Sense Organs

vitreous humor function

Helps give the eyeball its shape

Describe the sensory transduction of vision

Light enters the eye and is focused on the retina. With in the retina, it hits the photoreceptors and activates pigments within the rods and cones of the photoreceptors, generating a signal. The signal is modified by horizontal cells and then sent to bipolar cells where it is then passed to ganglion cells. The signal goes down the axons of the ganglion and exit the eye through the optic disc. Once the axons exit the eye, they become the optic nerve. The optic nerve then sends the signal to the brain to be processed.

What structure has been affected if you have trouble detecting vertical movement?

Macula sacculi

Put the middle ear bones in order from the tympanic membrane to the inner ear.

Malleus, incus, stapes

Describe the sensory transduction of sound

Sound waves enter the ear by way of the auditory canal and hit the tympanic membrane, causing it to vibrate. This vibration in turn vibrates the ossicles, that send the vibrations to the oval window. When the vibrations go from the oval window to the cochlea, it vibrates the fluids inside it. The fluid vibration sends a wave down the basilar membrane. This wave vibrates hair cells on the organ of corti and creates an electrical potential that opens ion channels. When these ion chanels open, potassium ions flood into the hair cell and depolarizes it. This depolarization causes the haircell to release neurotransmitters that excite the vestibulocochlear nerve and the signal gets sent to the brain.

Basal Cell function

Stem cells that synapse with sensory fibers of the taste bud

The ear drum is better know as the ________ membrane

Tympanic

suspensory ligament function

attaches the lens to the ciliary body and flattens in through tension

For taste receptors to be stimulated, the tastants must... a. stimulate basal cells b. be dissolved in water c. combine with a secondary messenger d. dissolve in mucous

b

Most people can distinguish as many as ______ odors a. 40,000 b. 4,000 c. 400 d. 40

b

semicircular canals function

balance and coordination

The "stem" cells of the olfactory system are called _______

basal cells

What is the order of events that produce an action potentials in response to head movement? 1. hairs bend 2. endolymph moves 3. action potential is initiated 4. cupula moves

2,4,1,3

What arrangement of the following structures describes the path of olfactory sensation beginning with the inhalation of an odorant? 1. cribriform plate 2. Mitral cell 3. Olfactory cell 4. mucous 5. olfactory nerve

4,3,1,2,5

Given the following parts of the retina, list the parts in the order electrical signals travel through them after light strikes the retina. 1. bipolar layer 2. ganglion cells 3. optic disc 4. optic nerve 5. photoreceptor cells

5,1,2,3,4

Describe the sensory transduction of taste.

A tastant dissolves in saliva, then floods the taste poor. This causes a depolarization of the appropriate receptor cells which then synapses with the appropriate gustatory neuron for that particular taste, creating a new action potential on the gustatory neuron which then carries the signal to the appropriate section of the brain.

Describe the sensory transduction of smell

An odorant bind to a receptor on an olfactory hair. This activates G protein, which then activates adenylate cyclase, which catalyzes ATP into cAMP, anctivating the cAMP second messenger system. The second messenger opens ion chanels and sodium or calcium ions enter the cell. This depolaries the cell and creates an action potential that travels up the olfactory receptor cell and down the axon by way of the olfactory nerve. The olfactory nerve carries the signal into the olfactory bulb where the nerve's axons converge in the glomeruli where they synapse with olfactory bulb neurons. The olfactory bulb neurons then carry the signal down the olfactory tract to the brain.

A woman is on a high altitude flight which results in a decrease in pressure. Which organ helps alleviate the pressure changes she may experience?

Auditory (eustacean) tube

How are hydrophobic odorants transported to an odor hair?

By an odor binding protein.

What is the evolutionary advantage of bitter taste?

Determining whether food is spoiled or toxic

Describe the sequence of a second messenger system.

