- delecate two layer membrane - Pigment and neural layer

Exam 4: FINAL (Smell and Eye) Flashcards by Kaitlyn Seymour

Sense of Smell

Organ is olfactory epithelium, which covers the superior nasal concha

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What type of cells are Olfactory receptor cells

bipolar neurons with radiating olfactory cilia

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Where do basal cells lay

at base of epithelium

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GFP

Green Fluorescent protein
makes jelly fish biolumesence

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What is the process of Olfactory Transduction

Oderant protein binds–> gets active with ATP and CAMP–> Na+ influx–> depol. of olfactory receptor cell membrane triggers AP in axon–> glomeruli

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What is the olfactory pathway

Olfactory receptor cells synapse with mitral cells–> glomerular mitral cells process odor signals–> mitral cells send impulses to olfactory cortex and hypothalamus, amygdala and limbic system

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What percentage of all sensory receptors are in the eye

70%

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what are the accessory structures of the eye

eyebrows, eyelids, conjunctive, lacrimal apparatus and extrinsic eye muscles

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What shapes does the eye have specific cells for

I, /,\, -, O, semi circles

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What is the vascular tunic

iris

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what does the iris do

regulates the amount of light entering the eye

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What is the iris

the colored part of the eye

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When do the pupils constrict

during close vision and bright lights

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When do the pupils dilate

during distant vision and dim light, when the subject matter is appealing or requires problem solving skills

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What is the sensory tunic

retina

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What does the retina pigmented layer contain

outer layer that absorbed light and prevents its scattering

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What is the retina

delecate two layer membrane
Pigment and neural layer

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What does the retina neural layer contain

photoreceptors to transduce light
Bipolar cells and ganglion cells
Amacrine and horizontal cells
Cones and rods

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What are ganglion axons

axons that run along the inner surface of the retina

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What is another name for the optic disk

blindspot

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What is retinal detatchment

condition where pigmented and neural layers separate, allowing for the virtuous humor to seep between them

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What can retinal detachment lead too

perm. blindness

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How do you treat retinal detachment

reattach with lazer surgery

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What colors are visible light broken into

blue, green, red

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What is the visible light spectrum

380-750nm

Are rods and cones excited by other wavelengths or just the visible spectrum

just the visible spectrum

What determines if the rods and cones get excited

their structure

What is the first refraction in the eye

air--> cornea

What is the second refraction in the eye

cornea--> lens, focuses light

What is a normal eye called

- emmetropic eye - focus point is the retina

What is a nearsighted eye called

- Myopic eye - Eyeball is too long - focal point is in front of retina

How do you correct the myopic eye

by concaving the lens to move the focal point back

What is a farsighted eye called

- Hyperopic eye - Eyeball too short - focal point is behind retina

How do you correct the hyperopic eye

by convexing lens which moves the focal point forward

When babies has glasses what is wrong with their eye

it is genetic so it is the shape of the eye, they cant simply move and change the lens

What is accommodation in the eye

ability of lens to change shape by the ciliary myos to increase refractory power

What are the photoreceptors of the retina

rods and cones

Rods

- Responds to dim light, night vision - Used for peripheral vision

Cones

- Response to bright light - Have high acuity for color - Concentrated in the fovea contralis

What are the functional characteristics of a rod

- Sensitive to dim light and best suited for night vision - Absorb all wavelengths of visible light - Perceived input is in grey tones - Sum of visual input from many rods to a single ganglion cell - If fuzzy since less resolution

What are the functional characteristics of a cone

- Need bright light for activation - Have pigments that give a vividly colored view - Each cone synapses with a single ganglion cell, 1:1 relationship - Very detailed vision

What is photoreception

the precess by which the eye detects light energy

electromagnetic radiation

all energy waves from short gamma rays to long radio waves

What do rods and cones contain

visual pigment (Photopigments) called rhodopsin

How are the photopigments arranged

in a stack of disk like infolding of the plasma membrane that changes shape as they absorb light

What is constriction of the eye

pupillary reflex constricts the pupils to prevent divergent light rays from entering the eye

What is convergence of the eye

medial rotation of the eyeballs towards the object being viewed

Pathway of light

Cornea, aqueous humor, lens, vitreous humor, neural layer of retine to photoreceptors

what is rhodopsin made up of

opsin and cis retinal

What type of molecule is retinal

a light absorbing molecule

What are the two isomers

11-cis and all-trans

What does the isomerization of retinal initiate

electrical impulses in the optic nerve

What are the three types of cones

red, blue, green

how are intermediate colors perceived

by activation of more than one type of cone

Is the method of excitation similar for cones and rods

yes

What does light energy split rhodopsin into

all-trans retinal which released activated opsin

Process of transduction

1. Light energy splits rhodopsin into all-trans retinal, releasing activated opsin 2. The freed opsin activates G protein transducin 3. Transducin catalyzes activation of phosphodiesterase (PDE) 4. PDE hydrolyzes cGMP to GMP and releases it from sodium channels 5. Without bound cGMP, sodium channels close, the membrane hyperpolarizes, and neurotransmitter cannot be released

What are the two types of rods

A and B

Do cones function in low light

no they dont

Rod A

Rod B

What does on-center field mean

- Stimulated by light hitting the center of the field - Inhibited by light hitting the periphery of the field

What does off-center field mean

- Inhibited by light hitting the center of the field - Stimulated by light hitting the periphery of the field

What is dark adaptation

- When moving from bright light into darkness, we see blackness because: - Cones stop functioning in low-intensity light - Bright light bleached rod pigments, so they are still turned off - Pupils dilate

What is Light adaptation

- When moving from darkness into bright light we see glare because: - Both rods and cones are strongly stimulated - Large amounts of pigments are broken down instantaneously, producing glare - Pupils constrict

In light adaptation are the rods on or off

off

When does rhodopsin accumlate

in the dark so retinal sensitivity increases

Exam 4: FINAL (Smell and Eye) Flashcards

(67 cards)