Nursing practice questions with comprehensive rationales
NurseDive Free Nursing Practice Question
In an isotonic contraction, the muscle:
A. rapidly resynthesizes creatine phosphate and ATP
This choice confuses metabolic processes with mechanical muscle activity. While creatine phosphate and ATP are essential for muscle contraction, their resynthesis is not specific to isotonic contraction. These energy molecules are replenished during recovery phases and are not the defining feature of isotonic contractions.
B. maintains the same length while generating tension
This describes isometric contraction, not isotonic. In isometric contractions, the muscle generates force without changing its length—such as holding a plank position. Isotonic contractions, by contrast, involve a change in muscle length.
C. changes length while maintaining constant tension
This is the correct answer. Isotonic contractions involve the muscle changing length while maintaining constant tension. There are two types: concentric (muscle shortens) and eccentric (muscle lengthens). These contractions are typical in dynamic movements like lifting or lowering weights.
D. remains relaxed and passive during movement
This is incorrect. Muscles do not remain relaxed during isotonic contractions. Instead, they actively contract and generate force to produce movement. Passive relaxation does not contribute to the mechanics of isotonic contraction.
This question is an excerpt from Nurse Dive's nursing test bank - Anatomy and physiology proctored exam. Take the full exam now
Full Explanation
Choice A reason: This choice confuses metabolic processes with mechanical muscle activity. While creatine phosphate and ATP are essential for muscle contraction, their resynthesis is not specific to isotonic contraction. These energy molecules are replenished during recovery phases and are not the defining feature of isotonic contractions.
Choice B reason: This describes isometric contraction, not isotonic. In isometric contractions, the muscle generates force without changing its length—such as holding a plank position. Isotonic contractions, by contrast, involve a change in muscle length.
Choice C reason: This is the correct answer. Isotonic contractions involve the muscle changing length while maintaining constant tension. There are two types: concentric (muscle shortens) and eccentric (muscle lengthens). These contractions are typical in dynamic movements like lifting or lowering weights.
Choice D reason: This is incorrect. Muscles do not remain relaxed during isotonic contractions. Instead, they actively contract and generate force to produce movement. Passive relaxation does not contribute to the mechanics of isotonic contraction.
Similar Questions
_____ are the most movable joints.
A. symphyses
Symphyses are cartilaginous joints where bones are joined by fibrocartilage. They allow limited movement, such as in the pubic symphysis, but are not the most movable joints.
B. synovial joints
Synovial joints are the most movable type of joints in the body. They feature a joint cavity filled with synovial fluid, which reduces friction and allows for a wide range of motion. Examples include the shoulder, hip, and knee joints.
C. syndesmoses
Syndesmoses are fibrous joints where bones are connected by ligaments. They allow more movement than sutures but are still relatively limited compared to synovial joints.
D. gomphoses
Gomphoses are immovable joints found between teeth and their sockets. These joints are highly stable but do not permit movement.
E. synchondroses
ynchondroses are cartilaginous joints where bones are joined by hyaline cartilage. These joints are typically immovable or allow very slight movement, such as in the epiphyseal plates of growing bones.
Full Explanation
Choice A reason: Symphyses are cartilaginous joints where bones are joined by fibrocartilage. They allow limited movement, such as in the pubic symphysis, but are not the most movable joints.
Choice B reason: Synovial joints are the most movable type of joints in the body. They feature a joint cavity filled with synovial fluid, which reduces friction and allows for a wide range of motion. Examples include the shoulder, hip, and knee joints.
Choice C reason: Syndesmoses are fibrous joints where bones are connected by ligaments. They allow more movement than sutures but are still relatively limited compared to synovial joints.
Choice D reason: Gomphoses are immovable joints found between teeth and their sockets. These joints are highly stable but do not permit movement.
Choice E reason: Synchondroses are cartilaginous joints where bones are joined by hyaline cartilage. These joints are typically immovable or allow very slight movement, such as in the epiphyseal plates of growing bones.
Which of the following surrounds the individual muscle cell?
A. perimysium
Perimysium surrounds bundles of muscle fibers known as fascicles, not individual muscle cells. It provides structural support and carries blood vessels and nerves.
B. epimysium
Epimysium is the outermost layer of connective tissue that surrounds the entire muscle. It does not envelop individual muscle cells.
C. endomysium
Endomysium is the correct answer. It is a thin layer of connective tissue that surrounds each individual muscle fiber (cell), providing structural integrity and facilitating capillary exchange.
D. myofibril
Myofibrils are intracellular structures within muscle cells that contain the contractile proteins actin and myosin. They are not connective tissue and do not surround muscle cells.
Full Explanation
Choice A reason: Perimysium surrounds bundles of muscle fibers known as fascicles, not individual muscle cells. It provides structural support and carries blood vessels and nerves.
Choice B reason: Epimysium is the outermost layer of connective tissue that surrounds the entire muscle. It does not envelop individual muscle cells.
Choice C reason: Endomysium is the correct answer. It is a thin layer of connective tissue that surrounds each individual muscle fiber (cell), providing structural integrity and facilitating capillary exchange.
Choice D reason: Myofibrils are intracellular structures within muscle cells that contain the contractile proteins actin and myosin. They are not connective tissue and do not surround muscle cells.
A bundle of muscle fibers is a(n):
A. myofilament
Myofilaments are the smallest contractile units within myofibrils, composed of actin and myosin. They do not represent bundles of muscle fibers.
B. fascicle
Fascicle is the correct term for a bundle of muscle fibers. Each fascicle is surrounded by perimysium and contains multiple muscle cells.
C. myofibril
Myofibrils are microscopic structures within individual muscle cells that contain the contractile machinery. They are not bundles of muscle fibers.
D. whole muscle
Whole muscle refers to the entire organ composed of multiple fascicles, connective tissues, blood vessels, and nerves. It is a larger structure than a bundle of muscle fibers.
Full Explanation
Choice A reason: Myofilaments are the smallest contractile units within myofibrils, composed of actin and myosin. They do not represent bundles of muscle fibers.
Choice B reason: Fascicle is the correct term for a bundle of muscle fibers. Each fascicle is surrounded by perimysium and contains multiple muscle cells.
Choice C reason: Myofibrils are microscopic structures within individual muscle cells that contain the contractile machinery. They are not bundles of muscle fibers.
Choice D reason: Whole muscle refers to the entire organ composed of multiple fascicles, connective tissues, blood vessels, and nerves. It is a larger structure than a bundle of muscle fibers.