Ch 10- Sensory Physiology

Front 1

3 classifications of sensory receptors

Back 1

1. type of signal they transduce

2. type of info sent to brain

3. Origin of information

Front 2

Subclassifications of type 1 (type of signal)

Back 2

1. Chemoreceptors: chemicals in environment / blood

2. Photoreceptors: light

3. Thermoreceptors: cold /heat

4. Mechanoreceptors: mechanical deformation

5. nociceptors: pain

Front 3

subclassifications of type 2 receptors (info delivered to brain)

Back 3

1. proprioceptors: sense of body position

2. cutaneous receptors: touch, pressure, heat, cold, pain

3. special senses

Front 4

subclassifications of type #3 receptors (origin of info)

Back 4

exteroceptors and interoceptors

Front 5

Phasic vs tonic receptors

Back 5

Phasic: fast adapting; burst of activity when stimulus is first applied

tonic: maintains high firing as long as stimulus is applied (pain)

Front 6

Law of Specific Nerve Energies

Back 6

Information from any given nerve fiber will only be experienced as one stimulus type

ex: punch to the eye is experienced as a flash of light

ex: paradoxical coldness

Front 7

Receptor potential

Back 7

similar to EPSPs; graded response

Front 8

Receptive fields

Back 8

size depends on density on receptors; small receptive fields = higher density = greater tactile acuity

Front 9

Lateral inhibition

Back 9

receptors most strongly stimulated inhibit neighboring receptors ; results in sharpening of sensation ; occurs in CNS

Front 10

Explain different cutaneous receptors

Back 10

Touch and pressure: merkel's discs; meissner's corpuscles; pacinian corpuscles; ruffini corpuscles

capsaicin receptors: heat and capsaicin

Front 11

Gustatory receptors

Back 11

taste buds located on papillae of tongue; papillae types: fungiform, circumvallate, foliate

Front 12

5 categories of taste and chemicals they are sensitive to

Back 12

Salty: Na+ ion channel

Sour: H+ ion channel

Sweet: Sugar; G-proteins / 2nd messenger

Umami: Glutamate; G-proteins / 2nd messenger

Bitter: Quinine; G-proteins / 2nd messenger

Front 13

Olfaction receptors

Back 13

Olfactory apparatus; bipolar neurons; sustentacular cells and basal stem cells

Front 14

Olfaction process

Back 14

G-protein receptors;

1. Odor binds; activates adenosine cyclase; leads to cAMP and phosphate

2. cAMP opens Na+ and Ca2+ channels

3. Produces a graded Depolarization ; stimulates AP

Front 15

Structures / functions of vestibular apparatus

Back 15

Otolith organs; utricle and saccule // linear acceleration

Semicircular canals ; rotation acceleration

Front 16

Depolarization vs. hyperpolarization of hair cells

Back 16

Depolarization: stereocilia bend toward kinocilium; K+ influx and NT release

Hyperpolarization: stereocilia bend away from kinocilium

Front 17

Specialized epithelium of otolith organs

Back 17

Macula

Front 18

Explain rotational acceleration

Back 18

Semicircular canals; endolymph circulates, pushing cupula and bending hair cells

Front 19

Vestibular nystagmus

Back 19

Jerky eye movement due to eye moves being opposite of spinning direction; after spinning stops, intertia causes cupula to bend and eye movements persist

Front 20

Explain sound transmission

Back 20

Vibrations from oval window displace perilymph in Scala vestibuli; vibrations then pass to scala tympani and leave inner ear through round window ; soundwaves transmitted through perilymph displace basilar membrane

Front 21

How does sound frequency affects where sound goes?

