Fill in the Blanks — HP-05 Master Sheet
Section A: Muscle Types
- Skeletal muscle is ________ and ________ (striations + control).
- Cardiac muscle is ________ but ________ (striations + control — the NEET trap).
- The special junctions between cardiac muscle cells that enable synchronized contraction are called ________.
- Smooth muscle cells are ________ (one nucleus per cell).
- The shape of smooth muscle cells is ________ (scientific term).
Section B: Sarcomere Structure 6. The sarcomere is bounded between two ________. 7. The ________ band remains constant during contraction because it spans the full length of ________ filaments. 8. The ________ band contains only actin and ________ during contraction. 9. The ________ zone is the central myosin-only region within the ________ band. 10. The ________ line anchors myosin filaments at the center of the H zone.
Section C: Sliding Filament Theory 11. The neurotransmitter released at the neuromuscular junction is ________. 12. Action potentials travel into the muscle interior via ________. 13. Calcium is stored in and released from the ________. 14. Ca2+ binds to ________ on the thin filament to initiate contraction. 15. The protein that blocks myosin-binding sites in resting muscle is ________. 16. Without ATP, muscle remains permanently contracted — a state called ________.
Section D: Skeleton 17. The adult human skeleton has ________ bones total. 18. The axial skeleton has ________ bones; appendicular has ________. 19. The hyoid bone is unique because it does not ________ with any other bone. 20. The atlas-axis joint is an example of a ________ joint.
Answer Key
- Striated; voluntary | 2. Striated; involuntary | 3. Intercalated discs | 4. Uninucleate | 5. Fusiform (spindle-shaped) | 6. Z-lines (Z-discs) | 7. A; myosin (thick) | 8. I; decreases | 9. H; A | 10. M | 11. Acetylcholine (ACh) | 12. T-tubules | 13. Sarcoplasmic reticulum (SR) | 14. Troponin-C | 15. Tropomyosin | 16. Rigor mortis | 17. 206 | 18. 80; 126 | 19. Articulate | 20. Pivot