Question

A muscle fiber is_________ 1 pt a muscle cell a rod-like structure consisting of sarcomeres placed end to end an arrangement of actin and myosin filaments deep within a muscle cell the elaborate arrangement of smooth endoplasmic reticulum inside a muscle cell

Answer 1

Step-by-step explanation:

Muscle fibers can be categorized into 3 types:

Cardiac muscle cells: Cardiac muscle cells or cardiomyocytes are the muscle cells (myocytes) that make up the cardiac muscle (heart muscle).

Skeletal muscle cells: An individual skeletal muscle may be made up of hundreds, or even thousands, of muscle fibers bundled together and wrapped in a connective tissue covering. Many muscles are named by the action the muscle performs. These include:

• The flexor and extensor; abductor and adductor; levator and depressor; supinator and pronator; sphincter, tensor, and rotator muscles.[6]
• A flexor muscle decreases the anterior angle at a joint; an extensor increases the anterior angle at a joint.
• An abductor moves a bone away from the midline; an adductor moves a bone closer to the midline.
• A levator raises a structure; a depressor moves a structure down.
• A supinator turns the palm of the hand up; a pronator turns the palm down.
• A sphincter decreases the size of an opening; a tensor tenses a body part; a rotator turns a bone around its axis.

Smooth muscle cells: Also called involuntary muscle and non-striated muscle, it shows no cross stripes under microscopic magnification. It consists of narrow spindle-shaped cells with a single, centrally located nucleus. Smooth muscle tissue, unlike striated muscle, contracts slowly and automatically. It constitutes much of the musculature of internal organs and the digestive system.

Answer 2

The correct answer to the question: A muscle fiber is:____, would be: A rod-like structure consisting of sarcomeres placed end to end.

Step-by-step explanation:

Muscle fibers are the units that form that organ system that we call the musculoskeletical system. Their purposes are various, but maybe the central one is movement. There are different types of muscle in the body, but essentially their structure is the same. Muscle is formed by sarcomeres, better known as muscle cells, and these sarcomeres, each one, is composed of myofribils known as actin and myosin. Together with other elemental structures, actin and myosin are responsible for the capacity of muscle fibers to perform activity and movement. Sarcomeres in muscle are not separated, individualized units, but rather they are a tightly packed group that comes together within muscle fibers. These muscle fibers then are really rows of sarcomeres grouped together in a rod-like structure that is surrounded and divided from other such fibers by connective and protective layers called fascicles. A muscle, then, is formed by the clustering, or grouping, of several muscle fibers.