Problem 164 - Objective Biology for NEET

Question

Assertion: Skeletal muscles are striated muscles Reason: They have striped appearance under the microscope

Step-by-Step Solution

Answer

The assertion and reasoning are true, and the reasoning is the correct explanation for the assertion.

Step 1 - Understanding the terms

Firstly, understand the involved terms. Skeletal muscles refer to muscles which are voluntary in nature & attached to the skeleton, providing structure & movement to the body. Striated muscles are a type of muscle tissue in which the contractile fibrils are aligned, giving it striped appearance under the microscope.

Step 2 - Comparing definitions

After understanding the terms, we can compare their definitions. Here, we see that the definition of skeletal muscle aligns with the definition of striated muscle tissue, as one of the features of skeletal muscle is the presence of striations when viewed under a microscope.

Step 3 - Arriving at the conclusion

Given the definitions and their comparison, we can infer that the assertion is true - skeletal muscles are indeed a type of striated muscles because they have a striped appearance when viewed under a microscope.

Key Concepts

Striated Muscles

Striated muscles have a distinctive feature in which the muscle fibers are organized in a parallel pattern, giving them a striped appearance when viewed under a microscope. This striping is due to the arrangement of the contractile proteins, actin and myosin, within the muscle cells. Striated muscles are not restricted to skeletal muscles alone; cardiac muscles exhibit striations too, though they function differently.

Key characteristics of striated muscles include:

• Presence of sarcomeres, the basic unit of muscle contraction, responsible for the striated appearance.
• High efficiency in converting chemical energy into mechanical work, enabling precise body movements.
• Typically associated with voluntary movement, meaning they are under conscious control.

The intricate structure of striated muscles allows them to contract powerfully and quickly, making them essential for any kind of motion.

Muscle Tissue

Muscle tissue is one of the four primary types of tissue found in the body, alongside epithelial, connective, and nervous tissues. It is specialized to produce force and cause movement, whether within internal processes or through physical movement of the body.

The main types of muscle tissue are:

• Skeletal Muscle: Attached to bones and typically under voluntary control, responsible for body movements.
• Cardiac Muscle: Found only in the heart, involuntary, and responsible for pumping blood.
• Smooth Muscle: Located in walls of hollow organs (like intestines and blood vessels), it is involuntary, helping move substances through organ systems.

Each type of muscle tissue is distinct in function and structure, and all are vital for maintaining the body's operations. For instance, skeletal muscle tissue is highly organized with striations, enabling rapid and controlled movement. In contrast, smooth muscle is not striated and operates autonomously to regulate internal flow and pressure.

Voluntary Muscles

Voluntary muscles are those that we can control consciously. This capability allows us to perform a wide range of actions, from simple tasks like blinking or lifting a glass to complex movements in sports.

The primary type of voluntary muscle is the skeletal muscle, which has a structure built to support quick responses to neural stimuli. Such muscles are attached to bones by tendons and work in pairs or groups to move body parts.

Key aspects of voluntary muscles include:

• Control: Under voluntary control through the nervous system, allowing for intentional movements.
• Adaptability: Can adapt in strength and endurance with training, helping improve physical performance.
• Coordination: Works in coordinated groups for precise and fluid movements.

Understanding how voluntary muscles function provides insight into how fitness, rehabilitation, and muscle-specific treatments can be optimized.