Chapter 11

What effect does fascicle arrangement have on a muscle's action?

Fascicle arrangements determine what type of movement a muscle can make. For instance, circular muscles act as sphincters, closing orifices

Why are the muscles of the face different from typical skeletal muscle?

Most skeletal muscles create movement by actions on the skeleton.Facial muscles are different in that they create facial movements and expressions by pulling on the skin—no bone movements are involved

Movements of the body occur in joints. Describe how muscles are arranged around the joints of the body.

Muscles work in pairs to facilitate movement of the bones and joints Agonists are the prime movers Antagonists oppose the movements of the agonists Synergists assist the agonists Fixators stabilize a muscle's origin

Which muscles form the hamstrings? How do they function together?

The biceps femoris, semimembranosus, and semitendinosus form the hamstrings. The hamstrings flex the leg at the knee joint. responsible for stabilizing the shoulder joint

List the general muscle groups of the shoulders and upper limbs as well as their subgroups.

The muscles that make up the shoulders and upper limbs include the muscles that position the pelvic girdle, the muscles that move the humerus, the muscles that move the forearm, and the muscles that move wrists, hand, and fingers.

Which muscles form the quadriceps? How do they function together?

The rectus femoris, vastus medialis, vastus lateralis, and vastus intermedius form the quadriceps. The quadriceps muscles extend the leg at the knee joint.

The tendons of which muscles form the rotator cuff? Why is the rotator cuff important?

The tendons of the deep subscapularis, supraspinatus, infraspinatus, and teres minor connect the scapula to the humerus, forming the rotator cuff (musculotendinous cuff), the circle of tendons around the shoulder joint.

Describe the different criteria that contribute to how skeletal muscles are named.

Word roots are Latin or Greek Portions of the word give clues about the function, shape, or action of the muscle

Explain how a synergist assists an agonist by being a fixator.

Agonists are the prime movers while antagonists oppose or resist the movements of the agonists Synergists assist the agonists, and fixators stabilize a muscle's origin

Describe the fascicle arrangement in the muscle of the abdominal wall. How do they relate to each other?

Arranged into layers The muscles of the abdominal wall are the internal and external obliques, which run on diagonals The rectus abdominis runs straight down the midline of the body The transversus abdominis wraps around the trunk of the body

Describe the muscles of the anterior back.

Arranged to facilitate swallowing and speech. They work on the hyoid bone, with the suprahyoid muscles pulling up and the infrahyoid muscles pulling down.

Explain the differences between axial and appendicular muscles.

Axial muscles originate on the axial skeleton (the bones in the head, neck, and core of the body) Appendicular muscles originate on the bones that make up the body's limbs

What are some similarities and differences between the diaphragm and the pelvic diaphragm?

Both diaphragms are thin sheets of skeletal muscle that horizontally span areas of the trunk. The diaphragm separating the thoracic and the abdominal cavities is the primary muscle of breathing. The pelvic diaphragm consists of, two paired muscle, the coccygeus and the levator ani, forms the pelvic floor and the inferior end of the trunk.