Nursing practice questions with comprehensive rationales
NurseDive Free Nursing Practice Question
_____ is attached to the Z disc.
A. Myosin
Myosin is the thick filament in muscle fibers and is not directly attached to the Z disc. It anchors in the center of the sarcomere at the M line and interacts with actin during contraction.
B. Actin
Actin is the correct answer. It forms the thin filaments in muscle fibers and is directly anchored to the Z disc. This attachment allows actin to slide past myosin during muscle contraction, shortening the sarcomere.
C. Troponin
Troponin is a regulatory protein complex that binds calcium and controls the position of tropomyosin on actin filaments. It is located along the actin filament but is not attached to the Z disc.
D. Myofibrils
Myofibrils are bundles of actin and myosin filaments organized into sarcomeres. While they span the length of the muscle fiber and include Z discs, they are not themselves attached to the Z disc.
E. Tropomyosin
Tropomyosin is a regulatory protein that lies along the actin filament and blocks myosin-binding sites in a relaxed muscle. It is not anchored to the Z disc.
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Full Explanation
Choice A reason: Myosin is the thick filament in muscle fibers and is not directly attached to the Z disc. It anchors in the center of the sarcomere at the M line and interacts with actin during contraction.
Choice B reason: Actin is the correct answer. It forms the thin filaments in muscle fibers and is directly anchored to the Z disc. This attachment allows actin to slide past myosin during muscle contraction, shortening the sarcomere.
Choice C reason: Troponin is a regulatory protein complex that binds calcium and controls the position of tropomyosin on actin filaments. It is located along the actin filament but is not attached to the Z disc.
Choice D reason: Myofibrils are bundles of actin and myosin filaments organized into sarcomeres. While they span the length of the muscle fiber and include Z discs, they are not themselves attached to the Z disc.
Choice E reason: Tropomyosin is a regulatory protein that lies along the actin filament and blocks myosin-binding sites in a relaxed muscle. It is not anchored to the Z disc.
Similar Questions
Loss of muscle mass from lack of activity is termed:
A. Myopathy
Myopathy refers to any disease of the muscle tissue, often involving weakness or dysfunction, but not specifically due to inactivity.
B. Dystrophy
Dystrophy refers to genetic disorders that cause progressive muscle degeneration, such as muscular dystrophy. It is not caused by inactivity.
C. Apathy
Apathy is a psychological term referring to lack of interest or emotion. It has no relevance to muscle physiology.
D. Atrophy
Atrophy is the correct answer. It refers to the wasting away or reduction in size of muscle tissue due to disuse, immobilization, or lack of neural stimulation. It is a common consequence of inactivity or prolonged bed rest.
E. Treppe
Treppe, or the staircase effect, describes the gradual increase in muscle contraction strength with repeated stimulation. It is unrelated to muscle loss.
Full Explanation
Choice A reason: Myopathy refers to any disease of the muscle tissue, often involving weakness or dysfunction, but not specifically due to inactivity.
Choice B reason: Dystrophy refers to genetic disorders that cause progressive muscle degeneration, such as muscular dystrophy. It is not caused by inactivity.
Choice C reason: Apathy is a psychological term referring to lack of interest or emotion. It has no relevance to muscle physiology.
Choice D reason: Atrophy is the correct answer. It refers to the wasting away or reduction in size of muscle tissue due to disuse, immobilization, or lack of neural stimulation. It is a common consequence of inactivity or prolonged bed rest.
Choice E reason: Treppe, or the staircase effect, describes the gradual increase in muscle contraction strength with repeated stimulation. It is unrelated to muscle loss.
Which of the following bone tissues is adapted to support weight and withstand twisting stresses?
A. Irregular bone
Irregular bones have complex shapes and serve various functions, such as protection and muscle attachment, but they are not specialized for weight-bearing or resistance to twisting.
B. Trabecular bone
Trabecular bone, also known as spongy bone, is lightweight and porous. It helps absorb shock and supports bone marrow but is not optimized for resisting twisting stresses.
C. Interstitial bone
Interstitial bone refers to remnants of old osteons found between newer ones in compact bone. It is not a distinct tissue type adapted for mechanical stress.
D. Compact bone
Compact bone is the correct answer. It is dense and organized into osteons, which provide strength and resistance to compressive and torsional forces. It forms the outer layer of bones and is especially prominent in the diaphysis of long bones.
E. Spongy bone
Spongy bone is adapted for shock absorption and lightness but lacks the dense structure needed to resist twisting and heavy loads.
Full Explanation
Choice A reason: Irregular bones have complex shapes and serve various functions, such as protection and muscle attachment, but they are not specialized for weight-bearing or resistance to twisting.
Choice B reason: Trabecular bone, also known as spongy bone, is lightweight and porous. It helps absorb shock and supports bone marrow but is not optimized for resisting twisting stresses.
Choice C reason: Interstitial bone refers to remnants of old osteons found between newer ones in compact bone. It is not a distinct tissue type adapted for mechanical stress.
Choice D reason: Compact bone is the correct answer. It is dense and organized into osteons, which provide strength and resistance to compressive and torsional forces. It forms the outer layer of bones and is especially prominent in the diaphysis of long bones.
Choice E reason: Spongy bone is adapted for shock absorption and lightness but lacks the dense structure needed to resist twisting and heavy loads.
The most common deformity of the spine is an abnormal lateral curvature called:
A. Scoliosis
Scoliosis is the correct answer. It is characterized by a lateral curvature of the spine, often diagnosed in adolescence. It can range from mild to severe and may require bracing or surgery depending on progression.
B. Lordosis
Lordosis refers to an exaggerated inward curvature of the lumbar spine. It is a spinal deformity but not the most common.
C. Kyphosis
Kyphosis is an exaggerated outward curvature of the thoracic spine, leading to a hunched posture. It is less common than scoliosis.
D. Osteosis
Osteosis is not a recognized spinal deformity. It may be a misused or fictional term.
E. Slipped disc
A slipped disc, or herniated disc, involves displacement of intervertebral disc material. It causes pain and nerve compression but is not classified as a spinal deformity.
Full Explanation
Choice A reason: Scoliosis is the correct answer. It is characterized by a lateral curvature of the spine, often diagnosed in adolescence. It can range from mild to severe and may require bracing or surgery depending on progression.
Choice B reason: Lordosis refers to an exaggerated inward curvature of the lumbar spine. It is a spinal deformity but not the most common.
Choice C reason: Kyphosis is an exaggerated outward curvature of the thoracic spine, leading to a hunched posture. It is less common than scoliosis.
Choice D reason: Osteosis is not a recognized spinal deformity. It may be a misused or fictional term.
Choice E reason: A slipped disc, or herniated disc, involves displacement of intervertebral disc material. It causes pain and nerve compression but is not classified as a spinal deformity.