Back 21

High frequency: travels toward base of cochlea

Low frequency: travels toward apex of cochlea

Front 22

Explain how we hear

Back 22

Sounds enter cochlea duct and hair cells bend; K+ channels open leading to Depolarization ; glutamate is released which stimulates sensory neurons

Front 23

Describe place theory of pitch

Back 23

Hair cells located on different places of basilar membrane respond to different frequencies of sound ; outer hair acts as an amplifier for cochlea

Front 24

Explain sound localization

Back 24

Interaural time difference: difference in time of arrival of sound in each ear

Interaural intensity difference: difference in loudness of sound in each ear

Front 25

Conduction deafness

Back 25

Sound waves aren't conducted properly; affects all hearing frequencies.

causes: earwax, fluid in middle ear, otosclerosis

treatment: hearing aids

Front 26

Sensorineural / perceptive deafness

Back 26

Nerve impulses aren't conducted from choclea to auditory cortex ; may only impair certain frequencies

causes: damaged hair cells (noise induced), damaged nerve, age (presbycusis)

treatment: cochlear implants

Front 27

Describe pathway of light through eye

Back 27

1. Cornea

2. Anterior chamber

3. Pupil

4. Lens

5. Vitreous chamber

6. Retina

Front 28

Explain pupils in dim light vs bright light

Back 28

Dim light: pupils dilate by contraction of radial muscles via sympathetic stimulation

Bright light: pupils constrict by contraction of circular muscles via parasympathetic stimulation

Front 29

Explain how real images look in light refraction

Back 29

inverted, upside down, smaller

Front 30

Describe lens accommodation for distant and near vision

Back 30

Distant: ciliary muscles relax, sensory ligaments taut, lens thins and flattens

Near: ciliary muscles contract, suspensory ligaments relax, lens thickens and rounds

Front 31

Presbyopia

Back 31

Loss of lens accommodation with age ; lens can't thicken for near vision

Front 32

Emmetropia / myopia / hyperopia /astigmatism

Back 32

Emmetropia: normal vision

Myopia: nearsighted ; cause is elongated eyeball; treatment is concave lenses

Hyperopia: farsighted; cause is shortened eyeball; treatment is convex lenses

Astigmatism: light focuses as lines instead of points on retina ; cause is asymmetry of cornea; correction is cylindrical lenses

Front 33

Two layers of retina

Back 33

1. pigmented layer

2. neural layer

- photoreceptors; bipolar, horizontal, and amacrin cells; ganglion cells

Front 34

difference between rods versus cones

Back 34

Rods: dim light, peripheral vision

cones: detailed, color vision

Front 35

What protein do rods contain that causes a bleaching reaction

Back 35

rhodopsin

Front 36

explain visual cycle of retinal

Back 36

1. light adaptation from dim light to bright light

2. rhodopsin is made of opsin and retinal (11 - cis - retinal)

3. in response to light, retinol is converted to all- trans- retinol and dissociates from opsin (bleaching reaction)

Front 37

Explain electrical activity of retinal cells in the dark

Back 37

1. photoreceptors depolarize and inhibitory neurotransmitters are released

2. bipolar neurons are hyperpolarized and inhibited

3. no stimulation of ganglion cells leads to no signal in the brain

Front 38

explain electrical activity of retinal cells in light

Back 38

1. photo receptors are hyperpolarized and inhibited

2. bipolar cells depolarize and release glutamate

3. ganglion cells depolarize and send action potentials to brain

4. brain perceives light

Front 39

describe the three types of cones in trichromatic vision

Back 39

1. s: shortwave; blue

2. M: medium wavelength; green

3. L: long wavelength; red

Front 40

define the three different types of color blindness

Back 40

1. Deuteranopia: absence of M cones

2. protonopia: absence of L cones

3. tritonopia: absence of S cones

Front 41

explain visual sensitivity

Back 41

sensitivity is convergence of many rods onto a single bipolar cell and many bipolar cells onto a single ganglion cell ; increases light sensitivity

Front 42

explain visual fields

Back 42

right side is projected onto left side of retina, left side is projected onto right side of retina

crossover at optic chiasma

Front 43

Describe neural pathway for vision

Back 43

1. retina/ganglion cells

2. optic nerve

3. optic chiasma: information from lateral portion of retina stays on the same side, but information from medial portion of retina crosses

4. optic tract

5. lateral geniculate nucleus/thalamus

6. striate cortex / occipital lobe

Front 44

describe saccadic eye movement, smooth pursuit movements, and vergence movements

Back 44

1. Saccadic eye movement: high velocity movements that keep the image focused on the fovea Centralis

2. smooth pursuit movements: match the speed of a moving object

3. vergence movements: allows both eyes to converge so an image is at fovea of both eyes