Quizz for 11/21/13 Flashcards by Laura Pitt

respond to

touch,
pressure,
vibration,
stretch,
and itch

STIMULUS TYPE

Mechanoreceptors

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sensitive to changes in temperature

-within a range

STIMULUS TYPE

Thermoreceptors

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Respond to light energy

-retina in the eye

STIMULUS TYPE

Photoreceptors

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Respond to chemicals

smell,
taste,
changes in blood chemistry

STIMULUS TYPE

Chemoreceptors

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Sensitive to pain-causing stimuli

extreme heat or cold
excessive pressure
inflammatory chemicals

STIMULUS TYPE

Nociceptors

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Respond to stimuli arising outside of body
Found near the body surface (skin)
-Sensitive to touch, pressure, pain and temperature
–ex: Merkel disc, Pacinian Corpuscle, Free nerve endings
Include the Special Sense Organs
-eye, ear, nose, taste buds

LOCATION TYPE

Exteroceptors

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AKA: Enteroceptors, Visceroceptors
Respond to stimuli arising WITHIN the body
-Found in internal viscera and blood vessels
Sensitive to chemical changes, smooth muscle stretch, and core temperature changes
-ex: baroreceptors (blood pressure), and chemoreceptors (CO2 and H+)

LOCATION TYPE

Interoceptors

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Respond to degree of stretch of the associated structures
-found in: skeletal muscles, tendons, joints, ligaments, connective tissue coverings of bones and muscles
Continuously inform the brain of one’s movements and position in space
-Ex: Muscle spindles; Golgi tendon organ

LOCATION TYPE

Proprioceptors

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Receptors classified as either:

Simple
or Complex

STRUCTURAL COMPLEXITY

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General sensory receptors

- include encapsulated and nonencapsulated varieites

STRUCTURAL COMPLEXITY

Simple

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Simple receptors with free dendritic endings, include

Thermoreceptors
Nociceptors
Light touch receptors

ex: free nerve endings, Merkel discs, root hair plexus

STRUCTURAL COMPLEXITY

Simple - Nonencapsulated

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(10º - 40º C), found in superficial dermis

STRUCTURAL COMPLEXITY

Cold Thermoreceptor (Simple Nonencapsulated)

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(32º - 48º C); found in deeper dermis

STRUCTURAL COMPLEXITY

Heat Thermoreceptor (Simple Nonencapsulated)

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Respond to

pinching,
inflammatory chemicals from damaged tissue,
temperature changes outside the range of the thermoreceptors,
Capsaicin

STRUCTURAL COMPLEXITY

Nociceptors (Simple Nonencapsulated)

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Receptors include:

Merkel discs (light pressure),
Hair follicle receptors (light touch)

STRUCTURAL COMPLEXITY

Light Touch Receptors (Simple nonencapsulated)

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Simple receptors that ALL respond as mechanoreceptors
ex:
Meissner corpuscles
Pacinian corpuscles
Ruffini Endings

Encapsulated - Simple

Structural Complexity

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-discriminative touch

Meissner’s Corpuscles
Encapsulated - Simple

Structural Complexity

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deep pressure and vibration

Pacinian (lamellated) corpuscles
Encapsulated - Simple

Structural Complexity

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deep continuous pressure

Ruffini endings
Encapsulated - Simple

Structural Complexity

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Muscle stretch

Muscle Spindles
Encapsulated - Simple

Structural Complexity

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Muscle load

Golgi tendon Organs
Encapsulated - Simple

Structural Complexity

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Stretch in synovial joint capsules

Joint kinesthetic receptors
Encapsulated - Simple

Structural Complexity

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Special Sense organs have ___ complexity

Organization is specific to special sense organ and is polysynaptic
Involve with:
-vision
-hearing
-equilibrium
-smell
-taste

Complex receptors

Complex receptors
Structural Complexity

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cornea
aqueous humor
lens
vitreous humor
neural layer of retina
photoreceptors

Pathway of light entering the eye

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majority of light refraction occurs at ____

cornea

but light refracts in these three places

1. entering the cornea 2. entering the lens 3. exiting the lens

___ muscle alters lens curvature and shape to allow for fine focusing of an image

ciliary

ciliary body is attached to lens via ___

suspensory ligaments

light from a distance needs ___ refraction for proper focusing

very little FOCUSING FOR DISTANCE VISION

the distance beyond which the lens does not need to change shape to focus -is 20 feet in the emmetropic (normal) eye

