Neurotransmitter

Definition

A neurotransmitter is a chemical messenger that transmits signals across a synapse from one neuron to another or to target cells in muscles and glands. These molecules play a crucial role in the communication within the nervous system and are integral to physiological control systems, influencing feedback mechanisms that help maintain homeostasis in the body.

5 Must Know Facts For Your Next Test

1. Neurotransmitters can be classified into different types, such as excitatory, which promote signal transmission, and inhibitory, which reduce signal transmission.
2. Common neurotransmitters include serotonin, dopamine, acetylcholine, and norepinephrine, each with distinct roles in regulating various physiological functions.
3. The balance of neurotransmitter activity is essential for maintaining homeostasis; imbalances can lead to disorders such as depression, anxiety, or neurological diseases.
4. Neurotransmitters not only influence nerve signal transmission but also modulate other physiological processes like heart rate, digestion, and mood.
5. Feedback mechanisms often involve neurotransmitters acting on specific receptors to either amplify or dampen responses in physiological control systems.

Review Questions

• How do neurotransmitters facilitate communication between neurons and contribute to physiological control?
  • Neurotransmitters enable communication between neurons by being released from the presynaptic neuron and binding to receptors on the postsynaptic neuron. This binding can either excite or inhibit the target neuron’s activity, thereby influencing its response. Through these interactions, neurotransmitters help regulate various physiological processes and maintain balance within the body's systems.
• Discuss how an imbalance of neurotransmitter levels can affect feedback mechanisms in physiological control systems.
  • An imbalance of neurotransmitter levels can disrupt normal feedback mechanisms within physiological control systems. For instance, excessive levels of excitatory neurotransmitters may lead to overactivity in certain pathways, resulting in heightened responses or stress on organs. Conversely, a deficiency in inhibitory neurotransmitters can impair the body's ability to modulate responses effectively, potentially leading to conditions like anxiety or depression. This disruption highlights the importance of balanced neurotransmitter activity for overall health.
• Evaluate the role of neurotransmitters in homeostatic regulation and how they interact with other systems in the body.
  • Neurotransmitters play a pivotal role in homeostatic regulation by coordinating communication between the nervous system and various organ systems. For example, neurotransmitters influence heart rate through their action on the autonomic nervous system, modulating cardiovascular responses during stress or relaxation. Additionally, they can affect hormonal release from endocrine glands, further impacting metabolic processes. This interconnectedness shows how neurotransmitters are essential for maintaining stability within the body by allowing different systems to respond appropriately to internal and external changes.

Related terms

Synapse: The junction between two neurons where neurotransmitters are released to transmit signals.

Receptor: A protein molecule on the surface of a cell that binds to specific neurotransmitters, initiating a cellular response.

Action Potential: An electrical impulse that travels along the axon of a neuron, leading to the release of neurotransmitters at the synapse.