Membrane potential - a nerve cell set and ready to fire;
"The wave of reverse polarity" i.e. sodium versus potassium trans-cell-membrane ion passaging - a nerve cell firing; and
Recharge period - the regeneration time.
I think you're looking for three ... over the long run. But the trick is that K+ doesn't need to be pumped in. Membrane proteins act as variable sized pore in the membrane (channels) and the potassium flows in under electrostatic forces ... all the work is done pumping the Na+ out.
The refractory period for a membrane is the time it takes for the membrane to reset and be able to respond to another stimulus. During this period, the membrane is temporarily unable to respond to additional stimuli. This impacts the ability of the membrane to rapidly and continuously transmit signals, as it needs time to recover before it can respond again.
It's true that the structure of the neurone and its synapses mean that transmission will only be in one direction. However, the fibre itself is capable of transmitting in both directions: if you artificially stimulated the axon in the middle, impulses would go out in both directions from the point of stimulation. However, in a working neurone, there has to be some mechanism preventing the impulse from echoing back on itself all the time. This is prevented by the refractory period. When any one part of the neurone has an action potential, local electrical currents stimulate the next part - hence transmission. But the part which has just had an action potential is in the refractory period - it is temporarily hyperpolarised, so the local currents have no effect. This hyperpolarisation only lasts for about half a millisecond, so another action potential can come along very soon afterwards. Hyperpolarisation is due to potassium gates in the membrane being open, so positively charged K+ ions diffuse in.
The hymen is a thin membrane that partially covers the vaginal opening and does not completely block the flow of menstrual blood. Menstrual blood can still pass through the hymen and out of the body during a period.
During the absolute refractory period, the neuron is unable to generate another action potential, regardless of the stimulus strength. This is because sodium channels are inactive and unable to open. This period ensures that action potentials are discrete and travel in one direction along the axon.
sodium-potassium pump
The chief positive intracellular ion in a resting neuron is a potassium ion. Just inside the cell of a resting neuron, the membrane is negative.
I think you're looking for three ... over the long run. But the trick is that K+ doesn't need to be pumped in. Membrane proteins act as variable sized pore in the membrane (channels) and the potassium flows in under electrostatic forces ... all the work is done pumping the Na+ out.
§Labor and management§Productivity§Wage levels§Training needs§Local infrastructureMeasuring site potential in step 3 involves determining whether a site can supply adequate resources needed to carry out the proposed business activity. Key issues include:•For many companies the most important resources will be labor and management.•The productivity and wage levels of local labor and managers.•The cost of training local managers, which can mean substantial investments of time and money.•And the efficiency of local infrastructures, including roads, bridges, airports, seaports, and telecommunications systems.
The first element in the fourth period of the periodic table is potassium with the atomic number 19.
Potassium (K) is a metal in Group I of the Periodic Table of the Elements. K has an atomic number of 19 and a molecular weight of 39.10 grams per mole.
The first element in the fourth period of the periodic table is potassium (K).
Potassium
Potassium belongs to group-1. It has one valence electron.
Potassium and magnesium are not in the same period on the periodic table. Potassium is in the fourth period (row) while magnesium is in the third period. They are both in the same group (column), Group 2, which are known as the alkaline earth metals.
Chlorine is the halogen that is in the same period as potassium. They are both in period 3 of the periodic table.
As the action potential passes an area on the axon, sodium channels are closed, preventing influx of more sodium ions. At the same time, voltage-sensitive potassium channels open, allowing the membrane potential to fall quickly. After this repolarization phase, membrane permeability to potassium remains high, allowing for the "afterhyperpolarization" phase. During this entire period, while the sodium ion channels are forced closed, another action potential cannot be generated except by a much larger input signal. This helps to prevent the action potential from moving backwards along the axon.