Effects of NaCl Concentration on Red Blood Cell Volume A red blood cell (rbc) will attempt to regulate its volume when placed in a solution of impermeable substances dissolved in water (Randall, 1997). A solution is considered to be isosmotic when it has an osmolality equal to that of normal plasma (Freedman, 1998). The osmolarity is the osmotic pressure that a cell effectively has exerted upon it (Randall, 1997). The osmotic pressure is the pressure that is created by osmosis between different solutions that are separated by a semipermeable membrane (Randall, 1997). If a rbc is placed in an isotonic solution, the cell will maintain its normal volume because no osmotic pressure is developed. A hypotonic solution has a lower concentration of solutes than the interior of the cell. Therefore, a hypotonic solution will cause water to flow into the cell, as the concentration of solutes inside of the cell is higher. If this water influx continues for a long period of time (with ineffective (or absence of) volume regulation by the cell), the cell my lyse (burst) as the pressure builds up inside to a magnitude greater than can be handled by the cellular membrane. here are a number of ways in which red blood cells (and animal cells in general) cope with changes in solute concentration on the outside of their membrane surfaces. There may be a volume regulatory decrease (RVD) or increase (RVI) depending upon the concentration of the solutes on the outside of the cellular membrane (Freedman, 1998). The response that is activated by the swelling of the cells usually involves an increase in the K+/Cl- transporters (see figure 2) in ducks, sheep, rabbits, and some other mammals (Freedman, 1998; Motais et al, 1997). The swelling response may also trigger the formation of a channel (in which band 3 is involved) that allows osmolytes such as taurine (and other small, organic, osmotically active solutes) to be transported out of the cell (Freedman, 1998; Motais et al, 1997). The shrink activated response in red blood cells involves the activation of Na+/K+/2 Cl- cotransporters (in general, and in the case of the duck (Freedman, 1998)). The molarity in plasma of NaCl is approximately 0.15M, therefore the concentration of 0.15M NaCl treatment would be considered isosmotic to red blood cell plasma. The change in concentration to 0.12 M NaCl would be a hypotonic condition, and the conditions of 0.21, 0.33, 0.157, and 1.05M NaCl would be hypertonic conditions. Solution Effects of NaCl Concentration on Red Blood Cell Volume A red blood cell (rbc) will attempt to regulate its volume when placed in a solution of impermeable substances dissolved in water (Randall, 1997). A solution is considered to be isosmotic when it has an osmolality equal to that of normal plasma (Freedman, 1998). The osmolarity is the osmotic pressure that a cell effectively has exerted upon it (Randall, 1997). The osmotic pressure is the pressure that is created by osmosis between different soluti.

1. Effects of NaCl Concentration on Red Blood Cell Volume
A red blood cell (rbc) will attempt to regulate its volume when placed in a solution of
impermeable substances dissolved in water (Randall, 1997). A solution is considered to be
isosmotic when it has an osmolality equal to that of normal plasma (Freedman, 1998). The
osmolarity is the osmotic pressure that a cell effectively has exerted upon it (Randall, 1997). The
osmotic pressure is the pressure that is created by osmosis between different solutions that are
separated by a semipermeable membrane (Randall, 1997). If a rbc is placed in an isotonic
solution, the cell will maintain its normal volume because no osmotic pressure is developed. A
hypotonic solution has a lower concentration of solutes than the interior of the cell. Therefore, a
hypotonic solution will cause water to flow into the cell, as the concentration of solutes inside of
the cell is higher. If this water influx continues for a long period of time (with ineffective (or
absence of) volume regulation by the cell), the cell my lyse (burst) as the pressure builds up
inside to a magnitude greater than can be handled by the cellular membrane.
here are a number of ways in which red blood cells (and animal cells in general) cope with
changes in solute concentration on the outside of their membrane surfaces. There may be a
volume regulatory decrease (RVD) or increase (RVI) depending upon the concentration of the
solutes on the outside of the cellular membrane (Freedman, 1998). The response that is activated
by the swelling of the cells usually involves an increase in the K+/Cl- transporters (see figure 2)
in ducks, sheep, rabbits, and some other mammals (Freedman, 1998; Motais et al, 1997). The
swelling response may also trigger the formation of a channel (in which band 3 is involved) that
allows osmolytes such as taurine (and other small, organic, osmotically active solutes) to be
transported out of the cell (Freedman, 1998; Motais et al, 1997). The shrink activated response in
red blood cells involves the activation of Na+/K+/2 Cl- cotransporters (in general, and in the
case of the duck (Freedman, 1998)).
The molarity in plasma of NaCl is approximately 0.15M, therefore the concentration of 0.15M
NaCl treatment would be considered isosmotic to red blood cell plasma. The change in
concentration to 0.12 M NaCl would be a hypotonic condition, and the conditions of 0.21, 0.33,
0.157, and 1.05M NaCl would be hypertonic conditions.
Solution
Effects of NaCl Concentration on Red Blood Cell Volume
A red blood cell (rbc) will attempt to regulate its volume when placed in a solution of

2. impermeable substances dissolved in water (Randall, 1997). A solution is considered to be
isosmotic when it has an osmolality equal to that of normal plasma (Freedman, 1998). The
osmolarity is the osmotic pressure that a cell effectively has exerted upon it (Randall, 1997). The
osmotic pressure is the pressure that is created by osmosis between different solutions that are
separated by a semipermeable membrane (Randall, 1997). If a rbc is placed in an isotonic
solution, the cell will maintain its normal volume because no osmotic pressure is developed. A
hypotonic solution has a lower concentration of solutes than the interior of the cell. Therefore, a
hypotonic solution will cause water to flow into the cell, as the concentration of solutes inside of
the cell is higher. If this water influx continues for a long period of time (with ineffective (or
absence of) volume regulation by the cell), the cell my lyse (burst) as the pressure builds up
inside to a magnitude greater than can be handled by the cellular membrane.
here are a number of ways in which red blood cells (and animal cells in general) cope with
changes in solute concentration on the outside of their membrane surfaces. There may be a
volume regulatory decrease (RVD) or increase (RVI) depending upon the concentration of the
solutes on the outside of the cellular membrane (Freedman, 1998). The response that is activated
by the swelling of the cells usually involves an increase in the K+/Cl- transporters (see figure 2)
in ducks, sheep, rabbits, and some other mammals (Freedman, 1998; Motais et al, 1997). The
swelling response may also trigger the formation of a channel (in which band 3 is involved) that
allows osmolytes such as taurine (and other small, organic, osmotically active solutes) to be
transported out of the cell (Freedman, 1998; Motais et al, 1997). The shrink activated response in
red blood cells involves the activation of Na+/K+/2 Cl- cotransporters (in general, and in the
case of the duck (Freedman, 1998)).
The molarity in plasma of NaCl is approximately 0.15M, therefore the concentration of 0.15M
NaCl treatment would be considered isosmotic to red blood cell plasma. The change in
concentration to 0.12 M NaCl would be a hypotonic condition, and the conditions of 0.21, 0.33,
0.157, and 1.05M NaCl would be hypertonic conditions.