BIO 250 Exam 2 Special Senses

Hearing

One of the two senses of the ear, responsible for perceiving sound.

Equilibrium

The sense of balance, maintained by the inner ear.

Mechanoreceptors

Receptors in the ear stimulated by motion, triggering action potentials.

Vestibulocochlear nerve

The nerve that transmits sensory information from the ear to the brain.

Tympanic membrane

Also known as the eardrum; it separates the external ear from the middle ear.

External acoustic meatus

The auditory canal that leads into the ear.

Auricle (pinna)

The visible part of the outer ear that helps to gather sound.

Ossicles

Three tiny bones in the middle ear: malleus, incus, and stapes.

Cochlea

The spiral-shaped organ in the inner ear responsible for hearing.

Static equilibrium

Balance maintained when the head is stationary, related to the vestibule.

Dynamic equilibrium

Balance maintained during head movements, related to semicircular canals.

Spiral organ of Corti

The structure within the cochlea, containing hair cells that detect sound.

Pressure waves

Waves created by sound that travel through fluid in the cochlea.

Hearing loss

A condition resulting from disruptions in sound wave transmission or damage to the nervous system structures involved in hearing.

High-pitch sounds

Sounds that stimulate short, stiff fibers of hair cells in the basilar membrane.

Low-pitch sounds

Sounds that stimulate longer, floppy fibers of hair cells further along the cochlea.

General Senses

Senses located throughout the entire body, including temperature, pressure, touch, and pain receptors.

Special Senses

Senses that have dedicated organs; include sight, hearing, smell, taste, and balance.

Proprioceptors

Receptors that sense stretch and tension in muscles and joints.

Conjunctivitis

Inflammation of the conjunctiva, often referred to as 'pink eye'.

Lacrimal Apparatus

Components including lacrimal glands and ducts that produce and drain tears.

Extrinsic Eye Muscles

Six muscles outside the eyeball responsible for moving the eyes.

Sclera

Outer fibrous layer of the eyeball, known as the 'white' of the eye.

Cornea

Transparent, central part of the sclera that allows light to pass through.

Choroid

Middle layer of the eye that is highly vascularized and pigmented to absorb light.

Iris

Part of the eye that controls the size of the pupil and hence the amount of light entering.

Ciliary Body

Intrinsically modifies the shape of the lens to enable focusing.

Retina

Inner layer of the eye containing photoreceptor cells that detect light.

Photoreceptor Cells

Cells in the retina (rods and cones) that are stimulated by light and trigger action potentials.

Fovea Centralis

The area on the retina responsible for sharp central vision.

Accommodation

The process by which the lens changes shape to focus on near or distant objects.

Myopia

Nearsightedness, where distant objects appear fuzzy.

Hyperopia

Farsightedness, where near objects appear fuzzy.

Astigmatism

A condition where vision is distorted due to irregularities in the cornea or lens.

Auricle (Pinna)

The external part of the ear that captures sound waves.

Tympanic Membrane

Also known as the eardrum, it vibrates in response to sound waves.

Cochlea

The inner ear structure that contains the sensory organ for hearing.

Organ of Corti

The sensory organ within the cochlea that contains hair cells for hearing.

Conductive Hearing Loss

Hearing loss caused by disruption in sound wave transmission through the external or middle ear.