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Q1. Which of the following facial bones is unpaired?  

• Lacrimal  
• Palatine  
• Nasal  
• Vomer  

Solution

Facial bones include 2 nasals, 2 maxillae, 2 palatines, 2 zygomatic or cheek bones, 2 lacrimals, 2 inferior nasal conchae, 1 vomer and 1 mandible. The vomer is one of the unpaired facial bones of the skull. It forms the posterior part of the nasal septum, with the anterior part formed by the ethmoid bone.  

Q2. The number of vertebrae present in the cervical, thoracic, lumbar, sacral and coccyx regions, respectively, are

• 12, 7, 5, 1, 1
• 1, 7, 5, 12, 1
• 7, 5, 1, 12, 1
• 7, 12, 5, 1, 1
• 5, 12, 7, 1, 1

Solution

The vertebrae are grouped into five categories: Cervical vertebrae: 7, present in the neck Thoracic vertebrae: 12, present in the upper back Lumbar vertebrae: 5, located in the abdomen Sacral vertebrae: 5, present in the pelvis Coccygeal vertebrae: 4, present in the vestigial tail

Q3. ATPase enzyme needed for muscle contraction is located in  

• Myosin  
• Actin  
• Actinin  
• Troponin  

Solution

During muscle contraction, hydrolysis of ATP into ADP and inorganic phosphate occurs. The energy released during the process raises the meromyosin head to a high-energy state. The enzyme myosin ATPase catalyses the reaction in the presence of Ca²⁺ and Mg²⁺.      

Q4. The number of bones in the human skull is

• 26
• 28
• 107
• 29

Solution

The skull includes bones of the cranium (8), ear bones (3 in each ear = 6), facial bones (14) and hyoid bone (1). So, there are a total of 29 bones in the human skull.

Q5. The H zone in the skeletal muscle fibre is due to the

• Central gap between myosin filaments in the A band.
• Central gap between actin filaments extending through myosin filaments in the A band.
• Extension of myosin filaments in the central portion of the A band.
• Absence of myofibrils in the central portion of the A band.

Solution

The dark A band in the skeletal muscle fibre has a middle light zone called the H zone. It occurs due to the central gap between actin filaments extending through myosin filaments in the A band.

Q6. The only immediate source of energy for muscular contraction is

• ATP
• Phosphocreatinine
• Phosphoarginine
• Glucose

Solution

ATP is the only immediate source of energy for muscular contraction. ATP is replenished within muscle fibres from creatine phosphate (anaerobic respiration), by glycolysis (anaerobic respiration) and by cellular respiration (aerobic respiration).

Q7. Which of the following gives the correct total number?  

• Types of diabetes - 4  
• Cervical vertebrae in humans - 8  
• Floating ribs in humans - 4  
• Amino acids found in proteins - 16  

Solution

There are 3 main types of diabetes - Type I diabetes, type II diabetes and gestational diabetes.     7 cervical vertebrae are present in humans.     The 11^th and 12^th pairs of ribs (total 4 ribs) are called floating ribs.     A total of 20 amino acids are found in proteins.  nbsp;

Q8. Cells which contain marrow cells are called

• Osteocytes
• Chondrocytes
• Osteoclasts
• None of the above

Solution

Osteocytes are bone-forming cells which have become entrapped within the bone matrix. Chondrocytes are cells found in the cartilage connective tissue. Osteoclasts are multinuclear cells derived from the hematopoietic stem cells which break down bone and are responsible for bone resorption.

Q9. The largest muscle in the human body is  

• Sartorius  
• Gluteus  
• Stapedius  
• Masseter  

Solution

The largest muscle in the human body is gluteus maximus, which is also known as the buttock muscle. It is large because its main function is to keep the body upright.  

Q10. The elbow joint is an example of

• Ball and socket joint
• Pivot joint
• Hinge joint
• Gliding joint

Solution

The hinge joint allows movements in one plane only. The knee joint, elbow joint, ankle joint and the joints between the phalanges are all examples of a hinge joint.

Q11. Read the statements carefully and comment on them. A. A bands of muscle fibre are dark and contain myosin. B. I bands of muscle fibre are light and contain actin. C. During muscle contraction, the A bands contract. D. The part between two Z lines is called sarcomere. E. The central part of the thin filament not overlapped by the thick filament is the H zone.

