Human Skeletal System MCQ Quiz in বাংলা - Objective Question with Answer for Human Skeletal System - বিনামূল্যে ডাউনলোড করুন [PDF]

The correct answer is A-II, B - III, C - IV, D - I

Explanation:

A. Joint between humerus and pectoral girdle: Ball and Socket joint

• A ball and socket joint is a type of synovial joint that allows for multi-directional movement and rotation.
• This joint features a spherical "ball" at the end of one bone fitting into a cup-like "socket" of another bone, enabling the bones to move and rotate in several directions.

B. Knee joint: Hinge joint

• Hinge joints allow movement primarily in one axis, permitting flexion (bending) and extension (straightening).
• The range of motion is similar to the movement of a door hinge, predominantly in one plane (sagittal plane).
• Examples: The elbow and the knee are classic examples of hinge joints.

C. Joint between atlas and axis: Pivot joint

• A pivot joint, also known as a rotary joint or trochoid joint, allows for rotational movement around a single axis.
• Atlas (C1): The first cervical vertebra that supports the skull. It has a ring-like shape.
• Axis (C2): The second cervical vertebra, characterized by the presence of the odontoid process (or dens), a peg-like projection that extends upwards.
• The atlantoaxial joint enables the head to turn from side to side. This rotational movement is essential for a wide range of head and neck mobility.

D. Joint between carpals: Gliding joint

• Gliding joints, also known as plane joints, are a type of synovial joint where the articular surfaces are nearly flat or slightly curved, allowing bones to slide past one another.
• These joints are characterized by limited movement, primarily in the form of gliding actions.
• They are crucial for providing stability and enabling small adjustments in the positions of bones, which is essential for various functional movements. 

The correct answer is option 3 i.e It involves release of \(Ca^{++}\) from sarcoplasmic reticulum (SR) and pumping \(Ca^{++}\) back in SR

Explanation:

• Muscle contraction is the activation of tension- generating sites within muscle fibres.
• The sequence of events in the contraction of muscle fibre is as follows: -
• It begins with a signal- the neurotransmitter, Ach - from the motor neuron innervating that fibre.
• The local membrane of the fibre will depolarize as positively charged Na+ ions enter, triggering an action potential that spreads to the rest of the membrane will depolarize, including the T-tubules.
• This triggers the release of \(Ca^{++}\) ions from the sarcoplasmic reticulum.
• These \(Ca^{++}\) ions initiate contraction, which is sustained by ATP.
• As long as \(Ca^{++}\) ions remain in the sarcoplasm to bind to troponin, which keeps the actin-binding sites unshielded and as long as ATP is available to drive the cross bridge cycling and pulling of actin strands by myosin.
• Muscle contraction usually ends when signalling from the neuron ends and after this \(Ca^{++}\) ion pumped back to the SR. Hence, correct answer is option 3.

The correct answer is option 3.

Concept: 

• There are two types of muscle fiber in birds and mammals, which are red and white muscle fiber.
• Red muscle fibers are rich in myoglobin and mitochondria.
• White muscle fibers are longer and thicker in size. These are less vascularized and light-colored, so lack myoglobin and do not store oxygen.
• Each muscle fiber is composed of myofibrils.
• Muscle fiber has a functional unit called the sarcomere.

​

Explanation:

Fast muscle fibers-lactic acid:

• It is known that the fast muscle fibers (white muscle fibers) carry less amount of myoglobin and mitochondria, therefore, they depend upon anaerobic oxidation, which produces lactic acid. 
• It is to be noted that they also exhibit a fast rate of contraction.

Slow muscle fibres-Myoglobin

• Red Muscles are also called slow twitch fibers.
• This type of muscle fiber is rich in myoglobin and mitochondria.
• They appear red in color due to the presence of myoglobin.
• They are called slow twitch fibers as they exhibit a slow rate of contraction.

​

Actin filament- I band

• Muscle fiber comprises myofibrils.
• They exhibit alternate dark and light bands.
• The dark bands are made up of mainly myosin protein and the light bands comprise actin protein.
• Actin filaments form the isotropic part of the sarcomere.

​

Sarcomere- Contractile unit

• The functional unit of muscle fiber is called the sarcomere.
• The sarcomeres have a large number of parallelly arranged filaments known as myofibrils.
• These myofibrils consist of light and dark bands
• The light bands are made up of actin filaments, known as an I-band or Isotropic band, whereas dark bands are composed of myosin filaments, known as Anisotropic or A-band.
•  
  The sarcomere is the fundamental contractile unit of the myofibril.
• In the center of each I-band, a Z-line is present and an M-line is present in the A-band, the A & I-bands are arranged alternately throughout the myofibrils.
• The portion between 2 successive Z-line is called Sarcomere.
• Therefore, the correct answer is option 3. A - ii, B - i, C - iv, D - iii.
• 

