Exam #1 Study Guide
*****This is not a comprehensive list just a guide to get you started. I have included
a guide of important topics that I think you should spend time familiarizing yourself
with the concepts. Please make sure that you review all your notes and refer to
reading for further clarification. Good luck studying. Please email me with
questions. *****
Module 1 Cellular biology, Membrane physiology, action potentials,
skeletal/smooth muscle contraction, and Altered cellular tissue
Extracellular Fluid: Mostly Sodium Na+. Also known as Plasma.
Intracellular Fluid: Mostly Potassium K+
Positive and negative feedback – what are they? Understand basics of
what they do and how they affect physiology
Negative feedback: Promotes stability, cancels out the original response
Example: Hyperglycemia; the pancreas releases insulin to decrease the blood
sugar
Positive Feedback: Promotes a change in one direction, instability, disease
Example: Labor contractions; get stronger and closer so there is an
exaggerated response as the labor process goes on
Transport of molecules through the membrane; diffusion and what
affects it; facilitated diffusion, active transport; and osmosis and what it
is.
Cell Membrane: A lipid bilayer with a hydrophilic head and a hydrophobic tail. The
head has a charge and the tail is uncharged (fatty acid). Proteins are embedded in
the membrane that provide selectivity to a membrane. Act as channels, carriers,
transporters, receptors or messengers.
Cell Energy: ATP is the fuel for the cell. ATP is created in the presence of oxygen. A
maximum of 38 molecules of ATP are formed per molecule of glucose broken down.
Only 2 molecules are created in an anaerobic state.
Diffusion: Major mechanism of transport across the cell membrane.
Simple/Passive Diffusion: Does NOT require energy. Occurs down a concentration
gradient. Movement from an area of higher concentration to an area of lower
concentration to equalize the charge across the membrane. Depends largely on the
permeability of the membrane.
Factors that affect the net rate of diffusion;
1. Concentration difference. Molecules move from high concentration to low
concentration. The greater the difference, the faster things move.
, 2. Electrical Potential (EMF): The charge difference on each side of the
membrane matters too. The larger the difference of charge on either side
of the membrane will also increase the net rate of diffusion.
3. Pressure Difference: Higher pressure results in increased energy available
to cause net movement from higher to lower pressure areas.
Osmosis: The passive transport of fluid across a membrane (NOT diffusion of fluid),
from an area of lower solute concentration (hypotonic) to and area of higher solute
concentration (hypertonic). The pressure difference is what causes water to move.
Water moves down its concentration gradient. Osmosis stops when enough fluid has
moved through the membrane to equalize the solute concentration (isotonic).
Facilitated Diffusion: Molecules move along its electrochemical concentration
gradient (downhill) attached to a carrier protein molecule that facilitates its
passage. Does not move against electrochemical gradient. No energy is required.
Active Transport: Both require energy and use a carrier protein.
1. Primary Active Transport: Molecules are pumped against or uphill a
concentration. Direct use of energy or ATP. Example: Sodium potassium
pump.
2. Secondary Active Transport: Movement occurs because of energy
created by the movement of another molecule, usually Na+. Indirect use of
energy.
A) Co-transport or co-porters; When a substance is transported in the
same direction as the “driver” ion (usually Na+). Amino Acids &
Glucose.
B) Counter-transport or anti-porters; When a substance is transported
in the opposite direction as the “driver” ion (usually Na+). Calcium &
Hydrogen (in renal tubules)
Sodium Potassium Pump: Carrier protein located on the plasma membrane of all
cells. Na/K ATPase is the enzyme that converts ATP to ADP to release energy. Plays
an important role in regulating osmotic balance by maintain Na+ and K+ balance,
preventing the cells from swelling and bursting. Requires 2/3 of cells energy. Also
important in establishing negative electrical voltage inside the cell which is the basis
for nerve function. For every 3 Na+ that is pumped out of the cell, 2 K+ are pumped
into the cell.
Membrane permeability and ion permeability
Diffusion potentials: The potential difference generated across a membrane when
an ion diffuses down its gradient. Measured in Millivolts (Mv). Sign (negative or
positive) depends on the charge of the diffusing ion.
Equilibrium Potential: The diffusion potential that exactly balances or opposes the
tendency for the diffusion down the concentration gradient.
-Nernst Potential is the diffusion potential level across a membrane that exactly
opposes the net diffusion of a particular ion through the membrane.
