Ch. 8 Human Anatomy Test

The segment of a muscle fiber that contains both actin and myosin is the

A band

The dark bands in skeletal muscle that contribute to its striated appearance are known as

A bands

What are fascicles?

A small bundle of muscle fiber

A person feels out of breath after vigorous exercise because of oxygen debt. Which of the following statements helps explain this phenomenon?

Anaerobic respiration increases during strenuous activity, Conversion of lactic acid to glycogen occurs in the liver and requires energy, Priority in energy use is given to ATP synthesis

A motor neuron connects to a single muscle fiber.

False

An influx of potassium ions into the muscle fiber is responsible for cross-bridging of actin and myosin filaments.

False

Layers of connective tissue that extend into muscle and form compartments within the muscle are fascicles.

False

Much of the heat of the body is produced by the metabolic activities of viscera.

False

Oxygen is stored in muscle tissue in molecules of located near mitochondria.

False

The energy source for conversion of ADP to ATP in an actively contracting muscle is creatine phosphate.

False

The sarcoplasmic reticulum is composed of invaginations of the muscle cell membrane that contain extracellular fluid.

False

List the three types of muscle

Skeletal, smooth, cardiac

A skeletal muscle fiber is an individual cell that contracts and shortens when stimulated.

True

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

True

Muscle fatigue is the inability to contract after a period of sustained, strenuous exercise.

True

Skeletal muscle is composed of multiple layers surrounded by connective tissue.

True

Skeletal muscle is composed of skeletal muscle tissue, nervous tissue, blood, and connective tissue.

True

The severity of muscle strain depends on the number of muscle fibers that are damaged.

True

The sarcomere, the basic unit of skeletal muscle extends from

Z line to Z line

Describe the structure and function of a sarcomere

a contractile unit in a striated muscle fiber (cell) extending from one Z line to the next Z line

What is a cross-bridge?

a myosin molecule composed of two twisted protein strands with globular parts

Define all-or-none response

a skeletal muscle fiber normally does not contract partially; if it contracts at all, it contracts fully

Muscle tone refers to

a state of sustained, partial contraction of muscles that is necessary to maintain posture

The chemical that is necessary for the transmission of an impulse from a nerve to a muscle fiber is

acetylcholine

When a nerve impulse reaches the end of a motor neuron,

acetylcholine is released

Two neurotransmitters that affect smooth muscle are ___________ and ____________

acetylcholine, norepinephrine

The action of acetylcholine is halted by the enzyme

acetylcholinesterase

The characteristic striated appearance of skeletal muscle is due to the arrangement of alternating protein filaments composed of __________ and __________

actin, myosin

What is the function of these channels?

activate the muscle contraption mechanism when the fiber is stimulated

The energy used in muscle contraction is supplied by the decomposition of

adenosine triphosphate (ATP)

myosin filaments contain

an enzyme ATPase

During high intensity exercise, muscle fibers rely upon what process for energy?

anaerobic respiration

Smooth body movements depend on _____________ giving way to prime movers

antagonists

When this tissue extends beyond the muscle to form a sheetlike structure, it is called a(n) _____________

aponeuroses

A fibrous, flattened, sheet-like tendon is known as

aponeurosis

The muscle that compresses the cheeks inward when it contracts is the

buccinator

The ion necessary to link myosin and actin is

calcium

Peristalsis is due to which of the following characteristics of smooth muscle?

capacity of smooth muscle fibers to excite each, rhythmicity

The kind of energy that muscles use to contract is

chemical

A substance that stores energy released when stores of the substance in number 10 are in low supply is ____________ __________

creatine phosphate

Opposing ends of cardiac muscle fibers are connected by ____ - ____ ____________

cross-bands intercalated discs

Atrophy refers to a(n) (increase, decrease) in the size and strength of a muscle

decrease

The muscle that abducts the upper arm and can both flex and extend the gamers is the

deltoid

The muscle that abducts the upper arm and can both flex and extend the humerus is the

deltoid

The connective tissue that surrounds individual muscle fibers is

endomysium

A skeletal muscle is held in position by layers of fibrous connective tissue called _________

fascia

An individual skeletal muscle is separated from adjacent muscles by

fascia

Which of the following muscles produce plantar flexion?

