Q1. Three of the following pairs of the human skeletal parts are correctly matched with their respective inclusive skeletal category and one pair is not matched. Identify the non-matching pair.
Pairs of skeletal parts
Category
(a) Sternum and Ribs
Axial skeleton
(b) Clavicle and Glenoid cavity
Pelvic girdle
(c) Humerus and Ulna
Appendicular skeleton
(d) Malleus and Stapes
Ear ossicles
Correct Answer: (b)
Clavicle and Glenoid cavity are structures belonging to the pectoral (shoulder) girdle, not the pelvic girdle.
Q2. Which of the following diseases is an autoimmune disorder?
Correct Answer: (b)
Myasthenia gravis is an autoimmune disorder in which autoantibodies attack nicotinic acetylcholine receptors at the neuromuscular junction, leading to fatigue and muscle paralysis.
Q3. Glenoid cavity articulates :
Correct Answer: (c)
The shallow glenoid cavity located at the lateral angle of the scapula articulates with the head of the humerus to form the glenohumeral (shoulder) joint.
Q4. Low Ca++ in the body fluid may be the cause of:
Correct Answer: (a)
Low serum calcium levels (hypocalcemia) increase neuronal membrane permeability and excitability, causing wild spasms and sustained involuntary muscle contractions called tetany.
Q5. The number of floating ribs in the human body, is
Correct Answer: (d)
There are 2 pairs of floating ribs (11th and 12th pairs) which lack any ventral attachment to sternum or costal cartilages.
Q6. Which of the following joints would allow no movement?
Correct Answer: (d)
Fibrous joints (synarthroses), such as the sutures connecting skull bones, are held firmly together by dense fibrous connective tissue and permit no movement.
Q7. Long bones function in
Correct Answer: (b)
Long bones serve a structural function by offering body support and leverage for movement, while their red bone marrow functions in hematopoiesis (synthesizing erythrocytes and leucocytes).
Q8. Which one of the following is the correct matching of three items and their grouping category?
Items
Group
(a) ilium, ischium, pubis
coxal bones of pelvic girdle
(b) actin, myosin, rhodopsin
muscle proteins
(c) cytosine, uracil, thiamine
pyrimidines
(d) malleus, incus, cochlea
ear ossicles
Correct Answer: (a)
Each coxal (hip) bone of the pelvic girdle is formed by the fusion of three bones: ilium, ischium, and pubis. Rhodopsin is a visual pigment (not muscle protein); thiamine is Vitamin B1 (thymine is pyrimidine); cochlea is part of inner ear (not ear ossicle).
Q9. Calcium is important in skeletal muscle contraction because it
Correct Answer: (a)
Action potential causes the sarcoplasmic reticulum to release calcium ions (Ca2+) into the sarcoplasm. These calcium ions bind to a subunit of troponin on actin (thin) filaments, inducing a conformational change that removes the masking of active binding sites for myosin heads.
Q10. Select the correct matching of the type of the joint with the example in human skeletal system:
Type of joint
Example
(a) Cartilaginous joint
between frontal and parietal
(b) Pivot joint
between third and fourth cervical vertebrae
(c) Hinge joint
between humerus and pectoral girdle
(d) Gliding joint
between carpals
Correct Answer: (d)
A gliding joint occurs between flat surfaces of bones like intercarpal bones. Skull sutures (frontal/parietal) are fibrous joints; intervertebral joints are cartilaginous; humerus with pectoral girdle forms a ball and socket joint.
Q11. What will happen if ligaments are cut or broken?
Correct Answer: (c)
Ligaments are dense fibrous connective tissues connecting bone to bone. If broken or severed, the joint loses stability and articulating bones become unfixed/dislocated.
Q12. An acromion process is characteristically found in the:
Correct Answer: (b)
The acromion process is a prominent bony projection present on the spine of the scapula in the mammalian pectoral (shoulder) girdle, articulating with the clavicle.
Q13. Extremities of long bones possess cartilage
Correct Answer: (d)
Articular extremities of long bones forming synovial joints are covered by smooth, slick hyaline cartilage (articular cartilage) to reduce friction and absorb shock.
Q14. Haversian canals occur in
Correct Answer: (a)
Haversian canals (containing blood vessels and nerves running parallel to the long axis) are characteristic microscopic features of compact bone in mammalian long bones such as the humerus.
Q15. Sliding filament theory can be best explained as:
Correct Answer: (b)
According to the Sliding Filament Theory (proposed by Huxley and Huxley), during muscle contraction, thin (actin) and thick (myosin) filaments do not shorten in length; instead, thin actin filaments slide past the thick myosin filaments towards the center of the sarcomere.
Q16. Total number of bones in the hind limb of man is
Correct Answer: (b)
Each human hind limb contains 30 bones: 1 femur, 1 patella, 1 tibia, 1 fibula, 7 tarsals, 5 metatarsals, and 14 phalanges.
Q17. Which one of the following pairs of chemical substances is correctly categorized?
