Aphy 101 Exam #4 Practice Questions And Verified Answers Solution.

Find the false statement below, if any, concerning the functions of the muscular system - correct answer It produces all types of blood cells. What does the word "voluntary" mean, as it pertains to muscle tissue? - correct answer It means that the muscle tissue contracts in response to the person willing the action to occur. Which of the following sets of characteristics correctly describes smooth muscle tissue? - correct answer Non-striated, single nucleus in each cell, involuntary, and arranged in layers. Which types of muscle tissue is/are striated? - correct answer Skeletal and cardiac The striations found in some muscle tissue are the result of - correct answer The banding pattern of actin and myosin filaments. Perimysium - correct answer A layer of dense connective tissue that surrounds each fascicle in a skeletal muscle. Tendon - correct answer A cord of dense connective tissue that connects a muscle to a bone. Troponin - correct answer One of the proteins that forms a cap over the binding site on actin molecules, preventing crossbridging during muscle relaxation. Sarcolemma - correct answer The cell membrane of a muscle fiber, which is arranged to allow electrical impulse conduction. T-tubule - correct answer An organelle that folds inward from the cell membrane, and transmits impulses into a muscle fiber. How is skeletal muscle unique? In other words, how is it different than the other types of muscle tissue? - correct answer It is the only one that is voluntary. What is the function of the synaptic cleft in a neuromuscular junction? - correct answer It acts as a gap across which neurotransmitter molecules can travel from the neuron to the muscle fiber. According to the sliding filament theory, what event occurs in each sarcomere that shortens a muscle during muscle contraction? - correct answer The myosin heads form crossbridges with the actin, and then flip over, pulling the actin. What is the role of Ca+2 in the process of skeletal muscle contraction? - correct answer It binds to and removes the "cap" from the binding sites on actin, so the myosin can form crossbridges with actin. When a person suddenly begins to exercise, where do the muscles obtain energy for the first few seconds of exercise? - correct answer ATP reserves What effect does the tetanus toxin (produced by the anaerobic bacteria, clostridium tetani) have on the process of muscle contraction? - correct answer It causes muscle fibers to contract in the absence of neural stimulation. The period of time, during muscle contraction, during which it can only be stimulated to contract again by a high-intensity stimulus, is called the - correct answer Relative refractory period Find the false statement below, if any, concerning fast-twitch and slow-twitch skeletal muscle fibers - correct answer Fast-twitch fibers have a smaller diameter than slow-twitch fibers. What is the most common cause of muscle fatigue? - correct answer Accumulation of lactic acid, and the resulting decrease in blood pH in the area. Throughout the body, muscles often act in groups. The muscle that acts as the main muscle in a group is called the - correct answer Prime mover. All of the following muscles are part of the rotator cuff except - correct answer Rhomboideus major Find the false statement below, if any, concerning the Quadriceps femoris muscles - correct answer Their main action is flexion of the knee What are the most likely characteristics of a hypothetical muscle called the Pronator carpi medius rectus? - correct answer It turns the hand so that the palm is facing backward, it is in the wrist, it is the middle sized muscle in a group of 3, and it runs parallel to the midline of the arm. Plantar flexion - correct answer Bending of the foot downward at the ankle, so that the toes point down. Depression - correct answer Lowering of a part of the body, as in drooping of the shoulders. Adduction - correct answer Movement of a part of the body toward the midline, as in as in returning an outstretched arm back toward the hip. Protraction - correct answer Movement of a part of the body forward, as in forward thrusting of the chin. Inversion - correct answer Twisting of the foot, so that the sole points inward, toward the midline of the body. Which of following muscles has the origin and insertion listed below? Origin: Upper portion of the posterior surface of the scapula Insertion: Greater Tubercle of the humerus - correct answer Supraspinatus Platysma - correct answer Draws the corners of the mouth downward, as in pouting; lowers the mandible and tenses the neck. Brachialis - correct answer Runs down the anterior side of the humerus; flexes the arm at the elbow. Internal obliques - correct answer Tenses the abdominal wall and compresses its contents. Semimembanosus - correct answer A large muscle located in the thigh; belongs to the hamstring group; flexes the knee Soleus - correct answer Located in the lower leg; accomplishes plantar flexion of the foot.