The correct answer is option 3 i.e It involves release of \(Ca^{++}\) from sarcoplasmic reticulum (SR) and pumping \(Ca^{++}\) back in SR

Explanation:

• Muscle contraction is the activation of tension- generating sites within muscle fibres.
• The sequence of events in the contraction of muscle fibre is as follows: -
• It begins with a signal- the neurotransmitter, Ach - from the motor neuron innervating that fibre.
• The local membrane of the fibre will depolarize as positively charged Na+ ions enter, triggering an action potential that spreads to the rest of the membrane will depolarize, including the T-tubules.
• This triggers the release of \(Ca^{++}\) ions from the sarcoplasmic reticulum.
• These \(Ca^{++}\) ions initiate contraction, which is sustained by ATP.
• As long as \(Ca^{++}\) ions remain in the sarcoplasm to bind to troponin, which keeps the actin-binding sites unshielded and as long as ATP is available to drive the cross bridge cycling and pulling of actin strands by myosin.
• Muscle contraction usually ends when signalling from the neuron ends and after this \(Ca^{++}\) ion pumped back to the SR. Hence, correct answer is option 3.

The correct answer is option 3 i.e It involves release of \(Ca^{++}\) from sarcoplasmic reticulum (SR) and pumping \(Ca^{++}\) back in SR

Explanation:

• Muscle contraction is the activation of tension- generating sites within muscle fibres.
• The sequence of events in the contraction of muscle fibre is as follows: -
• It begins with a signal- the neurotransmitter, Ach - from the motor neuron innervating that fibre.
• The local membrane of the fibre will depolarize as positively charged Na+ ions enter, triggering an action potential that spreads to the rest of the membrane will depolarize, including the T-tubules.
• This triggers the release of \(Ca^{++}\) ions from the sarcoplasmic reticulum.
• These \(Ca^{++}\) ions initiate contraction, which is sustained by ATP.
• As long as \(Ca^{++}\) ions remain in the sarcoplasm to bind to troponin, which keeps the actin-binding sites unshielded and as long as ATP is available to drive the cross bridge cycling and pulling of actin strands by myosin.
• Muscle contraction usually ends when signalling from the neuron ends and after this \(Ca^{++}\) ion pumped back to the SR. Hence, correct answer is option 3.

Key Points

• The first cervical vertebra is the atlas.

Atlas:

• The vertebrae extend from the base of the skull and constitute the main framework of the trunk.
• Each vertebra has a central hollow portion (neural canal) through which the spinal cord passes.
• It articulates with the occipital condyles.
• 

Important Points

Axis:

• The second cervical vertebra (C2) of the spine, the axis is directly beneath the atlas and serves as the head's support.
• It is also known as the Epistropheus.

Spinal cord:

• A component of the central nervous system is the spinal cord.
• It is a long, pipe-like structure that extends from the medulla oblongata, a section of the brain made up of a group of nerve fibers.
•  It runs through the spine's vertebral column.

Ribs:

• There are 12 pairs of ribs.
• Each rib is a thin flat bone connected dorsally to the vertebral column and ventrally to the sternum.
• It has two articulation surfaces on its dorsal end and is hence called bicephalic.

The correct answer is option 2.

Concept: 

• Muscles are contractile tissues present in the human and animal bodies and function in a group to coordinate the efficient functioning of human and animal organs.
• The muscle tissue cells are made up of protein filaments of actin and myosin.
• The protein filaments are arranged one upon the other to help in muscle movement and provide flexibility to the muscles.

Explanation: ​

Option 1:

• Smooth muscles are 'involuntary' and non-striated muscles as they cannot be controlled directly like skeletal muscles which are voluntary, controlled, and possess striations.
• The inner walls of the alimentary canal are non-striated and involuntary muscles. 
• Therefore, this is an incorrect answer.

​​Option 2:

• The heart muscles are made of cylindrical, branched striated cells that are involuntary.
• They are the cardiac muscles.
• Therefore, this is the correct answer.

​Option 3:

• The muscles of the hands and legs are voluntary and are made of cylindrical and striated cells.
• They are the skeletal muscles.
• Therefore, this is an incorrect answer.

​​​Option 4:

The correct answer is option 3.

Concept: 

• Muscles are contractile tissues present in the human and animal bodies and function in a group to coordinate the efficient functioning of human and animal organs.
• The muscle tissue cells are made up of protein filaments of actin and myosin.
• The protein filaments are arranged one upon the other to help in muscle movement and provide flexibility to the muscles.

Explanation: ​

Option 1:

• The heart muscles are made of cylindrical, branched striated cells that are involuntary.
• They are the cardiac muscles.
• Therefore, this is the correct statement and hence the incorrect answer.

​Option 2:

• The muscles of the hands and legs are voluntary and are made of cylindrical and striated cells.
• They are the skeletal muscles.
• Therefore, this is the correct statement and hence the incorrect answer.

​​Option 3: