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?