Nervous System Part 2

Question 1

(page 8)

label parts a and b of the labyrinth.

Answer 1

A: semi circular canals
B: vesibule

Question 2

(page 8)

label membrane sacks found inside part a and b shown at 1 and 2.

Answer 2

1: ampullae (three total)
2: saccule, utricle

Question 3

(page 8)
what tiny organ is found within structure one? what term is used to describe its role in maintaining balance for the body?

Answer 3

each ampullae contains the crista ampularis which is responsible for dynamic equilibrium.

Question 4

what tiny organ is found within the two structures? what term is used to describe its role in maintaining balance for the body?

Answer 4

the saccule and utricle both contain the macculae which is responsible for static equilibrium.

Question 5

define the terms dynamic equilibrium and static equilibrium.

Answer 5

dynamic equilibrium (by the crista ampularis) informs the brain of rotational movements. 
static equilibrium (by the macculae) informs the brain of changes in the head position (head tilt) plus horozontal and vertical movements of the body (linear movements) which includes changes in speed.

Question 6

when talking about balance perception, the term vestibular apparatus is used. what does this mean?

Answer 6

the vestibular apparatus is the five organs used for balance perception- two macculae and three crista ampularis.

Question 7

in the labyrinth image on (page 8) label parts c and 3 and name the organ that is found inside 3.

Answer 7

c is the cochlea and 3 is the cochlear duct and inside three is the organ of corti.

Question 8

the macculae, organ of corti, and crista ampularis are all nearly identical in structure. what do they all have in common? which of the three has something unique in its structure and why?

Answer 8

all contain hair cells and neurons with stereocilia that produce action potentials. all have a bottom layer of epithelia in which the hair cells are sitting in a gel like roof that the stereocilia are imbedded in. the macullae, however, has teeny calcium crystals in the cell like membrane “roof” called otolits that allow the macculae to respond to the pull of gravity- to literally flop backward or forward, left or right, so that the changes in head position and changes in linear movements can be accuaratley detected.

Question 9

(page 9)
as sound waves enter the ear, vibrations of several structures lead to fluid vibrations in the cochlea. list the sequence of structures ending with the structure which begins the fluid vibrations.

Answer 9

sound waves (air vibrations) that enter the external auditory canal start vibrations in the tempantic membrane which then passes the vibrations > malleous > incus > stapes > oval window (of cochlea). the mallous, incus and stapes are tiny bones known as the ear ossicles.

Question 10

the process in which sound waves are directed to the cochlea is called sound wave conduction. this process includes pressure amplification of sound waves. what does this mean.

Answer 10

because air vibrations are being turned into fluid vibrations the energy of the air vibration needs to be increased. this is because it takes more effort to move fluid than air.

Question 11

how does pressure amplification of sound waves take place?

Answer 11

the energy of the sound (air vibrations) is increased by transferring the vibrations of the tempanic membrane into a much smaller structure, the oval window of the cochlea. the oval window of the cochlea is about 1/20th of the ear drum. which means the energy of the vibration is increased by 20 percent. this increase is necessary to start the fluid vibrations inside the cochlea.

Question 12

there are three conditions which commonly cause conduction deafness. what is the overall cause of hearing loss in this type of hearing loss? what are the major causes?

Answer 12

the conduction deafness hearing loss occurs when sound vibrations are prevented from reaching the cochlea. the major causes are otitis media, otosclerosis, and a ruptured typantic membrane. the last two are often caused by ottits media but may occur for other reasons.

Question 13

besides the sound wave conduction, what other important activity are the ear ossicles involved in?

Answer 13

the ear ossicles can reduce the volume of extreme sounds (to avoid damage) by a process called the sound attenuation reflex.

Question 14

describe how the ear protects itself from loud noises. include what controls this process.

Answer 14

sound attenuation reflex: the trigeminal and facial cranial nerves are both connected to the ear ossicles by teeny muscles. these nerves cause the muscles to contract which pulls on the ossicles and slows their vibrations reducing the ear bones vibrations lowers the volume of the sound being transmitted in to the cochlea.

Question 15

what are the shortcomings (limits) of the sound attenuation reflex?

Answer 15

the sound attenuation reflex cannot protect against sudden explosive noises OR substained noised of longer than ten minutes. it only protects against slowly building noises, that are brief in length.

