In the sympathetic division of the autonomic nervous system, what are the swollen bead-like structures found along the terminal branches of axons called?

• A. Synaptic boutons
• B. Varicosities
• C. Dendritic spines
• D. Nodes of Ranvier

Answer: (B)

Verified step by step guidance

1. Understand the context: The sympathetic division of the autonomic nervous system is responsible for the 'fight or flight' response. It uses neurotransmitters to communicate with target tissues, and the structures involved in neurotransmitter release are key to this process.
2. Identify the anatomical structure in question: The problem refers to swollen bead-like structures found along the terminal branches of axons. These structures are specialized for neurotransmitter release.
3. Clarify the function of these structures: These bead-like structures, known as varicosities, contain vesicles filled with neurotransmitters. They release neurotransmitters into the extracellular space to affect nearby target cells, such as smooth muscle or glandular tissue.
4. Differentiate from other terms: Synaptic boutons are found at the ends of axons and are involved in neurotransmitter release at synapses. Dendritic spines are small protrusions on dendrites that receive synaptic input. Nodes of Ranvier are gaps in the myelin sheath of axons that facilitate rapid signal conduction. None of these terms describe the bead-like structures along axons in the sympathetic division.
5. Conclude the identification: The correct term for the swollen bead-like structures along the terminal branches of axons in the sympathetic division is 'varicosities.' These structures are essential for neurotransmitter release in the autonomic nervous system.