Bio 20: Quiz Ch. 13: Mader (Q&A: 62 questions) – Flashcards
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What do smooth, cardiac, and skeletal muscle all have in common?
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The cells of these muscles are all called muscle fibers.
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Of the three types of muscle tissue, which has multinucleated fibers?
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skeletal muscle
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Of the three types of muscle tissue, which is voluntary?
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skeletal muscle
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Of the three types of muscle tissue, which is not striated?
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smooth muscle
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Skeletal muscle contractions play a role in returning the venous blood to the heart.
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True: The skeletal muscle contractions play a role in returning the venous blood to the heart.
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What is found within the intercalated disks of cardiac muscle?
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gap junctions
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List the functions of the skeletal muscles.
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Support and Movement. Skeletal muscles move the body. Skeletal muscle contractions pull on tendons, which are attached to bones. If contraction of the muscle causes the muscle to shorten, the bone and, thus, the body part will move.
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Because the heart beats continuously, cardiac fibers never relax completely.
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False: Cardiac fibers relax completely between contractions, which prevents fatigue.
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Explain the structural differences between the thick and thin myofilaments.
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Myofibrils consist of bundles of thick and thin protein filaments, generally called myofilaments. Thick filaments are composed of myosin only. ... The A band is the region occupied entirely by the thick filament with some overlap by thin filaments at either side.
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Which of the following is not a function of skeletal muscles?
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pumping of blood throughout the body
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Explain the differences between fast-twitch and slow-twitch muscle fibers.
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Slow-twitch muscles help enable long-endurance feats such as distance running, while fast-twitch muscles fatigue faster but are used in powerful bursts of movements like sprinting.
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From the outside of a muscle coming in, the first thing encountered would be
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fascia.
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What structure attaches a muscle to a bone?
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tendons
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What muscle works in a pair with the biceps brachii?
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the triceps brachii
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Muscles can only pull; they cannot push.
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True: Muscles can only contract and pull on the bone they are attached to.
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The origin of a muscle is on a stationary bone.
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True: The origin is on the stationary bone while the insertion is on the bone that moves.
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Which of the following is not a term that refers to how muscles work?
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synergism
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What is the deltoid muscle shaped like?
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a triangle
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What does the word brevis mean when referring to a muscle?
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short
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What is the name of the muscle that is responsible for blinking and winking?
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orbicularis oculi
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What information does the word rectus give you about a muscle?
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the direction of muscle fibers
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Which of the following does not attach to the sternocleidomastoid muscle?
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rib
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Which way does the adductor longus move the thigh?
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toward the midline
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What is the biggest muscle (in terms of mass) in the body?
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gluteus maximus
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What does the word sarco mean?
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muscle
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Several of the structures in the muscle cell are given special names. For example, the cytoplasm of a muscle fiber is called the sarcoplasm. Which of the following is truly a unique structure to muscle cells (not just a renamed one)?
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transverse (T) system
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A muscle fiber is made up of many
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myofibrils.
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One sarcomere
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extends from Z line to Z line.
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What ion is responsible for initiating muscle contraction?
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Ca2+
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When a muscle contracts, the H zone almost disappears.
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True: The H zone is the area in the center of the sarcomere that almost disappears when the muscle contracts.
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What happens to the actin and myosin filaments when a muscle contracts?
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both stay the same length
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What supplies the energy for muscle contraction?
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ATP
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Each actin molecule is shaped like a golf club, with a straight portion ending in a globular head.
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False: Each myosin molecule is shaped like a golf club.
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What does troponin bind to and what happens when it binds?
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Ca2+, tropomyosin shifts
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What is the name of the small gap that separates the axon terminal of a nerve from the sarcolemma?
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synaptic cleft
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When the nerve signal reaches the axon terminal what happens next?
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The synaptic vesicles release neurotransmitter.
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One motor neuron activates one muscle fiber.
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False: One motor neuron can stimulate from a few to several muscle fibers of a muscle because each axon has several branches.
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One motor unit obeys a principle called the all-or-none law.
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True: All the muscle fibers in a motor unit are stimulated at once. They all either contract or do not contract.
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Why is the innervation ratio in the ocular muscles one motor axon per 23 muscle fibers, whereas in the gastrocnemius muscle it is one motor axon per 1000 muscle fibers?
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The ocular muscles require finer control than moving the legs
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Which of the following is not a phase of a single muscle twitch?
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stimulation period
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What is happening during the latent period of a muscle twitch?
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The neurotransmitter is diffusing across the synaptic cleft causing an electrical signal in the muscle cell.
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Which of the following does not occur when a muscle fatigues?
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Tetanus is achieved.
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In good muscle tone, how many motor units are contracted?
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some
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Contraction of a muscle requires all the motor units to be undergoing tetanic contraction.
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False: Some motor units are contracting maximally while others are resting, allowing sustained contractions to occur.
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Which of the following is not an energy source for muscle contraction?
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starch
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Which of the following is not a source of ATP for muscle contraction?
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ATP in the blood
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Of the three pathways for obtaining ATP for muscle contraction, which one requires oxygen?
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only respiration
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Of the three pathways for supplying ATP to the muscle, which pathway(s) do slow-twitch fibers prefer?
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aerobic respiration
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Jillian is a top level cross country runner due to her having predominantly slow-twitch muscle fibers.
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True: Slow-twitch muscle fibers are aerobic, have steady power, and have endurance--all required for cross country running.
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Why are slow-twitch muscles dark?
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They contain myoglobin.
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What is the name of a sudden and involuntary muscular contraction, often accompanied by pain?
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spasm
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What is the difference between a tic and a spasm?
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A tic is a spasm that can be controlled voluntarily.
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Which of the following injuries is most likely to happen to the ankle?
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sprain
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Fibromyalgia is a temporary condition of achy muscles, usually due to overuse.
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False: Fibromyalgia is a chronic condition whose symptoms include achy pain, tenderness, and stiffness of muscles.
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Which muscle injury is characterized by a twisting of a joint leading to swelling and injury?
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sprain
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Which disease is an autoimmune disease characterized by weakness that especially affects the muscles of the eyelids, face, neck, and extremities?
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myasthenia gravis
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Leiomyomas are a type of smooth muscle cancer that occurs in the uterine wall.
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True: True, leiomyomas are a type of smooth muscle cancer that occurs in the uterine wall.
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What is the reservoir for Ca2+ in the body?
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bones
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Which of the following does not occur when you are very, very cold?
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More blood flows to the surface of the body.
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What happens when the arrector pili muscles contract?
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The hairs on your skin stand on end.
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Temperature sensitive neurons in the skin are responsible for initiating shivering.
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False: These neurons are located in the hypothalamus of the brain.
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If you lock your knees while standing you may pass out because of the lack of venous return to the heart.
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True: The skeletal muscles aid in the process of venous return by pushing blood back toward the heart. If you lock your knees, there is a shortage of blood returning to the heart and you may pass out.
