Signal Transmission and the Nervous System

Cell Signalling The process by which cells communicate and coordinate their activities Perception The ability of cells to sense and respond to their microenvironment Neurotransmitters Chemical messengers that transmit signals in the nervous system Luigi Galvani Italian scientist who discovered that muscles of dead frogs twitched when exposed to an electrical spark Cell Potential The electric potential present in every cell, which allows for cellular communication Andrew Ure Scottish physician who used a voltaic battery to make a corpse convulse, demonstrating the role of electricity in muscle movement Membrane Potential The electric potential difference across the cellular membrane, essential for signal transmission Microelectrode A device used to measure the voltage inside a nerve cell Resting Membrane Potential The stable electric potential of an unstimulated neuron, typically ranging from -60 to -90mV Na/K ATP-ase Pump A protein pump that maintains the concentration of sodium (Na+) and potassium (K+) ions across the cell membrane Ion Channels Proteins that allow specific ions to diffuse across the cell membrane, playing a crucial role in signal transmission Active Transporters Proteins that move specific ions against their concentration gradients, requiring energy 1/3 Polarized Membrane A membrane with a potential difference across it, allowing for the transmission of electrical signals Depolarized Membrane A membrane where the potential becomes more positive, a key step in generating an action potential Hyperpolarized Membrane A membrane where the potential becomes more negative, making it less likely to generate an action potential Action Potential A rapid and temporary change in the membrane potential of a cell, essential for transmitting signals Axon Hillock The region of a neuron where the action potential is initiated Synapse The junction where the action potential is transmitted from one neuron to another or to a target cell Voltage-Gated Sodium Channels Specialized channels required for the generation and propagation of action potentials in neurons Propagation of Action Potential The transmission of the action potential along the axon of a neuron Dendrite The branch-like extensions of a neuron that receive signals from other neurons Potassium Channels Channels that open during repolarization of the cell membrane, restoring the resting membrane potential All-or-Nothing Principle The principle that states that action potentials are either fully initiated or not at all Local Anesthetics Substances that bind to voltage-gated sodium channels, preventing the generation of action potentials 2/3 Brainstem The base of the brain that connects the cerebrum with the spinal cord and controls basic functions Cranial Nerves The 12 pairs of nerves that relay information between the brain and various parts of the body Autonomic Nervous System (ANS) The part of the nervous system that regulates the activity of internal organs and involuntary functions Sympathetic Nervous System The division of the autonomic nervous system that prepares the body for physical action or stress Parasympathetic Nervous System The division of the autonomic nervous system that opposes or balances the sympathetic nervous system Enteric Nervous System (ENS) A network of neurons in the gastrointestinal system that controls digestion and gut functions Gut-Brain Axis The bidirectional communication pathway between the gut and the brain, influencing various physiological processes 3/3