Sense Organs — Important Questions

To produce oil and wax

Sebaceous glands in the external ear produce oil, while ceruminous glands produce wax. Together, they keep the ear canal lubricated and prevent dust and harmful particles from entering deeper into the ear. Tears are produced by lacrimal glands in the eye, sound detection occurs through hair cells in the cochlea, and balance is maintained by the vestibular apparatus in the inner ear.

Dermis

The dermis is the deeper layer of skin that contains most sensory receptors including tactile receptors for touch, pacinian corpuscles for pressure, and temperature receptors. The epidermis is the protective outer layer with fewer receptors. The subcutaneous layer is mainly fat tissue, and the stratum corneum is the outermost dead cell layer of the epidermis with no functional receptors.

Point where optic nerve leaves the eye

The blind spot occurs at the point where the optic nerve exits the eye and connects to the brain. At this location, there are no photoreceptors (rods or cones), so no light can be detected there. We don't normally notice this blind spot because our brain fills in the missing information and our two eyes cover each other's blind spots. Lens damage, corneal clouding, or weak eye muscles cause different vision problems.

Semicircular canals

The semicircular canals in the inner ear are responsible for maintaining body balance and detecting head movements. These three curved tubes are filled with endolymph fluid and contain sensors that detect rotation and tilting. The cochlea is for hearing, the eardrum vibrates with sound, and the pinna collects sound waves. The semicircular canals work with the vestibule to form the vestibular apparatus for balance.