ANP Exam: Muscular System Quiz!

Explanation
Antagonists are muscles that work in opposition to each other. They have opposite actions and are responsible for controlling movement and maintaining balance in the body. When one muscle contracts to produce a movement, the antagonist muscle relaxes to allow for that movement to occur smoothly. For example, when the biceps muscle contracts to flex the elbow, the triceps muscle relaxes to allow for the movement. This relationship between agonist and antagonist muscles is crucial for coordinated movement and stability in the body.

Explanation
The insertion of a muscle refers to the point where the muscle attaches to the bone that moves when the muscle contracts. This is usually the more movable attachment compared to the origin, which is the point where the muscle attaches to the bone that remains stationary when the muscle contracts. The insertion point allows the muscle to exert its force and cause movement when it contracts.

Explanation
The biceps brachii is the antagonist of the triceps brachii. Antagonist muscles are responsible for opposing the actions of a particular muscle. In this case, the triceps brachii is responsible for extending the forearm at the elbow joint, while the biceps brachii is responsible for flexing the forearm at the elbow joint. Therefore, the biceps brachii acts as the antagonist to the triceps brachii, as it opposes the movement of extending the forearm.

Explanation
The gluteus maximus is the correct answer because it is the largest muscle in the buttocks and is responsible for extending the hip joint. It works to bring the thigh bone backward and helps in movements like standing up from a sitting position, climbing stairs, and running. The other muscles listed, such as the sartoris, tensor fascia latae, gluteus medius, and gluteus minimus, have different functions and do not primarily extend the hip.

Explanation
The correct answer is "sarcomere." A sarcomere is a structural unit of a muscle fiber, consisting of overlapping myofilaments that slide past each other during muscle contraction. It is not a part of the organized levels of skeletal muscle, which include the muscle, fascicle, myofibril, and myofilaments.

Explanation
A fascicle is a bundle of individual muscle cells. It is a structural unit within a muscle, consisting of multiple muscle fibers or cells grouped together. These fascicles are surrounded by connective tissue and work together to generate force and movement. Tendons, on the other hand, are fibrous connective tissues that attach muscles to bones. Myofibril refers to the contractile units within muscle fibers. Therefore, the correct answer is fascicle.

Explanation
Myosin is the protein that makes up thick myofilaments. Thick myofilaments are one of the two types of filaments found in muscle cells, the other being thin myofilaments made up of actin. Myosin is responsible for the contraction of muscles by interacting with actin filaments, forming cross-bridges and sliding them along each other, resulting in muscle contraction.

Explanation
The correct answer is sarcomere. A sarcomere is the contractile unit of a muscle cell. It is the basic structural and functional unit of a muscle fiber, responsible for muscle contraction. It consists of thick and thin filaments, called myofilaments, which slide past each other during muscle contraction. The arrangement of these myofilaments within the sarcomere gives muscles their striated appearance.