Lecture 13 (Fluid, Electrolytes, and Acid-Base Balance) Flashcards
fluid, electrolyte, and acid-base balance within the body maintain the health and function of which body system?
all of them
why does the characteristics of body fluids influence body system function why?
because of their effects on cell function
what are the characteristics of body fluids that affect cell function(4)?
1) volume (amount)
2) osmolarity (concentration)
3) electrolyte concentration (composition)
4) pH (degree of acidity)
how much total body water is in intracellular fluid in adults?
about 2/3
how much total body water is in extracellular fluid in adults?
about 1/3
what are the two major divisions of extracellular fluid?
1) intravascular fluid (liquid part of blood-plasma)
2) interstitial fluid (between cells and the outside of blood vessels
what are the two minor division of extracellular fluid?
transcellular fluid (cerebrospinal fluid, pleural, peritoneal, and synovial fluids)
fluid that contains a large number of dissolved particles is (BLANK) than the same fluid that contains only a few particles
more concentrated
what is the osmolarity of a fluid?
a measure of the number of particles per kg of water
some particles can cross easily through cell membranes. can sodium?
it can but not easily
what sets the tonicity of a fluid?
presence of particles that can not cross easily across cell membranes
what is tonicity?
the effective concentration of a fluid
what is an isotonic fluid?
a fluid with the same tonicity as blood
e.g. blood
what is a hypertonic solution?
a solution that is more concentrated than blood
what is a hypotonic solution?
a solution that is more dilute than blood
what is fluid homeostasis?
the dynamic interplay of three processes:
1) fluid intake and absorption
2) fluid distribution
3) fluid output
what is fluid intake?
drinking and eating
what is fluid distribution?
the movement of fluid among its various compartments and between the intracellular and extracellular compartments
how does fluid distribution between intracellular and extracellular compartments occur?
by osmosis
how does fluid distribution between vascular and interstitial portions of the ECF occur?
by filtration
what are examples of fluid output?
urine and sweat
to maintain homeostasis, intake and output have to be…
equal to each other
how much is the average fluid intake via eating and drinking?
2300mL for healthy adults
describe thirst(2)
1) regulates fluid intake when plasma osmolarity increases
2) thirst-control mechanism is located in the hypothalamus
what are osmoreceptors?
receptors that continuously monitor plasma osmolarity. when it increases, they cause thirst by stimulating neurons in the hypothalamus
what is angiotensin 2’s role in the thirst response?
binds to the hypothalmus in the brain, stimulating thirst
describe the relationship between hormones and the kidneys when it comes to fluid output
the kidneys respond to some hormones that influence urine production
which hormones influence urine production in the kidneys(3)?
1) antidiuretic hormone (ADH)
2) renin-angiotensin-aldosterone mechanism
3) atrial natriuretic peptides (ANPs)
what are the avenues of fluid output(4)?
1) kidneys
2) skin
3) lungs
4) GI tract
what is insensible fluid output?
fluid output that is not visible
1) skin (sweat)
2) lungs
what is sensible fluid output?
visible fluid output
1) kidneys
2) GI tract
how much fluid moves into the GI tract then returns to the ECF?
3 - 6 L
the average adults excretes how much fluid each day through feces?
100mL
what are S/Sx of clinical dehydration(2)?
1) ECV deficit
2) hypernatremia
what is another name for ADH?
vasopressin
- A patient is diaphoretic and has an oral temperature of 104° F. These are classic signs of:
A. ADH deficit.
B. extracellular fluid loss.
C. insensible water loss.
D. sensible water loss.
A
what are normal sodium (Na+) lab values?
136-145mEq/L
what are normal potassium (K+) lab values?
3.5-5.0 mEq/L
what are normal chloride (Cl-) lab values?
98-106 mEq/L
what are normal total CO2 lab values?
22-30 mEq/L
what are normal bicarbonate (HCO3) lab values?
arterial: 21-28 mEq/L
venous: 24-30 mEq/L