Chapter 16 - Special Senses

Receptors are not free endings of sensory neurons. There are _____ _______ cells.

special receptor

What does gustation refer to

taste

Where are taste receptors located

taste buds within tongue papillae

Are there structural differences among taste buds

no

Primary cranial nerves for gustation

facial (anterior) and glossopharyngeal (posterior)

Where are the majority of sensory cell receptors in the body

in the eye

External wall of eye is composed of what three tunics. What are they?

Fibrous, vascular, sensory

The interal cavity of the eye contains what

Fluid (aqueous and vitreous humors)

What is the most external layer of the eye

fibrous tunic

What are the two regions of the fibrous tunic

sclera (posterior 5/6) and cornea (anterior 1/6)

Sclera is what region of the eye

white, opaque region; provides anchoring sight for muscles 

Is the cornea vascular or avascular

avascular

The middle coat of the eyeball is what?

vascular tunic

what makes up the vascular tunic? (3 elements)

Choroid, ciliary body and iris

what is the choroid

vascular, darkly pigmented membrane; makes up poster 5/6

What is the iris

visible part of the eye; composed of smooth muscle

Sensory tunic is the deepest layer and is commonly called what

retina

Two types of photoreceptors

rods and cones

Which photoreceptor is more sensitive to light

rod cells

which photoreceptor enables color vision

cone cells

Posterior segment (cavity) is filled with what

vitreous humor

What does vitreous humor do and how is it unique

helps maintain intraocular pressure; it does not regenerate

Anterior segment is filled with what

aqueous humor

what is special about aqueous humor

renewed continuously and supplies nutrients to avascular tissues like the lens and cornea

Where does most visual information travel

cerebral cortex; responsible for conscious seeing

Which fibers reach the primary visual cortex

fibers of the optic radiation

Information in the left visual field goes to which part of the brain

right side of brain

What makes up the outer ear

Auricle (pinna), external acoustic meatus and the tympanic membrane (ear drum)

What does the tympanic membrane do?

forms boundary between external and middle ear

What makes up the middle ear

tympanic cavity, pharyngotympanic tube, three bones

Where is the tympanic cavity

in the petrous portion of the temporal bone

what does the pharyngotympanic tube do

links middle ear and pharynx

What are the bones of the inner ear

Malleus, Incus, and Stapes

Where does the malleus attach

to the tympanic membrane

where is the incus

between the malleus and stapes

what does the stapes do

vibrates against the oval window

What is the inner ear called

the labyrinth

Where is the inner ear

within the petrous portion of the temporal bone (inner)

What does the bony labyrinth consist of

semicircular canals, vestibule and cochlea

what is the membranous labyrinth

membrane walled sacs and ducts that fill the bony labyrinth

What are the the three main parts of the membranous labyrinth

semicircular ducts, utricle and saccule (in vestibule) and cochlear duct

What is the membranous labyrinth filled with

endolymph

what is the bony labyrinth filled with

perilymph

What are the functions of the semicircular canals

equilibrium and rotational acceleration of head

what is the function of the vestibule

equilibrium, static equilibrium and linear acceleration of head

what is the function of the cochlea

hearing

what are the utricle and saccule suspended in

perilymph

Where is the macula

in the vestibule

what does the macula do

monitors the position of the head at equilibrium

what are in the macula

hair cells synapse on vestibular nerve

how many semicircular canals are there and how are they orientated from each other

there are 3 and they are 90 degrees from each other (3 planes)

Membranous ampulla is in the semicircular ducts. The ampulla contains what?

crista ampullaris (able to detect rotational acceleration)

The cochlear duct contains receptors for hearing. These are in what structure?

Organ of corti

What is the role of the round window

relieve pressure

Equilibrium pathway goes where in the brain

Lower brain centers (reflex center)

Ascending auditory pathway goes where in the brain?

cerebral cortex