Chpater 17 - Special Senses

Front 1

How many Olfactory receptors?

Back 1

10-20 million

Front 2

Olfactory receptors

Back 2

highly-modified neurons with dendrites that have olfactory clia which are exposed to outside. Olfactory cilia are covered with watery mucus produced by olfactory glands, which keeps the surface moist and dissolves odorant molecules

Front 3

To be detected, ororant molecules must be....

Back 3

dissolved in watery mucus

Front 4

Olfactory glands are innervated by the...

Back 4

facial nerve, so strong smells like ammonia or onions stimulate both glands and you end up with tears and a running nose.

Front 5

Olfactory reception occurs on the ...

Back 5

olfactory epithelium when chemicals interact with specific receptors

Front 6

Steps to smell

Back 6

- Binding of olfactory molecules causes a graded potential

- If sufficient depolarization occurs, an action potential is triggered and travels through openings in cribriform plate of the ethmoid bone via the olfactory nerve to the olfactory bulb of the cerebrum

- the sensory inplulses of smell travel through the emotiojnal area of the brain. Therefore, certain odors often have emotional overtones or are related to particular memories.

Front 7

Adaption to odours occurs _____.

Back 7

rapidly

Front 8

Gustation

Back 8

the sense of taste

Front 9

Lingual papillae

Back 9

many small projections on the tongue which contain taste buds.

Front 10

An adults has ____ taste buds

Back 10

3000

Front 11

Taste bud is oval body made up of _____ ___ and supporting ____ ____.

Back 11

gustatory cells, epithelial cells

Front 12

Gustatory reception occurs when dissolved chemicals interact with specific ___ on the ____ of gustatory cells.

Back 12

receptors, microvilli

Front 13

When a gustatory cell detects that a chemical has bound to a receptor, a _____ ____ occurs.

Back 13

graded potential

Front 14

Chemicals must be ___ to be tasted.

Back 14

dissolved

Front 15

Four primary taste sensations are:

Back 15

salty, sour, bitter, sweet

Front 16

Two additional taste sensations:

Back 16

umani (meaty taste) , water receptors (located in the pharynx)

Front 17

Salty and sour receptors are __-____ channels

Back 17

chemically gated

Front 18

Sweet, bitter and umani tastes sensations are ___ ____ that use a second messenger system to produce their effects.

Back 18

G proteins (gustducins)

Front 19

We are most sensitive to _____ substances.

Back 19

bitter. This is for protection.

Front 20

Tastes receptors undergo __, so oyu taste something strongly for 1-5minutes, then adapt and taste it less or not at all.

Back 20

adaption

Front 21

Opthamology

Back 21

the science that deals with the eye and its disorders

Front 22

Otorhinolaryngology

Back 22

the science that deals with the other special senses. Ear, nose and throat specialists.

Front 23

Lens

Back 23

- located posterior to the pupil and iris

- made of thin lens fibers that contain large protein called ____.

-

Front 24

Crystalins

Back 24

large proteins in the lens

Front 25

Together the ___ and the ___ focus images on the ____ to facilitate clear vision.

Back 25

cornea, lens, retina

Front 26

Light is ____ as it passes through the ___ and ___. This ____ focuses light rays from an object toward a focal point on the _____.

Back 26

refracted, cornea, lens, bending, central fovea

Front 27

What helps control the shape of the lens? Whats this called?

Back 27

ciliary bodies and suspensory ligaments, accomodation.

Front 28

Refraction and accommodation result in the projection of a clear miniature image of what we are looking at, onto the retina, but the image arrives at the retina ____ and ___.

Back 28

upside down, backwards

Front 29

Cataracts

Back 29

cloudy lens... can be surgically corrected by removing lens and replacing with artificial one.

Front 30

intraocular pressure

Back 30

pressure inside of eye that maintains it shapes -> aqueous humor

Front 31

Glaucoma

Back 31

higher than normal intraocular pressure

a disorder that affects about 2% of population over 40. Can be corrected by surgery in which the small passages that usually allow to drain eye fluid are reopened.

Front 32

Retina

Back 32

lines the posterior three-quaters of the eyevall and is beginning of visual pathway.

Front 33

Photoreceptors

Back 33

specialized cells of the retina that transduce light rays into graded potentials

Front 34

Two types of photoreceptors:

Back 34

Rods and Cones

Front 35

Rods (4)

Back 35

- used for black & white vision in low light

- about 125 million in each retina, mostly around periphery

- allow us to descriminate between different shades of dark and light

- used to see shapes and movements.

