BIOL 251 Human Anatomy and Physiology Study Guide Exam Module 5 2026

BIOL 251 Human Anatomy and Physiology Study Guide Exam Module 5 2026 What are the four major functional characteristics of muscle tissue? - Correct Ans Contractibility, Excitability, Extensibility, and Elasticity What are the three types of muscle tissue? - Correct Ans-Skeletal, Smooth, and Cardiac. In terms of their nuclei, skeletal muscle fibers are different than most cells in two ways. What are those ways? - Correct Ans-1. Multinucleated skeletal muscle 2. nuclei lay at the edge of the cell Label the parts on question 6 of Study Guide Module 5 (page 151) - Correct Ans-a. Actin Myofilament b. Myosin Myofilament c. Z-disk d. I Band e. A band f. H zone The concentration of calcium ions in the sarcoplasmic reticulum is decreasing. Is the muscle fiber starting to contract or has it finished contracting? - Correct Ans-The muscle fiber is starting to contract The myosin heads of a sarcomere have just received a boost of energy. Is the power stroke or the return stroke about to happen? - Correct Ans-The return stroke A myosin head has ADP attached to it but not an individual phosphate. Which is going to happen next: the return stroke or the power stroke? - Correct Ans-The power stroke Label the parts of the neuromuscular junction on page 152 of Study Guide 5 - Correct Ans-a. presynaptic terminal of motor neuron b. mitochondria c. synaptic vesicles d. synaptic cleft e. postsynaptic membrane If you could look at several muscle fibers while they are in action, how could you determine which cells are a part of thee same motor unit? - Correct Ans-The cells will contract at the same time BIOL 251 BIOL 251 What is the function of acetylcholinesterase? If it were not for acetylcholinesterase, what would happen to a muscle? - Correct Ans-1. inactivates ACh after it has interacted with the postsynaptic membrane. 2. The muscle would not relax. There are two major roles that ATP plays in muscle contraction and relaxation. The first involves the sarcoplasmic reticulum, while the second involves the myosin heads. What are those two roles? - Correct Ans-1. to give the sarcoplasmic reticulum energy 2. ATP attaches to myosin heads, releasing active sites and giving them energy for the return stroke A muscle is stiff. It can neither contract nor relax. What is wrong in the sarcomere? What causes this? - Correct Ans-1. the myosin heads aren't releasing the active sites 2. The lack of ATP in the sarcomere When a muscle fiber relaxes, does it automatically extend back to its resting size? - Correct Ans-No A motor unit has just been recruited. What has just happened to its motor neuron? - Correct Ans-It is sending caution potentials through its axon All of the motor units in a muscle have been recruited. If more stimulus is applied, what is that called? - Correct Ans-Supramaximal Stimulus A muscle is expending energy faster than it can be replaced by aerobic respiration. There is also no creatine phosphate left. What can the cell do? - Correct Ans-Anaerobic respiration What will build up in the described in the last question? - Correct Ans-Lactic acid When we breathe hard after are finished exercising , what two things is the increased oxygen supply doing for the muscle fibers? - Correct Ans-1. Getting oxygen 2.Converting lactic acid to glucose