Answer
Answer (b). Maculae
Maculae are equilibrium receptors within utricle or saccule which are membranous sacs within the bony vestibular cavity. The hair cells of the maculae respond to changes in the pull of gravity. Gravity changes the shape of the otoconial membrane. When this membrane presses on the cilia of the hair cells, it generates impulses. These impulses carry information to the brain regarding changes in vertical and horizontal orientation of the head. The brain sends back efferent impulses to muscles that adjust the position of head and neck appropriately.
Work Step by Step
The maculae of utricle and saccule have sensitive hair cell receptors that respond to changes in the pull of gravity. Changes in horizontal or vertical orientation of the head cause the gel-like otolith membrane to press on the cilia of the hair cells of the maculae, This pressure generates impulses which are transmitted to centers in the brain for integration and interpretation. The maculae of the utricle responds to changes in the horizontal plane ; the receptors of the saccule respond to changes caused by vertical ( rising and falling) motions. Sensory inputs go to brainstem nuclei, cerebellum and cerebral cortex. Motor outputs , modified by feed backs, go to skeletal muscle of limbs, trunk as well as eye muscles .