Correct Answer: (c)
Troponin (associated with actin) and myosin are complex contractile/regulatory proteins essential for the contraction of striated (skeletal and cardiac) muscles. Thymosin is secreted by the thymus, prolactin is a pituitary hormone, and rhodopsin is a visual pigment.
Q18. Which of the following is not an autoimmune disease?
Correct Answer: (d)
Alzheimer's disease is a neurodegenerative disorder linked to extracellular amyloid plaques and neurofibrillary tangles, not an autoimmune disease. Psoriasis, Rheumatoid arthritis, and Vitiligo are autoimmune conditions.
Q19. The characteristics and an example of a synovial joint in humans is:
Characteristics
Examples
(a) Fluid filled between two joints, provides cushion
Skull bones
(b) Fluid filled synovial cavity between two bones
Joint between atlas and axis
(c) Lymph filled between two bones, limited movement
Gliding joint between carpals
(d) Fluid cartilage between two bones, limited movements
Knee joint
Correct Answer: (b)
Synovial joints are characterized by a fluid-filled synovial cavity between articulating bones, allowing free movement. A classic example is the pivot joint between atlas and axis.
Q20. The H-zone in the skeletal muscle fibre is due to:
Correct Answer: (b)
The central region of the thick myosin filament (A-band) that is not overlapped by thin actin filaments during the resting phase is called the H-zone (Hensen's zone).
Q21. In human body, which one of the following is anatomically correct?
Correct Answer: (d)
Humans have 2 pairs of floating ribs (11th and 12th pairs). Collar bones (clavicles) are 1 pair; major salivary glands are 3 pairs; cranial nerves are 12 pairs.
Q22. The joint found between sternum and the ribs in humans is
Correct Answer: (c)
The costosternal articulation between true ribs and sternum is made via costal (hyaline) cartilages, forming cartilaginous joints.
Q23. Select the correct statement with respect to locomotion in humans:
Correct Answer: (a)
Accumulation of uric acid (monosodium urate) crystals in synovial joint cavities triggers gouty arthritis causing inflammation. Thoracic vertebrae are 12; intervertebral joints are cartilaginous; osteoporosis in elderly women is primarily linked to decreased estrogen levels.
Q24. Select the correct statement with respect to disorders of muscles in humans
Correct Answer: (b)
In myasthenia gravis, autoimmune destruction of acetylcholine receptors impairs neuromuscular transmission, causing muscle weakness that affects swallowing (dysphagia) and facial movements.
Q25. Select the correct option:
Correct Answer: (d)
In humans, 1st to 7th pairs are vertebrosternal (true) ribs attached ventrally to sternum; 8th, 9th, and 10th pairs are vertebrochondral (false) ribs attached to 7th rib via hyaline cartilage; 11th and 12th pairs are vertebral (floating) ribs.
Q26. Number of cervical vertebrae in camel is
Correct Answer: (c)
Almost all mammals (including camel, rabbit, whale, horse, and humans) characteristically possess 7 cervical vertebrae regardless of neck length.
Q27. Parathormone deficiency produces muscle cramps or tetany as a result of
Correct Answer: (a)
Parathormone (PTH) acts to raise blood Ca2+ levels. Its deficiency (hypoparathyroidism) lowers serum Ca2+ levels, resulting in hypocalcemic tetany characterized by painful muscle cramps.
Q28. Select the correct statement regarding the specific disorder of muscular or skeletal system:
Correct Answer: (b)
Osteoporosis is an age-related systemic skeletal disorder characterized by reduced bone mass, diminished microarchitecture, and increased risk of fractures. Gout is due to uric acid deposition.
Q29. Which statement is correct for muscle contraction?
Correct Answer: (b)
During muscle contraction, the length of the A-band remains constant while the I-band shortens, the H-zone narrows/decreases, and the two Z-lines come closer together.
Q30. A deltoid ridge occurs in
Correct Answer: (d)
A distinct V-shaped elevation called the deltoid ridge (tuberosity) is present on the shaft of the humerus, serving as the attachment site for the deltoid muscle.
Q31. Elbow joint is an example of:
Correct Answer: (a)
The elbow joint between the trochlea of the humerus and trochlear notch of the ulna is a hinge joint allowing movement in a single plane.
Q32. The pivot joint between atlas and axis is a type of:
Correct Answer: (b)
The pivot joint between the first (atlas) and second (axis) cervical vertebrae is a subtype of synovial joint characterized by a fluid-filled synovial cavity that permits rotation.
Q33. Which of the following muscular disorders is inherited?
Correct Answer: (b)
Muscular dystrophy (such as Duchenne muscular dystrophy) is an inherited genetic disorder caused by mutations leading to progressive degeneration of skeletal muscle.
Q34. Which of the following pairs, is correctly matched?
Correct Answer: (b)
The joints between pre- and post-zygapophyses of adjacent vertebrae are plane synovial/gliding joints. Intervertebral discs form cartilaginous joints; skull sutures are fibrous joints; interphalangeal joints are hinge joints.
Q35. Match the following columns and select the correct option.
