Special Senses

What are the chemical senses?

Taste and smell, which rely on chemoreceptors to detect dissolved molecules.

How does capsaicin affect taste perception?

Capsaicin binds to taste receptors, triggering action potentials interpreted as burning, despite no actual heat.

Which cranial nerve is responsible for smell?

Cranial nerve I, which bypasses the thalamus.

What is the function of the olfactory bulbs?

They process smell signals and are the largest evolutionary cranial nerve.

What is the role of the cribriform plate?

It is part of the ethmoid bone with pores for nerve filaments involved in smell.

How does smell influence memory?

Smell profoundly influences memory formation through connections with the hippocampus.

What is the anterior chamber of the eye?

It contains structures like the cornea, iris, pupil, and lens, essential for vision.

What is myopia?

Nearsightedness caused by the cornea being too elongated, focusing images before the retina.

What is hyperopia?

Farsightedness where images focus behind the retina.

What is hyphema?

A medical emergency where blood fills the anterior chamber due to ruptured vessels.

What are the two types of photoreceptors in the retina?

Rods, which detect light/dark, and cones, which detect color.

What is the function of the macula?

It is the retinal region with the highest concentration of cones, responsible for central vision.

What is the fovea centralis?

The center of the macula with maximum cone density, providing the sharpest vision.

What are floaters in the eye?

Chunks of vitreous humor casting shadows on the retina, typically a normal aging process.

What is the inverted retina problem?

In humans, photoreceptors face backward, requiring light to pass through multiple layers before reaching them.

What is the blind spot phenomenon?

A permanent gap in vision where the optic nerve exits the eye, filled in by the brain using surrounding data.

What is sex-linked color blindness?

A condition where males, having only one X chromosome, are more likely to have color vision deficiencies.

What are the three divisions of the ear?

Outer ear (sound collection), middle ear (sound amplification), and inner ear (hearing and balance).

What is the primary function of the Y chromosome?

Male sex determination through the SRY gene, which activates at six days of gestation.

What is trichromatopsia?

A condition of complete color vision loss affecting all three cone types, impacting taste perception.

What is the function of the pinna?

It collects sound waves.

What structure vibrates in response to sound waves in the outer ear?

Tympanic membrane (eardrum)

What are the three ossicles found in the middle ear?

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

What is the purpose of the Eustachian tube?

It connects the middle ear to the nasal pharynx and allows pressure equalization.

What is the cochlea's role in hearing?

It processes sound signals.

What are otoliths and their function?

Calcium carbonate crystals in the utricle and saccule that detect acceleration and deceleration.

What is tinnitus?

Ringing or buzzing in the ears, often due to hair cell damage.

What is the pathway of sound transmission in the ear?

Sound wave → tympanic membrane → ossicles → oval window → cochlea.

What is the organ of Corti?

The hearing sensor located in the cochlea containing hair cells.

How does the cochlea maximize frequency detection?

Its spiral shape increases surface area in a compact space.

What causes noise-induced hearing damage?

Sound exceeding 80 decibels, affecting hair cells and the basilar membrane.

What are the components of the vestibular system?

Semicircular canals, utricle, and saccule.

What is spatial disorientation in aviation?

Incorrect perception of aircraft attitude due to unreliable inner ear signals without visual cues.

What is Meniere's disease?

A balance disorder caused by faulty ampullary signals, lasting 2-3 days.

What is the function of the semicircular canals?

They detect rotational movement.

What is the primary cause of motion sickness?

Conflicting signals between the inner ear and visual system.

What is the role of the vestibulocochlear nerve?

It carries hearing and balance signals to the temporal lobe.

What is a cochlear implant used for?

To treat congenital hearing loss or damaged hair cells by directly stimulating the auditory nerve.

What happens during the Valsalva maneuver?

It equalizes pressure in the middle ear.

What is the duration of debarkment syndrome?

Temporary, occurring post-cruise or flight.

What is the physiological process behind car sickness?

Sensory conflict between the inner ear and visual confirmation leads to nausea.

What is the function of the utricle and saccule?

They detect linear acceleration and gravity.

What can dislodge otoliths and cause balance deficits?

Traumatic injury, such as a baseball bat strike.

What is the significance of hair cell properties in frequency mapping?

