Locomotion and Movement MCQ: Introduction and Explanation

Ans. (c) Myology

Explanation: Myology is the study of the muscular system that includes the study of its structure, the function performed by it and also disease related to it. The muscular system consists of three types of Muscles namely Cardiac muscle, skeletal muscle, and smooth muscle.

Ans. (b) Support, erythrocyte and leucocyte synthesis

Explanation: A long bone is a bone that has a shaft and 2 ends and it is usually longer than it is wide. All of the bones in the arms as well as in the legs, except the patella, and the wrist bone and ankle, are long bones. The function performs by it includes supporting the weight of the body and facilitating movements, erythrocyte and leucocyte synthesis.

Ans. (d) Double refractive index

Explanation: Myofibrils are generally thread-like structures, consisting of the protein myosin. The striations of striped muscles result from the fact that the thin and thick filaments have double or different refractive indices when observed from the microscope. Thus, myosin filaments appear dark.

Ans. (a) Synovial membrane

Explanation: Synovial fluid which is also called joint fluid, is a thick liquid located between the joints. This fluid secretes a watery fluid that helps in lubrication and provides cushion to the joints.

Ans. (b) Nematode sperms

Explanation: Actin filaments are present in most of the cells and are abundantly present in muscle cells but are absent in Nematode sperms as nematode sperm undergo drastic physiological change during spermiogenesis. Nematode sperms are amoeboid cells and their motility is driven by cytoskeleton composed of major sperm protein only.

Ans. (b) Actin

Explanation: Actin protein is an important contributor to the contractile property of muscle and other cells. It generally exists in two forms: G – actin (globular actin) and F – actin (fibrous actin), these are the forms involved in the muscular contraction. Even in the non-muscular cells, the meshwork of actin filament plays role in various types of cellular movements.

Ans. (b) Osteoporosis – decrease in bone mass and a higher chance of fracture with advancing age

Explanation: Osteoporosis is more likely to occur in a person who has very low calcium intake in the diet. A lifelong lack of calcium (Ca) plays a vital role in the development of osteoporosis. And if calcium intake is low it contributes to diminishes bone density, early bone loss and a higher chance of fracture with the advancing age.

Ans.  (b) Z line and Z line

Explanation: The contractile unit of the muscle fibre is present between the Z – line and Z – line. This is because the sarcomere length between two Z – lines decreases during the muscular contraction. This so occurs because of the sliding of thin filaments over the thick filaments.

Ans. (c) Pivot

Explanation: The pivot joint is present between the atlas and the axis. It allows only a rotatory movement of a bone on the other, that remains stationary. A rounded end of a bone fits into the shallow pit of another bone as the joint between the atlas and axis enables the head to turn from side to side.

Ans. (a) Muscle injury

Explanation: The muscle injury or muscle strain or pulled muscle, occurs when your muscle is overstretched or torn. This usually occurs as a result of fatigue, overuse, or improper use of the muscle. When diagnosed it is identified when myoglobin is present in the bloodstream.

Ans. (c) Sarcomere

Explanation: The sarcomere is a broad, cylindrical chain of contractile proteins, or myofibrils, that make up the entire cross-section of the muscle fibre. One myofibril is composed of fragments called a sarcomere. The end of the sarcomere is marked by the presence of a Z disc.

Ans. (a) Myosin

Explanation: Myosin contains a very important enzyme i.e., ATPase which is very necessary for muscle contraction to take place. Without the presence of ATP which is actually energy, it is impossible for a muscle to contract. During the muscular contraction, myosin cross-bridges heads. ATPase is activated by Ca²⁺ and Mg²⁺  ions hence easing the contraction.

Ans. (a) Heart

Explanation: The papillary muscles are the muscle which is present in the ventricle of the heart. They attach to the cusps of mitral and tricuspid valves and then contract to prevent inversion or prolapsed of these valves or systole.

Ans. (b) Myasthenia Gravis

Explanation: Myasthenia Gravis is caused by a problem with the signals sent between the nerves and the muscles. It is an autoimmune disorder that means it is the result of the immune system (it’s a body’s natural defence system to fight against the infection) mistakenly attacking the healthy part of the body.

Ans. (b) Glenoid cavity

Explanation: The glenoid cavity or the glenoid fossa of the scapula is a part of the shoulder. It is generally a hollow, pyriform articular surface, which is located on the lateral angle of the scapula.