InterActive Physiology® Exercise Sheet Answers
Answers for Muscular System: Neuromuscular Junction 1. 2. 3. 4. 5. 6. 7. 8. 9. 10.
Endomysium Acetylcholine (ACh) Voltage-regulated Ca (same as voltage-gated) Exocytosis Chemically-regulated (chemically-gated) Depolarization By the enzyme – Acetylcholinesterase (AChE) Sarcolemma, T-tubules Ca a. Decreased muscle contractions b. Competed with ACh by blocking receptor sites on channel c. Curare 11. a. Increased muscle contractions b. Prevented breakdown of ACh c. Neostigmine 12. a. Increased muscle contractions b. Binds to ACh receptor but is not broken down by AChE c. Nicotine
Answers for Muscular System: Sliding Filament Theory 1. a. Myosin b. Power stroke 2. a. ATP b. Actin 3. a. Actin b. Tropomyosin c. Troponin 4. ATP 5. high energy 6. backsliding 7. a. Energize the power stroke b. Disconnect the myosin cross bridge c. Actively transport Ca into the sarcoplasmic reticulum
8. Actin 9. b, c 10. a. Rigor mortis b. Lack of ATP after death
Answers for Muscular System: Contraction of Whole Muscle 1. b 2. muscle twitch 3. a. Contraction b. Relaxation c. Latent 4. a. second stimulus applied before complete relaxation b. ↓ 5. Order
Stage
Description
5
Fatigue
↓ tension due to ↓ ATP and ↑ buildup of lactic acid
3
Incomplete Tetanus
Rapid cycles but some relaxation seen
1
Treppe
↑ tension due to warming and ↑ enzyme efficiency
4
Complete Tetanus
Smooth sustained contraction
2
Temporal Summation
↑ tension due to repeated stimulation prior to complete relaxation
6. a. b. 7. a. b. c. 8. a. b.
Many Few 0.3 V 0.4 V 1.5 V Moderate Overstretched