Different hair cell lengths detect different sound frequencies.

What do chemoreceptors in the mouth detect?

Dissolved molecules, which are essential for the sense of taste.

What sensation does capsaicin from spicy foods trigger?

An illusion of burning, as it binds to taste receptors without actual heat.

Which cranial nerve is responsible for smell?

Cranial nerve I, which bypasses the thalamus.

What is the function of the olfactory bulbs?

They process smell signals and are the largest evolutionary cranial nerve.

What is the role of the cribriform plate?

It is part of the ethmoid bone that contains pores for olfactory nerve filaments.

How does smell influence memory formation?

Smell connects to the hippocampus, triggering vivid memories associated with familiar scents.

How do primates differ from most mammals regarding olfaction?

Primates primarily rely on vision rather than olfaction, resulting in weaker smell capabilities.

What structures are found in the anterior chamber of the eye?

Cornea, iris, pupil, and lens.

What is the function of the cornea?

It is the outer curved layer of the eye that contains dense nerve endings.

What does the iris control?

The size of the pupil.

What are the two types of vision problems?

Myopia (nearsightedness) and hyperopia (farsightedness).

What is hyphema?

A medical emergency where blood fills the anterior chamber due to ruptured vessels.

What are the two types of photoreceptors in the retina?

Rods (detect light/dark) and cones (detect color).

What is the macula's role in vision?

It is the retinal region with the highest concentration of cones, responsible for central vision.

What is the fovea centralis?

The center of the macula with maximum cone density, providing the sharpest vision.

What are floaters in the eye?

Chunks of vitreous humor casting shadows on the retina, a normal aging process.

What is the inverted retina problem?

In humans, photoreceptors face backward, requiring light to pass through multiple layers before reaching them.

What is the blind spot phenomenon?

A gap in vision created by the optic nerve exit, where the brain fills in missing information.

What is sex-linked color blindness?

A condition where males have no backup X chromosome for color vision genes, leading to higher rates of color blindness.

What are the three divisions of the ear?

Outer ear (sound collection), middle ear (sound amplification), and inner ear (hearing and balance).

What is the primary function of the Y chromosome?

Male sex determination through the SRY gene.

What is trichromatopsia?

A condition of complete color vision loss affecting all three cone types.

What is the function of the pinna?

It collects sound waves.

What structure vibrates in response to sound waves in the outer ear?

Tympanic membrane (eardrum)

What are the three ossicles found in the middle ear?

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

What is the role of the Eustachian tube?

It connects the middle ear to the nasal pharynx and allows pressure equalization.

What is the cochlea responsible for?

It is the hearing organ that processes sound signals.

What structures in the inner ear are responsible for balance?

Semicircular canals and vestibule (utricle and saccule)

What is the function of otoliths?

They detect acceleration and deceleration through movement.

What is tinnitus?

A condition characterized by ringing or buzzing in the ears, often due to hair cell damage.

What is the pathway of sound transmission in the ear?

Sound waves enter the ear, vibrate the tympanic membrane, transmit through ossicles, and reach the cochlea.

What is the organ of Corti?

The hearing sensor located in the cochlea that contains hair cells.

How does frequency mapping occur in the cochlea?

Different hair cell properties detect different frequencies based on their location.

What causes noise-induced hearing damage?

Excessive sound levels over 80 decibels, affecting hair cells and the basilar membrane.

What is the role of the vestibulocochlear nerve?

It carries hearing and balance signals to the temporal lobe.

How do cochlear implants function?

They capture sound, process signals, and stimulate the auditory nerve directly, bypassing damaged hair cells.

What is spatial disorientation in aviation?

It occurs when the vestibular system provides false orientation information without visual cues.

What is Meniere's disease?

A balance disorder caused by faulty ampullary signals, lasting 2-3 days post-travel.

What is debarkment syndrome?

A temporary condition caused by overstimulated balance cells after a cruise or flight.

What is the physiological process behind motion sickness?

It occurs when there is a sensory conflict between the inner ear and visual systems.

What factors increase the risk of motion sickness in the back seat of a car?

Limited visibility, high sensory conflict, and inability to predict motion.

What happens to the utricle and saccule in a zero-G environment?

Their function is disabled, leading to sensory conflict and motion sickness.