NEET Previous Year Questions (2016-2025): Locomotion & Movement

Ans: (b)
The correct answer is option (b) because:

• Skeletal muscles are attached to bones, such as the triceps, and have a striped appearance.
• Smooth muscles are found in the walls of internal organs like the stomach and intestines, and they do not have stripes.
• Cardiac muscles are unique to the heart, are striated, and work involuntarily.

Ans: (d)
To match List I (Types of Joints) with List II (Descriptions/Functions), let us consider each type:
Fibrous Joints (A): These joints are found where bones are closely fitted together, allowing very little or no movement, such as in the sutures of the skull. So, Fibrous joints correspond to: III. Skull, don't allow any movement
Cartilaginous Joints (B): These joints occur where the connection between the articulating bones is made up of cartilage, such as between vertebrae in the spine. These allow for limited movement. So, Cartilaginous joints correspond to: I. Adjacent vertebrae, limited movement
Hinge Joints (C): These include joints like the elbow and knee, where movement is primarily in one axis (like opening and closing a door). So, Hinge joints correspond to: IV. Knee, help in locomotion
Ball and Socket Joints (D): These joints, such as the hip and shoulder joints, allow for a wide range of movement including rotational. So, Ball and socket joints correspond to: II. Humerus and Pectoral girdle, rotational movement
The correct matching based on the descriptions and joint types is: A-III, B-I, C-IV, D-II

Ans: (c)

• Vertebrochondral ribs (A): These are the 8th, 9th, and 10th pairs of ribs that are indirectly connected to the sternum through cartilage. This corresponds to (II) in List II.
• Floating ribs (B): These are the 11th and 12th pairs of ribs, which do not have any anterior attachment to the sternum or cartilage, making them "floating." This corresponds to (IV) in List II.
• Scapula (C): The acromion is a bony process on the scapula that forms the highest point of the shoulder. This corresponds to (III) in List II.
• Coxal Bone (D): The coxal bone (also called the pelvic bone) consists of three parts: the ilium, ischium, and pubis. This corresponds to (I) in List II.

Thus, the correct match is:

• A-II: Vertebrochondral ribs are the 8th, 9th, and 10th pairs.
• B-IV: Floating ribs are the 11th and 12th pairs.
• C-III: The acromion is part of the scapula.
• D-I: The coxal bone consists of the ilium, ischium, and pubis.

Ans: (a)

• A. Joint between humerus and pectoral girdle: This is a Ball and socket joint (II), which allows rotational movement. It is the shoulder joint.
• B. Knee joint: The knee is a Hinge joint (III), allowing movement in one plane (flexion and extension).
• C. Joint between atlas and axis: This is a Pivot joint (IV), which allows rotation, such as the rotation of the head.
• D. Joint between carpals: The joints between the carpal bones in the wrist are Gliding joints (I), which allow limited sliding movements.

Thus, the correct matches are:

• A-II: Ball and socket joint for the humerus and pectoral girdle.
• B-III: Hinge joint for the knee.
• C-IV: Pivot joint for the atlas and axis.
• D-I: Gliding joint for the carpals.

Ans: (a)

• A. It is initiated by a signal sent by CNS via sensory neuron: This statement is incorrect because the signal for muscle contraction is sent from the motor neuron (not sensory neuron) to the muscle.
• B. Neurotransmitter generates action potential in the sarcolemma: This is correct. The neurotransmitter (acetylcholine) released at the neuromuscular junction generates an action potential in the sarcolemma (muscle cell membrane), which triggers muscle contraction.
• C. Increased Ca⁺⁺ level leads to the binding of calcium with troponin actin filaments: This is correct. When calcium ions (Ca⁺⁺) are released from the sarcoplasmic reticulum, they bind to troponin, causing a conformational change that allows actin and myosin filaments to interact.
• D. Masking of active site for actin is activated: This statement is incorrect. The active sites on actin are masked by tropomyosin under resting conditions, and unmasked (exposed) when calcium binds to troponin.
• E. Utilizing the energy from ATP hydrolysis to form cross bridge: This is correct. ATP is hydrolyzed to provide energy for the formation of the cross-bridge between actin and myosin, which is essential for muscle contraction.

