NEUROBIO EXAM 3

only ________ cells fire action potentials

ganglion

in central retina, few photoreceptors send info to a

ganglion cell (high resolution)

Refraction by the cornea

refractive power of cornea is greater than the lens

Accommodation

refractive power of lens can be changed (Added)

suprachiasmatic nucleus of hypothalamus

regulates most circadian rhythms if body (sleep, wakefulness)

brainstem

related to alertness and attentiveness

Photoreceptors

respond to light

2 types of photoreceptors in the retina

rods and cones

Cornea

The clear tissue that covers iris

Sympathetic neurons->

Dilator pupilae (radial) muscles -> incr pupil size (Dilation)

Hot color

lower frequency (lower energy)

3 ossicles in the middle ear

malleus (hammer), incus (anvil), stapes (stirrup)

motor proteins (prestin)

membranes of outer cells hair cells can change the cell length in response to sound

uvea

middle coat of the eyeball; includes the iris-pupil, ciliary body, and choroid

Conjunctiva

mucous membrane that lines the eyelids and outer surface of the eyeball

Phototransduction occurs in

outer segment of rods and cones

photoreceptor structure

outer segment(discs containing photopigments), inner segment(cell body), synaptic terminal

ventral stream

perception of visual motion and visual control of action

ventral stream

perception of visual world and recognition of objects- shape, color, texture

Horizontal cells

receive input from the photoreceptors and project to other photoreceptors and bipolar cells

iso frequency bands

contain neurons that have similar characteristic frequencies frequencies

scala media (cochlear duct)

continuation of membranous labyrinth into cochlea

Phototransduction

conversion of light energy recieved by photoreceptors into changes in membrane potential (electrical signals)

Sclera

-white of the eye -dense connective tissue -covers entire eyeball EXCEPT cornea

Structures in retina

Macula lutea, Fovea centrails, Optic disc, vitreous humor

primary visual corte

80% of excitatory synapses onto LGN neurons

Visual acuity

-Ability to distinguish 2 nearby points -Depends on photoreceptor density in retina and precision of refraction

lateral geniculate nucleus (LGN)

A structure in the thalamus, part of the midbrain, that receives input from the retinal ganglion cells and has input and output connections to the visual cortex.

choroid

-Lines most of the internal surface of the sclera. -Highly vascularized: Provide nutrients to the posterior surface of the retina -Contains melanocytes: Melanin pigments absorb stray light rays and prevent reflection and scattering of light in the eyeball.

ciliary body

-anterior portion of vascular layer -melanocytes: dark color -consists of ciliary processes and ciliary muscles

scala vestibuli

-begins at vestibular (oval) window -filled with perilymph

ciliary muscle

-circular smooth muscle that contracts to control the shape of the lens -adapts lens for near and far vision (accommodation)

Iris

-colored portion of eye- between cornea and lens, attached ciliary process -Melanocytes -Regulates amount of light entering eye

eustachian tube (auditory tube)

-connects meddle ear with nasopharynx -controls pressure in middle ear, making it equal with atmospheric pressure

ciliary processes

-contain capillaries that secrete aqueous humor. -Zonular fibers (suspensory ligaments) extend from ciliary processes and attach to lens

structure of fovea centralis

-the ganglion cell layer and the inner nuclear layer are displaced laterally -light hits photoreceptors directly

superior colliculus

-dorsal midbrain -involved in eye + head movements for tracking moving images and scanning stationary images

scala tympani

-ends at cochlear (round) window -filled with perilymph

Optic disc

-exit site of optic (II) nerve -blood vessels enter eyeball -blind spot

central vision

-greater visual acuity at photopic light levels(daylight) -blind at scotopic light levels (dim light) -better in discriminating colors

Fovea centrails

-highest visual acuity (Resolution) -contains only cones

peripheral vision

-more sensitive to scotopic light levels

Rods

-more than 1000x more sensitive than cones -vision in scotopic conditions(dim) -black/white vision

pretectum in midbrain

-regulation of pupil size (light reflex) -light evoked brinks -REM sleep triggering

middle ear

-small air filled cavity -3 ossciles

cones

-stimulated in photopic conditions (brighter light) -produce color vision -3 types (blue,green,red cones)

wall of the eyeball

1. fibrous layer 2. vascular layer- uvea 3. inner layer- retina

3 scalae of cochlea

1. scala vestibuli 2. scala media 3. scala tympani

Refraction

Bending of light rays (cornea, lens)

inner ear (labyrinth)

Bony labyrinth - cavity consisting of semicircular canals, vestibule and cochlea. Membranous labyrinth - walls and sacs within the bony labyrinth. Membranous labyrinth- inside bony, receptors for hearing and equilibrium

tastants

Chemicals that stimulate gustatory receptor cells

sour

Hydrogen

diopter

reciprocal of focal distance; measurement of refractive power

fungiform papillae

Mushroom-like protuberances often containing taste buds and located on the sides and tip of the tongue.