gastrocnemius

The heaviest muscle in the body, which serves to straighten the leg at the hip during walking is the

gluteus maximus

Less than half the energy released by cellular respiration is available for metabolic processes. The rest is lost as _________

heat

Where is multiunit smooth muscle found?

in the irises of the eyes and the walls of blood vessels

Describe recruitment

increase in the number of motor units being activated

Oxygen debt secondary to strenuous exercise is due to

insufficient oxygen to promote conversion of lactic acid to glucose, lack of available oxygen to convert ADP to ATP

The rapidity with which an impulse spreads in cardiac muscle is due to

intercalated disks between muscle fibers

After prolonged muscle use, muscle fatigue occurs due to an accumulation of ________ ________

lactic acid

The period of time between a stimulus to a muscle and muscle response is called the

latent period

The band of tough connective tissue that extends from the xiphoid process to the symphysis pubis and serves as an attachment for muscles of the abdominal wall is the _________ ___________

linea alba

Muscles that are involved in chewing are attached to the

mandible

The insertion of the sternocleidomastoid is the

mastoid process of the temporal bone

An injury in which a few muscle fibers are torn but the fascia is left intact is called a _________ __________ __________

mild muscle strain

Define threshold stimulus

minimal strength required to cause a contraction

Smooth muscle contracts (more slowly, more rapidly) than skeletal muscle following stimulation

more slowly

A motor neuron and the muscle fibers it controls are called a ________ _________

motor unit

Two types of smooth muscle are __________ muscle and ____________ muscle

multiunit, visceral

What substance in muscle seems able to store oxygen temporarily?

myoglobin

Rhythmicity is a property of

neither

The union between a nerve fiber and a muscle fiber is the

neuromuscular junction

Skeletal muscle cells contain many

nuclei and mitochondria

The strength of a muscle in response to different levels of stimulation is determined by the

number of motor units receiving a threshold stimulus

The strength of a muscle contraption in response to different levels of stimulation is determined by the

number of motor units stimulated

The attachment of a muscle to a relatively fixed part is called the _________; the attachment to a relatively movable part is called the ____________

origin, insertion

The muscles that flex, extend, and rotate the head include all of the following except

pectoralis minor

Antagonistic muscles

perform functions opposite to those performed by the prime mover

The toxin of clostridium botulinum causes death by

preventing the release of acetylcholine

Impulses travel relatively (rapidly, slowly) through cardiac muscle

rapidly

The network of membranous channels in the cytoplasm of muscle fibers is the ___________ ___________. The other channels found in the cytoplasm are the _________ _________.

sarcoplasmic reticulum, transverse tubules

When the cross-bridge of the myosin molecule forms linkages with actin filaments, the result is

shortening of the muscle fiber

List the tissues found in skeletal muscle

skeletal muscle tissue, blood, nervous tissue, connective tissue

List the kinds of tissue present in skeletal muscle

skeletal muscle tissue, nervous tissue, blood, connective tissue

The muscle that moves the head to one side is the

sternocleidomastoid

The result of summation and recruitment together is

sustained tetanic contraction

Which of the following is not characteristic of the motor end plate on a muscle fiber?

synaptic vesicles

Muscles that assist the prime mover in producing a movement are called

synergists

This tissue extends beyond the end of a skeletal muscle to form a cordlike _________

tendon

Layers of connective tissue extending into the muscle to form partitions between muscle bundles are continuous with attachments of muscle to periosteum called

tendons

The primary extensors of the upper arm are the

teres major and latissimus dorsi

ATPase is stored in

the globular portion of the myosin filament

Where is visceral smooth muscle found?

the walls of hollow organs such as stomach, intestines, urinary bladder, uterus

two major protein filaments

thick filament myosin, thin filament actin

Describe a single muscle fiber

thin, elongated cylinder with rounded ends. Contracts in response to stimulation, relaxes when stimulation ends

The minimal strength stimulus needed to elicit contraction of a single muscle fiber is called a(n) __________ ___________

threshold stimulus

The properties of smooth muscle that allows peristalsis are ____________ and ____________

transmission of impulses, rhythmicity

Actin filament contain

troponin and tropomyosin

Describe summation

when the degree of change in membrane potential directly correlates with stimulation frequency