Far Point of Vision FOCUSING FOR DISTANCE VISION

normal eye

emmetropic

Distance vision requires (parasympathetic/sympathetic) input

sympathetic FOCUSING FOR DISTANCE VISION

Ciliary muscles are (relaxed/taut), meaning the suspensory ligaments are (relaxed/taught) so the lens remains (flat/round) for DISTANCE vision

RELAXED ciliary muscle TAUT suspensory ligaments =flattened lens FOCUSING FOR DISTANCE VISION

Light from a close object (converges/diverges) as it approaches the eye and requires active adjustments to place image at the fovea focal point

Diverges FOCUSING FOR CLOSE VISION

=the closest point at which we can focus clearly. representing the maximum lens bulge achieveable

= Near point of vision | FOCUSING FOR CLOSE VISION

What is the near point of vision for an emmetropic eye?

4 inches

What are the three required simultaneous responses for close vision?

1. Accommodation 2. Constriction 3. Convergence FOCUSING FOR CLOSE VISION

=changing the lens shape by ciliary muscles; increases refraction

= Accommodation FOCUSING FOR CLOSE VISION

Close vision requires (parasympathetic/sympathetic) input

Parasympathetic FOCUSING FOR CLOSE VISION

1. Ciliary muscles are (relaxed/taut), meaning the suspensory ligaments are (relaxed/taught) so the lens remains (flat/round) for CLOSE vision

Ciliary muscles taut Suspensory ligaments loose Lens becomes rounder 1. Accomodation FOCUSING FOR CLOSE VISION

2. =the pupillary reflex (constricts/relaxes) the pupils to prevent the most divergent light rays from entering the eyes for close vision

CONSTRICTS =Constriction FOCUSING FOR CLOSE VISION

3. (Medial/Lateral) movement of the eyeballs toward the object being viewed for close vision

Convergence. -Medial FOCUSING FOR CLOSE VISION

-normal eyeball length and eye function with light focused properly

Emmetropic Eye PROBLEMS OF REFRACTION

- the FOCAL POINT is in FRONT of the retina due to a longer than normal eyeball - difficulty with distant vision - corrected with CONCAVE lens

Myopia (Nearsightedness) PROBLEMS OF REFRACTION

- The FOCAL POINT is BEHIND the retina due to a shorter than normal eyeball - difficulty with close vision - corrected with convex lens

Hyperopia (Farsightedness) PROBLEMS OF REFRACTION

- caused by unequal curvatures in different parts of the cornea or lens - corrected with cylindrically ground lenses, corneal implants, or laser procedures

Astigmatism PROBLEMS OF REFRACTION

the awareness of changes in the internal and external environment

Sensation

The conscious interpretation of those stimuli

Perception

Input comes from exteroceptors, proprioceptors, and interoceptors

Sensory Integration

Input is relayed toward the brain but is processed along the way -Known as ___ Ex: processing in the thalamus

Sensory Integration

Sensory integration involves processing at three levels

1. Receptor 2. Circuit level 3. Perceptual level

sensory receptors

Receptor Sensory Integration

Ascending pathways

Circuit Level Sensory Integration

Neuronal Circuits in the Cerebral Cortex

Perceptual Level Sensory Integration

To be processed at the receptor level, | The receptor must have ___y for the stimulus energy

specificity

To be processed at the receptor level, The receptor’s ___ (area the receptor monitors) must be stimulated

receptive field

Stimulus energy must be converted into a graded potential=

Transduction | Processing at the Receptor Level

___ occurs when sensory receptors are subjected to a constant, unchanging stimulus

Adaptation (of Sensory Receptors)

Over time, - Receptor membranes become less responsive - Graded potentials decline in frequency or stop

Adaptation of Sensory Receptors

___ receptors signal the beginning or end of a stimulus, thus fast-adapting Examples: receptors for pressure, touch and smell

Phasic receptors

___ receptors are slow-adapting or non-adapting

Tonic receptors

Slow-adapting examples of ___ receptors: Merkel discs, Ruffini endings and chemoreceptors