Question 16

(page 11)

name the fluid found in the three ducts or chambers.

Answer 16

vestibular duct = perilymph
cochlear duct = emdolymph
tympanic duct = perilymph

Question 17

(page 11)
which chamber has fluid vibrations that are started by the stapes at the oval window? how do the fluid vibrations reach the organ of corti and eventually exit cochlea?

Answer 17

the stapes knocks against the oval window- opening in the top chamber, or vestibular duct, which begins perilymph vibrations inside. the fluid vibrations are passed downward as follows: perilymph and vestibular duct > endolymph in cochlear duct (organ of corti location) > perilymph in tympanic duct > exit cochlea through round window of tympanic duct.

Question 18

(page 11)

label parts a through f

Answer 18

a: basilar membrane
b: outer hair cell
c: stereocilia
d: tectorial membrane
e: cochlear nerve
f: inner hair cell

Question 19

when the endolymph surrounding the organ or corti vibrates, what happens that allows us to hear sounds?

Answer 19

when the endolymph vibrates, it causes the basilar membrane to vibrate. vibration of the basilar membrane causes the hair cells to dance up and down which bends the stereocilia of the hair cells. this causes the inner hair cells to produce action potentials. these action potentials flow down the cochlear nerve into the brain and the brain hears sound because of them.

Question 20

what is the cochlear amplifier? how is it related to inner hair cells and outer hair cells?

Answer 20

the cochlear amplifier is made up of three rows of outer hair cells (OHCs). the OHCs do not make the AP’s that are sent to the brain for hearing- only the IHCs do that. instead the OHCs amplify/enhance the performance of the inner hair cells- they help the IHCs select which sounds to pay attention to and allow the IHCs to distinguish between a large number of pitches. certain antibiotics damage the OHCs causing permanent hearing loss- which shows the OHCs importance in the hearing process.

Question 21

(page 12)

how does the height, or amplitude, of a sound wave affect sound.

Answer 21

the amplitude of the sound wave is what determines sound volume.

Question 22

(page 12)

what kind of sound is the sound wave marked with?

Answer 22

a short sound wave is a low amplitude wave or a soft (low volume sound).

Question 23

how do inner hair cells of the organ of corti tell the brain whether a sound is loud of soft?

Answer 23

in response to soft sounds, hair cells fire of a small number of AP’s. (this is called a low frequency of AP’s). in response to loud sounds, hair cells fire off a large number of AP’s. (a high frequency of AP’s).

Question 24

complete the sentence:

the louder the sound, the _____ the amplitude or _____ of the sound wave.

Answer 24

taller; height.

Question 25

the brain can tell the difference between a soft versus a loud sound based upon the _____ of AP's the organ of corti produces.

Answer 25

number (frequency)

Question 26

(page 13) | how does a low pitch sound differ from a high pitch sound?

Answer 26

a low pitch sound has a small number of waves per second. therefore, a low pitch sound is a low frequency sound wave. a high pitch sound has a large number of waves per second or is a high frequency sound wave.

Question 27

(page 13) | in the image above, which sound wave is a high pitched sound?

Answer 27

B.

Question 28

(page 13) | how does the organ of corti tell the brain what the pitch of the sound is?

Answer 28

the specific part of the basilar membrane that vibrates is what tells the brain about the pitch of a sound. this also means that the pitch is determined by how far the sound travels down the basilar membrane.

Question 29

(page 13) | how does the thickness of the basilar membrane change as you go from the front (the base) to its end (the apex)?

Answer 29

the basilar membrane gets increasingly thinner from start to end. it begins narrow and stiff at the base and thins until it is wide and floppy at its end, the apex.

Question 30

(page 13) | what types of sounds can vibrate from the beginning (base) of the basilar membrane?

Answer 30

sounds with large numbers of waves per second have maximal vibrations at the base. this means high pitched sounds vibrate at the base. (notice the image says 20,000 hZ at the base- this means 20,000 waves per second). high frequency sound wave = high pitch sound.

Question 31

what types of sounds can vibrate the end (apex) of the basilar membrane?

Answer 31

sounds with a small number of waves per second (low frequency) or low pitched sounds. (notice that the lowest pitch we can hear is a 20 hZ or 20 waves per second.)

Question 32

what is a major cause of sensorineural deafness?

