Final answer:
The vestibular system in the inner ear contains the maculae, which are specialized receptors that detect the body's position with respect to gravity by responding to linear accelerations.
Step-by-step explanation:
The position of the body with respect to gravity is detected by cells in the vestibular system. The vestibular system, located in the inner ear, contains specialized receptors called maculae. These receptors are sensitive to linear acceleration, such as when gravity acts on the tilting head. The maculae consist of hair cell stereocilia embedded in an otolithic membrane.
When the head moves or tilts, the difference in inertia causes a shearing force that bends the stereocilia in the direction of the linear acceleration. This bending generates nerve signals that the brain interprets as changes in head position regarding gravity. This sensory information is crucial for maintaining balance and spatial orientation.