Topics:
Animal Physiology, Animal Refresher
Cardiac Muscle – Striated Uninucleated with Intercalated Discs
Striated, uninucleated muscle cells connected by intercalated discs are:
- Skeletal muscle
- Cardiac muscle — Correct Answer
- Smooth muscle
- Both skeletal and cardiac
Explanation:
Correct Answer: Cardiac muscle
Cardiac muscle is unique — it is striated like skeletal muscle but uninucleated (one central nucleus) like smooth muscle. The cells are connected by intercalated discs which contain gap junctions, allowing electrical coupling and synchronized contraction.
Key Features of Cardiac Muscle
- Striated, uninucleated (one central nucleus)
- Cells connected by intercalated discs → acts as a functional syncytium
- Involuntary control
- Has intrinsic rhythmicity (automaticity) — SA node acts as natural pacemaker
- Resting membrane potential: −90 mV
- Cannot undergo tetanus (long refractory period)
Intercalated Discs Function
Intercalated discs contain: (1) Desmosomes — mechanical coupling; (2) Gap junctions — electrical coupling, allowing action potentials to pass rapidly between cells, enabling coordinated pumping.
📚 About this Topic — Animal Physiology
This multiple choice question is from Animal Physiology, Animal Refresher. It has 4 options with a detailed explanation of the correct answer. Practice more MCQs from Animal Physiology to strengthen your preparation.
