Special Senses

Question 1

Gustatory cells are

Answer 1

Epithelial cells

Question 2

Alkaloids excite gustatory hairs mostly at the

Answer 2

back of the tongue and circumvallate papillae

Question 3

cranial nerves that are part of the gustatory pathway include

Answer 3

Facial & glossopharyngeal

Question 4

This cranial nerve controls contractions of the circular smooth muscle of the iris

Answer 4

Oculomotor

Question 5

The cornea is nourished by

Answer 5

aqueous humor

Question 6

In focusing for far vision

Answer 6

The lens is at its thinnest; the light rays are nearly parallel

Question 7

Convergence

Answer 7

Requires contraction of the medial rectus muscles of both eyes

Question 8

These are paired correctly

Answer 8

Vestibule-Macula

Semicircular duct-ampulla

Question 9

Movement of the ____ membrane triggers bending of hairs of the hair cells in the spiral organ of Corti

Answer 9

Tectorial

Question 10

Sounds entering the external acoustic meatus are eventually converted to nerve impulses via a chain of events including

Answer 10

• vibration of the eardrum
• vibratory motion of the ossicles against the oval window
• stimulation of hair cells in the spiral organ of Corti

Question 11

Name 3 accessory eye structures that help to lubricate the eyeball, and name the secretion of each.

Answer 11

-Lacrimal Glands: Saline solution & lysosomes
-Tarsal & Ciliary glands: Oily secretion
-Conjuctiva: Mucous


Question 12

Why do you often have to blow your nose after crying?

Answer 12

The lacrimal secretions drain via the nasolacrimal duct into the nasal cavities

Question 13

Diagram & label the internal sturctures of the eye & give the major function of each strucuture.

Answer 13

• —Internal Structures
• Lens: Major focusing apparatus of the eye
• Retina: Light (photoreceptive) sensitive area
• Choroid: The nutritive (vascular) coat of the eye
• Ciliary Body & Ciliary Zonule: Smooth muscle structure that regulates the shape of the lens for focusing.
• Iris: Smooth muscle structure that controls the amount of light entering the eye
• Sclera: Protective (fibrous) coat
• Cornea: Transparant part of the sclera that allows light to enter the eye
• Pupil: Opening through which light passes
• Aqueous Humor: Helps maintain interocular pressure & provide nutrients to the lens & cornea
• Scleral venous sinus: Reabsorbs aqueous humor in the bloodstream
• Vitreous humor: Helps prevent the eyeball from collasping inward
• Fovea Centralis: Contains only cones & is the area w/the greatest visual acuity
• Optic Nerve: Transmits nerve impulses to the optic cortex
• Optic Disc: Blind spot where nerve leaves eyeball
• Central Artery & Vein of the retina”: Provides nutrients & removes waste products

Question 14

Name the extrinsic eye muscles that allow you to direct your eyes

Answer 14

Superior, Inferior, lateral, & medial rectus muscles; & the superior & inferior oblique muscles

Question 15

Describe the 2 humors of the eye

Answer 15

• Vitreous Humor: Posterior to the lens; Reinforces eyeball

- Aqueous Humor: Anterior to lens; Reinforces eyeball & provide nutrients to the avascular lens & cornea

Question 16

What is the “blind spot” and why is it called this?

Answer 16

The portion of the retina w/no photoreceptors bcuz it is the site at which the optic nerve leaves the eyeball. Light focused on this spot is not converted into vision or photoreception.

Question 17

The structure that controls light entry into the eye

Answer 17

Iris

Question 18

What is the fovea centralis & why is it important?

Answer 18

A small pit in the retinal layer that contains cones only is located lateral to the optic disk in each eye. Anything that must be viewed (discriminative vision) is focused on the fovea bcuz its the area of greatest visual acuity.

Question 19

Trace the pathway of light from the time it hits the cornea until it excites the rods & cons

Answer 19

Cornea to aqueous humor, through pupil to aqueous humor to lens to vitreous humor to retina. The path of light goes through the ganglion cells 1st, then the bipolar cells before stimulating the rods & cones.

