Concept explainers
Introduction:
Muscles are defined as soft tissues that are found in humans and animals. There are three types of muscles found in humans such as skeletal muscle, cardiac muscle, and smooth muscle. It contains filament protein such as actin and myosin that are responsible for the contraction of the muscle. Muscles also help to produce force and motion.
Answer to Problem 1MC
Correct answer:
Structures that range from largest to smallest are muscle, muscle fiber, myofibril, thick and thin filaments. Therefore, option (d) is correct.
Option (d) is given as “muscle, muscle fiber, and myofibril, thick and thin filaments”.
Explanation of Solution
Justify reasons for the correct statement:
Muscle cells are soft tissue and are composed of thick and thick filaments that are attached to each other and form cross-bridge and cause muscle contraction. Muscle fibers are surrounded by a plasma membrane called sarcolemma and they also contain cytoplasm called sarcoplasm. Each muscle fiber contains parallel cylindrical myofibrils and is found in striated muscle. Muscle fibers contain multinucleated cells and these cells combine together to form muscle. Myofibril is surrounded by specialized reticulum called sarcoplasmic reticulum. The thick and thin filaments are myosin and actin. Actin filament contains two accessory proteins such as troponin and tropomyosin.
Hence, option (d) is correct.
Justify reasons for the incorrect statements:
Option (a) is given as “motor unit, muscle, myofibril, muscle fiber, thick and thin filament”.
Motor unit is formed when motor neuron synapses with multiple muscle fibers in a single muscle. It consists of motor neuron and skeletal muscle fibers. Hence, it is a wrong answer.
Option (b) is given as “muscle, muscle cell, myofibril, muscle fiber, actin, and myosin”.
Muscle is a part of the skeletal system which includes all the structures such as muscle cell, myofibril, muscle fiber, and actin and myosin filament. Hence, it is a wrong answer.
Option (c) is given as “muscle cell, thick and thin filaments, sarcomeres, myofibril”.
Muscle cell, thick and thin filaments, sarcomeres and myofibril are the structures that together form a muscle cell. Hence, it is a wrong answer.
Hence, options (a), (b), and (c) are incorrect.
Muscle is a soft tissue, which is made of myofibrils, muscle cells, and fibers, a thick and thin filament such as actin and myosin.
Want to see more full solutions like this?
Chapter 41 Solutions
Biology
- Which component is responsible for initially stimulating a muscle contraction? a. proteins b. electrochemical signals c. plasma membranes d. striationsarrow_forwardWhat structure in skeletal muscle cells functions in calcium storage? a.myofibrillar network b.sarcoplasmic reticulum c.intermediate filament network d.mitochondriaarrow_forwardWhich choice lists the components of a muscle from the smallest unit to the largest unit? A. myofibril, filament, sarcomere, muscle fiber B. filament, sarcomere, myofibril, muscle fiber C. sarcomere, filament, muscle fiber, myofibril D. muscle fiber, filament, sarcomere, myofibrilarrow_forward
- When sarcomeres contract during muscle contraction, which of the following occurs? A. The myosin filaments lengthen. B. The myosin filaments "walk" along the actin microfilaments. C. The myosin filaments shorten. D. The actin filaments shorten.arrow_forwardContraction of muscles requires binding of various components of muscle fiber. Which of the following rows correctly matches two components of muscle fibre that bind with each other? Row Component of muscle fibre Component of muscle fibre A. Ca2+ myosin B. troponin myosin C. troponin tropomyosin D. actin Ca2+arrow_forwardWhich of the following changes takes place when a skeletal muscle contracts?A. Z discs move farther apart.B. Actin filaments contract.C. Myosin filaments contract.D. Sarcomeres become shorter.arrow_forward
- Which of the following statements about the connective sheath of skeletal muscle is false? a. the endomysium wraps around every single muscle fiber b. the perimysium wraps around groups of muscle fibers c. the epimysium wraps around the whole muscle organ d. all of the above e. none of the abovearrow_forwardThe mechanism of muscle contraction is best explained by the sliding filament model. According to this model, thin ___i___ filaments slide over thick ___ii___ filaments.The statement given above is completed by information in row Row i ii A. myosin actin B. myosin myosin C. actin actin D. actin myosinarrow_forwardWhich of the following is arranged in order from smallest tolargest?a. Motor unit < sarcomere < muscle cell < actin subunitb. Muscle cell < actin subunit < sarcomere < motor unitc. Actin subunit < sarcomere < muscle cell < motor unitd. Sarcomere < motor unit < actin subunit < muscle cellarrow_forward
- The correct order for the smallest to the largest unit oforganization in muscle tissue is ________.a. fascicle, filament, muscle fiber, myofibrilb. filament, myofibril, muscle fiber, fasciclec. muscle fiber, fascicle, filament, myofibrild. myofibril, muscle fiber, filament, fasciclearrow_forwardThe Sarcomere 2 Thin filaments are often named for which protein? a. actin b. myosin c. troponin d. tropomyosinarrow_forwardIdenttidy which among the list represents the hierarchy of muscle structure from the largest unit to the smallest? A.muscle fiber → myofibril → sarcomere → filaments B.sarcomere → myofibril → filaments → muscle fiber C.muscle fiber → sarcomere → myofibril → filaments D. myofibril → muscle fiber → sarcomere → filamentsarrow_forward
- Human Biology (MindTap Course List)BiologyISBN:9781305112100Author:Cecie Starr, Beverly McMillanPublisher:Cengage LearningHuman Physiology: From Cells to Systems (MindTap ...BiologyISBN:9781285866932Author:Lauralee SherwoodPublisher:Cengage Learning
- Comprehensive Medical Assisting: Administrative a...NursingISBN:9781305964792Author:Wilburta Q. Lindh, Carol D. Tamparo, Barbara M. Dahl, Julie Morris, Cindy CorreaPublisher:Cengage LearningConcepts of BiologyBiologyISBN:9781938168116Author:Samantha Fowler, Rebecca Roush, James WisePublisher:OpenStax College