Muscles – Flashcards

Muscles exhibit the property of excitability. This means that the muscle A) shortens its length. B) recoils to its original resting length. C) stretches beyond its normal length. D) responds to stimulation by the nervous system. E) excites itself.

The capacity of a muscle cell to shorten forcefully is known as A) contractility. B) excitability. C) extensibility. D) elasticity. E) flexibility.

Identify the statement concerning general functional characteristics of muscle that is true. A) Muscle tissue shortens forcefully but lengthens passively. B) Muscle tissue shortens passively but lengthens forcefully. C) Muscle tissue can get shorter, but can not get longer. D) Muscle tissue can get longer, but can not get shorter. E) None of the above statements are true.

Identify the statement concerning skeletal muscle that is true. A) It comprises about 20% of the body's weight. B) It propels urine through the urinary tract. C) Its function is largely under involuntary control. D) It is a kind of connective tissue. E) It is responsible for locomotion.

Which of the following actions is caused by contraction of skeletal muscle? A) contraction of the heart B) moving your feet in walking C) movement of food through the G.I. tract D) emptying of the urinary bladder E) vasoconstriction

Smooth muscle and cardiac muscle are similar in that they both A) are under involuntary control. B) are striated. C) are widely distributed in the body. D) have multiple nuclei. E) are under voluntary control.

Which of the following is true? A) Skeletal muscle is capable of spontaneous contraction. B) Smooth muscle is found in the walls of hollow organs. C) Cardiac muscle cells have multiple nuclei. D) Smooth muscle cells are long and cylindrical. E) There is a small amount of smooth muscle in the heart.

Hypertrophy of skeletal muscles from weight lifting is caused by an increase in the A) number of muscle fibres. B) size of muscle fibres. C) number of striations. D) number of nuclei within the muscle fibres. E) number of muscle cells.

Skeletal muscle fibres A) possess striations. B) can contract but are not extensible or excitable. C) do not require nerve innervation to contract. D) increase dramatically in number after birth. E) are found in the walls of the stomach.

A fascicle (or fasciculus) A) is a bundle of reticular fibers. B) is surrounded by perimysium. C) is only found in smooth muscle. D) possesses an external lamina. E) is a bundle of collagen fibers.

Endomysium is a delicate network of loose connective tissue that A) surrounds each muscle fibre. B) forms a sheath around a fasciculus. C) is composed of elastic fibers. D) separates individual muscles. E) penetrates muscle fibers.

Which of the following connective tissue layers is outside all the others? A) perimysium B) endomysium C) epimysium D) paramysium E) sarcolemma

Muscle myofibrils A) are found in the sarcolemma. B) extend from the sarcolemma to the T-tubule. C) contain myosin and actin myofilaments. D) hold muscle cells together. E) do not appear striated.

T tubules A) provide nutrients to the muscle fiber. B) generate new muscle fibers. C) conduct action potentials deep into the muscle cell. D) release acetylcholine. E) store calcium ions

The sarcoplasmic reticulum A) stores calcium ions. B) shortens during muscle contraction. C) transmits nerve impulses to the myofibrils. D) connects adjacent sarcomeres. E) covers the muscle fiber.

The sites where a chemical substance is transmitted from the presynaptic terminal of an axon to the postsynaptic membrane of a muscle fiber are called A) neuromuscular junctions. B) sarcomeres. C) myofilaments. D) Z disks. E) cell body of neuron.

Electric signals called action potentials A) cause a muscle cell to contract. B) transfer information from cell to cell. C) make complex mental processes possible. D) send information to the brain. E) all of the above

Which of the following correctly describes myoglobin's special function in muscle tissue? A) breaks down glycogen B) synthesizes ATP C) acts as a reservoir for oxygen D) produces action potentials E) stores glucose.

Body temperature A) is raised by sweating. B) results from the heat produced when muscles contract. C) will increase after blood vessels in the skin constrict. D) is lowered by shivering. E) decreases when the rate of the chemical reactions increase.

