Sensory Perception

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Sensory Perception
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I. Sensory Perception
A. Special senses
B. General senses
C. Sensation
1. Stimulus
2. Receptor
3. CNS
4. Translated
D. Adaptation
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II. General Sensation - Receptors
A. Free Nerve endings
1. Pain
2. Itch
3. Movement
4. Temperature
B. Merkels disks

• light touch

C. Hair follicle receptors

• bending of hair light touch

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D. Pacinian corpuscles

• deep pressure - vibration

E. Meissners corpuscles

• two-point discrimination

F. Ruffinis end organs

• touch or pressure

G. Golgi tendon ogans

• stimulated by tension on the tendon

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III Olfaction
A. Olfactory epithelium
1. Bipolar neurons (olfactory
neuron)

• Olfactory vesicle (knob)

• axons -gt olfactory bulb

2. Odor reception

• olfactory binding proteins

• depolarize -gt AP

C. Signal transmission

• bipolar to mitral and tufted cells in Olfactory
  bulb

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• axons of tufted/mitral synapse in cortex

Lateral olfactory area conscious perception
Medial olfactory area
visceral emotional
Intermediate olfactory modify
olfactory signals
VI. Taste
A. Structures
1. Taste buds

• Fungiform papillae

• Foliate

• Vallate

2. Taste pore
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3. Gustatory hairs

• receptor cells

B. Taste reception
1. Sour sides of tongue

• acids H enter channels

- bind (prevent K leaving)
- bind (open ion channel)
2. Salty tip of tongue

• low sensitivity

• Na diffuses

3. Bitter back of tongue

• high sensitivity

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• G protein

4. Sweet tip of tongue

• low sensitivity

• G protein

C. Signal transmission
1. Afferent nerves

• Facial nerve anterior 2/3

• Glossopharyngeal nerve posterior 1/3

2. Medulla oblongata

• synapse w/ 2nd neurons

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3. Thalamus

• synapse w/third neuron

4. Cortex

• terminates in postcentral gyrus

V. Hearing
A. External ear
1. Auricle
2. External auditory meatus
B. Middle ear
1. Tympanic membrane
2. Ossicles Malleus, Incus, Stapes
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C. Inner Ear
1. Oval window

• connects middle and inner ear

2. Bony Labyrinth
a.) Cochlea

• Scala vestibuli

perilymph

• Scala tympani

b.) Vestibule
c.) Semicircular canals
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3. Membranous Labyrinth

• vestibular membrane (beneath scala vestibuli)

• basilar membrane (above scala tympani)

• cochlear duct (endolymph)

Spiral organ -gt hair cells
D. Signal Transmission

• Sound waves cause vibrations

Tympanic membrane -gtossicles
-gtoval window -gt

• create waves in perilymph (scala vestibuli)
  

• deflect membranes

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• microvilli on hair cell bends

• hair cell depolarizes

• action potential in cochlear nerve fibers

• synapse w/ cochlear nuclei in medulla

Superior Olivary Nucleus
Inferior colliculus
Medial geniculate nucleus of
thalamus
auditory cortex
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VI. Visual Perception
A. Light

• Photon

• Wave

B. Perception
1. Cornea and lens
2. Retina

• Photoreceptors (Rods/Cones)

• fovea high cone concentration

• Optic disc blind spot

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3. Photoreceptors
a) Rods

• low light

• achromatic

b) Cones

• reguires more light

• chromatic

C. Phototransduction
1. Photopigment

• Rhodopsin - rods

Retinal/Opsin

• Iodopsin - cones

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2. Light

• retinal changes shape

• opsin protein changes

• activates G protein (transducin)

• activation of cGMP phosphodiesterase

• breaks down cGMP

• closes Na channels

• photoreceptor -gt hyperpolarizes

• reduction in Glutamate released

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3. Dark vs.
Light
cGMP opens Na channels
Na channels closed no cGMP (G protein)
Photoreceptor depolarize
Photoreceptor hyperpolarize
Glutamate released
Decrease in Glutamate
Bipolar - hyperpolarizes
Bipolar - depolarizes
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4. Bipolar cell

• synapses with photoreceptors

• depolarizes w/light

• synapses with ganglion cells

5. Ganglion cell

• synapses with bipolar cells

• axons extend into optic nerve

6. Horizontal cells

• connect multiple photoreceptors cells

7. Amacrine cells

• connect multiple ganglion cells

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D. Neuronal pathway

• optic nerves from both eyes optic chiasma

• nasal retina inf cross over

• temporal retina inf same side

Lateral geniculate nucleus of
thalamus
Visual cortex
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