23 Questions with Answers and Explanations on Musculo-Skeletal System for Biology Students.
1. Intercostal muscles occur in
(a) abdomen
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(b) thigh
(c) ribs
(d) diaphragm.
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Answer and Explanation:
1. (c): Intercostal muscles (External intercostal and Internal intercostal) are attached with the ribs which help in the movement of rib cage during breathing.
2. Extremities of long bones possess which of the following cartilages?
(a) calcified
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(b) fibrous
(c) elastic
(d) hyaline.
Answer and Explanation:
2. (d): Hyaline cartilage has a clear, homogeneous, translucent, bluish-green matrix. It often contains a good number of very fine collagen fibres, which are difficult to observe. This cartilage is flexible, elastic and compressible. It is found in the sternal ribs, extremities of leg bones, tracheal and bronchial rings, laryngeal wall, nasal septum and superscapula. Elastic cartilage is found in the pinna, epiglottis, eustachian tubes and tip of nose. Calcified cartilage is found in the suprascapula of frog. Fibrous cartilage is found in the intervertebral discs and pubic symphysis.
3. A deltoid ridge occurs in
(a) radius
(b) ulna
(c) femur
(d) humerus.
Answer and Explanation:
3. (d): In the humerus bone, pectoral and deltoid ridges are important points of muscle attachment.
4. Number of cervical vertebrae in camel is
(a) more than that of rabbit
(b) less than that of rabbit
(c) same as that of whale
(d) more than that of horse.
Answer and Explanation:
4. (c): The vast majority of mammals have seven cervical vertebrae (neck bones), including camel, bats, giraffes, whales, and humans. The few exceptions include the manatee and the two-toed sloth, which each have only six cervical vertebrae, and the three-toed sloth with nine cervical vertebrae.
5. Long bones function in
(a) support
(b) support, erythrocyte and leucocyte synthesis
(c) support and erythrocyte synthesis
(d) erythrocyte formation.
Answer and Explanation:
5. (b): Long bones strengthen the legs and arms, provide support and also synthesize erythrocytes and leucocytes due to presence of bone marrow in their cavities.
6. The cervical vertebrae in human is
(a) same as in whale
(b) more than that in rabbit
(c) double than that of horse
(d) less than that in giraffe.
Answer and Explanation:
6. (a): The number of cervical vertebrae are same in man and whale that is 7 in number.
7. The type of joint between the human skull bones is called
(a) cartilaginous joint
(b) hinge joint
(c) fibrous joint
(d) synovial joint.
Answer and Explanation:
7. (c): Fibrousjoint is present between the human skull bones. It does not allow movement because the bones are held firmly together by bundles of strong white collagen fibres. Cartilaginous joints are present between the centra of vertebrae, at the pubic symphysis and between ribs and sternum. Knee joint, elbow joint and ankle joint are types of hinge joint. Synovial joint occurs between limb and bones.
8. Which of the following components is a part of the pectoral girdle?
(a) sternum
(b) acetabulum
(c) glenoid cavity
(d) ilium
Answer and Explanation:
8. (c): The pectoral girdle lies on the posterolateral aspect of the upper region of the thorax. It consists of 2 bones: scapula and clavicle. The scapula, also called shoulder blade, is a large, flat, triangular bone placed at the back of the shoulder. It has at its lateral angle a shallow concavity, the glenoid cavity, for the articulation of the head of the humerus. Acetabulum and ilium are parts of pelvic girdle. Sternum is a long, narrow, flat vertical bone in the middle of the front wall of the chest.
9. The number of floating ribs in the human body is
(a) 3 pairs
(b) 2 pairs
(c) 6 pairs
(d) 5 pairs.
Answer and Explanation:
9. (b): Rib is a curved, slightly twisted, strip of bone forming part of skeleton of the thorax, which protects the heart and lungs. There are 12 pairs of ribs. The first seven pairs – the true ribs, the next three (8, 9 and 10th) are false ribs and the last two pairs (11th and 12th) are floating ribs. Tt and Tp are called floating ribs as they are not attached with the sternum.
10. When a muscle bends one part upon the other, it is called
(a) abductor
(b) regulator
(c) extremor
(d) flexor.
Answer and Explanation:
10. (d): Flexor muscle bends one part of a limb on another at a joint, e.g. biceps. It brings the fore arm towards the upper arm. Flexor work antagonistically with extensors. Abductor (levator) is a type of muscle whose function is to move a limb away from the body. Eg. deltoides of shoulder.
11. Total number of bones in each limb of a man is
(a) 24
(b) 30
(c) 14
(d) 21.
Answer and Explanation:
11. (b): Each arm and each leg contains 30 bones. Flexors work antagonistically with extensors. E.g. each arm contains humerus in the upper arm, radius and ulna in the forearm, 8 carpals in the wrist, 5 metacarpals in the palm and 14 phalanges in the fingers. Each hind limb contains femur in thigh, patella in knee, tibia and fibula in shank, 7 tarsals in ankle, 5 metatarsals in sole and 14 phalanges in toes.
12. The functional unit of contractile system in striated muscle is
(a) sarcomere
(b) Z-band
(c) cross bridges
(d) myofibril.
Answer:
(a) sarcomere
13. Which of the following is the contractile protein of a muscle?
(a) tropomyosin
(b) tubulin
(c) myosin
(d) all of these.