Front 36

Cones: (3)

Back 36

- specialized for colour vision and precision of vision (acuity)

- about 6 million in each retina, concentrated at the central fovea

- Supply most of our visual information and loss of cones can lead to legal blindness (more detrimental than rods)

Front 37

Central Fovea

Back 37

highest density of cones found in eye and its where light strikes the retina when you look directly at something

- has the greatest visual acuity

Front 38

Macula

Back 38

surrounds the fovea... contributes further to the increased acuity of the fovea.

Front 39

Macula Degeneration

Back 39

is a complex condition that can lead to a debilitating loss of acute colour vision, which is limited to this area of the eye

Front 40

Both rods and cones contain a ___ that react to the presence of ____, the basic units of visible light.

Back 40

visual pigment, photons

Front 41

Explanation of vision: (4)

Back 41

1. photon strikes visual pigment which causes chemical change in pigment that affects flow of Na+ across photoreceptor membrane

2. Sensory impulses travel forwards to surface of retina, via bipolar cells and then ganglion cell... then laterally to optic nerve

3. Axons of ganglion cells converge on the optic disc, penetrate the wall of eye and continue toward the diencephalon of brain as the optic nerve

4. Optic nerve conduct electrical impulses to the cerebral cortex of the cerebral hemispheres.

Front 42

The special senses of equilibrium and hearing are provided by various ___ cells in the ____ ear.

Back 42

hair, inner

Front 43

____ sensations inform us of the position of the head in space by monitoring gravity, acceleration and rotation

Back 43

equilibrium

Front 44

____ enables us to detect and interpret sounds waves.

Back 44

hearing

Front 45

Equilibrium

Back 45

provided by the vestibular apparatus, the combination of the vestibules and semicircular canals

Front 46

Two types of Equilibrium

Back 46

Dynamic and Static

Front 47

Dynamic Equilibrium

Back 47

Sensory receptors in the semi-circular ducts/canals respond to rotational movements of the head

Front 48

Endolymph

Back 48

fluid in ducts that moves hairs of semi-circular canal

Front 49

Ampulla

Back 49

a house for the equilibrium receptors

Front 50

Dynamic equilibrium process

Back 50

movement of the head in the direction of a duct causes movement of endolymph along the length of that duct. This movement pushes the cupula and bends the enclosed stereocilia, resulting in stimulation of the hair cells. i.e. depolarization or hyperpolarization depending on the direction of movement.

Front 51

Static Equilibrium

Back 51

Sensory receptors in the vestibule (Saccule and Utricule) respond to changes in head position relative to the force of gravity.

Front 52

Statoconia (a.k.a.)

Back 52

Otoliths - calcium carbonate crystals that covered hair cells

Front 53

Otolithic Membrane

Back 53

the whole structure of otoliths, haircells and gelatinous material.

Front 54

Otolith rests on hair cells and moves in response to ___ and __, specifically ____ and ____.

Back 54

gravity, movement, acceleration, deceleration

Front 55

Kinocilium

Back 55

a single large cilium

Front 56

Movement of the otolith bends the ___, resulting in stimulation of the hair cells. Movement towards the kinocilium causes ___ whereas movement away causes ___.

Back 56

stereocilim, Depolarization, hyperpolarization

Front 57

Nerve impulses for sense and perceiving equilibrium are carried to the brain via the _____ of the _____ nerve.

Back 57

vestibular branch, vestibulocochlear

Front 58

Hearing is provided by the hair cells of the _____ duct.

Back 58

cochlear

Front 59

Frequency is measured in

Back 59

cycles/second of Hertz (Hz)

Front 60

Normal frequency range of human hearing

Back 60

20-20,000 Hz

Front 61

Speech occurs in the frequency range of...

Back 61

100-3000 Hz

Front 62

Hearing damage can occur as the result of exposure to either ____ or _____ loud sounds in the range of ____ and higher.

Back 62

acute, chronic, 80dB

Front 63

Six steps to hearing

Back 63

1. Sound waves arrive at the tympanic membrane, which vibrates when struck

2. Vibration cause displacement of the auditory ossicles (malleus, incus, stapes)

3. Vibrations of the stapes are transmitted to the oval window, which establishes pressure waves in the prerilymph of the vestibular duct

4. The pressure waves distort the basilar membrane on their way to the round window of the cochlea

5. Vibration of the basilar membrane causes vibration of hair cells against the tectorial membrane which displaces the endolymph, which in turn opens of sodium channels in the hair cells.

6. Nerve impulses for hearing are carried to the brain via the cochlear branch of the vestibulocochlear nerve

Front 64

Hair cells are in

Back 64

Organ of Corti

Front 65

Endolymph vs Perilymph locations

Back 65

Endolymph: cochlear duct

Perilymph: vestibular duct and tympanic duct