Action Potential

• The action potential is an electrical signal that travels along the axon of a neuron.
• The resting membrane potential (RMP) is maintained by the balance between ion channels and pumps.
• During an action potential, there is a rapid depolarization followed by repolarization and hyperpolarization.
• Action potentials are generated by changes in membrane voltage, which can be triggered by various stimuli such as chemical signals or mechanical forces.
• The threshold voltage is -55 mV.
• The action potential reaches its peak at +30 mV.
• The resting membrane potential is -70 mV.
• Neurotransmitters are chemical messengers that transmit signals across the synapse from the presynaptic neuron to the postsynaptic neuron.
• Repolarization occurs when K+ channels open and allow K+ to leave the cell.
• Depolarization occurs when sodium channels open, allowing Na+ to enter the cell.
• Excitable cells include muscle fibers, cardiac myocytes, and endocrine cells.
• Hyperpolarization occurs when more K+ leaves than enters the cell during repolarization.
• Ions are charged particles, with positive charges called cations and negative charges called anions.
• Depolarization occurs when sodium channels open, allowing Na+ to enter the cell down its concentration gradient.
• Sodium-potassium pump maintains RMP by actively transporting Na+ out of the cell and K+ into the cell against their concentration gradients.
• Repolarization occurs when potassium channels open, causing K+ to leave the cell down its concentration gradient.
• Leakage channels allow small amounts of Na+ to enter the cell and K+ to leave the cell down their electrochemical gradient.
• Neurons have specialized structures called dendrites and synapses that allow them to communicate with other cells.
• The resting membrane potential is the electrical charge of a neuron when it is not active.
• Synaptic transmission involves the release of neurotransmitters from one cell onto another, leading to either excitation or inhibition.
• Repolarization occurs when potassium channels open, causing K+ to leave the cell.
• Hyperpolarization occurs when Na+ channels close and K+ channels remain open.
• Sodium-potassium pump maintains RMP
• Hyperpolarization occurs when more K+ leaves than enters the cell.
• Refractory period refers to the time during which a nerve cannot generate another action potential.
• Excitatory neurotransmitters increase the likelihood of an action potential being fired in the postsynaptic cell, while inhibitory neurotransmitters decrease this likelihood.
• Leakage channels allow small amounts of Na+ to enter and K+ to exit
• Glutamate is an excitatory neurotransmitter involved in memory formation and plasticity.
• Acetylcholine (ACh) is an excitatory neurotransmitter involved in muscle contraction and learning/memory processes.
• Depolarization occurs when Na+ channels open and allow Na+ to enter the cell.
• Hyperpolarization occurs when potassium channels open, causing more K+ to exit the cell than enter it.
• Hyperpolarization occurs when K+ channels remain open and more K+ leaves the cell than enters it.
• Sodium-potassium pump maintains concentration gradients by actively transporting Na+ out of the cell and K+ into the cell.
• Refractory period refers to the time during an AP when the neuron cannot generate another AP.
• Sodium-potassium pump maintains the concentration gradient by actively transporting three Na+ out of the cell for every two K+ brought into the cell.
• Leakage channels allow small amounts of Na+ and K+ to passively diffuse through the membrane.
• Sodium-potassium pumps actively transport three Na+ out of the cell and two K+ into the cell.
• Leakage channels allow some Na+ and K+ to passively diffuse through the membrane.
• Resting membrane potential (RMP) is maintained by the balance between leakage channels and the sodium-potassium pump.
• Resting membrane potential (RMP) is maintained at approximately -70mV due to an unequal distribution of ions inside and outside the cell.