• A, B and C are correct, while D and E are incorrect.
• A, C and E are correct, while B and D are incorrect.
• A and B are correct, while C, D and E are incorrect.
• A, B and D are correct, while C and E are incorrect.

Solution

A bands of muscle fibre are dark and contain myosin. I bands of muscle fibre are light and contain actin. The part between two successive Z lines is called a sarcomere. During muscle contraction, the I bands contract. The central part of a thin filament not overlapped by a thick filament is the Z line.

Q12. Which one of the following is the correct pairing of a body part and the kind of muscle tissue which moves it?  

• Iris - Involuntary smooth muscle  
• Heart wall - Involuntary unstriated muscle  
• Biceps of upper arm - Smooth muscle fibres  
• Abdominal wall - Skeletal muscle  

Solution

Iris - Involuntary smooth muscles     Heart wall - Cardiac muscles     Biceps of upper arm - Striated muscle fibres     Abdominal wall - Smooth muscles  

Q13. Which of the following statements about the mechanism of muscle contraction are correct?     A. Acetylcholine is released when the neural signal reaches the motor end plate.     B. Muscle contraction is initiated by a signal sent by CNS via a sensory neuron.     C. During muscle contraction, the isotropic band gets elongated.     D. Repeated activation of the muscle can lead to accumulation of lactic acid.  

• A and D are correct.  
• A and C are correct.  
• B and C are correct.  
• A, Band C are correct.  

Solution

When an impulse arrives at the end plate of an axon, the vesicles therein release acetylcholine, which diffuses across the nerve-muscle gap, binds to receptors on the sarcolemma and increases the permeability of sarcolemma to sodium ions. This causes depolarisation of the sarcolemma and results in the contraction of the muscle fibre.     Repeated activation of the muscle decreases the supply of oxygen to the muscle tissues, thereby causing accumulation of lactic acid.     During muscle contraction, the isotropic band gets shortened.  

Q14. Which one of the following is anatomically correct for the human body?  

• Collar bones: 3 pairs  
• Salivary glands: 1 pair  
• Cranial nerves: 10 pairs  
• Floating ribs: 2 pairs  

Solution

Floating ribs: 2 pairs     Collar bones/clavicles: 1 pair     Salivary glands: 3 pairs     Cranial nerves: 12 pairs  

Q15. The exoskeleton is absent in

• Scoliodon
• Frog
• Rabbit
• Fowl

Solution

The endoskeleton consists of hard parts present inside the body. The exoskeleton consists of hard parts present on the surface of the body. Amphibians do not show the presence of an exoskeleton. So, the exoskeleton is absent in frog.

Q16. The membranous areas between the cranial bones of the foetal skull are called  

• Areolas  
• Foramina  
• Sutures  
• Fontanelle  

Solution

Fontanelles comprise any of the soft membranous gaps between the incompletely formed cranial bones of a foetus or an infant. They allow for rapid stretching and deformation of the cranium as the brain expands faster than the surrounding bone can grow.  

Q17. Which of the following is a contractile protein of a muscle?

• Myosin
• Tropomyosin
• Actin
• Tubulin

Solution

Actin and tropomyosin are part of thin filaments of skeletal muscle. Tubulin is present in microtubules. Myosin is a contractile protein of muscles.

Q18. Pick out the correct match.  

• Sternum = 14 bones  
• Pelvis = 3 bones  
• Ribs = 20 bones  
• Face = 5 bones  

Solution

Pelvis = 3 bones (ilium, ischium, pubis)     Sternum = 1 bone     Ribs = 24 bones (12 pairs of ribs)     Face = 14 bones (2 nasals, 2 maxillae, 2 palatines, 2 zygomatic or cheek bones, 2 lacrimals, 2 inferior nasal conchae, 1 vomer and 1 mandible)  

Q19. Collagen is a

• Phosphoprotein
• Globulin
• Derived protein
• Scleroprotein

Solution

Scleroproteins are a class of generally insoluble proteins such as collagen found in the skeletal and connective tissues.

Q20. The pectoral girdle is constituted by

• Scapula and clavicle
• Radius and ulna
• Ilium and ischium
• Maxilla and mandible

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