Thus, the correct statements are B, C, and E. Therefore, the answer is (a).

Ans: (b)
(A) Cartilaginous Joint : These joints are connected by cartilage and allow limited movement. They are found between adjacent vertebrae in the vertebral column.
(B) Ball and Socket Joint : These joints consist of a ball-like structure fitting into a socket, allowing for a wide range of movement. They are found between the humerus and the pectoral girdle.
(C) Fibrous Joint : These joints are connected by fibrous connective tissue and allow little or no movement. They are found between flat skull bones.
(D) Saddle Joint : These joints have two bones with concave and convex surfaces that fit together, allowing movement in two planes. They are found between the carpal and metacarpal of the thumb.

Ans: (b)
Option (B) is the correct answer because statements B and C are only correct statements while A and D are incorrect statements.
Muscle bundles are held together by collagenous connective tissue layer called fascia. Muscle bundles are called fascicles. The portion of the myofibril between two successive 'Z' lines is considered as functional unit of contraction called sarcomere.

Ans: (d)

• (A) Palm bones: These are the Metacarpals (II). The metacarpals are the bones in the palm of the hand.
• (B) Wrist bones: These are the Carpals (III). The carpals are the eight bones that form the wrist.
• (C) Ankle bones: These are the Tarsals (IV). The tarsals are the bones in the ankle.
• (D) Digit bones: These are the Phalanges (I). The phalanges are the bones in the fingers and toes.

Thus, the correct match is:

• (A) II: Palm bones are the metacarpals.
• (B) III: Wrist bones are the carpals.
• (C) IV: Ankle bones are the tarsals.
• (D) I: Digit bones are the phalanges.

Ans: (c)
Option (c) is the correct answer because cardiac muscle fibres have special connections called intercalated discs. These discs enable the muscle cells to work together as a unit. When one cell receives a signal to contract, its neighbouring cells are also stimulated to contract.

Ans: (c)

Ans: (d)

• Option (d) is correct because myasthenia gravis is a chronic auto immune disorder affecting neuromuscular junction leading to fatigue, weakening and paralysis of skeletal muscle.
• Gout is caused due to deposition of uric acid crystals in joints leading to its inflammation.
• Arthritis is the swelling and tenderness of one or more number of joints. It is caused by injury, abnormal metabolism, and genetic makeup.
• Muscular dystrophy is a disease characterised by progressive degeneration of muscle fibres without the involvement of nervous system.

Ans: (b)

• Sternum is a flat bone on the ventral midline of thorax.
• Scapula is a large triangular flat bone situated in the dorsal part of the thorax between the second and the seventh ribs.
• Fibrous joints do not allow any movement.
• This type of joint is shown by the flat skull bones which fuse end-to-end with the help of dense fibrous connective tissues in the form of sutures, to form the cranium.
• In cartilaginous joints, the bones involved are joined together with the help of cartilages.
• The joint between the adjacent vertebrae in the vertebral column is of this pattern and it permits limited movements.

Ans: (c)
The correct option is (c) because the length of A-band is retained. During muscle contraction, the following events occur:
(1) The globular head of myosin acts as ATPase and hydrolysis ATP molecule and eventually leads to the formation of cross bridge.
(2) This pulls the actin filament towards the centre of 'A-band'.
(3) The Z-line attached to these actins are also pulled inwards thereby causing a shortening of the sarcomere.
(4) The thin myofilaments move past the thick myofilaments due to which the H-zone narrows. This reduces the length of I-band but retains the length of A-band.
(5) The myosin then releases ADP + Pi, and goes back to its relaxed state.

Ans: (b)

• The 11th and 12th pairs of ribs are known as floating ribs because they are not connected to the sternum at the front.
• The acromion is a flat, expanded part of the spine of the scapula.
• The clavicle's lateral end connects with the acromion.
• The scapula is a flat, triangular bone located in the back of the thorax, situated between the 2nd and 7th ribs.
• The glenoid cavity of the scapula connects with the head of the humerus, forming the shoulder joint.

