12-lead ch.2 Flashcards
Where are actin and myosin molecules located in relation to the cell?
Outside edges edges of the barrel wall of the cells
Explain what cell barrels are made of including myofibrils and sheets.
The outside barrels are fused to form long bands called myofibrils. The bands are held together with connective tissue that make up the sheets. The sheets are covered in extra cellular fluid.
What are the positive and negative ions in cells?
Positive ions are: sodium, potassium and calcium. Chloride is the negative ion.
Which ions are intra and extra-cellular? What charges do each carry?
Potassium is generally inside the cell while sodium has a higher concentration outside the cell making it mor positive. Calcium also is on the outside of the cell generally making it even more positive outside the cell.
Why do cells need a sodium-potassium pump?
Ions naturally want to cancel themselves out so the natural tendency is for sodium to enter the cell and potassium to leak out. So the pump is necessary to keep them on their proper sides of the cell.
How many ions can the pump shift?
The pump can push out 3 sodium ions and bring in two potassium ions at a time.
What is normal resting electrical potential?
-70 to -90mV
Which phase of action potential is slowly increasing the cell’s electrical potential?
Phase 4
When the cell becomes so positively charged that a new set of channels open this is called______, ________.
Threshold potential
What channels are opening at threshold potential?
The fast sodium channels
The most common ion outside the cell is____ and the rapid increase inside the cell causes action potential to fire; this is phase___.
Sodium. Phase 0
The point where the cell is not polarized or negatively charged is______.
Depolarized
The initial slowdown phase is when some negatively charged chloride ions enter and inflow of sodium slows.
Phase 1.
Two channels that open in phase 2 are_____ and ____ ____ channels.
Calcium and slow sodium channels.
Which phase is the plateau phase?
Phase 2
