"The Body Electric"
The transmembrane potential (Cell "battery" voltage) is the voltage DIFFERENCE between the inside and outside of a biological cell's bilayer lipid membrane (with the interior membrane being more NEGATIVELY CHARGED relative to the exterior membrane). The membrane is a diffusion barrier to the movement of ions (electrically negatively or positively charged). Transmembrane protein Ion pumps/transporters actively push Ions across the membrane to establish a concentration gradient across the membrane, or ions travel passively through protein ion channels across cell membranes down those concentration gradients.
A healthy cell maintains a measurable resting "battery" voltage of about -60 to -100 millivolts (mV). Depends upon the cell type - typical healthy values are -60 to -90mV, heart cells are highest at -90 to -100mV.
In contrast, when a cell is poisoned, injured or nutrient-deprived, the "cell battery" voltage falls to a level as low as 40 mV. At this level the sodium / potassium pumps will malfunction, cellular energy production will stop, and the cell will either struggle to heal itself or die. In the case of a cancerous cell, the survival mechanism has "kicked in", enabling it only to multiply, but no longer perform its assigned task.
"Cell battery" voltage falls with age. Due to the stresses of life, malnutrition and a toxic, unnatural environment, the human cell loses approximately 10% of its original "cell battery" voltage every 24 years, diminishing roughly according to the following chart:
| Age: | Birth | 24 yrs | 48 yrs | 72 yrs | 96 yrs |
|---|---|---|---|---|---|
|
Percentage of Original Cell "Battery Voltage" |
100% |
90% |
80% |
70% |
60% |
Fortunately, there are methods available to us, which will recharge our depleted cell "batteries"
Beneficial Energy Charges the Cell Battery
The electrical charge difference or voltage across the membrane of a human cell is called the transmembrane potential (TMP) or more familiarly, the "Cell Battery" voltage. The charge difference is determined by a vital imbalance of mineral ions, such as K+, Na+, Ca++ and H+, separated on either side of the membrane.
The "cell battery"provides the driving force for active transport of ingredients across the cell membrane
The imbalance of ions across the cell membrane is maintained by powered membrane transport pumps (gated protein channels) that move ions across the semi-permeable membrane in the opposite direction to their concentration gradient. Ions can move without help from a higher concentration to a lower concentration (i.e. by diffusion), but need a "push" to move against their concentration gradient. Most ion channels are "gated", meaning they must be stimulated to open or close by electrical (and sometimes mechanical or chemical) mechanisms.
- Important membrane pumps (actually enzymes):
For more information on how substances cross the cell membrane:
It is mainly the Na/K pumps (Sodium-Potassium Adenosine Triphosphatase) that keep the "Cell Battery" charged. Cells maintain a transmembrane potential difference across their cell membranes by keeping a specific balance of potassium ions (K+) INSIDE and sodium ions (Na+) OUTSIDE their cells. This is accomplished by using membrane Na/K pumps to pump Na+ ions out of the cell and K+ ions into the cell against their concentration gradients (i.e. the opposite of diffusion). This maintains a low sodium / high potassium ion concentration inside the cell.
For those quirky people, who would like to see more detail about how the resting potential difference is established, see:
The Cell "Battery" Resting potential
The Na/K pumps are opened or closed by a change in the "cell battery" voltage. Stimulated by the transmembrane potential, the opening of the Na/K pumpsgenerates an inward current that affects the membrane potential itself (creating a reinforcing positive loop).
The "cell battery" voltage must be maintained at a healthy level to enable delivery (via secondary active transporters) of "outside" supplies (glucose, amino acids and other nutrients) for mitochondrial ATP energy production and for the cell to function. At least 30% of the ATP energy produced by the cell mitochondria is used to power the membrane pumps.
The "Cell Battery" voltage affects all Electrical activity of the cell. The membrane resting potential prepares the "excitable" nerve and muscle cells for the propagation of action potentials leading to nerve impulses and muscle contraction. E.g. the heart muscle cells (myocardial cells) require a sufficient membrane potential for the heart to beat; pain messages are passed via nerve impulses.
