A fibrous, flattened, sheet-like tendon is known as
|C)||a tendon sheath|
|D)||a broad ligament|
The connective tissue that surrounds individual muscle fibers is
Choose the true statement regarding skeletal muscle cells.
|A)||Another term for a skeletal muscle cell is myofibril.|
|B)||Each skeletal muscle cell has many nuclei and mitochondria.|
|C)||The muscle cell membrane is called the sarcoplasm.|
|D)||Skeletal muscle cells do not extend the full length of a muscle.|
The dark bands in skeletal muscle that contribute to its striated appearance are known as
The sarcomere, the basic unit of skeletal muscle, extends from
|A)||A band to A band|
|B)||M line to M line|
|C)||H band to H band|
|D)||Z line to Z line|
Which of the following is not characteristic of the motor end plate on a muscle fiber?
|D)||extensive folding of the sarcolemma|
When the cross-bridge of the myosin molecule forms linkages with actin filaments, the result is
|A)||shortening of the muscle fiber|
|B)||creation of a high energy bond|
|D)||release of acetylcholine|
ATPase is stored in
|A)||the actin filament helix|
|B)||the globular portion of the myosin filament|
|D)||muscle cell cytoplasm|
When a nerve impulse reaches the end of a motor neuron,
|A)||the number of synaptic vesicles increases|
|B)||muscle fibers stretch|
|C)||calcium ions move out of the cytoplasm of the neuron|
|D)||acetylcholine is released|
The toxin of clostridium botulinum causes death by
|A)||decreasing the permeability of the sarcolemma to calcium|
|B)||increasing the release of acetylcholinesterase|
|C)||halting the formation of new synaptic vesicles|
|D)||preventing the release of acetylcholine|
During high intensity exercise, muscle fibers rely upon what process for energy?
|B)||increased metabolism of glucose|
|D)||increased blood supply|
Muscle fatigue can be caused by all of the following except
|A)||lowering of pH due to lactic acid build-up|
|B)||interruption of blood supply|
|C)||formation of a cramp|
|D)||lack of acetylcholine|
The strength of a muscle in response to different levels of stimulation is determined by the
|A)||level of stimulation delivered to individual muscle fibers|
|B)||number of fibers that respond in each motor unit|
|C)||number of motor units receiving a threshold stimulus|
|D)||characteristics of each muscle group|
The result of summation and recruitment together is
|B)||sustained tetanic contraction|
Muscle tone refers to
|A)||a state of sustained, partial contraction of muscles that is necessary to maintain posture|
|B)||a feeling of well-being following exercise|
|C)||the ability of a muscle to maintain contraction against an outside force|
|D)||the condition athletes attain after intensive training|
Which of the following is not a characteristic of smooth muscle cells?
|A)||some are responsive to hormones|
|B)||contraction is triggered by an influx of calcium ions|
|C)||stimulation by acetylcholine or norepinephrine|
|D)||highly organized arrangement of actin and myosin filaments|
Peristalsis is due to which of the following characteristics of smooth muscle?
The rapidity with which an impulse spreads in cardiac muscle is due to
|A)||increased amounts of neurotransmitters|
|B)||the presence of striated muscle fibers|
|C)||intercalated disks between muscle fibers|
|D)||the property of excitability|
Muscles that assist the prime mover in producing a movement are called
|A)||are always located on the opposite side of the body from the prime mover|
|B)||have different speeds and strengths of contraction|
|C)||produce extension rather than abduction|
|D)||perform movements opposite to those performed by the prime mover|
Muscles that are involved in chewing are attached to the
|B)||mandibular process of the temporal bone|
The muscle that compresses the cheeks inward when it contracts is the
All of the following muscles flex the knee except
The insertion of the sternocleidomastoid is the
|A)||anterior surface of the sternum|
|B)||mastoid process of the temporal bone|
|D)||spinous processes of the lower cervical vertebrae|
The primary flexor of the vertebral column is the
The muscle that abducts the upper arm and can both flex and extend the humerus is the
Which muscle produces plantar flexion?
|D)||extensor digitorum longus|
When a skeletal muscle contracts, the insertion is pulled toward the origin.
Layers of connective tissue that extend into muscle and form compartments within the muscle are fascicles.
During a tetanic contraction, all motor units in a muscle have been recruited.
It is possible for a skeletal muscle to be both synergist and antagonist to another muscle.
The sarcoplasmic reticulum is composed of invaginations of the muscle cell membrane that contain extracellular fluid.
The severity of muscle strain depends on the number of muscle fibers that are damaged.
A motor neuron connects to a single muscle fiber.
During muscle contraction, the head of myosin cross-bridges attach to actin binding sites and bend slightly, pulling the actin filament toward the center of the sarcomere.
An influx of potassium ions into the muscle fiber is responsible for cross-bridging of actin and myosin filaments.
Creatine phosphate stores energy that is used to convert ADP to ATP during muscle contraction.
Oxygen is stored in muscle tissue in molecules of hemoglobin located near mitochondria.
Oxygen debt is the amount of oxygen needed to convert lactic acid into glucose after strenuous exercise.
The insertion of the temporalis is the coracoid process of the mandible.
The psoas major and iliacus muscles flex the thigh.