Pre-lab Senses

Question 1

What is the retina composed of?

Answer 1

neural tissue layer consisting of 2 types of photoreceptors, rods, and cones

Question 2

The function of photoreceptors is to convert ___?

Answer 2

light energy into nerve impulses which transmit to the optic cortex in brain, resulting in visual perception

Question 3

Photoreceptors are distributed over the entire retina except where?

Answer 3

where axons of the ganglion cells exit through the optic nerve which is called the optic disc

Question 4

Optic disc result in ___?

Answer 4

a blind spot

Question 5

what position are fibers in at the optic chiasm?

Answer 5

Fibers from the medial retina from each eye cross over to opposite side, and lateral fibers of each eye remain on same side

Question 6

The medial and lateral fibers extend as ___ and ___ with neurons in lateral geniculate body of the thalamus and terminate in visual cortex in occipital lobe?

Answer 6

optic tracts and synapse

Question 7

True or false: each eye receives light from both left and right hemifields?

Answer 7

true

Question 8

What happens to speed of transmission and rays when light rays pass from one medium to another?

Answer 8

speed of transmission changes and rays are bent/refracted

Question 9

Light travels faster in the ___ than other mediums like liquid?

Answer 9

air

Question 10

Lights rays slow down and are refracted when they pass through the ___, ___, and ____ of eye to reach retina

Answer 10

cornea, lens, and vitreous humor

Question 11

Do the cornea and vitreous humor refractive index remain constant? What varies?

Answer 11

Yes, but lens refractive index/bending power can be varied based on lens’ shape

Question 12

The greater the lens’ convexity, or bulge, the ___ light will refract?

Answer 12

greater

Question 13

Greater than 20 ft away, the lens __?

Answer 13

does not need to change its convexity for it to focus light from distant object

Question 14

What happens to lens when focusing light from a near object onto the retina?

Answer 14

the lens becomes more convex (its surface curves more outwards becoming thicker in middle and thinner at edges)

Question 15

lens becoming more convex occurs when the ___?

Answer 15

ciliary muscles contract, decreasing tension on suspensory ligament attached to lens and allowing lens to “plump up”

Question 16

Adjustments made regarding vision is known as?

Answer 16

accommodation

Question 17

What 2 muscles are needed for proper eye functioning?

Answer 17

intrinsic and extrinsic

Question 18

What are the characteristics of intrinsic eye muscles?

Answer 18

They are smooth muscles and include ciliary muscles (alter lens curvature in focusing) and muscles of iris (control pupil size)

Question 19

What are the characteristics of extrinsic muscles?

Answer 19

They are skeletal muscles and attach to outside of eye

Question 20

What doe extrinsic eye muscles control?

Answer 20

eye movement and make it possible to keep moving objects focused on fovea centralis

Question 21

Extrinsic muscles are also responsible for ____?

Answer 21

convergence or medial eye movement which is essential for near vision

Question 22

What is visual acuity?

Answer 22

sharpness of vision

Question 23

What is visual acuity tested with?

Answer 23

a Snellen eye chart

Question 24

What is astigmatism?

Answer 24

a condition resulting in unequal curvature of either cornea or lens

Question 25

An individual with astigmatism prevents their ____?

Answer 25

light rays from being focused with equal sharpness on retina

Question 26

Color blindness involves the sensation of ___?

Answer 26

color vision depending on degree to which impulses are formed by 3 types of cones in retina

Question 27

the three cones are?

Answer 27

receptors for red, green, and blue

Question 28

Why is color blindness more common in men than in women?

Answer 28

the genes for red and green color receptors are located on X chromosome, which males have one an females have two

Question 29

What is the most common type of color blindness? what is it caused by?

Answer 29

red-green color, caused by a deficit in cone stimulated by either red or green light; making it harder to distinguish between red & green

Question 30

The mechanism of hearing begins as?

