Exercise 25 Review Sheet Art-Labeling Activity 1 (2024)

FAQs

What is the role of the endolymph of the semicircular ducts? ›

The vestibular apparatus is composed of the utricle, saccule, and three semicircular ducts. The acceleration of endolymph within regions of the vestibular apparatus allows for our perception of balance and equilibrium.

Receptors for two sensory modalities (hearing and equilibrium) are housed in the ear. The external ear, the middle ear, and the cochlea of the inner ear are involved with hearing. The semicircular canals, the utricle, and the saccule of the inner ear are involved with equilibrium.

Hearing disorders

It is spanned by a chain of three tiny bones—the malleus, incus and stapes, collectively called the auditory ossicles. This ossicular chain conducts sound from the tympanic membrane to the inner ear, through an aperture in the bony inner ear known as the oval window.

Vibration of the stapes transmits the sound wave via the oval window to the scala vestibuli, generating fluid waves in the perilymph. The displacement of the perilymph causes a wavelike displacement of the basilar membrane and organ of Corti, ultimately causing distention of the round window membrane.

The semicircular canals are three tiny, fluid-filled tubes in the inner ear that help you keep your balance.

-Cochlear duct: fluid waves in the endolymph of the cochlear duct stimulate the receptor cells, which in turn translate their movement into nerve impulses that the brain perceives as sound.

Your inner ear has three main parts: your cochlea, semi-circular canals (labyrinth) and your vestibule. Your cochlea supports your hearing and your vestibule and semi-circular canals support your balance.

Vestibulocochlear nerves (VIII)

The vestibular nerve handles balance and equilibrium, while the cochlear nerve is responsible for hearing. The vestibulocochlear nerves originate in the monitoring receptors of the internal ear—the vestibule and cochlea.

There are two sets of end organs in the inner ear, or labyrinth: the semicircular canals, which respond to rotational movements (angular acceleration); and the utricle and saccule within the vestibule, which respond to changes in the position of the head with respect to gravity (linear acceleration).

The function of the ossicles (malleus, incus, and stapes) is to conduct physical auditory waves from the outer ear to the inner ear.

Which ossicular bone is the largest? ›

The largest of the ossicles, the malleus has: A head. A neck. A handle (called the manubrium)

The auricle (pinna) is the visible portion of the outer ear. It collects sound waves and channels them into the ear canal (external auditory meatus), where the sound is amplified. The sound waves then travel toward a flexible, oval membrane at the end of the ear canal called the eardrum, or tympanic membrane.

Microanatomy. The walls of the hollow cochlea are made of bone, with a thin, delicate lining of epithelial tissue. This coiled tube is divided through most of its length by an inner membranous partition. Two fluid-filled outer spaces (ducts or scalae) are formed by this dividing membrane.

The tympanic membrane is also called the eardrum. It separates the outer ear from the middle ear. When sound waves reach the tympanic membrane they cause it to vibrate. The vibrations are then transferred to the tiny bones in the middle ear.

Three extracellular fluids have been identified in the cochlea: endolymph, perilymph and intrastrial fluid (Table 1; Wangemann & Schacht, 1996).

The physiology of the endolymphatic sac and its role in longitudinal endolymph flow. The ELS has absorptive and secretory functions as well as phagocytic and immune defence functions. It has been known for many years that debris placed into the cochlear duct passes to the ELS.

The three semicircular canals are endolymph-filled rings specialized to detect angular acceleration. Each canal has a swelling, called the ampulla (Figure 1(c)), which contains the mechanoreceptive epithelium (the ampullary crista). In humans, each crista bears about 7000 hair cells.

Located in the inner ear, the semicircular canals are three very small tubes whose primary job is to regulate balance and sense head position.

Scientists believe that the endolymphatic duct and sac help to ensure that the fluid in the inner ear contains the correct amounts of certain chemicals called ions. Ions are needed to help start the nerve signals that send sound and balance information to the brain.