO3− (below 22 mEq/
liter) and decreased pH (below 7.35)
if no compensation
causes: Loss of bicarbonate ions due to diarrhea, accumulation of acid (ketosis), renal dysfunction.
mechanism: Respiratory: hyperventilation=increases loss of CO2 = pH normal but HCO3− low
87
metabolic alkalosis
def: Increased HCO3− (above 26 mEq/
liter) and increased pH (above 7.45) if no compensation
causes: Loss of acid due to vomiting, gastric suctioning, or use of certain diuretics; excessive intake of alkaline drugs
mechanism: Respiratory: hypoventilation = slows loss of CO2 = pH normal but HCO3− high
88
respiratory vs renal compensation
fixes metabolic by hyper/hypoventilation, within minutes to hours
vs
fixes respiratory by changing secretion of H+ and reabsorption of HCO3−, begin within minutes but takes days
89
respiratory acidosis/alkalosis are disorders resulting from changes in the ____ ____ ___ ___ (____) in systemic arterial blood (normal range is _____ mmHg). By contrast, both metabolic acidosis/alkalosis are disorders resulting from changes in ______ concentration (normal range is _____ mEq/liter in systemic arterial blood)
partial pressure of CO2 (PCO2)
35-45
HCO3-
22-26
