Postganglionic neurons

Definition

Postganglionic neurons are the neurons that transmit signals from autonomic ganglia to target tissues or organs in the body. These neurons play a vital role in the peripheral nervous system, particularly within the autonomic nervous system, influencing involuntary physiological functions like heart rate, digestion, and respiratory rate.

5 Must Know Facts For Your Next Test

1. Postganglionic neurons can be categorized into sympathetic and parasympathetic types, each responsible for different physiological responses.
2. These neurons release neurotransmitters such as norepinephrine or acetylcholine to communicate with their target tissues.
3. In the sympathetic nervous system, postganglionic neurons typically have longer axons, enabling them to reach distant target organs quickly.
4. In contrast, postganglionic neurons in the parasympathetic nervous system have shorter axons, often acting on nearby target tissues for localized control.
5. The activity of postganglionic neurons is crucial for maintaining homeostasis by regulating involuntary functions like blood pressure and digestion.

Review Questions

• How do postganglionic neurons differ in function between the sympathetic and parasympathetic nervous systems?
  • Postganglionic neurons in the sympathetic nervous system primarily prepare the body for 'fight or flight' responses by activating various organs through longer axons. In contrast, those in the parasympathetic nervous system promote 'rest and digest' activities by acting on nearby target tissues with shorter axons. This fundamental difference highlights how postganglionic neurons help maintain balance within the body's involuntary functions.
• Discuss the role of neurotransmitters released by postganglionic neurons and their impact on target organs.
  • Postganglionic neurons release neurotransmitters such as norepinephrine and acetylcholine, which are critical for communication with target organs. In the sympathetic system, norepinephrine generally increases heart rate and blood flow to muscles. Conversely, acetylcholine released by parasympathetic postganglionic neurons slows heart rate and stimulates digestion. The specific neurotransmitter influences how target organs respond to stimuli.
• Evaluate how dysfunctions in postganglionic neuron signaling can affect overall health and bodily functions.
  • Dysfunctions in postganglionic neuron signaling can lead to various health issues, such as hypertension due to excessive sympathetic activity or digestive disorders from inadequate parasympathetic response. These imbalances can significantly disrupt homeostasis, impacting vital functions like cardiovascular health and metabolic processes. Understanding these dysfunctions is essential for developing targeted treatments to restore proper autonomic function.

Related terms

Preganglionic neurons:

Neurons that originate in the central nervous system and synapse with postganglionic neurons in autonomic ganglia.

Autonomic nervous system: A division of the peripheral nervous system that controls involuntary bodily functions and is divided into sympathetic and parasympathetic systems.

Synapse:

The junction between two neurons where communication occurs, allowing signals to be transmitted from one neuron to another.