Topics:
Animal Physiology, Animal Refresher
Functional Unit of Myofibril
Functional unit of myofibril is:
- Sarcomere — Correct Answer
- Sarcolemma
- Myoglobulin
- Myofilament
Explanation:
Correct Answer: Sarcomere
The sarcomere is the basic structural and functional unit of skeletal muscle fiber (myofibril). It is the distance between two consecutive Z-lines (Z-discs).
Structure of a Sarcomere
- Z-line: Boundary of sarcomere; anchors thin (actin) filaments
- A-band (Anisotropic/Dark band): Region containing both actin and myosin filaments
- I-band (Isotropic/Light band): Region containing only actin (thin) filaments
- H-zone: Region containing only myosin (thick) filaments (center of A-band)
- M-line: Center of sarcomere; connects myosin filaments
Other Key Terminology
- Sarcolemma: Cell membrane of a muscle fiber
- Sarcoplasm: Cytoplasm of a muscle fiber
- Sarcoplasmic reticulum: Stores Ca²⁺; equivalent to ER in muscle cells
- Myoglobin: Oxygen-storing pigment in muscle (gives red color to muscle)
📚 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.
