Muscular System

A muscle ________ , also known as a muscle cell, contains a sarcolemma, sarcoplasm, myofilaments, and myofibrils.

Fiber

Activities requiring aerobic endurance are

characterized by sustained, low levels of activity

Transverse tubule

Tubes that form from sarcolemma that allow for electrical stimuli to reach deep into each fiber

Which of the following accurately lists the levels of organization within a muscle from largest to smallest?

muscle fiber, myofibril, myofilament

Which of the following areas of the human body are dominated by slow fibers?

back and calf muscles

Aponeurosis

Attaches muscle to muscle

Tendon

Attaches muscle to bone

Which of the following characteristics describes cardiac muscle?

Cardiac muscle cells are striated and branched with intercalated discs

The striated appearance of skeletal muscle results from myofilaments which are composed of proteins called

Cisternae placement

Which of the following statements about how skeletal muscles use and store energy is true?

During light activity, muscles generate energy through the aerobic breakdown of carbohydrates, lipids, or amino acids.

Skeletal muscle fibers differ from "typical cells" in that these muscle fibers

Have many nuclei

Which of the following parts of a sarcomere contain the protein actin only?

I band

Myofibrils

Made of bundles of myofilaments

A long, filamentous organelle found within muscle cells that has a banded appearance is called a

Myofibril

What structure divides the skeletal muscle into compartments and contains collagen fibers, elastic fibers, blood vessels, and nerves?

Perimysium

Curare is best known as the South American "poison arrow" toxin used for hunting. A synthetic form of curare is used routinely in emergency care to facilitate intubation. Curare specifically blocks acetylcholine (ACh) receptors. What is the result of administering curare to a skeletal muscle group?

Relaxation

The plasma membrane of the muscle cell is called the

Sarcolemma

The contractile unit of muscle is called a

Sarcomere

The skeletal muscles store calcium ions in the terminal cisternae of the

Sarcoplasmic reticulum

Which of the following statements best describes how muscles help maintain homeostasis?

Skeletal muscle contractions help maintain body temperature

A person whose genetic makeup makes him or her a better marathon runner than a sprinter probably has more ________ in his or her leg muscles.

Slow fibers

Nonstriated, involuntary muscle is

Smooth

Structures filled with extracellular fluid, formed by the tunneling of the sarcolemma through the muscle fiber, are called

T tubules

Myosin

Thick myofilaments

Actin

Thin myofilaments

Sarcoplasm

The cytoplasm

Sarcolemma

The plasma membrane

What is the biochemical explanation for rigor mortis?

The sarcoplasmic reticulum is unable to remove calcium ions from the sarcoplasm.

Sarcomere

The smallest functional unit of skeletal muscle formed by repeats of myofilament arrangements

Sarcoplasmic Reticulum

The smooth endoplasmic reticulum; produces calcium needed for contraction

endomysium

The type of connective tissue that covers each muscle fiber

Epimysium

The type of connective tissue that covers the entire muscle

Perimysium

The type of connective tissue that divides the muscle into bundles

Which of the following statements regarding fast skeletal muscle fibers is true?

They are large in diameter, with relatively few mitochondria