Term
| List the fluid compartments of the body. |
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Definition
-blood plasma
-interstitial fluid
-intracellular fluid |
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Term
| What fraction of TBW does the intracellular fluid make up? |
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Definition
| 2/3 of TBW or 40% of body weight |
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Term
| What fraction of TBW does extracellular fluid make up? What % of body weight? |
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Definition
| 1/3 of TBW or 20% of body weight. |
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Term
| How does age, adipose tissue, or gender effect total body of water? |
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Definition
-As you age %TBW decreases
-Increase in adipose tissue decreases the TBW
-Men have a greater % of TBW |
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Term
| What fluids make up the transcellular fluid compartment? |
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Definition
-fluid in the lumina of epithelial organs
-cerebrospinal fluid
-intraocular fluid |
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Term
| What organs communicate the ECF with the external environment? |
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Definition
-alimentary canal
-lungs
-kidneys
-skin |
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Term
| Where are Na and Cl the predominant ions? |
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Definition
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Term
| What is the predominant ion of ICF? |
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Definition
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Term
| T/F. Protein concentration is greater in ISF. Why or why not? |
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Definition
| False protein concentration is greater in plasma b/c the capillary epithelium does not allow proteins to freely cross into the ISF. |
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Term
| T/F. The osmolarity of plasma, ISF, and ECF are equal. |
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Definition
| True. This is because the capillaries and most plasma cell membranes are permeable to water so that osmolarity is about 295 mOsm/L. |
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Term
| What are three characteristics of a substance used to measure the distribution of water? |
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Definition
-nontoxic at concentrations used
-neither synthesized nor metabolized
-does not cause shifts in fluid distribution among the compartments |
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Term
| What substance is used to measure plasma volume? Why? |
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Definition
| Serum albumin labeled with radioactive iodine or Evan's blue dyeis used to measure plasma volume b/c albumin is a large protein that cannot pass through capillary walls. |
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Term
| What substance is used to measure extracellular fluid volume? Why is this substance used? |
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Definition
| Inulin is used to measure extracellular fluid volume b/c its can freely pass through capillary walls, but cannot cross cell membranes. |
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Term
| What is a complication to using inulin to measure extracellular fluid? |
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Definition
| Inulin is excreted by the kidney's so this volume must be taken into account when determining ECF volume. |
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Term
| What substance is used to measure total body water? |
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Definition
| Antipyrine, or deuterated or tritiated water are used b/c they can rapidly permeate cell membranes allowing for uniform distribution throughout the body. |
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Term
| T/F. Equilibrium of ICF and ECF osmolality occurs primarily through shifts in solutes. |
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Definition
| False. Equilibrium depends on shifts in water not shifts in solutes. |
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