WBBSEClass XLife Science01 (e) Locomotion as a type of response in Animals02 Mark2022 Easy

QQuestion

Explain what phenomena happen when the following muscles contract —

(a) Flexor muscle

(b) Extensor muscle

(c) Abductor muscle

(d) Rotator muscle

Exam-ready answer 02 Mark

Answer

(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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