Special Senses

Question 1

• Situated in the orbital cavity and supplied by the optic nerve (2nd cranial nerve).
• Almost spherical in shape and about 2.5 cm in diameter.
• Space between the eye and the orbital cavity is occupied by adipose tissue.
• The bony walls of the orbit and the fat protect the eye from injur

Answer 1

EYES and SIGHT

Question 2

-(white of the eye) forms the outermost layer of the eyeball

-Consists of a firm fibrous membrane that maintains the shape of the eye
-Gives attachment to the extrinsic muscles of the eye

Answer 2

Sclera

Question 3

Sclera continues as a clear transparent epithelial membrane, ____________

Answer 3

cornea

Question 4

Light rays pass through the cornea to reach the _____________

Answer 4

retina

Question 5

• Lines the posterior five-sixths of the inner surface of the sclera.
• Very rich in blood vessels
• Deep chocolate brown in color.

Answer 5

Choroid

Question 6

Light enters the eye through the _______________

Answer 6

pupil

Question 7

stimulates the sensory receptors in the ____________

Answer 7

retina

Question 8

• The anterior continuation of the choroid consisting of ciliary muscle (smooth muscle fibers) and secretory epithelial cells
• Acts like a sphincter
• Supplied by parasympathetic branches of the oculomotor nerve (3rd cranial nerve).

Answer 8

Ciliary Body

Question 9

• Visible colored ring at the front of the eye lying behind the cornea and in front of the lens.
• Composed of pigment cells and two layers of smooth muscle fibers - one circular and the other radiating

Answer 9

Iris

Question 10

In the center is an aperture called the ________________

Answer 10

pupil

Question 11

• Highly elastic circular biconvex body, immediately behind the pupil.

*Thickness is controlled by the ciliary muscle through the suspensory ligament.

Answer 11

Lens

Question 12

*Innermost lining of the eye

*Extremely delicate structure and well adapted for stimulation by light rays

*Composed of several layers of nerve cell bodies and their axons - sensory receptor cells, rods and cone

Answer 12

Retina

Question 13

▪Skin, muscle, and connective tissue

Answer 13

Eyelids

Question 14

✓Prevents surface from drying out
✓Keeps foreign material out of eye

Answer 14

Blinking

Question 15

▪Eye sockets
▪Form a protective shell around the eyes

Answer 15

Eye orbits

Question 16

✓Lateral edge of eyeballs
✓Produce tears

Answer 16

Lacrimal glands

Question 17

✓Medial aspect of eyeballs
✓Drain tears into nose

Answer 17

Nasolacrimal ducts

Question 18

impairment of distance vision

Answer 18

Myopia

Question 19

impairment of near vision

Answer 19

Hyperopia

Question 20

▪ Distinguish shades of gray
▪ Testing
* Pelli-Robson contrast sensitivity chart
* Vistech Consultants vision contrast system
▪ Detect cataracts or retinal problems before sharpness is impaired

Answer 20

Contrast sensitivity

Question 21

▪ Color-blindness
* May be inherited
* More common in males
▪ Tests
* Ishihara color system
* Richmond pseudoisochromatic color test
▪ Difficulties may indicate retinal or optic nerve disease

Answer 21

Color vision

Question 22

Many animals secrete odorous chemicals called __________ play an important part in chemical communication in, for example, territorial behavior, mating and the bonding of mothers and their newborn.

Answer 22

pheromones

Question 23

▪the sensory nerves of smell

Answer 23

Olfactory receptors

Question 24

respond to changes in chemical concentrations

Answer 24

Chemoreceptors

Question 25

concentrates volatile molecules in the roof of the nose- increases the number of olfactory receptors stimulated and thus perception of the smell

Answer 25

Sniffing

Question 26

*Chemical can stimulate receptors for limited time *Receptors fatigue and stop responding to chemical * No longer smell odor

Answer 26

Sensory Adaptation

Question 27

Taste buds contain chemoreceptors

Answer 27

found in the papillae of the tongue

Question 28

where taste is perceived

Answer 28

Parietal lobe of the cerebral cortex

Question 29

3 Different types of papillae

Answer 29

-vallate papillae -fungiform papillae -foliate papillae

Question 30

form a row at the back of the tongue

Answer 30

vallate papillae

Question 31

mushroom-shaped and are scattered over the entire surface of the tongue

Answer 31

fungiform papillae

Question 32

located in small trenches on the lateral margins of the tongue, but most of their taste buds degenerate in early childhood

Answer 32

foliate papillae

Question 33

3 CRANIAL NERVES IN TONGUE

Answer 33

-facial (VII) nerve -glossopharyngeal (IX) nerve -vagus (X) nerve

Question 34

serves taste buds in the anterior 2/3 of the tongue

Answer 34

facial (VII) nerve

Question 35

serves taste buds in the posterior 1/3 of the tongue

Answer 35

glossopharyngeal (IX) nerve

Question 36

serves taste buds in the throat and epiglottis

Answer 36

vagus (X) nerve

Question 37

the process of hearing

Answer 37

audition

Question 38

3 PRINCIPLE REGIONS OF EARS

Answer 38

- external ear - middle ear - internal ear

Question 39

uses air to collect and channel sound waves

Answer 39

external ear

Question 40

uses a bony system to amplify sound vibrations

Answer 40

middle ear

Question 41

generates action potentials to transmit sound and balance information to the brain

Answer 41

internal ear

Question 42

Collects sound waves

Answer 42

auricle

Question 43

Guides sound wave to tympanic membrane

Answer 43

External auditory canal

Question 44

* Separates external canal and middle ear * Vibrates when sound hits it

Answer 44

Tympanic membrane