Column-I
Column-II
(a) Floating Ribs
(i) Located between second and seventh ribs
(b) Acromion
(ii) Head of the Humerus
(c) Scapula
(iii) Clavicle
(d) Glenoid cavity
(iv) Do not connect with the sternum
Correct Answer: (c)
11th and 12th pairs of ribs do not connect ventrally with the sternum (Floating Ribs). Acromion is a flat process on the scapula spine that articulates with the Clavicle. Scapula is a large triangular bone on the dorsal thorax between 2nd and 7th ribs. Glenoid cavity articulates with the head of the humerus.
Q36. Characteristics of smooth muscle fibres are
Correct Answer: (a)
Smooth muscle fibers are non-striated (unstriped), spindle-shaped (fusiform) cells with a single centrally located nucleus (uninucleate), unbranched, and controlled involuntarily by the autonomic nervous system.
Q37. Which ion is essential for muscle contraction?
Correct Answer: (c)
Calcium ions (Ca2+) released from the sarcoplasmic reticulum are indispensable for binding to troponin, exposing active sites on actin filaments to allow myosin cross-bridge formation.
Q38. Which is part of pectoral girdle?
Correct Answer: (a)
Glenoid cavity is a depression on the scapula (part of pectoral girdle) into which the head of humerus articulates. Ilium and acetabulum belong to pelvic girdle.
Q39. Match the following joints with the bones involved:
Column-I
Column-II
(a) Gliding joint
(i) Between carpal and metacarpal of thumb
(b) Hinge joint
(ii) Between atlas and axis
(c) Pivot joint
(iii) Between the carpals
(d) Saddle joint
(iv) Between humerus and ulna
Correct Answer: (b)
Gliding joint occurs between carpals; Hinge joint is present between humerus and ulna (elbow joint); Pivot joint is located between atlas and axis; Saddle joint is located between carpal and metacarpal of thumb.
Q40. Which of the following hormones can play a significant role in osteoporosis?
Correct Answer: (d)
Estrogen deficiency in postmenopausal women increases bone resorption, while excessive Parathyroid Hormone (PTH) stimulates osteoclasts to mobilize Ca2+ from bone, both driving osteoporosis.
Q41. Out of 'X' pairs of ribs in humans only 'Y' pairs are true ribs. Select the option that correctly represents values of X and Y and provides their explanation:
Correct Answer: (d)
Humans have X = 12 pairs of ribs in total, out of which Y = 7 pairs (pairs 1–7) are true ribs because they articulate dorsally with thoracic vertebrae and directly attach ventrally to the sternum via costal cartilages.
Q42. ATPase enzyme needed for muscle contraction is located in
Correct Answer: (c)
The globular head of the myosin molecule contains an active ATPase site that hydrolyzes ATP into ADP and inorganic phosphate to provide energy for cross-bridge movement.
Q43. The functional unit of contractile system in striated muscle is
Correct Answer: (b)
The sarcomere, bounded between two successive Z-lines, is the basic structural and functional unit of contraction in striated skeletal muscle.
Q44. Which one of the following is a skull bone?
Correct Answer: (d)
Pterygoid is a small process/bone associated with the sphenoid bone of the skull. Atlas is 1st cervical vertebra; coracoid belongs to pectoral girdle; arytenoid is a laryngeal cartilage.
Q45. During muscle contraction in humans the
Correct Answer: (c)
During muscle contraction, thin actin filaments slide over thick myosin filaments into the A-band. Consequently, the I-band shortens, the H-zone narrows/disappears, and the sarcomere shortens, but the length of the A-band remains unchanged.
Q46. Which of the following is the contractile protein of a muscle?
Correct Answer: (a)
Myosin is the primary thick contractile protein forming the A-band of muscle fibers. Tropomyosin and troponin are regulatory proteins, while tubulin forms microtubules.
Q47. Which one of the following items gives its correct total number?
Correct Answer: (a)
There are 2 pairs of floating ribs in humans, which totals 4 individual bones (11th and 12th pairs). Standard amino acids in proteins are 20; cervical vertebrae in humans are 7.
Q48. What is sarcomere?
Correct Answer: (d)
A sarcomere is the functional contractile unit of a myofibril, defined as the region bounded between two successive Z-lines (Z-discs).
Q49. The lower jaw in mammals is made up of
Correct Answer: (a)
In mammals, the lower jaw consists of a single bone called the mandible (formed by fused dentary bones in adults).
Q50. Which of the following is not a function of the skeletal system?
Correct Answer: (b)
Production of body heat (thermogenesis) is a metabolic function performed primarily by muscular contraction and metabolic tissue activity, not by the skeletal system. Skeletal bones store minerals, produce blood cells (erythropoiesis), and facilitate locomotion.
Q51. Lack of relaxation between successive stimuli in sustained muscle contraction is known as
Correct Answer: (c)
Sustained muscle contraction without any relaxation phase between successive rapid stimuli is called tetanus (tetanic contraction). It occurs when the motor nerve fires action potentials at a high frequency.
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