Neuroanatomy Exam 3

Front 1

Function of vestibular system

Back 1

sense of equilibrium, senses position and movement of the head, contributes to conscious perception of body position in space, functions autonomically through reflexes

Front 2

Where are vestibular organs located

Back 2

in labyrinth

Front 3

Name two types of vestibular organs

Back 3

otolith organs and semicircular canals

Front 4

Function of otolith organs

Back 4

detect force of gravity and tilt of head

Front 5

Function of semicircular canals

Back 5

detect head rotation

Front 6

Membranous labyrinth containing vestibular receptors is embedded in..

Back 6

temporal bone

Front 7

surrounded by..

Back 7

perilymph

Front 8

filled by

Back 8

endolymph

Front 9

What are vestibular receptors

Back 9

hair cells similar to those in cochlea

Front 10

Name otolith organs

Back 10

Sacule and utricle

Front 11

What do saccule and utricle detect

Back 11

changes of head angle and linear acceleration of the head

Front 12

Macula

Back 12

sensory epithelium in sacule and utricle

Front 13

what is orientation of macule in sacule? utricle?

Back 13

vertical in sacule , horizontal in utricle

Front 14

Role of crystals of calcium carbonate

Back 14

hair cells are embedded within macula, cilia embedded in gelatinous cap, tiny crystals encrust surface of cap, as the head is tilted or accelerated, force is exerted on crystals, causes cap to move, this causes cilia to move

Front 15

Kinocilium

Back 15

one larger cilia, movement of other cilia dtowards or away from kinocilium cause hair cell to depolarize or hyperpolarize

Front 16

Name three semicircular canals

Back 16

superior, posterior and horizontal, oriented perpendicular to each other, detect turning movements of head from side to side or nodding

Front 17

Ampulla

Back 17

bulge along semicircular canals where hair cells are located

Front 18

What is the name of cells with hair cells

Back 18

crista

Front 19

Where do cilia project

Back 19

cilia project into gelatinous structure called cupula

Front 20

What are canals filled with

Back 20

endolymph, rotational movement causes endolymph to exert force on ampula, ampula bends and either depolarizes or hyperpolarizes

Front 21

Where do vestibular afferents project to

Back 21

vestibular nuclei - superior, lateral, medial inferior, some project directly to cerebellum

Front 22

Where do vestibular nuclei get input from

Back 22

cerebellum, visual system, somatosensory system (proprioceptors in neck), reticular formation

Front 23

Where do axons from otolith organs project to

Back 23

lateral nucleus

Front 24

Lateral vestibulospinal tract

Back 24

neurons from lateral nucleus project to alpha and gamma motor neurons in ventral horn of spinal cord, influence muscles that contribute to equilibrium and posture, somatotopic organization

Front 25

Where do axons from semicircuar canals project to

Back 25

medial vestibular nucleus

Front 26

Medial vestibulospinal tract

Back 26

neurons from medial nucleus synapse on motor neurons that innervate trunk and neck muscles that orient head

Front 27

Name one of the major ascending projections

Back 27

to the nuclei of extraocular muscles - occulomotor, trochlear and abducens

Front 28

Neurons in medial and superior nuclei project via..

Back 28

medial longitudinal fascicle

Front 29

What is the function of this pathway

Back 29

function of this pathway is to help ensure that retinal image is kept stationary when head moves

Front 30

What is vestibulocerebellum

Back 30

flocculonodular and vermis

Front 31

Vestiulo ocular reflex

Back 31

reflex that keeps vision focused on a particular area in space regardless of how head moves

Front 32

Name neurons of VOR

Back 32

primary afferent fibers from semicurcular canals, neurons in vestibular nuclei that project to nuclei of extraocular muscles, motor neurons in these nuclei that innervate the eye muscles

Front 33

How does VOR work

Back 33

by sensing rotations of the head and immediately commands a compensatory movement of the eyes in the opposite direction and with the same velocity

Front 34

Why is VOR important clinically

Back 34

abnormal VOR in comatose patient - sign of brainstem damage

Front 35

How do you test VOR in unconscious state

Back 35

using caloric stimulation

Front 36

How do problems with vestibular system manifest themselves?

Back 36

feelng of disequilibrium or vertigo

Front 37

Symptoms of labyrinth damage

Back 37

nystagmus, dizziness with vertigo, nausea, abnormal VOR

Front 38

Menieres disease

Back 38

episodic attacks of vertigo, hearing loss, tinnitus (ringing), sense of pressure in ear

Front 39

In the Muller-Lyer Illusion, why do you see one line as smaller than the other when in fact both lines are the same size?

Back 39

The line with the normal arrowheads is representative of an outside facing corner, reverse arrowheads - inward facing corner, eyes sees lines as the same, brain shrinks outside corner, enlarges inside corner

Front 40

Which wavelengths correspond to visual light on the electromagnetic spectrum?

Back 40

400-700 nm

Front 41

What is the tough connective tissue that forms the eyeball?

Back 41

sclera-->cornea

Front 42

What is its function

Back 42

protection, focusing

Front 43

Abnormalities of what structure underlie the most common visual problems?

Back 43

cornea

Front 44

what is astigmatism

Back 44

curvature of cornea is greater in one direction then another

Front 45

What structure focuses light onto the retina? Which muscles control this structure?

Back 45

lens, ciliary muscles

Front 46

What is accommodation?

Back 46

bringing into focus objects from various distances by adjusting lens with muscle

Front 47

What structure alters the amount of light entering the eye? Which muscles control this structure?

Back 47

iris

Front 48

Dilation of this structure occurs via what pathways from what brain structure? Contraction of this structure occurs via what pathways?

Back 48

constriction - pupillary constrictor muscles which receive parasympathetic information from occulomotor nerve, dilation via pupillary dilator muscle that receives sympathetic innervation from superior cervical ganglia

Front 49

Where is aqueous humor found?

Back 49

anterior chamber in front of lens

Front 50

Where is vitreous humor found?

Back 50

posterior chamber behind lens

Front 51

How many eye muscles control eye movement?

Back 51

three pairs of extraocular muscles

Front 52

What are the names of these muscles?

Back 52

medial rectus, lateral rectus, superior rectus, inferior rectus, superior olique, inferior oblique

Front 53

Why do you have a blind spot?

Back 53

blind spot is where optic nerve leaves eye