Answer 32

the major cause of sensorineural deafness hearing loss is the gradual loss/dissapearence of hair cells that occur with aging. sensorineural deafness: permanent hearing loss caused by damage to any type of neuron in the hearing pathway such as neuron damage in the cochleal (hair cells) cochlear nerve, and the brain stem.

Question 33

what causes high frequency hearing loss? what is happening in the cocheal?

Answer 33

the innability to hear high pitch sounds occurs as a result of prolonged exposure to loud noises or is often due to a single sudden explosive sound. excessivley loud sounds have air vibrations that are so violent that they tear the stereocilia off of hair cells which causes the hearing loss.

Question 34

what is the rarest type of sensineural deafness?

Answer 34

hearing loss due to neuron damage in the brain- specificallly damage in the auditory cortex of the temporal lobe.

Question 35

what is tennitus? what is one theory about this cause?

Answer 35

tennitus is ringing, buzzing or clicking in the ears in the absence of incoming sound of that type. it is a sign of damage and or irritation of inner ear structures often occuring after exposure to excessively loud sounds. one theory is it is caused when damaged hair cells spontaneuously make their own noises which are called otoacoustic emissions. the inner hair cells fire off AP's into the brain even though they are not being stimulated by sound waves- so they are producing their own noises out of thin air.

Question 36

controls the skeletal muscles of the face

Answer 36

facial nerve

Question 37

main nerve used to move the eyeball

Answer 37

ocularmotor

Question 38

has ophthalmic maxillary and mandibular

Answer 38

trigeminal nerve

Question 39

allows for hearing and balance

Answer 39

vestibulocochlear

Question 40

moves the eyeball laterally

Answer 40

abducens

Question 41

moves the tongue for speech

Answer 41

hypoglossal

Question 42

main nerve used for taste

Answer 42

facial

Question 43

allows for vision

Answer 43

optic nerve

Question 44

moves the eye out and down

Answer 44

trochlear

Question 45

has important role in the regulation of blood pressure and breathing rate.

Answer 45

glossopharyngeal, vagus

Question 46

controls mastication muscles

Answer 46

trigeminal

Question 47

regulated parasympathetic actions of almost all organs

Answer 47

vagus

Question 48

moves the tongue during swallowing

Answer 48

glossopharyngeal, hypoglossal

Question 49

has a section that crosses through the middle ear over the ear drum

Answer 49

facial nerve

Question 50

allows eyes to focus on nearby objects

Answer 50

oculomotor

Question 51

controls contractions of the trapezius and sternocleidomastoid muscles

Answer 51

accessory

Question 52

interprets taste and sensation for the tongue

Answer 52

glossopharyngeal

Question 53

main nerve for speech (controls larynx)

Answer 53

vagus (accessory helps)

Question 54

provides facial sensory information

Answer 54

trigeminal

Question 55

gets its name because it assists function of the vagus

Answer 55

accessory

Question 56

allows for smell

Answer 56

olfactory

Question 57

has five branches

Answer 57

facial nerve

Question 58

has only motor functions

Answer 58

oculomotor, trochlear, abducens, hypoglossal, accessory.

Question 59

has mixed functions

Answer 59

glossopharyngeal, vagus, facial, trigeminal

Question 60

involved in speech

Answer 60

hypoglossal (tongue), vagus, accessory (larynx)

Question 61

controls the sound attenuation reflex

Answer 61

trigeminal and facial

Question 62

contains the substantia nigra

Answer 62

midbrain (mesencphalon) (substania nigra makes dopamine)

Question 63

areas of diencephalon

Answer 63

thalamus, hypothalamus, pineal gland

Question 64

intermost mininge (directly touches the surface of the brain and spinal chord)

Answer 64

pia mater

Question 65

structure that filters blood to form CSF

Answer 65

choroid plexus (found in brain ventricles)

Question 66

area that controls basic consciousness

Answer 66

reticular formation

Question 67

cerebral lobe for hearing

Answer 67

temporal lobe

Question 68

controls eating and drinking behaviors.

Answer 68

hypothalamus (hunger thirst and satiety centers)

Question 69

space above the arachnoid mater

Answer 69

subdural space

Question 70

sends AP's from the eye, ear, and mouth to specific cerebral lobes so they can be turned into visual, auditory, and taste information.