Tonic receptors

Non-adapting examples of ___ receptors: Pain receptors and proprioceptors

Tonic receptors

In general sense receptors, the ___ potential and ___ potential (AP generator) arethe same thing

receptor potential; graded potentials

Stimulus ---> Receptor potential (graded potential --> ?

``` General Sense Receptors Action Potential (if threshold is reached) ```

In SPECIAL SENSE organs, there's intermediate step involving release of neurotransmitter. This is example of ___

Polysynaptism

For Special Sense Organs, 1. Stimulus 2. Receptor Potential (in receptor cell) 3. ??

3. Release of Neurotransmitter

For Special Sense Organs, 3. Release of Neurotransmitter 4. ??

4. Graded Potential

For Special Sense Organs, 4. Graded Potential 5. ???

5. ACtion Potential (if threshold is reached)

Pathways of 3 neurons conduct sensory impulses upward to the appropriate brain regions

Processing at the Circuit Level

Conduct impulses from the receptor level to the second-order neurons in the CNS

First order neurons | Processing at the Circuit Level

Transmit impulses to the thalamus or cerebellum

Second order neurons | Processing at the Circuit Level

Conduct impulses from the thalamus to the somatosensory cortex

Third order neurons | Processing at the Circuit Level

- Sensation is detected in the primary cortex related to sensory pathway

Processing at the Perceptual Level (Cerebral cortex circuits)

-Perception (conscious interpretation) in the related association cortex

Processing at the Perceptual Level (Cerebral cortex circuits)

Identification of the sensation depends on the specific location of the target neurons in the appropriate ___ cortex

sensory

conscious interpretation

Perception

Perception occurs in the related association cortex and involves 1) 2) 3)

1) Perceptual detection 2) Magnitude estimation 3) Spatial discrimination

Ability to detect a stimulus (requires a summation of impulses)

Perceptual Detection

intensity is coded in the frequency of impulses

Magnitude estimation

Identifying the site or pattern of the stimulus (studied by the two-point discrimination test0

Spatial discrimination

warns of actual or impending tissue damage

Perception of Pain

stimulus intensity where pain is first sensed by the brain

Pain threshold

Stimuli include extreme pressure and temperature, inflammatory chemicals

Pain threshold

Most potent stimuli for this are: histamine, K+, ATP, acids and bradykinin

pain threshold

Impulses for pain travel on fibers that release neurotransmitters ___ & ___

Glutamate | Substance P

individual, highly variable

pain tolerance

Blocked by inhibitory endogenous opioids (endorphins and enkephalins)

Pain Modulation

is often difficult yet critical to positive post-injury / post-op outcomes

Effective Pain Management

-can occur secondary to intense or prolonged pain

Chronic Pain

-Due to spinal cord pain amplification; must reduce signals to prevent synapse enhancement

Chronic Pain

-When the stimuli at the end of the remaining stump travels up the afferent pathway and terminates in the region of the sensory cortex mapped from the original body part

Phantom Limb Pain | follows amputation

The body part is missing, but the pathway is the same, so the brain interprets the part as present

Phantom Limb Pain

Improved by using epidural anesthesia which blocks spinal cord transmission

Phantom Limb Pain

Pain stimuli arising from the viscera are perceived as somatic in origin

Referred Pain

Visceral pain afferents travel along the same pathways as somatic pain fibers

Referred Pain

70% of all the body’s sensory receptors are in the

eye

Almost half of the cerebral cortex is involved in processing

visual information

Most of the eye is protected by a cushion of ___ and the ___

fat; | bony orbit

1. Eyebrows 2. Eyelids (Palpebrae) 3. Conjunctiva 4. Lacrimal Apparatus 5. Extrinsic Eye Muscle

Protect the eye Aid in Eye Function Accessory Structures of the Eye

Coarse hairs that overlie the supraorbital margins; | shade and stop perspiration

Eyebrows

Palpebrae

Eyelids

Protect the eye anteriorly

Palpebrae

separates eyelids

Palpebral fissure

Elevation at medial commissure; | contains oil and sweat glands

Lacrimal caruncle

Internal supporting connective tissue sheet for muscle attachment

Tarsal Plates:

This muscle closes the eye

Orbicularis oculi muscle

This muscle opens the eye

Levator Palpebrae Superioris

lubricating modified sebaceous glands

Tarsal Glands

initiate reflex blinking

Eyelashes

Transparent Membrane

Conjunctiva

