Consider the following statements about 'Cardiac Muscles': 1. They fatigue easily and require frequent rest periods. 2. They are involuntary muscles. 3. The cells are cylindrical, branched, and uninucleate. Which of the statements given above are correct?

The correct option is (c) 2 and 3 only. Explanation Cardiac muscles are a specialized type of striated muscle tissue found exclusively in the heart. They are structurally and functionally distinct from skeletal and smooth muscles, designed to pump blood continuously throughout an organism's life. Statement-wise Analysis - Statement 1 is Incorrect. Cardiac muscles are immune to fatigue under normal physiological conditions. They contain numerous mitochondria and have a rich blood supply, allowing for continuous aerobic respiration. Unlike skeletal muscles, they do not require rest periods and function rhythmically without stopping. - Statement 2 is Correct. Cardiac muscles are involuntary in nature. Their activity is controlled by the autonomic nervous system and the heart's internal pacemaker (Sinoatrial node), meaning they are not under the conscious control of the will. - Statement 3 is Correct. Structurally, cardiac muscle fibers are cylindrical, branched, and typically uninucleate (having a single central nucleus). The branching pattern creates a network that facilitates the rapid spread of electrical signals. They are connected by specialized junctions called intercalated discs. Key Takeaway: Cardiac muscles are involuntary, non-fatiguing, and structurally characterized by branching fibers with intercalated discs and a single nucleus.

Consider the following statements about 'Cardiac Muscles': 1.… - NCERT Class 9 Science MCQ

NCERT Class 9 Science — Chapter 2: Tissues

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Consider the following statements about 'Cardiac Muscles':

They fatigue easily and require frequent rest periods.
They are involuntary muscles.
The cells are cylindrical, branched, and uninucleate.

Which of the statements given above are correct?

NCERT textbook question

From NCERT Science - class 9 · Page 68

Options

A1 and 2 only
B2 only
C2 and 3 only
D1, 2 and 3

Did you get this right?

Solution

The correct option is (c) 2 and 3 only.

Explanation

Cardiac muscles are a specialized type of striated muscle tissue found exclusively in the heart. They are structurally and functionally distinct from skeletal and smooth muscles, designed to pump blood continuously throughout an organism's life.

Statement-wise Analysis

Statement 1 is Incorrect. Cardiac muscles are immune to fatigue under normal physiological conditions. They contain numerous mitochondria and have a rich blood supply, allowing for continuous aerobic respiration. Unlike skeletal muscles, they do not require rest periods and function rhythmically without stopping.
Statement 2 is Correct. Cardiac muscles are involuntary in nature. Their activity is controlled by the autonomic nervous system and the heart's internal pacemaker (Sinoatrial node), meaning they are not under the conscious control of the will.
Statement 3 is Correct. Structurally, cardiac muscle fibers are cylindrical, branched, and typically uninucleate (having a single central nucleus). The branching pattern creates a network that facilitates the rapid spread of electrical signals. They are connected by specialized junctions called intercalated discs.

Key Takeaway: Cardiac muscles are involuntary, non-fatiguing, and structurally characterized by branching fibers with intercalated discs and a single nucleus.

Your note

More from Chapter 2: Tissues

Consider the following statements regarding 'Complex Permanent Tissues': 1. They are made of more than one type of cell. 2. Each cell in the tissue functions independently without coordination. 3. Xylem and Phloem are examples of complex tissues. Which of the statements given above is/are correct?

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Consider the following statements about epithelial tissue: 1. It forms a barrier to keep different body systems separate. 2. It is directly connected to the underlying tissue without any separating membrane. 3. It contains large intercellular spaces to facilitate the movement of materials. Which of the statements given above is/are correct?

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Consider the following statements about 'Smooth Muscles': 1. They are also known as striated muscles. 2. They control involuntary movements like the movement of food in the alimentary canal. 3. They are multinucleate. Which of the statements given above are correct?

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With reference to the fundamental differences between plants and animals, consider the following statements: 1. Plants have a large quantity of supportive tissue which generally consists of dead cells. 2. Growth in plants is uniform throughout the body, whereas in animals it is limited to specific regions. 3. Animals consume more energy compared to plants due to active locomotion. Which of the statements given above is/are correct?

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Which one of the following is the most appropriate reason for the skin being made of 'Stratified Squamous Epithelium'?

easy

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