Answer 70

thalamus (sensory relay center)

Question 71

another name for the midbrain.

Answer 71

cerebral peduncles

Question 72

controls sleep/wake cycle

Answer 72

pineal gland (produces seratonin and melatonin)

Question 73

meninge composed of two layers one of which is the periosteum

Answer 73

dura mater

Question 74

controls the sympathetic and parasympathetic nerve effects on the body

Answer 74

hypothalamus (major autonomic control center)

Question 75

cerebral lobe for vision

Answer 75

occipital

Question 76

most important area for long term memory information

Answer 76

limbic system (specific part is the hippocampus)

Question 77

meninge where the major BV that supply the brain are found

Answer 77

pia mater (highly vascularized)

Question 78

two areas which control breathing

Answer 78

medulla and the pons

Question 79

four areas of the brain stem

Answer 79

medulla, pons, cerebellum, reticular formation

Question 80

overall emotional center of the brain

Answer 80

limbic system

Question 81

meninge that controls the velle which delivers CSF to the dural sinus

Answer 81

arachnoid mater

Question 82

controls the release of pituitary gland hormones.

Answer 82

hypothalamus (endocrine system control center)

Question 83

cerebral lobe for taste and smell

Answer 83

parital lobe

Question 84

cavity where CSF is found

Answer 84

subarachnoid space (space between arachnoid mater and pia mater in vertebral cavity in cranial cavity)

Question 85

important pathway for AP's controlling skeletal muscle movements

Answer 85

cerebral peduncles

Question 86

controls body temperature

Answer 86

hypothalamus

Question 87

allows us to select or ignore sensory information espicially sounds

Answer 87

reticular formation

Question 88

controls heart rate and blood pressure

Answer 88

medulla, hypothalamus (the medulla is the most important, it contains the cardiac center and vasomotor center. hypotalamus also alters HR and BP as part of its automatic control center functions)

Question 89

meninge made of aeriolar CT

Answer 89

pia mater

Question 90

a bridge for AP's moving from the cerebrum to the cerebellum

Answer 90

pons

Question 91

meninge which forms septa or partitions that prevent excessive movement in the brain and skull

Answer 91

dura mater

Question 92

cavity where anesthesia is injected

Answer 92

epidural space (space above dura mater in vertebral cavity and cranial cavity)

Question 93

controls the water balance of body using ADH

Answer 93

hypothalamus (ADH helps save water when dehydrated by affecting the kidneys)

Question 94

meninge made of dense CT

Answer 94

dura mater

Question 95

produces seratonin and melatonin

Answer 95

pineal gland (controls the sleep/wake cycle)

Question 96

contains vital reflex centers

Answer 96

medulla (the vital reflex centers control heart rate and BP. also causes breathing. cardiac respiratory vasomotor centers.)

Question 97

where the learning and planning of complex movements occur, controls posture and balance.

Answer 97

the cerebellum (gross motor coordination is the overall name for what the cerebellum of what the cerebellum is in charge of)

Question 98

when the eye focuses, what really is happening is that the light rays from an object entering the eye are bent _____ so that they come together _____ on a small pit on the retina.

Answer 98

refracted; converge

Question 99

what two main structures are responsible for bending the light rays in this manner? which of these is the most important in this rule?

Answer 99

cornea; lens. the cornea is the most important for refraction and convergence of light rays. the cornea has a refractive power of 42 diopters compared to a refractive power of 12 diopters for the lens.

Question 100

the small pit in the retina that light rays must fall on, the ______ is surrounded by a yellow area known as the _____.

Answer 100

fovea; macula lutea

Question 101

what change in shape occurs to the lens when the eye focuses on a nearby object?

Answer 101

the lens takes on a rounder shape

Question 102

what causes this shape change in the lens?

Answer 102

contraction of the cilliary muscles (which are connected to the lens by suspensory ligaments)

Question 103

the changes in the eye that occur for near vision are called _____ and are caused by _____.

Answer 103

accomidation; the oculomotor nerve

Question 104

besides the change in lens shape, what else happens when the eye focuses for near vision? (during accomodation)

Answer 104

constriction of the pupil and inward rotation of the eyes (which is also called convergence of the eyes)

Question 105

what three important aspects of vision are the cones in the retina responsible for?

