Chapter 45: Muscular System

Voluntary muscle

A group of fascicles are bound together by connective tissue to form a muscle. Because their contractions can usually be consciously controlled, skeletal muscles are described as

Myofibril

A skeletal muscle fiber contains bundles of threadlike structures called

Extensor

Contraction of the triceps muscle in the upper arm straightens the limb. The triceps muscle is an example of an ______, a muscle that straightens a joint

Striation

Each muscle fiber contains many nuclei and is crossed by light and dark stripes, called

Myosin

Each myofibril is made up of two types of protein filaments—thick ones and thin ones. Thick filaments are made of the protein

Actin

Each myofibril is made up of two types of protein filaments—thick ones and thin ones. Thin filaments are made of the protein

One-third

How much weight does muscle account for in the body?

Oxygen debt

However, after several minutes of heavy exertion, the circulatory system and the respiratory system are not able to bring in enough oxygen to meet the demands of energy production. Oxygen levels in the body become depleted. This temporary lack of oxygen availability is called

Involuntary

Is cardiac muscle involuntary or voluntary?

Yes

Is cardiac muscle striated?

Voluntary

Is skeletal muscle movement involuntary or voluntary?

Involuntary

Is smooth muscle movement involuntary or voluntary?

Muscle fatigue

Is the physiological inability of a muscle to contract

Tendon

Muscles are attached to the outer membrane of bone, the periosteum, either directly or by a tough fibrous cord of connective tissue called

Fascicle

Skeletal muscle fibers are grouped into dense bundles called

Muscle fiber

Skeletal muscle tissue is made up of elongated cells called

Involuntary muscle

Smooth muscle fibers are surrounded by connective tissue, but the connective tissue does not unite to form tendons as it does in skeletal muscles. Because most of its movements cannot be consciously controlled, smooth muscle is referred to as

Insertion

The point where the muscle attaches to the moving bone—in this case the radius—is called the

Origin

The point where the muscle attaches to the stationary bone—in this case, the scapula—is called the

Sarcomere

The region from one Z line to the next is called a

Z line

Thin actin filaments are anchored at their endpoints to a structure called the

Skeletal Smooth Cardiac

What are the three types of muscle tissue?

Connective Tissue

What covers and supports each muscle fiber and reinforces the muscle as a whole?

Sufficient nerve and blood supply

What does the health of a muscle depend on?

Myosin and actin

What filaments are arranged to form an overlapping pattern, which gives striated muscle tissue its striped appearance?

A skeletal muscle fiber

What is a single, multinucleated muscle cell?

Muscle contraction

What is an all or none response?

A muscle

What is an organ that can contract in a coordinated fashion and includes muscle tissue, blood vessels, nerves, and connective tissue?

Individual smooth muscle cells

What kind of cells are spindle-shaped, have a single nucleus, and interlace to form sheets?

Smooth

What kind of muscle forms the walls of the stomach, intestines, blood vessels, and other internal organs?

Cardiac

What kind of muscle makes up the walls of the heart?

Skeletal

What muscle is responsible for moving parts of the body such as the limbs, trunk, and face?

ATP

What supplies the energy that is used to make muscles contract?

The sarcomere

When a muscle contracts, myosin filaments and actin filaments interact to shorten the what?

Flexor

When the biceps muscle contracts, the elbow bends. The biceps muscle is known as a ______, a muscle that bends a joint

Periosteum

Where does the skeletal muscle attach to on the bone by a tendon?