MODULE 8 MAIN POINTS Q+A

What are the five special senses

Olfaction, gustation, hearing, equilibrium, vision.

What are the main components of the olfactory system

Olfactory epithelium, olfactory receptors, olfactory bulb, olfactory tract, olfactory cortex.

What is the olfactory pathway

Olfactory receptors → CN I → olfactory bulb → olfactory tract → olfactory cortex.

What are the main components of the gustatory system

Taste buds, taste receptors, CN VII, CN IX, CN X, brainstem, thalamus, gustatory cortex.

What are the five primary tastes

Sweet, sour, salty, bitter, umami.

How are the five tastes transduced

Sweet, bitter, umami use GPCRs; salty and sour use ion channels.

What are anosmia and ageusia

Anosmia = loss of smell; ageusia = loss of taste.

What are the main structures of the auditory system

Outer ear, tympanic membrane, ossicles, cochlea, Organ of Corti, CN VIII.

What is the auditory pathway

Cochlea → CN VIII → brainstem → thalamus → auditory cortex.

Where do high- and low-frequency sounds vibrate the basilar membrane

High frequencies = base; low frequencies = apex.

How does the brain localize sound

By comparing the timing and intensity of sounds reaching each ear.

What are the two types of hearing loss

Conductive = outer/middle ear; sensorineural = inner ear/nerve.

What detects rotational vs. linear movement in the vestibular system

Semicircular canals = rotational; utricle and saccule = linear/gravity.

How does the vestibular system maintain gaze stability

The vestibulo-ocular reflex moves the eyes opposite head movement.

What are the major structures of the eye

Cornea, iris, pupil, lens, retina, rods, cones, optic nerve, fovea.

What happens during accommodation for near vision

Ciliary muscle contracts and the lens becomes rounder/thicker.

How is an image projected onto the retina

The cornea and lens refract light and focus the image onto the retina.

What is the visible light range and what do the cones detect

400–700 nm; S = blue, M = green, L = red.

What happens during phototransduction in light vs. dark

Dark = depolarized; light = hyperpolarized.

What is the visual pathway

Retina → CN II → optic chiasm → optic tract → thalamus → optic radiations → visual cortex.

How are visual fields represented in the brain

Right visual field → left brain; left visual field → right brain.

What are the effects of AMD, diplopia, diabetic retinopathy, and visual field deficits

AMD = central vision loss; diplopia = double vision; diabetic retinopathy = retinal damage; visual field deficit = loss of part of vision.