Q1. Name the muscular disorder which affects the neuromuscular junction or motor-end plate.
Q2. Name the substance which when accumulated in muscles causes fatigue.
Q3. Name the two bones of the pectoral girdle.
Scapula and clavicle
Q4. Name the three types of muscles based on their location.
The three types of muscles based on their locations are Cardiac muscles Skeletal muscles Visceral muscles
Q5. Differentiate between skeletal muscles and visceral muscles.
Skeletal Muscles Visceral Muscles They show the presence of striations and are hence called striated muscles. Striations are absent, and they are hence called smooth muscles. Activities are under the control of the nervous system; hence, they are voluntary muscles.
Their activities are not under the control of the nervous system; hence, they are called involuntary muscles. They are responsible for locomotory actions and body posture. They are responsible for the movement of food through the digestive tract or the movement of gametes in the genital tract.
Q6. The number of vertebrae present in the cervical, thoracic, lumbar, sacral and coccyx regions, respectively, are
- 1) 5, 12, 7, 1, 1
- 2) 7, 12, 5, 1, 1
- 3) 7, 5, 1, 12, 1
- 4) 12, 7, 5, 1, 1
- 5) 1, 7, 5, 12, 1
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
Q7. State the different regions of the vertebral column and the number of bones present in each region.
Regions of the vertebral column Number of bones present Cervical region 7 Thoracic region 12 Lumbar region 5 Sacral region 1, fused Coccygeal region 1, fused
Q8. Name the muscles present in the inner wall of the reproductive tract.
Q9. Explain the structure of the pectoral girdle.
The pectoral girdle is made of the scapula and the clavicle. The scapula is a large triangular bone which is located on the dorsal part of the thorax between the second and the seventh ribs. It bears an elevated ridge called the spine which extends as the expanded flat process called the acromion.
The clavicle articulates with the acromion. The scapula bears a depression called the glenoid cavity below the acromion. The head of the humerus of the forelimb articulates with the glenoid cavity. The clavicle is a long slender bone with two curvatures. It is also called the collar bone.
Q61. Name the tissue which holds all the muscle bundles together in a muscle.
Q11. ATPase enzyme needed for muscle contraction is located in
- 1) Actin
- 2) Myosin
- 3) Actinin
- 4) Troponin
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+.
Q12. How many bones are present in the human skeletal system?
Q13. Which pairs of ribs are called false ribs? Why?
The 8th, 9th and 10th pairs of ribs are called false ribs. These three pairs of ribs do not articulate directly with the sternum. Instead they are joined to the 7th pair by the hyaline cartilage.
Q14. Name the cells which show amoeboid movement and are found in the human body.
Macrophages and leucocytes
Q15. Name the muscle involved in changes of body posture.
Q16. Name the bones which form the rib cage.
The thoracic vertebrae, ribs and sternum form the rib cage.
Q17. Name the neurotransmitter released at the neuromuscular junction.
Q18. Name the cavity to which the thigh bone articulates.
Q19. Which bone articulates with the glenoid cavity?
The head of humerus articulates with the glenoid cavity.
Q20. The largest muscle in the human body is
- 1) Stapedius
- 2) Masseter
- 3) Gluteus
- 4) Sartorius
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.
Q21. The membranous areas between the cranial bones of the foetal skull are called
- 1) Areolas
- 2) Sutures
- 3) Foramina
- 4) Fontanelle
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.
Q22. Which one of the following is the correct pairing of a body part and the kind of muscle tissue which moves it?
- 1) Biceps of upper arm – Smooth muscle fibres
- 2) Abdominal wall – Skeletal muscle
- 3) Iris – Involuntary smooth muscle
- 4) Heart wall – Involuntary unstriated muscle
Iris – Involuntary smooth muscles Heart wall – Cardiac muscles Biceps of upper arm – Striated muscle fibres Abdominal wall – Smooth muscles
Q23. Name the cartilage which helps vertebrochondral ribs to join the seventh rib.
Q24. Distinguish between fibrous joints and cartilaginous joints.
Fibrous Joints Cartilaginous Joints These joints are immovable joints and do not allow any movement. These joints provide limited movements. The flat bones are fused end-to-end by dense fibrous connective tissues. The bones are joined by the cartilage.
Q25. Name the three bones which fuse to form the coxal bone.
Ilium, ischium and pubis fuse to form the coxal bone of the pelvic girdle.
Q26. State the name for the plasma membrane of the muscle fibre.
Q27. Which parts of myosin filament act as ATPase?
The globular head of the myosin monomer acts as ATPase.
Q28. Distinguish between pectoral and pelvic girdles.
Pectoral Girdle Pelvic Girdle It consists of the scapula and the clavicle. It consists of the coxal bones made by the fusion of the ilium, ischium and pubis. It bears the glenoid cavity. It bears the acetabulum cavity. The two halves of the pectoral girdle are not joined to each other, but they are joined to the sternum on its either side. The two halves of the pelvic girdles are joined to each other by the pubic symphysis.
Q29. What is the technical term used for the knee cap?
Q30. Explain the structure of the myofibril.
Structure of Myofibril: The myofibril is a unit filament of a muscle fibre. It is made of two kinds of bands – dark band and light band. A dark band is also known as an A or anisotropic band (myosin filament) and contains myosin, while the light band is also known as an I or isotropic band (actin filament) and contains actin. Both the bands or filaments are arranged parallel to each other. Actin filaments are thinner than myosin filaments and are hence also called thin and thick filaments, respectively.
