Neurotransmitters

Definition

Neurotransmitters are chemical messengers that transmit signals between neurons, or nerve cells, in the body. They play a crucial role in the communication and function of the nervous system, including the brain, spinal cord, and peripheral nerves.

5 Must Know Facts For Your Next Test

1. Neurotransmitters can be excitatory, inhibitory, or modulatory, influencing the likelihood of the postsynaptic neuron generating an action potential.
2. The release of neurotransmitters is a calcium-dependent process that occurs when an action potential reaches the presynaptic terminal.
3. Imbalances in neurotransmitter levels can contribute to various neurological and psychiatric disorders, such as depression, anxiety, and Parkinson's disease.
4. Drugs that affect the synthesis, release, or reuptake of neurotransmitters are commonly used to treat neurological and psychiatric conditions.
5. The neurological exam often assesses the function of the nervous system, including the evaluation of reflexes, which are mediated by neurotransmitter-driven synaptic transmission.

Review Questions

• Explain the role of neurotransmitters in the communication between neurons.
  • Neurotransmitters are the chemical messengers that facilitate communication between neurons in the nervous system. When an action potential reaches the presynaptic terminal, it triggers the release of neurotransmitters into the synaptic cleft. These neurotransmitters then bind to specific receptors on the postsynaptic neuron, either exciting or inhibiting the likelihood of the postsynaptic neuron generating its own action potential. This neurotransmitter-mediated signaling is essential for the proper functioning of the nervous system, including the coordination of sensory, motor, and cognitive processes.
• Describe how imbalances in neurotransmitter levels can contribute to neurological and psychiatric disorders.
  • Neurotransmitter imbalances have been linked to various neurological and psychiatric disorders. For example, low levels of the neurotransmitter serotonin are associated with depression, while excessive dopamine signaling is implicated in schizophrenia. Parkinson's disease is characterized by the degeneration of dopamine-producing neurons, leading to motor impairments. Drugs that target the synthesis, release, or reuptake of neurotransmitters are often used to treat these conditions, as they can help restore the proper balance of neurotransmitters in the nervous system and alleviate the associated symptoms.
• Analyze the role of neurotransmitters in the neurological exam and how they contribute to the assessment of nervous system function.
  • Neurotransmitters play a crucial role in the neurological exam, as they are responsible for the proper functioning of reflexes and other neurological responses. For instance, the evaluation of deep tendon reflexes, such as the knee jerk reflex, relies on the neurotransmitter-mediated synaptic transmission between sensory neurons and motor neurons in the spinal cord. Abnormalities in these reflexes can indicate underlying neurological issues, such as nerve damage or disorders affecting the central or peripheral nervous system. Additionally, neurotransmitter imbalances can contribute to cognitive, sensory, or motor deficits that are assessed during the neurological exam, providing valuable insights into the overall health and function of the nervous system.

Related terms

Synaptic Cleft:

The small gap between the presynaptic and postsynaptic neurons where neurotransmitters are released and act on receptors.

Receptor:

A specialized protein on the surface of a postsynaptic neuron that binds to a specific neurotransmitter, triggering a response.

Reuptake: The process by which neurotransmitters are removed from the synaptic cleft and transported back into the presynaptic neuron or surrounding glial cells.