A&P Test 3 Chapters 9-11

Which of the following muscle types is both voluntary and striated?

skeletal muscle only

Muscle cells initiate nerve impulses.

False

Which of the following is a special adaptation present in skeletal muscle cells, but absent in most other cells?

Muscle cells have myoglobin; most other cells do not.

The final "go" signal for skeletal muscle contraction is __________.

an increase in intracellular calcium ion levels

The __________ are extensions of the sarcolemma, and serve as a rapid communication system that ensures that every myofibril in the muscle fiber contracts at virtually the same time.

T tubules

The thin myofilaments of skeletal muscle are composed chiefly of __________.

actin

Acetylcholinesterase __________.

breaks down acetylcholine

Myofibrils are composed of repeating contractile elements called __________.

sarcomeres

Which of the following statements is false?

During contraction, thin filaments slide past thick filaments so that actin and myosin filaments do not overlap.

When an action potential arrives at the neuromuscular junction, the most immediate result is __________.

the release of acetylcholine from the motor neuron

If a muscle is applied to a load that exceeds the muscle's maximum tension, __________.

the muscle length will not change during contraction

Properly controlled skeletal muscle contractions produced by changing the frequency of stimulation or the strength of stimulation are accomplished by __________.

graded muscle response

The most efficient means of producing ATP is __________.

aerobic respiration

What would occur if a muscle became totally depleted of ATP?

The muscle would remain in a contracted state due to an inability to break actin-myosin cross bridges.

Match the muscle fiber to the appropriate characteristic.

slow oxidative muscle fiber~ fatigue resistant

fast oxidative muscle fiber~ moderately fatigue resistant

fast glycolytic muscle fiber~ fatigues quickly

Which of the following is false regarding smooth muscle?

Once damaged, smooth muscle is unable to regenerate.

Choose the true statement.

Smooth muscle depends on the calcium-calmodulin system to regulate contraction while skeletal muscle relies on the calcium-troponin system to regulate contraction.

__________ are muscles that oppose or reverse a particular movement.

Antagonists

How many origins are there for the biceps brachii muscle?

two

Sphincters have a __________ arrangement of fascicles.

circular

Muscles with parallel fascicle arrangement tend to shorten a great deal upon contracting; thus, these types of muscles tend to be very powerful.

False

Standing on your toes is an example of a __________.

second-class lever

Which of the following is an infrahyoid muscle?

omohyoid muscle

The prime movers of back extension are the __________.

erector spinae muscles

The external intercostal muscles are used primarily in __________.

inhalation

When the diaphragm contracts, __________.

inhalation occurs

Voluntary control of urination is facilitated by the __________.

external urethral sphincter.

The prime mover of arm flexion is the __________.

pectoralis major

Which of the following is involved in tongue movement?

styloglossus

Match the following words to their correct meaning.

Correct Answer

rectus D. straight

transverse A. right angles

brevis C. short

deltoid E. triangle

costal B. rib

carpi F. wrist

The hamstrings and the gluteus maximus are primarily responsible for __________.

thigh extension

Plantar flexion is the weakest movement of the foot and ankle.

False

Which of the following best describes the concept of integration?

The nervous system processes and interprets sensory input and decides what should be done at each moment.

What is the primary difference between the somatic nervous system and the autonomic nervous system?

The somatic nervous system allows us to consciously control our skeletal muscles, and the autonomic nervous system controls activity that humans cannot consciously control, such as the pumping of the heart and the movement of food through the digestive tract.

Which of the following types of glial cells line the central cavities of the brain and spinal cord, where they help to circulate the cerebrospinal fluid?

ependymal cells

Which of the following types of glial cells are the most abundant and versatile, and aid in making exchanges between capillaries and neurons?

astrocytes

Which of the following is NOT a characteristic of neurons?

Neurons are relatively small, simple-structured cells.

What is the difference between the clusters of cell bodies called nuclei and those known as ganglia?

Nuclei exist in the CNS, ganglia in the PNS.

Dendrites and axons are both armlike processes that extend from cell bodies.

True

Which of the following are the main receptive or input regions found in neurons?

Dendrites

Which of the following is NOT a function of the myelin sheath?

to recapture and recycle released neurotransmitters

What is the difference between nerves and tracts?

Bundles of neuron processes are called tracts in the CNS and nerves in the PNS.

Which criterion is used to structurally classify neurons?

the number of processes extending from their cell body

Which of the following is NOT a structural classification of neurons?

sensory

Which of the following is NOT true of efferent neurons?

Efferent neurons are bipolar.

Which of the following membrane ion channels open and close in response to changes in the membrane potential?

voltage-gated channels

An action potential is a phenomenon that either happens completely or doesn't happen at all.

True

Which of the following diseases is directly related to demyelination?

multiple sclerosis

Which of the following is NOT true of chemical synapses?

They transmit nerve impulses directly from one neuron to another.

Which of the following is NOT a functional classification of neurotransmitters?

chemical

Which of the following circuit types is exemplified by impulses that travel from a single neuron of the brain, activate one hundred or more motor neurons in the spinal cord, and excite thousands of skeletal muscle fibers?

diverging circuits

Which type of ion channel opens when a chemical binds to it?

leakage channels

The movement of which ion through leakage channels establishes the negative membrane potential?

potassium

Which part of the action potential occurs when the Na+ channels are inactivating and K+ channels open?

repolarization