Lines the eylids

Palpebral conjunctiva

Covers the "whites" of the eyes

bulbar conjunctiva

Produces a lubricating mucus secretion | -prevents drying

Conjunctiva

inflammation; causes reddened, irritated eyes

Conjunctivitis

Consists of the lacrimal gland and associated ducts which connect to nasal cavity

Lacrimal Apparatus

Lacrimal glands secrete

tears

Contain mucus, antibodies and lysozyme

tears

Enter the eye via superolateral excretory ducts

tears

Exit the eye medially via paired lacrimal canaliculi at the lacrimal punctum

tears

Drain into the nasolacrimal duct

tears

Six strap-like muscles which originate from the bony orbit

Extrinsic Eye Muscles

- Enable the eye to follow moving objects | - Help maintain the shape of the eyeball

Extrinsic Eye Muscles

___ rectus muscles (common tendinous ring) & ___ oblique muscles (rotation)

4 | 2

(moves eye laterally)

Lateral rectus

Lateral rectus nerve?

CN VI | Abducens

moves eye medially

medial rectus

medial rectus nerve?

CN III | Oculomotor

elevates eye and turns it medially

Superior rectus

Superior rectus nerve?

CN III | Oculomotor

depresses eye and turns it medially

Inferior rectus

Inferior rectus nerve?

CN III | Oculomotor

Depresses eye and turns it laterally | got the cool hook thing

Superior oblique

Superior oblique nerve?

CN IV | Trochlear

elevates eye and turns it laterally

Inferior oblique

Inferior oblique nerve?

CN III | Oculomotor

- alternate eye focusing on objects due to weak extrinsic muscle - Treated by patching the strong eye to force weaker eye muscles to get stronger

Strabismus | WHAT UP

Three layers of eyeball

Fibrous Vascular Sensory

Internal cavity filled with fluids called

Humors | Aqueous and Vitrous

This separates the internal cavity into anterior and posterior segments

Lens

Outer Layer

Fibrous

composed of two dense avascular connective tissue regions

Fibrous Layer

Sclera and Cornea

Two Fibrous Layers of Eye

white, opaque, tough layer

Sclera

Protects and shapes the eyeball; anchors extrinsic muscles

Sclera

At the optic nerve, ___ is continuous with the dura mater

Sclera

transparent; anterior 1/6 of fibrous layer

Cornea

bends light as it enters the eye

Cornea

Numerous pain receptors contribute to blinking and tear reflexes

Cornea

Covers the iris and pupil

Cornea

Covered by the vascular conjunctiva

Sclera

fastest healing tissue in the body

Cornea

Gets O2 directly from the air | -Abrasions typically heal in 24-36 hours

Cornea

middle layer, pigmented

Vascular Layer (Uvea)

Has 3 regions: Choroid, Ciliary Body, Iris

Vascular Layer (Uvea)

Posterior portion of the uvea

Choroid region

Supplies blood to all eye layers of the eyeball

Choroid region

Contains brown pigment that absorbs light to prevent visual confusion that forms the posterior portion of the uvea

Choroid region

A thickened ring of tissue surrounding the lens

Ciliary Body

Composed of smooth muscle bundles (ciliary muscles) that control lens shape

Ciliary Body

Anchors the suspensory ligaments that holds the lens in place (text: ciliary zonule)

Ciliary Body

Ciliary processes contain capillaries that secrete fluid which forms the aqueous humor

Ciliary Body

Pigmented portion of the anterior eyeball (Brown is the only pigment)

Iris

central opening of the iris that regulates the amount of light entering the eye via two different muscles

Pupil | Iris

Close vision & bright light –muscles contract; pupils constrict Parasympathetic Control

sphincter pupillae | Iris

Distant vision & dim light –muscles contract; pupils dilate | Sympathetic Control

dilator pupillae | Iris

Changes in emotional state affect the muscles - | - pupils dilate when object is appealing or requires problem-solving skills

pleasing

Constrict/dilate when negative or lying

Constrict

is the innermost layer composed of a delicate two-layered membrane - Pigmented - Neural

Retina | Sensory Layer

Outer layer that absorbs light and prevents its scattering; | -stores Vitamin A

Pigmented | Retina

melanin granules

Pigmented Layer

Inner layer that covers the eyeball up to the ora serrata (where it joins the ciliary body)

Neural layer

where eyeball joints ciliary body

ora serrata

transmit signals and generate action potentials

Bipolar cells -Ganglion cells Neural Layer Retina

Its axons run along the inner surface of the retina

Ganglion cell

This layer has Photoreceptors that transduce light energy

Neural Layers of Retina

Connect the photoreceptors to the ganglion cells

bipolar cells

