Explain what phenomena happen when the following muscles contract —
(a) Flexor muscle
(b) Extensor muscle
(c) Abductor muscle
(d) Rotator muscle
WBBSE
Class X
Life Science
01 (e) Locomotion as a type of response in Animals
02 Mark
2022
| (a) Flexor muscle | When a flexor contracts, it bends a joint. Example — contraction of the biceps bends the elbow. |
| (b) Extensor muscle | When an extensor contracts, it straightens a joint. Example — contraction of the triceps straightens the elbow. |
| (c) Abductor muscle | When an abductor contracts, it moves a body part away from the midline. Example — the deltoid moves the arm away from the body. |
| (d) Rotator muscle | When a rotator contracts, it rotates a limb around its axis. Example — rotation of the arm is caused by the rotator cuff muscles. |
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