In order to complete Part I of the Neuron Worksheet, you will need a good understanding of various terms related to neurons. Neurons are the basic building blocks of the nervous system and are responsible for transmitting electrical and chemical signals throughout the body. Let’s explore some key terms that will help you complete Part I.
1. Dendrites: Dendrites are specialized extensions of a neuron that receive signals from other neurons or sensory organs. They play a crucial role in integrating information and transmitting it towards the cell body.
2. Cell body: Also known as the soma, the cell body is the main part of the neuron where most of the cellular functions take place. It contains the nucleus and other organelles necessary for the neuron’s survival and functioning.
3. Axon: The axon is a long, tube-like extension that carries electrical impulses away from the cell body to other neurons, muscles, or glands. It is covered by a fatty substance called myelin, which helps increase the speed of the impulses.
4. Myelin sheath: The myelin sheath is a protective covering that surrounds and insulates the axon, enabling faster transmission of electrical impulses. It is made up of specialized cells called glial cells.
5. Nodes of Ranvier: These are small gaps or interruptions in the myelin sheath along the axon. They play a crucial role in facilitating the rapid transmission of electrical signals.
6. Synapse: A synapse is a junction between two neurons where they communicate with each other. It consists of a presynaptic neuron that releases neurotransmitters into the synaptic cleft, a tiny gap, and a postsynaptic neuron that receives the neurotransmitters.
7. Neurotransmitters: Neurotransmitters are chemical messengers that transmit signals between neurons or between neurons and target cells (e.g., muscles or glands). They are released from the presynaptic neuron and bind to receptors on the postsynaptic neuron, initiating a response.
8. Action potential: An action potential is a rapid and brief change in the electrical potential of a neuron. It is generated when a stimulus exceeds the threshold level, causing an influx of ions, resulting in the rapid depolarization and repolarization of the neuron.
9. Resting potential: The resting potential is the stable electrical charge difference across the plasma membrane of a neuron when it is not active. Typically, the inside of the neuron is more negatively charged compared to the outside, with a resting potential of approximately -70 millivolts.
10. Excitatory neurotransmitters: Excitatory neurotransmitters increase the likelihood of a neuron firing an action potential by depolarizing the postsynaptic neuron. Examples include glutamate and acetylcholine.
11. Inhibitory neurotransmitters: Inhibitory neurotransmitters decrease the likelihood of a neuron firing an action potential by hyperpolarizing the postsynaptic neuron. Examples include gamma-aminobutyric acid (GABA) and glycine.
12. Neurotransmitter reuptake: Neurotransmitter reuptake refers to the process by which neurotransmitters are taken back up into the presynaptic neuron after they have been released into the synapse. This reuptake helps regulate the concentration of neurotransmitters in the synaptic cleft and terminate their signaling effects.
13. Synaptic pruning: Synaptic pruning is a process that occurs during brain development, where weak or unused synaptic connections are eliminated to refine and strengthen the neural networks. This pruning allows for the optimization of neural functioning.
14. Plasticity: Neural plasticity refers to the brain’s ability to change and adapt in response to experience and learning. It involves the formation and modification of synaptic connections, leading to changes in brain structure and function.
By familiarizing yourself with these terms, you will be better equipped to complete Part I of the Neuron Worksheet. These terms form the foundational knowledge necessary for understanding the structure and function of neurons. Remember to consult your textbook or lecture notes for more detailed information on each term.