Chapter 25: The Body Compartments: Extracellular and Intracellular Fluids; Edema Guyton and Hall,...
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Transcript of Chapter 25: The Body Compartments: Extracellular and Intracellular Fluids; Edema Guyton and Hall,...
Unit Five: The Body Fluids and Kidneys
Chapter 25: The Body Compartments: Extracellular and
Intracellular Fluids; Edema
Guyton and Hall, Textbook of Medical Physiology, 12th edition
Balance of Fluid Intake and Output
• Steady-State Balance
a. Daily intake of waterb. Daily loss of water-insensible water lossc. Fluid loss in sweatd. Water loss in fecese. Water loss by the kidneys
Normal Prolonged Heavy
Exercise
Intake
Fluids ingested 2100 ?
From metabolism
200 200
Total Intake 2300 ?
Output
Insensible-skin 350 350
Insensible-lungs
350 650
Sweat 100 5000
Feces 100 100
Urine 1400 500
Total Output 2300 6600
Table 25.1 Daily Intake and Output of Water (ml/day)
Body Fluid Compartments
Fig. 25.1 Summary of body fluid regulation, including the major body fluid compartments
Compartments (cont.)
• Body Fluid Compartments
a. Intracellularb. Extracellular-interstitial fluid and blood plasmac. Transcellular-fluids in the synovial, peritoneal,
pericardial, intraocular spaces, and the CSFd. Total body water for men is about 60% and 50%
for womene. Varies with age, gender, and degree of obesity
Compartments (cont.)
• Intracellular Fluid Compartment
a. Constitutes about 40% of the fluid in the averageperson
b. Concentration of substances is similar from cellto cell
Compartments (cont.)
• Extracellular Fluid Compartment
a. Interstitial fluid-makes up about 75% of the fluidb. Blood plasma-makes up 25% of the fluidc. Only real difference between the two types is the
protein composition of the plasma
Blood Volume
• Blood Volume
a. Makes up about 7% of the body weight (5 L)b. 60% plasma and 40% cellsc. Percentages vary according to gender, weight, etc.
• Hematocrit
a. Red blood cell fraction of the bloodb. 96% accurate because you cannot pack the cells
completelyc. Males (o.40) and females (o.30)
Constituents of Extra- and Intracellular Fluids
Fig. 25.2 Major cations and anions of intracellular and extracellular fluids.
Fig. 25.2 Nonelectrolytes of the plasma
Constituents of Extra- and Intracellular Fluids
Plasma (mOsm/L of
Water
Interstitial (mOsm/L of
Water
Intracellular (mOsm/L of
Water
Sodium 142 139 14
Potassium 4.2 4.0 140
Calcium 1.3 1.2 0
Magnesium 0.8 0.7 20
Chlorine 108 108 4
Bicarbonate 24 28.3 10
Phosphate 2 2 11
Sulfate 0.5 0.5 1
Phosphocreatine
45
Carnosine 14
Amino acids 2 2 8
Table 25.2 Osmolar substances in extracellular and intracellular fluids
Constituents of Extra- and Intracellular Fluids
Plasma (mOsm/L of
Water
Interstitial (mOsm/L of
Water
Intracellular (mOsm/L of
Water
Creatine 0.2 0.2 9
Lactate 1.2 1.2 1.5
ATP 5
Hexose monophosphate
3.7
Glucose 5.6 5.6
Protein 1.2 0.2 4
Urea 4 4 4
Others 4.8 3.9 10
Total mOsm/L 301.8 300.8 301.2
Corrected osmolar activity
282 281 281
Total Osmotic Pressure (37 C)
5443 5423 5423
Table 25.2 Osmolar substances in extracellular and intracellular fluids
Basic Principles of Osmosis and Osmotic Pressure
• Osmosis is the net diffusion of water across a selectively permeable membrane from a region of high water concentration to one that has a lower water concentration.
• Rate of diffusion of water is called the rate of osmosis.
Moles vs. Osmoles
• Osmoles-the total number of particles in a solution
• One osmole is equal to 1 mole of solute particles
• Osmole refers to the number of osmotically active
particles in a solution rather than to the molar
concentration
Osmolality vs. Osmolarity
• Osmolality = osmoles/kg of water
• Osmolarity = osmoles/L of solution
Osmotic Equilibrium
• Isotonic-occurs if the water concentration of both intra-
cellular and extracellular fluid is the same; cells do
shrink or swell
• Hypotonic-occurs if the water concentration is lower
inside the cell (solutes are higher inside) and
the cell will swell and possibly lyse
• Hypertonic-occurs if the water concentration is
higher inside the cell (solutes are lower inside)
and the cell shrivels (crenates); water flows out
of the cell
Fig. 25.5 Effects of isotonic, hypotonic, and hypertonic solutions on cell volume
Equilibrium (cont.)
• Isosmotic-solutions with an osmolarity the same as the cell
• Hyperosmotic-solutions with a higher osmolarity
• Hyposmotic-solutions with a lower osmolarity
Volume and Osmolality in Abnormal States
• Effect of adding saline to extracellular fluid
• Hyponatremia
• Hyperantremia
Edema
• Intracellular Edema
a. Hyponatremiab. Depression of metabolic systems of tissuesc. Lack of adequate nutrition to the cells
• Extracellular Edema
a. Abnormal leakage of fluid from plasmab. Failure of the lymphatics to return the fluid
(lymphedema)