- run along the inner surface of the retina | - Axons are bundled and leave the eye as the optic nerve

Ganglion cell axons

- Site where the optic nerve leaves the eye | - No photoreceptors, so no signal to the brain

Optic disc (blind spot)

Site where the optic nerve leaves the eye is the

optic disc

No photoreceptors at optic disc, so this creates the

blind spot

Approximately 250 million per eye

Photoreceptors

More numerous at peripheral region of retina

Rods

Operate in dim light; | provide indistinct, fuzzy, gray-scale peripheral vision

Rods

Found in the macula lutea | concentrated in the fovea centralis

Cones

Lens adjustments are made to get the focus of an object to land here

fovea

Respond to bright light and provide high-acuity color vision

Cones

blood vessels supplies the outer third of the retina (photoreceptors)

choroid

Branches from the central artery & vein of the retina supply inner two-thirds (bipolar and ganglion cells) of blood -Enter/exit from the center of the ___ nerve - Vessels branch from the optic disc and can be seen with an ____

optic | opthalmoscope

Damage to the retinal blood vessels secondary to diabetes mellitus

Diabetic retinopathy

Damage to the central visual field with detachment of the retina

Macular Degeneration

"yellow body"

macula lutea

The ___ & ___ ___ divide the internal eye into anterior & posterior segments

lens | suspensory ligaments

anterior segment contains

aqueous humor

posterior segment contains

vitreous humor

(clear gel – looks like egg white); formed embryonically

vitreous humor

Transmits light

vitreous humor

Supports the posterior surface of the lens

vitreous humor

Holds the neural retina firmly against the pigmented layer

vitreous humor

Contributes to intraocular pressure

vitreous humor

Has 2 chambers - anterior chamber - posterior chamber

Anterior Segment,

Chamber between the cornea and the iris

Anterior chamber | Anterior segment

Chamber between the iris and the lens

Posterior chamber | Anterior segment

contains aqueous humor

anterior segment

plasma-like fluid continuously filtered from capillaries of the ciliary processes

aqueous humor | anterior segment

Drains continuously via the scleral venous sinus (canal of Schlemm) at the sclera-cornea junction

aqueous humor

Supplies nutrients & oxygen to and removes wastes from the lens and cornea -Also supplies the retina via diffusion through the vitreous humor

Aqueous Humor

Abnormal increase in intraocular pressure

Glaucoma

Due to blocked drainager of the aqueous humor

Glaucoma

If untreated, leads to an increase in intraocular pressure which causes retina and optic nerve damage

Glaucoma

Treatment: eye drops with anti-inflammatory

Glaucoma

A biconvex, transparent, flexible and avascular structure encased in an elastic capsule

Lens

Can change shape to allow precise focusing of light onto the retina/fovea

Lens

Composed of epithelium and lens fibers

Lens

-anterior cuboidal cells; | differentiate into lens fibers throughout life

Lens Epithelium

cells filled with the transparent proteins known as crystallins

Lens fiber

With age, the lens becomes more compact and dense and loses/gains its elasticity

loses

Loses the ability to recoil to a round shape, thus loss of close vision =

=presbyopia

occur as a consequence of aging, diabetes mellitus, heavy smoking and frequent exposure to intense sunlight

=Cataracts | clouding of lens

transparent proteins

crystallins

packets of light that travel in a wavelike fashion)

=photons | Light

visible spectrum | the small portion of electromagnetic spectrum

400-700 nm

Different ___ in the retina respond to different wavelengths (blue, green, red)

cones

___ only have one type of visual pigment, so everything is perceived in gray tones

Rods

When light passes from one transparent medium to another at an oblique angle, it changes speed and bends =

Refraction

when a convex lens forms an image, the image is ___ and ___ right to left

image is upside down and reversed right to left

cornea, aqueous humor, lens, vitreous humor and neural layer of the retina to the photoreceptors

Pathway of light entering the eye

Refraction Goal

Get the image to the fovea centralis

Eyeball too short | Focal Pt?

Far Sighted Behind retina Hyperopic

process by which the eye detects light energy

Photoreception

what do rods and cones contain? what do they do as they absorb light?

Visual pigments which change shape

Arranged in stacks of ___which are embedded in the pigmented layer of the retina

discs | rods and cones