Question 20

Trace the pathway of nerve impulses from the photoreceptors in the retina to the visual cortex of the brain

Answer 20

Photoreceptors (rods & cones) to bipolar cells to ganglion cells to optic nerve through the optic chiasm to optic tract to thalamus to visual cortex in the occipital lobe via the optic radiation

Question 21

Define: Hyperopia; Myopia;

Answer 21

• Hyperopia: Farsightedness; The individ. has no problem with distance vision, which requires no accomadation; In near vision the image is focused behind the retina bcuz of a lazy lens or foreshortened eyeball
• Myopia: Nearsightedness; The individ has no problem with near vision, but in distance vision the image is focused anterior to the retina bcuz of an overly strong lens, an elongated eyeball, or a cornea that’s too curved.
• Emmetropia: Normal vision

Question 22

Why do most people develop presbyopia as they age? Which of the conditions in quest 21 does it resemble?

Answer 22

As we age the lens loose their elasticity, causing it to focus less acutly for close vision; Hyperopia

Question 23

There are only 3 types of cones. How can you explain the fact that we see many more colors?

Answer 23

When 2/more different cone types are stimulated simultaneously the color perceived is intermediate (in wavelength/light) btw them. Thus the stimulation of red & green cones produces the sensation of yellow; when all cones are simultaneously excited, we perceive white (white= all colors).

Question 24

why are ophthalmoscopic exams important?

Answer 24

they allow the examiner to determine the condition of the retina, as well as the the optic disc & internal vessels. Many blood vessel problems (ex: high bp, diabetes mellitus) and degeneration of the optic nerve and/or retina can be detected early from this exam. Its extremly import. in diagnosis.

Question 25

Why is it more of a strain on the extrinsic & intrinsic muscles to look at close objects than at far objects?

Answer 25

Close vision involves both convergence & accommodation. Convergence requires the activation of the external eye muscles & the ciliary body within the eye. Distance vision requires none of these specific muscle actions bcuz this position is when the eye is at rest.

Question 26

Name the structures of: outer, middle & inner ears and give the general function of each structure and each group of structures.

Answer 26

• Outer Ear: The auricle (pinna) has no function in humans. The external acoustic meatus conducts sound vibrations from the external enviroment to the tympanic membrane (eardrums), which is involved in hearing only.
• Middle Ear: The ossicles, which span the tympanic cavity, conduct vibrations received from the tympanic membrane to the oval window& fluids of the inner ear. The pharyngotympanic tube allows middle ear pressures to be equalized with those of the atmosphere. Involved in hearing only
• Inner Ear: Semicircular canals, vistibule, cochlea are all part of the bony labyrinth. The semicircular canals & vestibule function in equilibrium maintenance, whereas the cochlea functions in hearing.

Question 27

Trace the pathway of vibration from the eardrum to the spiral organ of Corti, where the hair cells are stimulated.

Answer 27

Eardrum–>ossicles (Hammer–>Anvil–>Stapes)–>Oval window–>Perilymph in the bony cochlea–>membraneous labyrinth–>endolyphy–>cochlear duct–>basilar membrane–>Organ of Corti

Question 28

Give 2 causes of conduction deafness.

Answer 28

-Cond. deafness arises from any interference with the outer to inner ear due to ear wax accumulations, otitis media, fusion of the ossicles or pressure imbalance btw the middle and outer ear

Question 29

Normal balance depends on info transmited from a number of sensory receptor types. Name 3 types.

Answer 29

-Inner ear vestibular apparatus (maculae in the vestibule & cristae ampullaris in the semicircular canals), eyes, proprioceptors of muscles & tendons

Question 30

What name is given to the taste receptors

Answer 30

Gustatory cells.
*In the taste buds-primarily in the paplillae on the tongue, but also in the buccal mucosa & on the palate & the pharynx mucosae.

Question 31

the 5 primary taste senses

Answer 31

sweet, sour, bitter, salty, umani

Question 32

Where are the olfactory receptors located, and why is that site poorly suited for their job?

Answer 32

In the superiormost mucosa of the olfactory pasageways. This is a poor site functionally bcuz most air (which carries odors) passes inferior to this site.

Question 33

Describe the effects or results of aging on the special sense organs.

Answer 33

Presbyopia

Question 34

What special sense requires the most learning?

Answer 34

Vision; Babies can initially focus on near objects; The eye must 1st enlarge, then external muscles coordination must develop, as must ability and color vision.Depth perception develops realtivly late, maturing just before school age.

Question 35

For each statment indicate where it applies to a macual or a crista (Check)

Answer 35

Crista Ampullaris- Inside a semicircular canal; Has a cupula; Responds to rotational acceleration and deceleration
Macuala-Contains Otoliths; Responds to linear acceleration and deceleration; Inside a vestibule