At the centre of each I band is an elastic fibre called Z-line to which thin filaments are firmly attached. The thick filaments in the A band are held together by an M line. The portion of the myofibril between two successive Z lines is considered functional and is called a sarcomere. In the resting state, the edges of thin filaments partially overlap the free ends of thick filaments on either side leaving the central parts of the thick filament non-overlapped; this is called the H zone.
Q31. Name the vertebra which articulates with the occipital condyles.
Q32. Define locomotion.
Voluntary movements which bring a change in place or location of the organism are called locomotion.
Q33. Which ions are stored by the sarcoplasmic reticulum in muscles?
Calcium ions are stored by the sarcoplasmic reticulum in muscles.
Q34. Name the filaments found arranged parallel in a muscle fibre.
Q35. Describe the synovial joint.
The synovial joint is characterised by the synovial cavity filled with the synovial fluid. The synovial cavity is present between the articulating bones of the joint. This arrangement and the presence of the lubricating fluid allow considerable movement. Some examples are the knee joint and the ball and socket joint present between the glenoid cavity and head of the humerus.
Q36. Name the joints which do not allow any movement.
Q37. Describe the structure of myosin as a contractile protein.
Structure of myosin filament: Each myosin filament is made of monomers of protein called meromyosin. Each meromyosin has two regions – heavy meromyosin (HMM), which is a globular head with a short arm, and light meromyosin (LMM), which is the tail.
The globular head acts as an active ATPase, and it also has the binding site for actin. The globular head and the short arm project outwards at a regular distance and angle from each other and from the surface of the myosin filament. This structure is called the cross-arm.
Q38. Explain the contraction and relaxation of muscles by the sliding filament theory.
Muscle contraction is initiated by the signal sent by the central neural system to the motor end-plate. As soon as the motor end-plate receives the single, acetylcholine is released at the end-plate which sets the action potential in the sarcolemma. As the action potential spreads through the fibre, it causes the sarcoplasm to release calcium ions. Increase in the calcium level results in binding of calcium with the troponin present on the actin filament.
The binding of calcium with the troponin unmasks the active binding site for myosin which is present on the actin filament. Myosin binds with the active site forming the cross-bridge. The energy required for the binding of myosin is obtained from the hydrolysis of ATP. Formation of the cross-bridge pulls the attached actin filaments towards the centre of the A band, and the Z lines are pulled inwards, resulting in the contraction of the sarcomere.
As soon as ADP and iP are formed from ATP, myosin goes back to its relaxed state and the cross-bridge is broken. At some point, calcium ions are pumped back to the sarcoplasmic cisternae, which results in the masking of the active binding sites of myosin, resulting in the relaxation of muscle fibre.
Q39. What are the bones of the palm called?
Q40. Explain the following disorders: Osteoporosis Tetany Muscular dystrophy
Osteoporosis: A decreased level of oestrogen is the common cause. The bone mass is decreased due to which a risk of fracture increases. It usually occurs in old individuals. Tetany: Rapid spasms are experienced in muscles due to a low calcium ion level in body fluids. Muscular dystrophy: It is a genetic disorder. The skeletal muscles degenerate progressively.
Q41. What is a sarcomere?
Sarcomere is the functional region of the myofibril between two successive Z lines.
Q42. Name the bone present at the base of the buccal cavity.
Hyoid bone is present at the base of the buccal cavity.
Q43. Name the oxygen-storing pigments of muscles.
Q44. State the symptom of gout.
Symptom of gout: Inflammation of joints
Q45. Name the junction between a motor neuron and a sarcolemma.
Neuromuscular junction or motor end-plate
Q46. Which bone of the axial skeleton is made of 8 bones?
Q47. Name the embryonic layer from which the muscles originate.
Q48. State the two major divisions of the human skeletal system.
Two major divisions of the human skeletal system are Axial skeleton Appendicular skeleton
Q49. State the important functions of the vertebral column.
The functions of the vertebral column are as follows: It protects the spinal cord. It supports the head. It serves as the point of attachment for the ribs and the musculature of the back.
Q50. Name the monomer of myosin filament.
Q51. Name the central hollow portion of the vertebra.
Q52. Give any two examples of the synovial joints.
Two examples of the synovial joints are Joint between the humerus and the pectoral girdle Knee joint
Q53. Name the hormone responsible for osteoporosis.
Q54. Why are the ribs called bicephalic? What are true ribs?
Because the rib bones have two articulation surfaces on the dorsal side, they are called bicephalic. The first seven pairs of ribs are dorsally attached to the thoracic vertebrae, and they are ventrally connected to the sternum. These ribs are called true ribs.
Q55. Describe the structure of actin filament.
The actin filament is made of two polymer F actins which are helically wound to each other. Each F actin is made of a monomer called globular or G actin. Two filaments of a protein called tropomyosin run close to the F actins throughout their length. At regular intervals, a protein named troponin is distributed on the tropomyosin. In the resting phase, the active binding site for myosin present on the actin filament gets masked by the troponin.
Q56. Distinguish between red and white muscle fibres.
Red Muscle Fibre White Muscle Fibre Myoglobin content is high. Myoglobin content is low. Contain more number of mitochondria. Contain less number of mitochondria.
Q57. How many bones are present in the front part of the skull which protects the facial region?
Q58. Write any two special properties of muscles.
Extensibility and elasticity
Q59. Which cell organelle is abundantly present in aerobic muscles?
Q60. Name the two proteins present in the myofilaments of muscles.
Actin and myosin