The Muscular System
the muscle twitch is a brief and "jerky" movement, while the tetanic contraction is prolonged and continuous
A skeletal muscle twitch differs from a tetanic contraction in that ________.
fused, or complete, tetanus
A smooth, sustained contraction is called ________.
skeletal muscle tissue
Voluntary muscle tissue
atrophy
What condition results if muscles are not used, such as when immobilized in a cast for healing a broken bone?
knee extension
What is the main function of the quadriceps group?
scapular spine and clavicle
What is the origin of the deltoid muscle?
TRUE
When a muscle fiber contracts, the I bands diminish in size, the H zones disappear, and the A bands move closer together but do not diminish in length.
Z discs
When a skeletal muscle is fully contracted, the ________ are closer to the thick filaments.
hamstring group
Which muscle group includes the biceps femoris, semimembranosus, and semitendinosus?
rectus abdominis
Which muscle helps compress the abdominal contents during defecation or childbirth?
tibialis anterior
Which muscle is an antagonist to gastrocnemius?
sarcomere
Which of the following can actually shorten during a muscle contraction?
hematopoiesis
Which of the following is NOT a function of the muscular system?
pushing against an immovable wall
Which of the following is an example of an isometric contraction?
biceps brachii and triceps brachii
Which of the following muscles are antagonists?
both masseter and temporalis
Which of the following muscles closes the jaw?
acetylcholine (ACh) causes temporary permeability to sodium
Which of these events must occur first to trigger the skeletal muscle to generate an action potential and contract?
temporalis
Which of these muscles is a synergist to masseter?
method of attachment of the muscle to bone
Which one of the following is NOT a criterion generally used in naming muscles?
thick filaments
Which one of the following is composed of myosin protein?
deltoid
Which one of the following muscles is involved in abduction of the arm at the shoulder joint?
skeletal
Which type of muscle tissue contracts most quickly upon stimulation?
abduction
While doing "jumping jacks" during an exercise class, your arms and legs move laterally away from the midline of your body. This motion is called ________.
storing energy that will be transferred to ADP to resynthesize ATP as needed
Creatine phosphate (CP) functions within the muscle cells by ________.
Label C
The perimysium wraps a fascicle of muscle cells and is represented by ________.
sarcolemma
The plasma membrane of a skeletal muscle cell is called the ________.
origin
The point of muscle attachment to an immovable or less movable bone is known as the ________.
FALSE
Thick filaments are made of a protein called actin.
calcium triggers the binding of myosin to actin
Why are calcium ions necessary for skeletal muscle contraction?
oxygen
Anaerobic glycolysis occurs without ________.
buccinator
A nursing infant develops a powerful sucking muscle that adults also use for whistling or blowing a trumpet called the ________.
motor unit
A motor neuron and all of the skeletal muscle fibers it stimulates are termed a ________.
synergist only
A muscle group that works with and assists the action of a prime mover is a(n) ________.
pectoralis major
A muscle located on the ventral (anterior) side of the body is the ________.
FALSE
A muscle twitch results when the muscle is stimulated so rapidly that no evidence of relaxation is seen.
FALSE
A neuromuscular junction consists of one neuron and all the skeletal muscles it stimulates.
the contractile unit between two Z discs
A sarcomere is ________.
TRUE
Abduction and adduction are antagonistic actions.
a neurotransmitter that stimulates skeletal muscle
Acetylcholine is ________.
TRUE
Aerobic respiration requires the use of oxygen to generate ATP.
TRUE
Aerobic, or endurance, exercise involves jogging or biking.
TRUE
All types of muscle have endomysium covering individual muscle cells.
sarcoplasmic reticulum
An elaborate and specialized network of membranes in skeletal muscle cells that function in calcium storage is the ________.
muscular dystrophy
An inherited disease that causes muscles to degenerate and atrophy is known as ________.
oxygen
Anaerobic glycolysis requires ________ to make ATP.
FALSE
Bundles of muscle fibers are known as aponeuroses.
TRUE
Cardiac and skeletal muscle both possess striations.
isometric contractions
Contractions in which muscles shorten and produce movement are known as ________.
thin filaments
Cross bridges are created when myosin heads bind to ________.
actin filaments
During skeletal muscle contraction, myosin heads attach to binding sites associated with ________.
an individual muscle cell
Endomysium covers ________.
bind to receptors in the sarcolemma of the muscle cell
In ordIn order to excite a muscle cell, acetycholine must ________.er to excite a muscle cell, acetycholine must ________.