Answer and Explanation:
13. (c): Myosin is a contractile protein of muscle. Primary myofilaments are made up of this protein. Each myosin filament is a polymerised protein made of many monomeric protein called meromyosins. Secondary myofilaments are composed of a protein actin, having with it two regulatory proteins: tropomyosin and- troponin. Myosin interacts with actin to bring about contraction of muscle or cell movement. Tubulin is a protein of which the microtubules of cells are formed.
14. What is the name of joint between ribs and sternum?
(a) cartilaginous joint
(b) angular joint
(c) gliding joint
(d) fibrous joints.
Answer and Explanation:
14. (a): Cartilaginous joint is present between ribs and sternum. It allows only limited movement. An angular joint allows movement in two directions – side to side and back and forth. Wrist and metacarpophalangeal joints are of this type. Gliding joint permits sliding movements of two bones over each other, e.g. joints between sternum and clavicles. Fibrous joints do not allow movement and are present between the bones of cranium.
15. Bone related with skull is
(a) coracoid
(b) arytenoid
(c) pterygoid
(d) atlas.
Answer and Explanation:
15. (c): Pterygoid is a process that extends from sphenoid bone of skull to form a plate like structure. Above the glenoid cavity of scapula is present two processes – acromian and coracoid. Coracoid process is like a hook and is smaller that acromian process projecting upwards. Atlas is first cervical vertebra. Arytenoid is a cartilage that forms part of larynx.
16. Sternum is connected to ribs by
(a) bony matter
(b) white fibrous cartilage
(c) hyaline cartilage
(d) areolar tissue
Answer and Explanation:
16. (c): Sternum is connected to ribs by hyaline cartilage (= giving a shiny glass like appearance and gives flexibility and support at the joints). Sternum is also called breast bone. It is a narrow, elongated and flattened structure, present just under the skin in the middle of front of the chest.
It consists of three parts – manubrium, mesosternum and xiphoid process. Manubrium is the thickest, strongest part and articulates with the clavicle of pectoral girdle and 1st pair of ribs. Mesosternum provide articulation to second to sixth pairs of ribs and xiphoid process (also called metasternum) articulates with seventh pair of ribs in association with mesosternum.
17. Which statement is correct for muscle contraction?
(a) length of H-zone decreases
(b) length of A-band remains constant
(c) length of I-band increases
(d) length of two Z-line increases.
Answer:
(a) length of H-zone decreases
18. Which cartilage is present at the end of long bones?
(a) calcified cartilage
(b) hyaline cartilage
(d) elastic cartilage
(d) fibrous cartilage.
Answer and Explanation:
18. (b): Cartilage is an important component of skeleton. It consists of a firm matrix containing collagen and elastin fibres, and cells in fluid-filled lacunae. Cartilage has many types. Elastic cartilage occurs in the pinna and external auditory canal of the ear, epiglottis, eustachian tubes and tip of the nose to make these organs flexible. Fibrous cartilage is very strong yet has a degree of flexibility.
It is found in the intervertebral discs where it acts as a cushion and in pubic symphysis where it allows parturition without damage to the girdle. Hyaline cartilage occurs in sternal ribs where it allows expansion of chest during inspiration. It also forms the tracheal and bronchial rings, and supports larynx and nasal septum and also at the end of long bones.
19. What will happen if ligaments are torn?
(a) bones will move freely at joint & no pain
(b) bone less movable at joint & pain
(c) bone will become unfixed
(d) bone will become fixed.
Answer and Explanation:
19. (b): Ligaments join a bone with another bone in movable/synovial joints. Torn ligaments make movement at joints very painful and restricted.
20. Which of the following pairs is correctly matched?
(a) hinge joint- between vertebrae
(b) gliding joint- between zygapo- physes of the successive vertebrae
(c) cartilaginous joint- skull bones
(d) fibrous joint- between phalanges.
Answer and Explanation:
20. (b): Gliding joint permits sliding movements of two bones over each other. Hinge joint allows movements in one plane only. Knee joint, elbow joint, ankle joint are of this type. Cartilaginous joint is a slightly movable joint and is found between the centre of vertebrae, at the pubic symphysis and between ribs and sternum. Fibrous joint is an immovable joint which occur between the bones of cranium.
21. An acromian process is characteristically found in the
(a) pelvic girdle of mammals
(b) pectoral girdle of mammals
(c) skull of frog
(d) sperm of mammals.
Answer:
(b) pectoral girdle of mammals
22. The contractile protein of skeletal muscle involving ATP ase activity is
(a) troponin
(b) tropomyosin
(c) myosin
(d) a-actinin
Answer and Explanation:
22. (c): Myosin is a contractile protein that interacts with actin to bring about contraction of muscle or cell movement. The type of myosin molecule found in muscle fibres consists of a tail, by which aggregates with other myosin molecules to form so-called thick filaments and a globular head, which has sites for the attachment of actin and ATP molecule. Troponin, tropomyosin and cc-actinin are the actin in the thin filament.
23. In human body, which one of the following is anatomically correct?
(a) Collar bones – 3 pairs
(b) Salivary glands – 1 pair
(c) Cranial nerves – 10 pairs
(d) Floating ribs – 2 pairs.
Answer and Explanation:
23. (d): Ribs are 12 pairs of bony bars which form the sides of chest cage. Ribs are of 3 types true ribs, false ribs and floating ribs. Anatomically floating ribs are of 2 pairs (11th and 12th). These ribs are imperfectly formed and do not reach the sternum. They protect the kidney. Collar bones (Clavicle) – 2 pairs. Salivary glands – 3 pairs. Cranial nerves – 12 pairs.