Chapter 8 - Special Senses PowerPoint

What are the special senses?

Smell, taste, sight, hearing, and equilibrium.

What is the function of the accessory structures of the eye?

They include components like eyelids, extrinsic eye muscles, and lacrimal apparatus that aid in protection, movement, and moisture.

What are the basic functions of the nervous system in relation to special senses?

They gather sensory information that influences motor output and is processed in specialized areas of the cerebrum.

What is the main function of tears?

To cleanse, protect, moisten, and lubricate the eye.

What is the fibrous layer of the eyeball composed of?

It consists of the sclera and cornea.

What role do photoreceptors play in vision?

They are cells in the retina that detect light; rods help in dim light, and cones allow for color vision.

What is the purpose of the lens in the eye?

To focus light onto the retina and change shape for focusing on objects at varying distances.

How do sound vibrations travel from the outer ear to the inner ear?

They travel through the auricle, auditory canal, tympanic membrane, ossicles, oval window, and into the cochlea.

What are the two components of the vestibular apparatus?

Static equilibrium and dynamic equilibrium.

What are the five basic taste sensations?

Sweet, sour, bitter, salty, and umami.

What causes presbyopia?

Decreasing lens elasticity that can occur with aging.

What are the major organs responsible for hearing and balance?

The structures in the inner ear including the cochlea and vestibular apparatus.

How do aging affects taste and smell?

Taste and smell sensitivity decreases after age 40 due to a reduction in the number of receptors.

Where are olfactory receptors located?

In the roof of the nasal cavity.

What type of receptors are responsible for detecting sound vibrations in the cochlea?

Hair cells within the spiral organ of Corti.

What is convergence in terms of eye reflexes?

The reflexive movement of the eyes medially when focusing on a close object.

What is the role of the optic chiasma?

It is the location where the optic nerves cross and fibers from the medial side of each eye switch sides.

What is the function of the cornea?

To refract light and provide protection to the eye.

What is color blindness?

A genetic condition where individuals are unable to distinguish between certain colors, usually involving the cones of the retina.

What is the role of the eardrum?

To vibrate in response to sound waves, transmitting them to the middle ear.

What is the trigeminal nerve's connection to the special senses?

It transmits sensory information from the face, including sensations related to taste.

How does light adaptation occur in the eye?

It involves the adjustment of photoreceptors to changes in light intensity.

What is the role of the semicircular canals?

To help maintain balance by detecting rotational movements of the head.

What are taste buds?

Structures on the tongue that contain receptors for taste.

What is the difference between static and dynamic equilibrium?

Static equilibrium maintains balance when the body is stationary, while dynamic equilibrium helps maintain balance during movement.

How does the auditory tube function?

It connects the middle ear to the nasopharynx, helping to equalize pressure.

What is hyperopia?

A condition where distant objects are seen clearly, but close objects are blurry, due to the eye being shorter than normal.

What is the role of the retina in vision?

To convert light into neural signals that are transmitted to the brain.

What are the two types of photoreceptors in the retina?

Rods and cones.

What is the function of the auditory ossicles?

To amplify sound vibrations from the tympanic membrane to the inner ear.

What is the function of the lacrimal glands?

To produce tears that lubricate and protect the eye.

What part of the ear is responsible for balance?

The vestibular apparatus.

What is the main purpose of the pupil?

To control the amount of light entering the eye.

How does sound localization occur?

Through the brain processing the time and intensity differences of sound reaching each ear.

What is the difference between a cochlear implant and a hearing aid?

A cochlear implant directly stimulates the auditory nerve, while a hearing aid amplifies sound.

What are the consequences of damage to the auditory nerve?

It can lead to hearing loss or impairment.

What is the role of the pinna (auricle) in hearing?

To collect and funnel sound waves into the ear canal.

What is hyperopia (farsightedness)?

A condition where near objects are blurry, whereas distant objects are clear.

What causes hyperopia?

It occurs when distant objects are focused behind the retina, often due to an eyeball that is too short or a 'lazy lens.'

What is the middle ear cavity (tympanic cavity)?

It is the air-filled space in the ear that contains the three ossicles.

What are the three bones (ossicles) found in the middle ear cavity?

Malleus (hammer), Incus (anvil), and Stapes (stirrup).

What is the primary function of the ossicles in the middle ear?

To transmit and amplify vibrations from the tympanic membrane to the fluids of the inner ear.

How do vibrations travel through the ossicles?

Vibrations travel from the hammer (malleus) to the anvil (incus), then to the stirrup (stapes), and finally to the oval window of the inner ear.

Pathway of sound vibrations from the auricle to the cochlea

1. Auricle (pinna) 2. External acoustic meatus (auditory canal) 3. Tympanic membrane 4. Ossicles amplify the sound waves 5. Oval window 6. Basilar membrane in the spiral organ of Corti 7. Hair cells of the tectorial membrane are bent by vibrations.

What is the function of the oval window?

To transmit vibrations from the ossicles into the cochlea.

What is the role of the basilar membrane?

To support the organ of Corti and vibrate in response to sound waves.

What happens to the hair cells during sound stimulation?

They are bent when the basilar membrane vibrates against the tectorial membrane, leading to the generation of electrical signals.

What is the role of the tympanic membrane?

To convert sound waves into mechanical vibrations that are transmitted to the ossicles.

What do the ossicles consist of?

The three bones: malleus (hammer), incus (anvil), and stapes (stirrup), which amplify sound vibrations.

How do sound waves begin their journey through the ear?

They are collected by the auricle (pinna) and funneled into the auditory canal.

What is the purpose of the external acoustic meatus?

To channel sound waves from the auricle to the tympanic membrane.

What initiates an action potential in the auditory pathway?

An action potential starts in the cochlear nerve (cranial nerve VIII) in response to sound vibrations.

Where do auditory impulses travel after the cochlear nerve?

Auditory impulses travel to the auditory cortex in the temporal lobe for sound processing.