-Ek= -94 mV (potassium equilibrium potential)
*****This is not a comprehensive list just a guide to get you started. I have included
a guide of important topics that I think you should spend time familiarizing yourself
with the concepts. Please make sure that you review all your notes and refer to
reading for further clarification. Good luck studying. Please email me with
questions. *****
Module 1 Cellular biology, Membrane physiology, action potentials,
skeletal/smooth muscle contraction, and Altered cellular tissue
Extracellular Fluid: Mostly Sodium Na+. Also known as Plasma.
Intracellular Fluid: Mostly Potassium K+
Positive and negative feedback – what are they? Understand basics of
what they do and how they affect physiology
Negative feedback: Promotes stability, cancels out the original response
Example: Hyperglycemia; the pancreas releases insulin to decrease the blood
sugar
Positive Feedback: Promotes a change in one direction, instability, disease
Example: Labor contractions; get stronger and closer so there is an
exaggerated response as the labor process goes on
Transport of molecules through the membrane; diffusion and what
affects it; facilitated diffusion, active transport; and osmosis and what it
is.
Cell Membrane: A lipid bilayer with a hydrophilic head and a hydrophobic tail. The
head has a charge and the tail is uncharged (fatty acid). Proteins are embedded in
the membrane that provide selectivity to a membrane. Act as channels, carriers,
transporters, receptors or messengers.
Cell Energy: ATP is the fuel for the cell. ATP is created in the presence of oxygen. A
maximum of 38 molecules of ATP are formed per molecule of glucose broken down.
Only 2 molecules are created in an anaerobic state.
Diffusion: Major mechanism of transport across the cell membrane.
Simple/Passive Diffusion: Does NOT require energy. Occurs down a concentration
gradient. Movement from an area of higher concentration to an area of lower
concentration to equalize the charge across the membrane. Depends largely on the
permeability of the membrane.
Factors that affect the net rate of diffusion;
1. Concentration difference. Molecules move from high concentration to low
concentration. The greater the difference, the faster things move.
, 2. Electrical Potential (EMF): The charge difference on each side of the
membrane matters too. The larger the difference of charge on either side
of the membrane will also increase the net rate of diffusion.
3. Pressure Difference: Higher pressure results in increased energy available
to cause net movement from higher to lower pressure areas.
Osmosis: The passive transport of fluid across a membrane (NOT diffusion of fluid),
from an area of lower solute concentration (hypotonic) to and area of higher solute
concentration (hypertonic). The pressure difference is what causes water to move.
Water moves down its concentration gradient. Osmosis stops when enough fluid has
moved through the membrane to equalize the solute concentration (isotonic).
Facilitated Diffusion: Molecules move along its electrochemical concentration
gradient (downhill) attached to a carrier protein molecule that facilitates its
passage. Does not move against electrochemical gradient. No energy is required.
Active Transport: Both require energy and use a carrier protein.
1. Primary Active Transport: Molecules are pumped against or uphill a
concentration. Direct use of energy or ATP. Example: Sodium potassium
pump.
2. Secondary Active Transport: Movement occurs because of energy
created by the movement of another molecule, usually Na+. Indirect use of
energy.
A) Co-transport or co-porters; When a substance is transported in the
same direction as the “driver” ion (usually Na+). Amino Acids &
Glucose.
B) Counter-transport or anti-porters; When a substance is transported
in the opposite direction as the “driver” ion (usually Na+). Calcium &
Hydrogen (in renal tubules)
Sodium Potassium Pump: Carrier protein located on the plasma membrane of all
cells. Na/K ATPase is the enzyme that converts ATP to ADP to release energy. Plays
an important role in regulating osmotic balance by maintain Na+ and K+ balance,
preventing the cells from swelling and bursting. Requires 2/3 of cells energy. Also
important in establishing negative electrical voltage inside the cell which is the basis
for nerve function. For every 3 Na+ that is pumped out of the cell, 2 K+ are pumped
into the cell.
Membrane permeability and ion permeability
Diffusion potentials: The potential difference generated across a membrane when
an ion diffuses down its gradient. Measured in Millivolts (Mv). Sign (negative or
positive) depends on the charge of the diffusing ion.
Equilibrium Potential: The diffusion potential that exactly balances or opposes the
tendency for the diffusion down the concentration gradient.
-Nernst Potential is the diffusion potential level across a membrane that exactly
opposes the net diffusion of a particular ion through the membrane.
-Ek= -94 mV (potassium equilibrium potential)
