14. . Which one of the following statements is not related to the cardiac muscles?
(a) They muscles show rhythmic contraction and relaxation throughout life.
(b) They do not work according to our will, so they are called involuntary muscles.
(c) They are non-striated, multinucleated and unbranched muscles.
(d) The contraction and relaxation of the heart muscles help to pump and distribute blood
to different parts of the body.
Answers
Answer:
Option C states "They are non-striated, multinucleated and unbranched muscles" which is not related to the cardiac muscle.
Explanation:
The cardiac muscle is an involuntary, uni-nucleated muscle. It is an important part of human anatomy as the contraction and relaxation of the heart muscles help to pump and distribute blood to different parts of the body keeping the body alive. The muscles show rhythmic contraction and relaxation throughout life. Hence, it can be safely concluded that option C is not related to Cardiac muscle.
Explanation for correct option
c:
- Cardiac muscles are striated, branched, and single nucleated, and they are involuntary and intrinsically controlled.
- Repeating sarcomeres, the basic contractile units of cardiac muscle composed of interdigitating thin (actin) and thick (myosin) filaments that give the muscle its characteristic striated appearance, form the myofibrils.
Thus, it is false that cardiac muscles are non-striated, multinucleate and unbranched.
Explanation for incorrect options
a:
Throughout life, cardiac muscles contract and relax in rhythm.
Thus, option a is incorrect.
b:
- Involuntary cardiac muscles are those that are not controlled by our will.
- These muscles are found in the heart and are the only ones that can work continuously without becoming tired or fatigued.
Thus, option b is incorrect.
d:
Cardiac muscles help to pump and distribute blood to different parts of the body by contracting and relaxing the heart muscles.
Thus, option d is also incorrect.
Hence, option c) is correct.
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