FALSE
Isometric contractions produce movement when filaments slide past one another and the muscle shortens.
TRUE
Muscle development in babies occurs in a cephalic/caudal direction.
cardiac muscle tissue
Muscle tissue composed of branching cells and intercalated discs
cardiac muscle tissue
Muscle tissue found only in the heart
contractility
Muscle tissue has the ability to shorten when adequately stimulated, a characteristic known as ________.
smooth muscle tissue
Muscle tissue that activates arrector pili muscles to stand hairs on end
smooth muscle tissue
Muscle tissue that forms valves to regulate the passage of substances through internal body openings
skeletal muscle tissue
Muscle tissue that is multinucleate
antagonists
Muscles that perform opposite actions to one another are termed ________.
axon terminals of the motor neuron
Neurotransmitters are released upon stimulation from a nerve impulse by the ________.
motor unit
One neuron and all the skeletal muscles it stimulates is known as a ________.
iliopsoas
Paralysis of which of the following would make an individual unable to flex the hip ________.
FALSE
Plantar flexion at the ankle joint is accomplished by the tibialis anterior muscle.
extensor digitorum longus
Sandra is playing the piano for her recital. Which muscle is NOT involved in the movement of her hands and/or fingers ________.
involuntary
Smooth muscle cells are ________.
cardiac muscle
Striated involuntary muscle tissue found in the heart is ________.
cardiac
Striated involuntary muscle tissue is classified as ________ muscle.
FALSE
Supination and pronation refer to up and down movements of the foot at the ankle.
Label A
The A band within a skeletal muscle fiber is indicated by ________.
Label D
The H zone, located within the A band, lacks thin filaments and is represented by ________.
Label B
The I band within a skeletal muscle fiber is indicated by ________.
sarcoplasmic reticulum
The ________ is an organelle that wraps and surrounds the myofibril and stores calcium.
circular
The arrangement of fascicles in orbicularis oris is ________.
insufficient intracellular quantities of ATP due to excessive consumption
The condition of skeletal muscle fatigue can be best explained by ________.
TRUE
The deepest muscle of the abdominal wall is the transversus abdominis.
FALSE
The deltoid is a prime mover of arm adduction.
TRUE
The deltoid muscle is a common site for intramuscular injections.
TRUE
The effect of the neurotransmitter on the muscle cell membrane is to temporarily modify its permeability of ions such as Na+ and K+.
Label B
The endomysium that wraps individual muscle fibers is indicated by ________.
tendons; aponeuroses
The epimysium covering on the outside of the muscle can blend into cordlike ________ or sheetlike ________.
Label A
The epimysium is represented by ________.
FALSE
The fastest mechanism for producing ATP is aerobic respiration.
synaptic cleft
The gap between the axon terminal of a motor neuron and the sarcolemma of a skeletal muscle cell is called the ________.
synaptic cleft
The gap between the motor neuron and the muscle fiber it supplies at the neuromuscular junction is called the ________.
FALSE
The hamstring group inserts into the distal tibia.
extension; flexion
The hamstring group is the prime mover of thigh ________ and knee ________.
cross bridges
The heads of the myosin myofilaments are called ________ when they link the thick and thin filaments together during skeletal muscle contraction.
origin
The least movable point of muscle attachment to a bone is termed its ________.
a sliding of thin filaments past thick filaments
The mechanical force of contraction is generated by ________.
adduction
The movement opposite to abduction is ________.
Label D
The muscle fiber (cell) is indicated by ________.
orbicularis oculi
The muscle that closes each eye is the ________.
Label C
The myofilament composed of actin is indicated by ________.
TRUE
The neurotransmitter used by the nervous system to activate skeletal muscle cells is acetylcholine.
deltoid
The prime mover of arm abduction is the ________ muscle.
TRUE
The sarcoplasmic reticulum wraps like a sleeve around the myofibril and stores and releases calcium.
TRUE
The striations seen in skeletal muscle are actually alternating dark A and light I bands.
smooth muscle
The type of muscle tissue pictured in Figure 6.3 is ________.