Class 9, Science, Chapter-6, Lecture-5, Muscle Fibres (Notes)
Differences Between:
Striated Muscle Fibres | Smooth Muscle Fibres | Cardiac Muscle Fibres |
1. They are long cylindrical cells. | 1. The fibres are elongated, and spindle shaped. | 1. The cells are small and cylindrical. |
2. The fibres have blunt ends. | 2. The fibres have pointed ends. | 2. The fibres have broad ends. |
3. They possess striations or alternate light and dark bands. | 3. Striations or light and dark bands are absent. | 3. Striations are present but they are fainter than those of striated muscle fibres. |
4. Intercalated discs and cross-connections are absent. | 4. Intercalated discs and cross-connections are absent. | 4. Intercalated discs and cross-connections are present. |
5. The muscle fibre is multi-nucleate. | 5. Smooth muscle fibre is uni-nucleate. | 5. The cells are uni-nucleate. |
6. Nuclei are oval in outline. They occur peripherally below the sarcolemma | 6. Nucleus is centrally placed, oval or elongated. | 6. Nucleus in oval-rounded. It is centrally placed. |
7. They occur in bundles. | 7. They generally form sheets. | 7. They form a network. |
8. Striated muscle fibres occur in limbs, hands, feet, body wall, tongue, pharynx and upper part of oesophagus. | 8. The fibres occur in dermis, urinogenital tracts, digestive tract, lungs, iris, blood vessels, etc. | 8. The muscle fibres occur only in the wall of heart. |
9. They are voluntary. | 9. They are involuntary. | 9. They are involuntary. |
10. They are able to perform fast and powerful contractions. | 10. They perform slow but prolonged contractions. | 10. Cardiac muscle fibres perform powerful and rhythmic contractions. |
11. They soon get fatigued. | 11. Fatigue is rare. | 11. They seldom get fatigued. |