Chapter 27 Flashcards
body fluid percentage of total body mass
female 55%
male 60%
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
2/3
1/3
80%
20%
2 general barriers that seperate ICF, interstitial fluid, and blood plasma
- plasma membrane
- blood vessel walls (only capillaries allow exchange of water/solutes between plasma/interstitial)
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
20%
65%
75%
60%
60%
lower
55%
electrolytes
inorganic compounds that dissociate into ions
what are most solutes and what does that mean
most electrolytes
means fluid balance is closely related to electrolyte balance
2 ways body can gain water
ingestion
metabolic synthesis
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
1600
700
2300
metabolic water (def, what reactions, mL/day)
produced in the body mainly when electrons are accepted by O2 during aerobic resp and some during dehydration synthesis reactions
200mL per day
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
1500
600
400
200
300
100
When more ATP is produced, ____ water is formed
more
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
hypothalamus
5 stimuli that stimulate thirst center in hypothalamus
- 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
urinary salt (NaCl) loss determines
body fluid volume as “water follows solutes” in osmosis and the two main solutes in ECF/urine is sodium and chloride
urinary water loss determines
body fluid osmolarity
ADH produced/stored by and AKA
AKA vasopressin
produced by hypothalamus
stored by post pituitary
ADH stimulated by
increased body fluid osmolarity (mostly)
decrease BV/BP, pain, nausea, stress
ADH promotes insertion of what and where
aquaporin-2 in apical membrane of principal cells of late distal tubules and collecting ducts
wha inhibits ADH secretion
alcohol which is why you pee so much
The two most important hormones that regulate the extent of renal Na+ reabsorption (and how much is lost in the urine)
aldosterone
atrial natriuretic peptide
aldosterone vs ANP
increase Na+ reabsorption in kidneys
vs
increases excretion of Na+ in urine
aldosterone steps in Na+ regulation (start with what stimulates it)
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)
ANP steps in Na+ regulation (start with what stimulates it)
increased BV
-> increased stretch of atria
-> release of ANP
-> natriuresis + water excretion in urine due to osmosis
-> decrease BV/BP
increase in osmolarity of ECF (happens when/results in/what happens to fix it)
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
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
water intoxication happens because and symptoms
excessive blood loss, sweating, vomiting, diarrhea coupled with water intake
mental confusion, seizures, coma, and possibly death
hyponatremia
decreased Na+ concentration of ECF
The ions formed when electrolytes dissolve and dissociate serve
four general functions in the body:
- control the osmosis of water between fluid compartments
- help maintain the acid–base balance
required for normal cellular activities - carry electrical current, which allows production of action potentials and graded potentials
- serve as cofactors needed for optimal activity of enzymes
what is the concentration of ions measured in
milliequivalents per liter (mEq/liter)
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
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+
sodium percentage of ECF cations and blood plasma concentration
90%
136-148 mEq/liter
sodium function (2)
- plays a pivotal role in fluid and electrolyte balance as it accounts for almost 1/2 of the osmolarity of ECF
- flow of Na+ through voltage gated channels in the PM is necessary for the generation and conduction of AP in neurons and MF
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
normal blood plasma Cl− concentration is ______ mEq/ liter
95-105