Anatomy And Physiology Advanced - Qp3

1. Skeletal muscles are found only in the walls of the heart and are used to force blood into the circulatory vessels.

True

False

Skeletal muscles are not found in the walls of the heart. The walls of the heart are composed of cardiac muscle, which is a specialized type of muscle tissue. Skeletal muscles are found throughout the body and are responsible for voluntary movements.

Explanation

Skeletal muscles are not found in the walls of the heart. The walls of the heart are composed of cardiac muscle, which is a specialized type of muscle tissue. Skeletal muscles are found throughout the body and are responsible for voluntary movements.

2. Match the following statements:

This refers to muscle tissue being able to react to nervous stimulation.

This refers to the ability of muscle tissue to lengthen when contracting and provide the effort required to move the lever system, producing coordinated movement.

This refers to the ability of muscle tissue to return to its normal resting length once it has been stretched.

This refers to the capacity of a muscle to contract or shorten forcibly when stimulated by nerves and hormones.

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3. Match the following statements:

The many short fibres enable a high degree of force to be developed within the muscle, and therefore occur where much power and strength is required.

These muscles are strap-like and occur where muscle fibres lie parallel to each other and a tendon occurs at either end of the muscle belly.

These muscles occur where the base is much wider than the insertion, giving the muscle a triangular shape and enables the muscle to contract with great force.

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4. Match the following statements:

They therefore tend to have a greater resistance to fatigue, and are used in activities which are fairly high in intensity and of relatively short duration.

These are used for activities of very high intensity and have a much stronger force of contraction.

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5. Match the following statements:

This muscle increases in tension but does not allow any movement to take place.

This term can also be used to describe those muscles that assist the work of an agonist at a particular joint, making the movement more efficient.

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6. The muscle belly is the thick portion of muscle tissue sited between the origin and insertion.

True

False

The statement is true because the muscle belly is indeed the thick portion of muscle tissue that lies between the origin and insertion points. The origin is the point where the muscle attaches to a stationary bone, while the insertion is the point where the muscle attaches to a movable bone. The muscle belly is the fleshy part of the muscle that contracts and relaxes, allowing movement to occur at the joint.

Explanation

The statement is true because the muscle belly is indeed the thick portion of muscle tissue that lies between the origin and insertion points. The origin is the point where the muscle attaches to a stationary bone, while the insertion is the point where the muscle attaches to a movable bone. The muscle belly is the fleshy part of the muscle that contracts and relaxes, allowing movement to occur at the joint.

7. The myosin and actin filaments run adjacent to each other but at rest are not attached.

True

False

The statement is true because myosin and actin filaments in muscle cells are arranged in a way that they run parallel to each other, but they are not physically attached when the muscle is at rest. However, during muscle contraction, the myosin heads bind to the actin filaments, causing them to slide past each other and generate force. This interaction between myosin and actin is essential for muscle contraction and movement.

Explanation

The statement is true because myosin and actin filaments in muscle cells are arranged in a way that they run parallel to each other, but they are not physically attached when the muscle is at rest. However, during muscle contraction, the myosin heads bind to the actin filaments, causing them to slide past each other and generate force. This interaction between myosin and actin is essential for muscle contraction and movement.

8. Skeletal muscle has several important functions within the body which includes: (Select three)

Movement

Blood production

Support and posture

Heat production

Skeletal muscle is responsible for movement in the body, as it allows us to walk, run, and perform various activities. It also plays a crucial role in maintaining support and posture by providing stability to the skeletal system. Additionally, skeletal muscle generates heat through the process of muscle contraction, which helps regulate body temperature.

Explanation

Skeletal muscle is responsible for movement in the body, as it allows us to walk, run, and perform various activities. It also plays a crucial role in maintaining support and posture by providing stability to the skeletal system. Additionally, skeletal muscle generates heat through the process of muscle contraction, which helps regulate body temperature.

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9. Muscles comprise approximately 45% of total body weight, and there are in excess of ______ in the human body.

400 muscles

500 muscles

600 muscles

700 muscles

Muscles play a crucial role in the movement and stability of the human body. They are responsible for various functions such as locomotion, posture, and organ movement. With muscles comprising approximately 45% of total body weight, it is plausible to have a significant number of muscles in the human body. Out of the given options, 600 muscles seems like a reasonable estimate considering the complexity and diversity of muscle groups throughout the body.

Explanation

Muscles play a crucial role in the movement and stability of the human body. They are responsible for various functions such as locomotion, posture, and organ movement. With muscles comprising approximately 45% of total body weight, it is plausible to have a significant number of muscles in the human body. Out of the given options, 600 muscles seems like a reasonable estimate considering the complexity and diversity of muscle groups throughout the body.

10. Each fibre within a motor unit contracts according to the ______.

Golgi tendon organs

All or none law

Sliding filament theory

The correct answer is "all or none law". The all or none law states that once a motor unit is sufficiently stimulated, all of the muscle fibers within that motor unit will contract to their fullest extent. This means that either all of the fibers in the motor unit will contract or none of them will contract, there is no partial contraction. This principle helps to ensure that muscle contractions are coordinated and produce a smooth and efficient movement.

Explanation

The correct answer is "all or none law". The all or none law states that once a motor unit is sufficiently stimulated, all of the muscle fibers within that motor unit will contract to their fullest extent. This means that either all of the fibers in the motor unit will contract or none of them will contract, there is no partial contraction. This principle helps to ensure that muscle contractions are coordinated and produce a smooth and efficient movement.

11. ______ take place when a muscle increases in tension without actively shortening or lengthening.

Isotonic contractions

Isometric contractions

Isokinetic contractions

Isometric contractions occur when a muscle increases in tension without actively shortening or lengthening. In this type of contraction, the muscle remains at a constant length while generating force against an immovable object or resisting an external force. This can be seen, for example, when holding a weight in a static position without any movement in the joint. Isotonic contractions involve muscle shortening or lengthening, while isokinetic contractions involve the muscle contracting at a constant speed.

Explanation

Isometric contractions occur when a muscle increases in tension without actively shortening or lengthening. In this type of contraction, the muscle remains at a constant length while generating force against an immovable object or resisting an external force. This can be seen, for example, when holding a weight in a static position without any movement in the joint. Isotonic contractions involve muscle shortening or lengthening, while isokinetic contractions involve the muscle contracting at a constant speed.

12. All skeletal muscle reacts to an chemical stimulus, which is conducted from the brain to the muscle via nerves.

True

False

Skeletal muscle does not react to a chemical stimulus conducted from the brain to the muscle via nerves. Instead, skeletal muscle reacts to an electrical stimulus called an action potential, which is conducted from the brain to the muscle via nerves. This electrical stimulus triggers muscle contraction. Therefore, the given statement is false.

Explanation

Skeletal muscle does not react to a chemical stimulus conducted from the brain to the muscle via nerves. Instead, skeletal muscle reacts to an electrical stimulus called an action potential, which is conducted from the brain to the muscle via nerves. This electrical stimulus triggers muscle contraction. Therefore, the given statement is false.