What is the synaptic terminal for a rod called?

What is the synaptic terminal for a rod called?

• A. Spherule
• B. Pedicle
• C. Bouton
• D. Terminal knob

Answer: (A)

Rods have a distinctive spherical synaptic ending, reflecting how their terminals form tight invaginating contacts with the dendrites of bipolar and horizontal cells in the outer plexiform layer. This small, rounded structure is called a spherule, and it captures the specialized nature of rod synapses. Cones, on the other hand, terminate as cone pedicles, which are larger and structurally different. Generic terms like bouton or terminal knob aren’t specific to the rod’s unique spherical terminal, so spherule is the precise name for the rod’s synaptic terminal.

Rods have a distinctive spherical synaptic ending, reflecting how their terminals form tight invaginating contacts with the dendrites of bipolar and horizontal cells in the outer plexiform layer. This small, rounded structure is called a spherule, and it captures the specialized nature of rod synapses. Cones, on the other hand, terminate as cone pedicles, which are larger and structurally different. Generic terms like bouton or terminal knob aren’t specific to the rod’s unique spherical terminal, so spherule is the precise name for the rod’s synaptic terminal.