Overview
This lecture explains the structure and function of nerve cells (neurons), detailing how electrical signals are transmitted throughout the nervous system to control bodily movements.
Structure of a Neuron
- Neurons transmit electrical impulses within the body.
- The axon transmits electrical signals from one neuron to the next, ending at organs or muscles.
- Dendrites receive incoming signals from other neurons, organs, or the brain.
- The cell body houses the nucleus, which contains genetic material and regulates neuron growth.
- The myelin sheath insulates some neurons, speeding up signal transmission up to 120 meters per second.
Signal Transmission in Neurons
- The brain initiates an action potential (electrical impulse) to start movement, such as moving a thumb.
- An action potential travels through a network of neurons to reach the target muscle.
- Nerves are bundles of neurons within the nervous system.
- Synapse is the gap between two neurons where signal transmission occurs.
- Neurotransmitters are chemicals that cross the synapse to stimulate the next neuron’s action potential.
- Signals are relayed from dendrite through the cell body, along the axon, across synapses, until reaching the target muscle.
Key Terms & Definitions
- Neuron — a nerve cell responsible for transmitting electrical signals in the body.
- Axon — the long extension of a neuron that carries electrical signals away from the cell body.
- Dendrite — branches of a neuron that receive signals from other neurons.
- Cell body — the part of the neuron containing the nucleus.
- Nucleus — organelle within the cell body that holds genetic material and controls development.
- Myelin sheath — fatty layer covering some axons, increasing signal speed.
- Action potential — an electrical impulse that travels along the neuron.
- Synapse — the gap between two neurons where signal transfer occurs.
- Neurotransmitter — chemical messenger that carries signals across synapses.
Action Items / Next Steps
- Review the structure and function of each part of a neuron.
- Be able to explain the process of signal transmission between neurons.
- Prepare any questions on neuron function for the next class.