First, a messenger binds to a receptor within the plasma membrane. This signals the receptor to activate one of its G-proteins. When the G-protein is activates, it swaps the GDP it carries for a GTP. The G-protein then travels through the membrane until it reaches adenylate cyclase and binds to it. This binding triggers the adenylate cyclase to remove two phosphate groups from molecules of ATP, converting it into the second messenger cAMP. The cAMP travels within the cytoplasm until it binds with protein kinase-A. The kinase-A adds phosphate groups to a protein, which produces a response in the cell.

lens function

Focuses light onto retina

Why are night time images perceived in black and white?

Night vision is a function of the rods and they cannot perceive color

Function of a taste pore

Passage way for tastants to enter the cell

The opening of the _____ gates depolarizes sensory receptors in the cochlear that begin the transmission of information to the brain.

Potassium

function of the auditory canal

Serves as a passageway for sound to reach the eardrum

How and why does crying lead to a runny nose?

Tears flow through lacrimal ducts the leave the eye. The final of these ducts is the nasolacrimal duct which carries the tears into the inferior meatus, sometimes resulting in tears flowing out of the nose.

Contraction of the ciliary body's smooth muscle causes ______

The lens to become more spherical

If an individual has an ear infection and takes a flight, what structure is being affected and what would be the result of them being on a flight?

The tympanic membrane; the air pressure would put pressure on the membrane, causing increased pain.

Describe the sensory transduction of equilibrium

When the head moves, endolymph in the vestibular labrynth moves into the ampula. The ampula contains a structure called the macula that has hair like structures calles stereocilia protruding from it. The endolymph's movement moves the stereocilia and stimulates the hair cell it is attached to. These hair cells send a signal about which direction the steriocilia moved down the vestibular nerve where it carries the signal to the brain. The direction the steriocilia moved tells the brain how the head is oriented.

Which of the following is true about the taste sensation "bitter?" a. its a survival warning that a substance may be toxic b. it detects the presence of amino acids c. it enables you to distinguish between different carbohydrates d. it is ONLY present in toxic foods

a

auditory tube function

allows equalization in pressure of middle ear with atmospheric pressure

cornea function

allows light to enter the eye

Damage to the semicircular canals affects the ability to detect

angular (rotational) acceleration

Function of olfactory hairs

binding sights for odor molecules

Generation of an action potential on a taste receptor... a. sometimes occurs through the use of second messengers b. occurs ONLY through the use of second messengers c. Occurs through the use of hydrogen ion gated channels, sodium gated channels, or secondary messengers d. occurs ONLY through the use of sodium gated channels

c

_______ are the sensory cells responsible for color vision

cones

ciliary body function

controls the shape of the lens and produces vitreous humor

Iris function

controls the size of the pupil, blocks light from retina

Sclera function

covers and protects eyeball

Which of the following is NOT true about cones compared to rods? a. cones produce clear, sharp images b. cones produce color images, rods do not c. cones are less sensitive to light than rods d. cones are located in the retina's periphery

d

How are hydrophilic odorants transported to an odor hair?

diffusion

olfactory receptor cell function

fires action potentials to olfactory bulb

The sharpest visual images is produced on the _____ of the retina.

fovea centralis

The most common type of secondary messenger is the ________

g-protein

What causes sour taste?

hydrogen ions released by the acids in foods

What structure senses horizontal movement?

macula utriculi

function of cribriform plate in olfaction

passage way for olfactory nerve filaments

Function of taste receptor cells

pathway for action potential created by taste hair

cochlea function

processes sound and sends the info down the auditory nerve.

fovea function

produces more defined images

retina function

receive light that the lens has focused, convert the light into neural signals, and send these signals on to the brain for visual recognition

Function of a taste hair

receptor for tastants

vestibular nerve function

relays signals from the ear to the brain

olfactory bulb function

relays smell signals to the brain

Taste cell afferent nerve function

relays taste signals to second order neurons

Injury to the _______ _______ would result in impairment of dynamic balance.

semicircular canals

function of glomeruli

sight where mitral and tufted cells synapse

The sound pathway involves the conversion of ______ energy into _____ energy into ______ energy

sound; mechanical; electrochemical

stapes function

transmits and amplifies vibrations from the incus to the oval window

function of malleus

transmits vibrations to incus via synovial joint

function of tympanic membrane

vibrates when struck by sound waves