Question

Direction of Muscle Fibers: In relation to an imaginary line usually in the midline of the body or the longitudinal axis of a bone.

Number of Origins:

Location of Attachments: Named according to their points of origin and insertion

Muscle Action: (Flexor, Extensor, Abductor, Adductor)

Answer 1

ANS) Muscle fibers are cylindrical in shape having multiple nuclei. These contain thin actin and thick myosin proteins that are responsible for muscular contractions and movements.

DIRECTION OF MUSCLE FIBERS:

The muscle fibers that run in parallel direction are named Rectus, at perpendicular distance are named Transverse and which are present at angles are named as Oblique in relation to an imaginary line usually in the midline of the body or the longitudinal axis of a bone.

NUMBER OF ORIGINS:

There are three origins of muscular fibers:

Two headed muscle fibers that contain one long and one short head are known as BICEPS

Three-headed muscle fibers are known as TRICEPS, and

Four headed as QUADRICEPS.

LOCATION OF ATTACHMENTS:

Named according to their points of origin and insertion are:

For example: STERNOCLEIDOMASTOID originates at the sternum , TEMPORALIS originate at the temporal bone.

MUSCLE ACTION:

FLEXOR: helps in flexing or contracting.

EXTENSOR: helps in extending or stretching.

ABDUCTOR: helps in moving away laterally from midline of the body. For example abductor muscles of arm, moves apart from torso region of the body.

ADDUCTOR: helps in moving closer to the midline of the body.