Shivering A) increases heat loss from the skin. B) is a response of the nervous system to a high fever. C) helps raise body temperature. D) causes vasoconstriction. E) occurs when body temperature is slightly elevated

When comparing smooth and skeletal muscle cells, which of the following statements is true? A) Smooth muscle cells have striations. B) The myofilaments in smooth muscle do not form sarcomeres. C) Smooth muscle cells are larger than skeletal muscle cells. D) Smooth muscle has a lot of actin and myosin. E) Smooth muscle cells are multinucleated.

Cardiac muscle A) is found in the walls of blood vessels and in the heart. B) is largely under voluntary control. C) is striated. D) contraction is dependent on stimulation by the nervous system. E) is unaffected by hormones.

Smooth muscle A) is largely under voluntary control. B) is located in the coverings of solid organs. C) is striated. D) moves blood through the heart E) is regulated by the autonomic division of the nervous system.

Which of the following is a function of muscle tissue? A) absorbing heat from the environment B) storage of triglycerides C) controlling flow of materials out of the stomach and urinary bladder D) destabilizing body position E) storing calcium

The ability to respond to stimuli by producing action potentials A) is called electrical excitability. B) is a property of muscle tissue. C) is not exhibited by nervous tissue. D) A and B are correct. E) A, B and C are correct.

The ability of a muscle tissue to stretch without being damaged is called A) electrical excitability. B) contractility. C) extensibility. D) irritability. E) elasticity.

A muscle fibre (myofibre) is a muscle A) contractile unit. B) cell. C) protein. D) sarcomere. E) A and B are correct.

The outermost extension of deep connective tissue that surrounds a muscle is the A) endomysium. B) epimysium. C) perimysium D) tendon. E) aponeurosis.

A tendon A) attaches a muscle to a bone. B) is an extension of the fused endomysium, perimysium and epimysium of a muscle. C) contains parallel bundles of collagen fibers. D) A and B are correct. E) A, B and C are correct.

A skeletal myofibre A) has one centrally located nucleus. B) is derived from embryonic cells called myoblasts. C) retains mitotic potential even in the adult. D) A and B are correct. E) A, B and C are correct.

The sarcoplasm A) is the extracellular fluid around a myofiber. B) is enriched with glycogen. C) contains hemoglobin to store O2. D) contains few mitochondria. E) includes many nuclei.

The sarcoplasmic reticulum of muscle tissue A) stores Ca2+ ions required for muscle contraction. B) is called rough endoplasmic reticulum in other tissues. C) is part of the transverse tubule. D) is a thread of protein running the length of the muscle cell. E) removes Ca2+ from the sarcoplasm so that an action potential can be generated.

A neuromuscular junction (NMJ) A) is the synapse of a motor neuron with a muscle fibre. B) includes the synaptic end bulbs of the muscle fibre. C) includes the motor endplates of the motor neuron. D) uses Na+ as a neurotransmitter. E) All of the above are correct.

Each of the following is true EXCEPT that: A) a single muscle fibre is controlled by through a single neuromuscular junction. B) a single motor neuron controls a single muscle fibre. C) the strength of a muscle contraction depends on the number of motor units stimulated. D) the strength of a muscle contraction depends on the size of the motor units stimulated. E) a motor unit consists of a somatic motor neuron and the skeletal muscle fibres it controls

Cardiac muscle tissue A) is autorhythmic. B) contains branched cells that are connected by intercalated discs. C) obtains Ca2+ required for contraction from the sarcoplasmic reticulum and the interstitial fluid. D) maintains contractions for longer periods of time than skeletal muscle tissue. E) All of the above are correct.

A ___________ is the functional unit of muscle contraction

Both skeletal and _________ muscle are striated, but only skeletal muscle is voluntarily controlled.

List the following structures in order from smallest to largest. 1. muscle fibre 2. myofilament 3. myofibril 4. muscle fasciculus A) 4, 2, 3, 1 B) 2, 1, 4, 3 C) 3, 1, 4, 2 D) 2, 3, 1, 4 E) 1, 2, 3, 4

A single motor neuron and all of the fibres it innervates is a ____________________.

Functions of muscle include moving the body, thermogenesis, storage and movement of materials within the body and _____________________________________________.

________________ is a protein found in the sarcoplasm of skeletal muscle cells that binds and releases O2.

Muscular _____ is a wasting away of muscles that may arise from disuse or denervation.

________________ consist of motor neurons and the muscle fibers that they control.