Answer 105

vision and bright light, color vision, vision acuity. (a sharply focused image)

Question 106

what two important aspects of vision are the rods in the retina responsible for?

Answer 106

vision in dim light, black and white vision.

Question 107

what happens to rhodopsin, the photo pigment found in rods when it is exposed to bright light?

Answer 107

it stops sending AP's to the brain. it turns off. bright light causes it to break apart into its components. (retinal and opsin) and lose its purple color. this is known as bleaching.

Question 108

why does it take a few seconds for you to be able to see when you leave a bright room and walk out into the night?

Answer 108

since you have been in bright light, your rhodpsin is inactive. literally, broken in half. it takes a few seconds for it to be remade so the rods can produce AP's in dim light, allowing you to see.

Question 109

what is the focal distance of the eye? how is focal distance connected to eye shape?

Answer 109

focal distance is the distance it takes light rays to focus after entering the eye. this means the distance at which the light rays come together (converge into a point) on the fovea. (the cornea and lens are what determine the focal distance. the human eye has a focal distance on average of 22 mm.) assuming the cornea has the perfect shape/curvature causing the focal distance to be 22 mm. the human eye needs to be the perfect size for vision to be sharp/crisp.

Question 110

what is the clinical term for nearsidedness? how can eyeball shape cause this problem? where is the image focused?

Answer 110

myopia. (squint eye vision) the eyeball is too long causing light rays to focus in front of the fovea. the normal foval distance (22 mm) is too short to reach the fovea and needs to be increased.

Question 111

what type of lens is used to correct nearsidedness? how does the shape of the lens correct the problem?

Answer 111

a concave lens, or one that is relatively flat on both sides. a concave lens causes light rays that pass through to diverge or spread out. the concave lens increases the focal distance- allowing the light rays to travel farther before they focus- so they reach the fovea.

Question 112

what causes hyperopia? where is the image focused?

Answer 112

hyperopia is farsidedness. the eyeball is too short. this causes the light rays to focus behind the fovea. the normal focal distance (22 mm) is too long and needs to be shortened. (hyperopia means excessive major vision. the idea that the light rays go too far past the fovea)

Question 113

what kind of corrective lens is used to correct hyperopia?

Answer 113

a convex lens that is round.

Question 114

how is presbyopia, which is age related farsidedness, different from hyperopia or regular farsidedness?

Answer 114

presbyopia (old man vision) begins to develop in the mid 40's because the lens has lost elesticity. as we age, the lens becomes less flexible because more crystallines are added to it. this means it can no longer take on the round shape it needs (during accomodation) to properly focus for near vision.

Question 115

what two eye disorders can be caused by diabetes?

Answer 115

cataracts and retinal detachment (degeneration)

Question 116

astigmatism occurs with myopia or hyperopia. it results in blurring of an image either vertically or horozontally. what causes this?

Answer 116

the cornea that is aspheric or asymmetric. this means it may be flattened on one side or that its overall curvature is more oval than round.

Question 117

lens turns milky or opaque in color

Answer 117

cataracts

Question 118

blurring of images caused by the eyeball being too short

Answer 118

hyperopia (farsidedness)

Question 119

a hole that develops in the center of visual field.

Answer 119

maccular degeneration

Question 120

caused by inadequite amount of aqueous humor

Answer 120

cataracts (lack of aqueous humor causes the lens to degenerate, turns cloudy, because it is the only nutrient supply for the lens)

Question 121

loss of vision due to excess pressure which causes death of neurons in the retina of optic nerve

Answer 121

glaucoma

Question 122

blurring of images caused by the eyeball being too long

Answer 122

myopia (nearsidedness)

Question 123

leading cause of blindness in those over 50 years of age

Answer 123

macular degeneration

Question 124

loss of vision that occurs due to shrinking of the vitrious humor with advanced age

Answer 124

retinal detachment

Question 125

caused by too much aqueous humor

Answer 125

glaucoma (aqueous humor builds up because it fails to drain properly from the eye)

Question 126

blurring of images caused by an aspheric or asymmetrical cornea

Answer 126

astigmatism

Question 127

linked to high cholesterol, obesity, and smoking

Answer 127

macular degeneration

Question 128

blurring of images caused by the age related accumulation of protein cristalines in the lens

Answer 128

presbyopia (age related farsidedness)