Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
14 Cards in this Set
- Front
- Back
|
.......are electrically active and this ....... can be used as a mechanism to signal a cell to perform a particular function.
|
Cell, electrical potential
|
|
|
is defined as a separation of charged particles.
|
Voltage
|
|
|
When discussing a battery it's customary to talk about two battery terminals made of different metals where one end has electrons and the other end is lacking enough electrons. One terminal is negative and the other is positive. The greater the difference in numbers of electrons between each terminal the greater the........
|
Voltage
|
|
|
A cell's voltage is measured in terms of......
|
millivolts (mV)
|
|
|
describes the flow or movement of charged particles.
|
Current
|
|
|
An ...... ...... is created when charges are allowed to flow toward each other
|
electric current
|
|
|
A cell tends to have a more ...... charge on the outside of the membrane than on the inside of the membrane, which tends to be .......
|
positive,negative
|
|
|
The membrane voltage of a typical cell is around .
|
-70 mV...his is listed as -70mv because the inside of the cell is 70 mV more negative on the inside than the outside of the cell.
|
|
|
We can say the cell membrane is ...... due to the different charges on each side of the membrane.
|
polarized
|
|
|
Causes of Resting Membrane Potential
|
The first cause has to do with the fact that most cells have a large collection of negatively charged molecules inside the cell. Carbohydrates, phospholipids and amino and nucleic acids all can have negative charges on them.The second reason has to do with an uneven distribution of two particular ions, Na and K. There are high levels of Na+ outside cell compared to the inside. On the other hand, there are high levels of K+ inside compared to the outside. So there are two concentration gradients at work. Na is high on the outside of the cell and would like to move inside according to the laws of diffusion. K is high on the inside and would like to leave the cell.
|
|
|
The ........ is the protein used to perform this active transport function.
|
Na - K ion exchange pump..Both ions are transported by the same protein. Na is pumped out and K is pumped in. This restores the ion concentrations to their proper position. As it turns out, these ions are not transported in and out in equal numbers, three Na are pumped out and only two K are pumped in. Since both are positively charged ions, the cell is losing 3 positive charges and only gaining 2. That's a net loss of one positive charge so the inside of the cell become more negative than the outside.Think of this as a cash flow issue. If someone came up to you and offered you two dollars but you had to give them 3 dollars what would eventually happen to your money? In business this is called a negative cash flow situation. More money is going out than going in. This is when you should make a call home to the parents to add cash to your account. A similar thing happens inside a cell as it removes 3 positive charges and only replaces two.
|
|
|
The ....... generated by living cells is called an action potential.
|
electrical signal
|
|
|
Eventually the Na channels will close and prevent any more Na from entering the cell. At the same time, K channels open which allows the positively charged potassium ions to leave the cell. This has the effect of making the outside of the cell more positive than the inside. The charge gradient is then back to where it was at the beginning. This is called ....... The cell is now positive on the outside and negative on the inside but the Na and K gradients are all messed up.
|
Repolarization
|
|
|
An ....... is used by many women during childbirth rather than taking an oral narcotic that would also affect the baby
|
epidural procedure
|
