Human Physiology
Unit Three
- a covalently bonded,
polar molecule
Molecules are said to be
polar if they have slight
opposite charges on either
end
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The slight attraction
between the negative
end of one molecule and
the positive end of
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another results in a…
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- Polarity leads to adhesion and cohesion
- Adhesion and cohesion lead to capillary
action and surface tension
- High specific heat leads to temperature
stability
- High heat of vaporization leads to
evaporative cooling
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- Spheres of hydration form electrostatic
interactions, keeping ions from
interacting with each other
- This characteristic means water has a
high degree of solvency and chemical
reactivity
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- Water also ionizes into H+ and OH- which
can be incorporated into other molecules
or released from them
Fluid Mosaic Model of the
Plasma Membrane
Fluid Mosaic Model of the
Plasma Membrane
Fluid Mosaic
Model of the
Plasma Membrane
Fluid Mosaic Model of the
Plasma Membrane
Fluid Mosaic Model of the
Plasma Membrane
Does not require energy from the cell
Substances move from an area of
high concentration to an area of low
concentration
Substances can move in both
directions, depending on the
concentration gradient
Diffusion – the movement of a
substance from an area of high
concentration to an area of low
concentration
Facilitated diffusion – same as above,
but with the help of membrane
proteins
Osmosis – the diffusion of water
Osmo
sis
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Lysed
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Crenated
Osmosis
Osmosis
Osmosis
Therefore, the higher the solute
concentration, the higher the osmotic
pressure
Many body systems create high solute
concentrations so as to produce higher
osmotic pressure
Solute Concentration Measurements
Molarity = one mole of solute/Liter
Osmolarity = one mole of solute particles/Liter
1M C6H12O6 = 1osm (C6H12O6)
1M NaCl = 2osm (Na+ and Cl-)
1M CaCl2 = 3osm (Ca2+ and 2Cl-)
Does require energy from the cell
Substances move from an area of low
concentration to an area of high
concentration
Substances can move in only one
direction, against the concentration
gradient
Sodium/Potassium pump – a membrane
protein that moves sodium out, while
moving potassium in
Resting Membrane Potential
Resting membrane
potential:
+ polarization of
a cell due to
differences in
external & internal
ion
concentrations
Resting Membrane Potential
Resting Membrane Potential
Resting Membrane Potential
Resting Membrane Potential
The Nernst Equation
Ex = 61/z log [Xo]/[Xi]
Ex = equilibrium potential
z = valence of the ion
[Xo] = [ion] on outside of cell
[Xi] = [ion] on inside of cell
Resting Membrane Potential
Resting Membrane Potential
Action Potentials
Action potential:
+ an electrical
(nerve) impulse
+ generated by
chemically
mediated
channels
+ propagated by
Action Potentials
Action Potentials
Action Potentials