Which cardiac feature connects cardiac muscle cells?

• A. Myelin sheath
• B. Intercalated discs
• C. Dendrites
• D. Synaptic junctions

Answer: (B)

The connection between cardiac muscle cells is made by intercalated discs. These specialized junctions hold neighboring heart muscle cells together so they don’t pull apart during strong contractions, and they also enable rapid electrical communication. Inside each intercalated disc are desmosomes, which provide mechanical strength to withstand the force of continuous beating, and gap junctions, which create direct channels for ions to pass from one cell to the next. This ion flow allows action potentials to quickly propagate through the heart muscle, producing the synchronized contractions that move blood efficiently.

Other options don’t fit this role: myelin sheaths insulate nerve fibers, not heart muscle; dendrites are parts of neurons that receive signals; and synaptic junctions are contacts between neurons (or between a neuron and a muscle at the neuromuscular junction), not the structure that mechanically and electrically links cardiac muscle cells.