Multiple Choice:
b) -70 mV
b) Na⁺
a) Na⁺
b) Acetylcholine
b) Systole
b) Intercalated discs
b) Hydrostatic pressure
b) Binds calcium to initiate contraction
c) Motor neuron
b) Repolarization
Fill in the Blank:
11. stretch
12. sinoatrial node
13. absolute refractory
14. ATP
15. sarcoplasmic reticulum
16. hydrostatic pressure
17. alveoli
18. Intrapleural
19. ventricular
20. chemical
Matching:
21. a) Sustained muscle contraction without relaxation
22. c) The period during which no action potential can be triggered
23. d) Drives fluid out of capillaries into tissues
24. b) Theory explaining muscle contraction through actin and myosin interaction
25. e) Controls rhythmic movements such as walking
Short Answer:
26. Wave summation involves stronger contractions due to rapid stimuli before the muscle fully relaxes, while treppe refers to progressively stronger contractions with repeated stimulation.
27. The Na⁺/K⁺ pump maintains the resting membrane potential by pumping 3 Na⁺ out and 2 K⁺ into the cell, keeping the inside of the cell negative.
28. Excitation-contraction coupling links the action potential in the muscle fiber to the release of calcium from the sarcoplasmic reticulum, allowing muscle contraction.
29. The cardiac cycle consists of diastole (relaxation) when the chambers fill with blood, and systole (contraction), when blood is pumped out.
30. During the refractory period, the neuron is less excitable due to Na⁺ channel inactivation, preventing another action potential.
True/False:
31. True
32. True
33. False
34. False
35. True
Fill in the Blank:
36. CPG (central pattern generator)
37. Excitation
38. gas exchange
39. heart rate
40. cardiac