muscle test

The __________ is described as two strands of actin molecules wrapped together.

thick filament

thin filament

elastic filament

troponin-tropomyosin complex

terminal cistern

thin filament

Which of the following happens as actin and myosin filaments slide past each other during muscle contraction?

Actin filaments shorten, while myosin filaments do not.

Myosin filaments shorten, while actin filaments do not.

Either actin or myosin filaments shorten, but not both at the same time.

Both actin and myosin filaments shorten.

Neither actin nor myosin filaments shorten.

neither actin nor myosin filaments shorten.

Which of the following statements about the "heads" of the myosin molecules is true?

They form permanent links with actin filaments.

They can attach to different sites on the actin filament.

They straighten the myosin filaments.

They allow the myosin filaments to wrap around each other.

None of these are true statements.

they can attach to different sites on the actin filament.

Muscle contractions are initiated by the binding of __________ to __________.

potassium ions; troponin

potassium ions; tropomyosin

calcium ions; troponin

calcium ions; tropomyosin

calcium ions; troponin and tropomyosin

calcium ions; troponin

During muscle contractions, cross-bridges form between the _________ and the __________.

myosin heads; tropomyosin filaments

myosin heads; actin filaments

myosin heads; ATP molecules

actin heads; troponin filaments

actin heads; tropomyosin filaments

myosin heads; actin filaments

Which of the following is the site of ATP binding and hydrolysis?

Troponin

Tropomyosin

Actin

Myosin

Troponin and tropomyosin

Myosin

During contraction of a muscle, calcium ions bind to the __________.

actin myofilament

troponin molecule

tropomyosin molecule

sarcoplasmic reticulum

sarcolemma

troponin molecule

The bond between the active site on actin and the myosin head is broken when an __________.

ATP molecule binds to the myosin head

ATP molecule binds to the actin molecule

ATP molecule breaks down on the myosin head

ATP molecule breaks down on the actin molecule

ADP molecule and a phosphate molecule bind to the myosin head

ATP molecule binds to the myosin head

The sequence of cross-bridge formation and myofilament movement will be repeated as long as calcium ions and ATP are present.

True

False

true

An action potential causes calcium ions to diffuse from the ________ into the ________.

sarcoplasmic reticulum; sarcolemma

sarcoplasmic reticulum; sarcoplasm

sarcoplasm; sarcoplasmic reticulum

sarcoplasm; sarcolemma

sarcolemma; sarcoplasm

Sarcoplasm reticulum; sarcoplasm

Which of the following best describes the role of Ca2+ in muscle contraction?

It binds to tropomyosin, moving troponin, so that myosin heads can bind to actin.

It binds to tropomyosin, moving troponin, so that actin heads can bind to myosin.

It binds to troponin, moving tropomyosin, so that myosin heads can bind to actin.

It binds to troponin, moving tropomyosin, so that actin heads can bind to myosin.

It binds to actin, moving myosin, so that troponin can bind to tropomyosin.

t binds to troponin, moving tropomyosin, so that myosin heads can bind to actin.

Which of the following is not a filamentous protein?

Actin

Myosin

Troponin

Tropomyosin

Troponin

An action potential enters the depths of a muscle fiber by way of __________.

diffusion

the T tubules

the calcium ion channels

the sarcoplasmic reticulum

the actin myofilament

the T tubes

Which structure do the calcium ions bind to when muscle contraction is initiated?

The actin myofilament

The troponin molecule

The tropomyosin molecule

The sarcoplasmic reticulum

The sarcolemma

The troponin molecule

Cross-bridges form between the __________ and the __________.

troponin; tropomyosin

calcium; sodium

sarcolemma ; sarcoplasmic reticulum

T tubules; sarcolemma

actin filaments; myosin heads

actin filaments; myosin heads

Which of the following is not an example of an autonomic receptor?

Muscarinic

Nicotinic

Cholinergic

Adrenergic

Ganglionic

ganglionic

When body temperature increases, thermoreceptors are stimulated and send nerve signals to the CNS. The CNS sends motor signals to sweat glands, which attempt to reduce body temperature. This is an example of a __________ reflex.

stretch

tendon organ

withdrawal

visceral

somatic

visceral

The digestive tract has a nervous system of its own called the _________ nervous system.

enteric

parasympathetic

sympathetic

peripheral

central

enteric

Sympathetic

Active during physical stress

increases the amount of air entering the alveoli of the lungs

maintains blood pressure

releases norepinephrine to the heart

results in decreased urine production

Fight or flight

Parasympathetic

-associated with reduced energy expenditure

decreases the frequency of impulses initiated by the sinoatrial node of the heart

stimulates the smooth muscles of the digestive tract.

