The parts of the ear that function in static equilibrium are located within the vestibular system, specifically within the utricle and saccule. These structures are part of the inner ear and are filled with fluid and contain specialized sensory cells called hair cells.

Here's a breakdown:

* Utricle and Saccule: These are two small, fluid-filled sacs located in the inner ear.

* Utricle: Senses horizontal linear acceleration and head tilt.

* Saccule: Senses vertical linear acceleration and head tilt.

* Hair Cells: These cells are embedded in a gelatinous membrane called the otolithic membrane. Tiny crystals called otoliths are embedded within this membrane.

* Otoliths: These crystals are denser than the surrounding fluid, so when the head moves, the otoliths shift due to inertia. This shift bends the hair cells.

* Neural Signals: The bending of hair cells triggers nerve impulses that travel to the brain via the vestibulocochlear nerve. The brain interprets these signals to determine head position and movement in relation to gravity.

Static equilibrium refers to the sense of balance when the body is stationary. The utricle and saccule constantly monitor the position of the head relative to gravity, providing information for maintaining balance when the head is still.