Pupil constricts as

sphincter pupilae muscles of iris contract (parasympathetic)

fibrous layer

Outermost layer; dense avascular connective tissue (Sclera anf Cornea)

Which of the following is the correct sequence of sound wave transfer in the inner ear?

Oval window ---> Scala vestibuli --> Helicotrema --> Scala tympani ---> Round window

sequence of visual information transfer in the retina

Photoreceptors --> Bipolar cells --> Ganglion cells

Transduction

conversion of one form of energy into another. In sensation, the transforming of stimulus energies, such as sights, sounds, and smells, into neural impulses our brains can interpret.

salty

Sodium

Reflection

The bouncing back of a wave when it hits a surface through which it cannot pass.

Parasympthatetic neurons ->

Sphincter pupillae (circular) muscles -> decreases size of pupil (Constriction)

Attenuation reflex

adapts ear to loud sounds, protects inner ear, enables discern high frequency sounds more easily

dorsal stream

analysis of visual motion and the visual control of action

receptive field

area of retina where light would change firing rate of a neuron

Pupillary light reflex

autonomic reflex

outer hair cells amplify movement of

basilar membrane during low intensity sound stimuli- cochlear amplifer

iso high frequencies

caudal medial

when photoreceptor is at rest (in the dark)

cell is relatively depolarized

odorants

chemicals that bind to olfactory receptors and stimulate olfactory sensory neurons

Fovea centrailis contains

cones

constriction of pupils

decreases amount of light entering the eye

contraction of ciliary muscle

decreases tension in zonular fibers, lens becomes rounder/thicker, increase in refractive power

Pupil dilates as

dilator pupilae muscles of iris contract (sympathetic)

Focal Distance

distance from refractive surface to point where parallel light rays converge

Light

electromagnetic radiation that is visible to our eyes

viterous humor

fills space between retina and lens

auditory and vestibular systems use ____ cells as sensory receptors

hair cells

Cool color

high frequency (higher energy)

Pupil

hole in center of iris

activation of photoreceptor by light causes

hyperpolarizing receptor potential

more photopigments are bleached

incr light level

in the peripheral retina, many photoreceptor cells provide

input to a ganglion cell (detection of dim light)

bitter

ions (K+)

vallate papilae

large and few, posterior dorsal V, most buds within walls

bipolar cells receive direct inputs from photoreceptor cells

light-> photoreceptor cells -> bipolar cell

bipolar cells receive indirect inputs from photoreceptor cells

light-> photoreceptor cells -> horizontal cells-> bipolar cell

Retinal Info Processing

light-> photoreceptors -> bipolar cells -> ganglion cells -> brain

foliate papillae

located on lateral aspects of posterior tongue

optic (II) nerve axons from nasal retina project to

opposite side of brain (contralateral projection)

pathway of conscious visual perception

optic (II) nerve -> optic chiasm -> optic tract -> lateral geniculate nucleus of thalamus -> optic radiation -> primary visual cortex in occipital lobe of cerebum

rods are found mainly in

peripheral retina

intermediate frequencies

phase locking and tonotopy

outer ear

pinna (captures sound waves) and auditory canal (transmits sound to tympanic membrane)

receptive field center

provides a direct input from the photoreceptors to the bipolar cells

receptive field surround

provides indirect input from photoreceptors to bipolar cells via horizontal cells

Amacrine cells

receive input from bipolar cells and project to ganglion cells, bipolar cells, and amacrine cells

iso low frequencies

rostra/lateral

axons from temporal retina project to

same side of brain (lpsilateral projection)

we cannot perceive color differences at

scotopic light levels

gustation

sense of taste

speical senses

smell, taste, sight, hearing, balance

sweet

sugars

basic tastes

sweet, sour, salty, bitter, umami

chemical senses

taste and smell

gustatory receptors cells exist in the ___ and contain receptors for ____

taste buds; tastants

Frequency

the number of complete wavelengths that pass a point per second

Absorption

the transfer of light energy to particles or surface (color)

semicircular canals

three fluid-filled canals in the inner ear responsible for our sense of balance

macula lutea

yellow spot at posterior center of retina and relative absence of large blood vessels

high frequiencies

tonotopy

Visual field

total amount of space that can be viewed by retina when the eye is fixated straight ahead

auditory ossicles

transmit sound vibrations from tympanic membrane to oval window

phase locking

very low frequencies

electromagnetic radiation

wave of energy