Sensitive to dim light and best suited for night vision and peripheral vision

Rods: Functional Characteristics

Perceived input is in gray tones only

Rods: Functional Characteristics

Sum of visual input from many rods feeds into a single ganglion cell & pathways converge, resulting in fuzzy and indistinct images

Rods: Functional Characteristics

Need bright light for activation

Cones: Functional Characteristics

Have one of three pigments that furnish a vividly colored view (blue, green, red)

Cones: Functional Characteristics

Congenital lack of one or more pigments (X-linked)

Cones: Functional Characteristics

Each cone synapses with a single ganglion cell, so non-converging, resulting in detailed and high resolution images

Cones: Functional Characteristics

The light-absorbing molecule that combines with one of four opsins (protein) to form visual pigments

Retinal

Similar to and is synthesized from Vitamin A

Retinal

Two isomers: cis- and trans- form

Retinal

Conversion from one form to the other is the stimulus for a chain of enzyme reactions leading to transmission of APs in the optic nerve

Retinal

The visual pigment of rods is

Rhodopsin

In the dark, rhodopsin is formed and accumulates

Dark Phase

When light is absorbed, rhodopsin breaks down (changes form)

Light Phase

Retinal and opsin separate

Bleaching of the pigment | Light Phase

Retinal and opsin separate & ultimately | causes APs to be transmitted along the optic nerve

Stimulation of Photoreceptors

Its visual pigments are formed by retinal + opsins forming blue green and red cones

Excitation of Cones

are perceived by activation of more than one type of cone

Intermediate Colors

is perceived by activation of all of the cones equally

White

Occurs when moving from darkness into bright light

Light Adaptation | Photoreceptors

Large amounts of rod pigments are broken down instantaneously, perceived by visual cortex as

glare

Pupils constrict/relax to decrease the amount of light hitting retina

constrict

Dramatic decrease in retinal sensitivity; rod function ceases/increases; therefore, can’t see if return to the dark

ceases

cones and neurons adapt quickly; visual acuity is gained rapidly and improves over 5-10 minutes

Switching from rod to cone system

Occurs when moving from bright light into darkness

Dark Adaptation

Cones stop functioning in

low light

Pupils dilate/contract to capture as much light as possible

dilate

Rhodopsin will again accumulate/decompose in the dark and retinal sensitivity is restored within 20-30 minutes

accumulate

Medial fibers of the optic nerve decussate at

optic chiasma | (cross to contralateral side

Lateral fibers do/don't decussate

DO NOT | project to ipsilateral side

Most fibers of the optic tracts continue to the

Thalamus

Some optic tract fibers end in midbrain

superior colliculi (initiating visual reflexes)

Optic radiations travel from the thalamus to the

visual cortex in the occipital lobe

A small subset of visual fibers from the blue cones contain ___ (circadian pigment) which sets daily biorhythms (inhibit melatonin release from the pineal gland)

melanopsin;

is achieved by both eyes (binocular vision) viewing the same image from slightly different angles and visual cortex fusion of the slightly different images

Depth Perception

If only one eye is used, depth perception is lost and the observer must rely on learned clues

Truth

Visual Processing... | Involves many regions of the brain

You Ready?

-donut shaped rod receptive fields detect different light patterns on center or off-center -distinguishes edges/movement -cone receptive fields provide sharpness and color Receptive fields of ganglion cells detect different light patterns

Retinal Processing

-Relays information on movement; -segregates the retinal axons in preparation for depth perception; -sharpens the contrast information received by the retina

Thalamic Processing

Review: | Axons of Retinal Ganglion cells form the ___

optic nerve

Review | The optic nerve fibers cross at the

optic chiasma

Production of ___ from the pineal gland is inhibited by light hitting these cells containing melanopsin

melatonin

Primary visual cortex processes basic dark/bright and contrast information

Cortical Processing

Visual association areas process form, color, and movement

Cortical Processing

Visual information then proceeds anteriorly to the:

Temporal lobe – processes identification of objects | Parietal cortex and postcentral gyrus – processes spatial location

Quizz for 11/21/13 Flashcards

(277 cards)