2.2.2 Video

• an action potential is an electrical signal that is carried down a neuron and passed to a neighboring neuron
• an action terminal is generated through a sudden reverse of a charge
• Resting neuron: negatively charged inside the cell
• Action potential: cell becomes positive, and electricity moves down the neuron
• The cell membrane is composed of a phospholipid bilayer and proteins
• The phospholipid bilayer is made of two layers of phospholipids: hydrophilic head, and hydrophobic tail
• Proteins make up the channels and pumps that ions will flow through to create the charge of the action potential
• There is 2 channels and 1 pump
• Potassium channel: only allows potassium to exit the cell
• Sodium channel: only allows sodium to enter the cell
• The sodium/potassium pump uses energy to pump 3 sodium ions out the cell while pumping 2 potassium ions into the cell
• There are 5 potential stages in the action potential graph
• Stages in the following order: resting potential, depolarization, action potential, repolarization, and the refractory period
• Resting Potential: the interior and exterior of the cell are always opposite charges that depend on the location of the ions. Meaning if the inside is positive, the outside HAS to be negative.
• Resting Potential: inside the cell, anions like: phosphates, sulfates, organic acids, proteins, ATP, and RNA cannot leave
• Resting Potential: Neurons can be stimulated by: chemicals, light, heat, and mechanical distortion of the membrane
• Depolarization: the inside of the cell begins to become positive while the outside becomes negative
• Action Potential: an action potential occurs when the interior of a cell reaches its max positive charge of +30millivolts
• Action Potential: an action potential occurs as a result of the chemicals opening and closing in depolarization. No channels open or close when action potential occurs
• Repolarization: the interior of the cell begins to return to negative while the outside becomes positive
• Refractory Period: the cell is negative, but it needs to restore proper ion concentration in the order to return to resting
• it takes 70% of the energy requirements of the nervous system
• it takes 1/3 of the body's total energy