Rest and digest

All preganglionic fibers of the ANS pass through the sympathetic chain of ganglia, synapsing at least once there.

True

False

false

The autonomic nervous system controls all of the following except the __________.

adrenal gland

smooth muscle in the walls of the aorta

cardiac muscle in the right atrium

skeletal muscle in the rectus abdominis

parotid salivary gland

skeletal muscle in the rectus abdominis

he neurotransmitter(s) associated with autonomic ganglia is(are) __________.

norepinephrine (NE)

acetylcholine (ACh) and norepinephrine (NE)

acetylcholine (ACh)

dopamine

dopamine and norepinephrine (NE)

acetylcholine (ACh)

The effect of autonomic fibers on target cells is _________. The effect of somatic fibers on target cells is __________.

always excitatory; always excitatory

excitatory or inhibitory; always excitatory

excitatory or inhibitory; excitatory or inhibitory

always inhibitory; excitatory or inhibitory

always inhibitory; always excitatory

excitatory or inhibitory; always excitatory.

The motor pathway of the autonomic nervous system usually involves __________ neurons.

no

one

two

three

four

two

Most fibers of the parasympathetic nervous system travel in the __________.

vagus

trigeminal

splanchnic

facial

sciatic

vagus

Which of the following is not a feature of the sympathetic division of the ANS?

It originates in the thoracolumbar region of the spinal cord.

It has long postganglionic fibers.

It has long preganglionic fibers.

Its ganglia are adjacent to the spinal column.

It has an extensive neural divergence and a relative widespread effect.

its a long preganglionic fibers

Most preganglionic fibers in the sympathetic nervous system synapse with __________.

no neurons

somatic neurons

parasympathetic neurons

10-20 postganglionic neurons

effectors directly

10-20 postganglionic neurons

Which of the following is more effective in producing bronchodilation?

Acetylcholine

Nicotine

Muscarine

Norepinephrine

Thyroxine

norepinephrine

Antagonistic effects of the two divisions of the autonomic nervous system are exemplified in the control of __________.

blood clotting

blood flow to the skeletal muscles

sweating

hair erection

gastrointestinal motility

gastrointestinal motility

Sympathetic fibers do not release __________.

acetylcholine

nitric oxide (NO)

substance P

neuropeptide Y

norepinephrine

nitric oxide (no)

he sliding filament theory of muscle contraction has emerged from research only in the last 10 to 15 years.

True

False

false

An isometric contraction does not change muscle length.

True

False

true

Which of the following is predominately made up of myosin?

G actin

F actin

The thin filament

The thick filament

The elastic filament

the thick filament

During muscle contraction, a single myosin head consumes ATP at a rate of about __________ ATP per second.

1

3

5

7

9

5

Which fibers are primarily responsible for producing lactic acid?

Type I slow oxidative fibers

Type IIA intermediate glycolytic fibers

Type IIB fast glycolytic fibers

Type I slow-twitch fibers

Red fibers

Type IIB Fast glycolytic fibers

To stimulate muscle contraction, acetylcholine is released from the ___________ into the synaptic cleft.

synaptic vesicles

junctional folds

sarcoplasmic reticulum

sarcolemma

terminal cisterna

synaptic vesicles

The protein that acts as a calcium receptor in skeletal muscle is __________.

F actin

tropomyosin

troponin

titin

dystrophin

troponin

Where is dystrophin, the protein that is defective in muscular dystrophy, normally found?

Between the outermost myofilaments and the sarcolemma of a muscle fiber

As a transmembrane protein of the sarcolemma

In the Z discs of skeletal and cardiac muscle

In the dense bodies of smooth muscle

Bridging the gap between the sarcolemma and synaptic knob

between the outermost myofilaments and the sarcolemma of a muscle fiber

The transfer of phosphate from CP to ADP is catalyzed by __________.

myokinase

creatinine

cAMP

creatine kinase

ATP

creatine kinase

Which of the following individuals would have more mitochondria in her skeletal muscle?

A 50-year-old sedentary computer programmer

A 22-year-old soccer player

A long-term hospice patient

A model on a reduced-calorie diet

A newborn

A 22 year old soccer player

Why does one continue to breathe heavy after rigorous physical activity has stopped?

The diaphragm is waiting for its acetylcholine to run out.

The body requires more oxygen to restore levels of ATP and creatine phosphate.

The lungs can't stop breathing until the heart rate slows down.

Myosin heads need more oxygen to fully detach from actin.

The kidneys require oxygen to dispose of excess lactic acid.

the body requires more oxygen to restore levels of ATP and creatine phosphate.