anatomy

What is the biochemical explanation for rigor mortis?

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

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

They are large in diameter, with relatively few mitochondria.

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

actin and myosin.

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

back and calf muscles

Which of the following characteristics describes cardiac muscle?

Cardiac muscle cells are striated and branched with intercalated discs.

Activities requiring aerobic endurance are

characterized by sustained, low levels of activity

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

have many nuclei.

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

muscle fiber, myofibril, myofilament

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

myofibril

A sheath of connective tissue surrounding a fascicle ________.

perimysium

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 cytoplasm of the muscle cell is called the

sarcoplasm.

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

sarcoplasmic reticulum.

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.

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

the transverse tubule pattern. (T-tubule)

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

transverse tubules (T tubules

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.

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

I band

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

Skeletal muscle contractions help maintain body temperature.

Thin connective tissue surrounding each muscle cell

endomysium.

A layer of collagen fibers that surrounds an entire muscle is called

epimysium

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

fiber