Ans: (a)
Seven pairs of Ribs are vertebrosternal while 8^th, 9^th and 10^th pair of ribs are vertebrochondral and the last 11^th, 12^th pair are vertebral ribs. 

Ans: (c)

• Myasthenia gravis is a chronic auto immune disorder. It affects neuromuscular junction leading to fatigue, weakening and paralysis of skeletal muscles.
• Botulism is rare and dangerous type of food poisoning caused by bacterium Clostridium botulinum.
• Tetany is a rapid spasm in muscle due to low Ca2+ in body fluid.
• Muscular dystrophy is a genetic disorder. It is characterized by progressive degeneration of skeletal muscles, which are the muscles that control movement.

Ans: (a)
The sarcoplasmic reticulum to release calcium ions into the muscle interior where they bind to troponin, thus causing tropomyosin to shift from the face of the actin filament to which myosin heads need to bind to produce contraction.

Ans: (b)
Pivot joint is a type of synovial joint which provide freely movement between atlas and axis vertebrae of vertebral column.

Ans: (d)
In humans, there are 12 pairs of ribs. Out of these:

• 7 pairs (1st to 7th) are known as true ribs.
• These true ribs are attached:
  • Dorsally to the vertebral column
  • Ventrally to the sternum

The remaining ribs include:

• 3 pairs of false ribs (8th to 10th) that connect to the 7th rib via cartilage.
• 2 pairs of floating ribs (11th and 12th) that are not attached to the sternum.

This structure forms the rib cage, which protects vital organs in the thoracic cavity.

Ans: (a)
Calcium ion plays an important role in muscle contraction. Calcium ions bind to troponin causing a change in its shape and position. Thus, in turn alters shape and position of tropomyosin to which troponin binds. This shift exposes the active sites on F-actin molecules. Myosin cross-bridge are then able to bind to these active sites.

Ans: (c)
Osteoporosis is reduction in bone mineral density, resulting in bones that are brittle and liable to fracture. Infection, injury and synovitis can cause localised osteoporosis of adjacent bone. Generalised osteoporosis is common in the elderly and in women after menopause. After menopause the estrogen levels in blood plasma are much reduced. Estrogen helps to regulate bone cells called osteoclasts which are responsible for building new bone. When estrogen levels drop fewer osteoclasts are produced resulting in osteoporosis.

Ans: (c)

• The condition where there is a lack of relaxation between successive stimuli in muscle contraction is known as muscle tetanus.
• This occurs when muscles are stimulated repeatedly without rest.
• As a result, the muscle remains in a state of continuous contraction.

Ans: (b)
Production of  body heat is caused by the process of metabolism (respiration).

Ans: (d)
Fibrous joint is an attachment between bones, being held together by fibrous connective tissue. For example- suture between skull bones.

Ans: (b)
Sliding filament theory was given by Huxley and Huxley (1954). It states that Actin and Myosin filaments do not become short but rather slide pass each other. Because of sliding of actin filaments over myosin the length of I-band will change.

Ans: (c)

• The glenoid cavity connects the humerus to the scapula.
• This joint is crucial for the shoulder movement.
• It allows a wide range of motion in the arm.

Ans: (d) 
A gliding joint is a common type of synovial joint formed between bones that meet at flat or nearly flat articular surfaces. Gliding joints allow the bones to glide past one another in any direction along the plane of the joint - up and down, left and right, and diagonally. Many gliding joints are formed in the appendicular skeleton between the carpal bones of the wrist; between the carpals and the metacarpals of the palm; between the tarsal bones of the ankle; and between the tarsals and the metatarsals of the foot. 

Ans: (a)

• A motor neuron sends signals to muscle tissue.
• A motor unit consists of one motor neuron and the muscle fibres it controls.
• The area where the motor neuron connects with the muscle fibre is called the neuromuscular junction or motor end plate.
• When a signal reaches this junction, it releases a neurotransmitter, which generates an action potential in the muscle fibre.
• This action potential triggers the release of calcium ions from the sarcoplasmic reticulum.
• The increase in calcium levels allows myosin to bind to actin, leading to muscle contraction.