Answer 30

sound waves that pass through external auditory canal, tympanic membrane, and middle ear

Question 31

1. sound wave vibrate the ___? 2. Auditory ossicle ___, pressure is ___? 3. pressure waves created by stapes pushing on ____? 4a. sounds with frequencies below hearing range travel through ___? 4b. sounds in hearing range go through ___, vibrating the basilar membrane and ____?

Answer 31

1. tympanic membrane 2. vibrate, pressure is amplified 3. oval window move through fluid in Scala vestibuli 4a. the helicotrema and do not excite hair cells 4b. the cochlear duct, and deflecting hairs on inner hair cells

Question 32

In the inner ear, where do the vibration reach to?

Answer 32

spiral organ of the corti

Question 33

The spiral organ of the corti is where ___ for hearing are located and stimulated by ____ and ___?

Answer 33

mechanoreceptors, by sounds of various frequencies and amplitudes

Question 34

Once mechanoreceptors are stimulated what occurs to them?

Answer 34

they depolarize and begin a chain of nerve impulses

Question 35

the chain of nerve impulses are begin by way of the ___ to the ___?

Answer 35

cochlear nerve to the auditory centers of temporal lobe cortex

Question 36

What is toned or pitch determine by in hearing?

Answer 36

by the particular receptors that are stimulated based on the frequency of vibrations and part of brain that receives them

Question 37

__ frequency waves result in high pitch sounds detected close to oval window>

Answer 37

High

Question 38

___ frequency waves result in low-pitch sounds detected near the apex of the cochlea?

Answer 38

Low

Question 39

The ___ of sound waves which increase the ___ of nerve impulses that reach the brain determines loudness?

Answer 39

amplitude, frequency

Question 40

What are the two types of hearing loss?

Answer 40

Conduction deafness and nerve deafness

Question 41

Conduction deafness result from?

Answer 41

the blockage of sound waves reaching the inner ear, can be correct by surgery of hearing aids

Question 42

Conduction deafness is detected with __?

Answer 42

a Rhinne test

Question 43

What is nerve deafness (sensorineural) caused by?

Answer 43

damage to sound receptors or neurons that send impulses to brain, usually result of loud noise & is not correctable

Question 44

What test detects if there is a difference between the left and right ear simultaneously?

Answer 44

A Weber test

Question 45

If conduction deafness is present in one ear, sound will be heard ___ in the ear with hearing loss due to __?

Answer 45

more strongly, due to bone conduction of skull

Question 46

What is the equilibrium apparatus of the inner ear?

Answer 46

the vestibule and semicircular canals

Question 47

What does the vestibule contain?

Answer 47

the saccule and utricle

Question 48

what contain the semicircular ducts that are involved in the mechanism of dynamic equilibrium?

Answer 48

the semicircular canals

Question 49

Where is the ampulla located at? what does it house>

Answer 49

the base of each duct, houses the receptor region called crista ampullaris

Question 50

what do crista ampullaris consist of?

Answer 50

hair cells covered with a gelatinous cap or cupula

Question 51

What action bends the hair cells and creates an action potential?

Answer 51

changing your head position in an angular direction, causing the endolymph in canal to lag behind, pushing the cupula in opposite directions

Question 52

Maculae in the saccule and utricle contain?

Answer 52

the hair cells, receptors involved in the mechanism of static equilibrium

Question 53

What does the maculae respond to?

Answer 53

gravitational pull providing info on which way is up or down, and to linear changes in speed

Question 54

What is the otolithic membrane?

Answer 54

where the hair cells in each macula are embedded, it contains calcium carbonate (otoliths)

Question 55

When the head moves, the ___ move in response to gravitational pull?

Answer 55

otoliths

Question 56

What does a Barany Test detect?

Answer 56

nystagmus, the trailing of eye slowly in one direction, followed by their rapid movement in opposite direction

Question 57

What will one demonstrate if the semicircular canals are operating normally?

Answer 57

nystagmus after rotation, abnormal if otherwise

Question 58

The ___ test is used for the clinical assessment of disequilibrium or ataxia?

Answer 58

Romberg

Question 59

What three factors is equilibrium maintained through?

Answer 59

vestibular receptors, visual sensory input, and proprioception