Human A & P II Lecture: Chapter 16

Which type of retinal cells function as second-order neurons in the visual pathway, as well as occasionally functioning as photoreceptors?

Ganglion cell

The axons of which retinal cells form the optic nerve?

Ganglion cells

Which tastants bind to G-protein coupled receptors on taste hairs?

Glutamate, Sugars, Alkaloids

Which act as sensory receptors within the utricle and saccule?

Hair cells

Which serves as the sensory receptors in the semicircular ducts?

Hair cells

How many fibers of the optic nerve cross over at the optic chiasm?

Half of them

Which sensations result primarily from the activation of exteroceptors?

Hearing, Cutaneous sensations, Vision

___________ cells and amacrine cells form horizontal connections between rods, cones, and bipolar cells.

Horizontal

Name the two cell types that function primarily to enhance the perception of the edges of objects, contrast and light intensity in the retina?

Horizontal cells, Amacrine cells.

The retina is part of which tunic of the eyeball?

Inner

Pressure waves are transduced into neural signals in which section of the ear?

Inner ear

The orbitofrontal cortex is responsible for which of the following?

Integrating different types of sensory information into an overall perception of flavor.

Which term refers to a patch of cells in the center of the retina?

Macula lutea

Which term refers to the patch of hair cells and supporting cells positioned vertically on the wall of the saccule?

Macula sacculi

Which term refers to patches of sensory epithelium within the utricle and saccule?

Maculae

The retina is examined with an instrument called a(n) _________ which illuminates and magnifies the retina.

ophthalmoscope

The ______ membranes of the maculae sacculi and utriculi are important in sensing gravity and motion.

otolithic

The gelatinous membranes of the macula sacculi and macula utriculi are weighted by protein-calcium carbonate granules called _________.

otoliths

The taste ______ are found mainly on the lingual papillae and contain the sensory receptors for taste.

buds

The color of light is determined by

its wavelength

What are the effects of light exposure on the retina?

- Cis-retinal is converted to trans isoform. - Rods decrease rate of glutamate release onto bipolar cells.

Put the components of the visual projection pathway in order starting with the retina and ending with the brain.

1. Bipolar and ganglion cells of the retina. 2. Hemidecussation in optic chiasm. 3. Optic tracts. 4. Lateral geniculate nucleus of thalamus. 5. Optic radiations. 6. Primary visual cortex in the occipital lobe.

Trace the auditory projection pathway from start to finish by placing these structures in order, starting with the nerve leaving the inner ear.

1. Cochlear nerve 2. Cochlear nuclei of medulla 3. Inferior colliculi 4. Thalamus 5. Primary auditory cortex

Which is associated with a louder sound?

1. Greater number of hair cells excited. 2. Higher firing frequency of axons in the cochlear nerve. 3. More vigorous vibration of the basilar membrane.

Place the following events in the correct order starting with what happens first:

1. Odorant molecules bind to G-protein coupled receptors on some olfactory hairs. 2. Activation of cAMP second messenger system inside olfactory cells. 3. Ion channels open in the olfactory cells' membranes. 4. Influx of cations depolarize olfactory cells. 5. Action potentials travel down the olfactory nerve.

Place the following events in order starting with the vibration of the oval window and ending with the depolarization of hair cells.

1. Oval window vibrates. 2. Pressure wave travels through the perilymph of the scala vestibuli. 3. Basilar membrane moves up and down. 4. Inner hair cells are pushed against the tectorial membrane. 5. Stereocilia bend and tip-link proteins open K+ channels. 6. K+ ions enter hair cell causing depolarization.

Put the following events in order the describe the effects of light exposure on the retina. Start with rhodopsin absorbing light, and finish with ganglion cells firing action potentials.

1. Rhodopsin absorbs light. 2. Cis-retinal isomerizes to trans-retinal. 3. Opsin triggers signaling cascade in outer segment of rod cells. 4. Glutamate release from rod cells decreases. 5. Bipolar cells detect changes in glutamate release. 6. Ganglion cells fire action potentials.

Put the following events in order to describe how the semicircular canals detect angular acceleration. Start with rotation of the semicircular canals.

1. Rotation of semicircular canals. 2. Endolymph pushes against cupula. 3. Stereocilia bend. 4. Hair cells depolarize. 5. Action potentials travel down vestibular nerve.

List the steps (in order) involved in detecting a change in static equilibrium.

1. Tilt of the head. 2. Shift of otolithic membrane. 3. Bending of stereocilia. 4. Depolarization of hair cells.

How many neurons make up most somatosensory projection pathways?

3 Reason: Somatosensory signals travel along a three-neuron pathway (first, second, and third order neurons) before reaching the brain.

Unlike in most other sensory projection pathways, auditory signals must travel along how many neurons before they reach the cortex?

4

What wavelengths of light are visible to the human eye?

400 -700 nm

What is the cupula?

A gelatinous cap surrounding the stereocilia and kinocilium of the hair cells.

Which describes the optic disc?

An area of the retina lacking photoreceptors.

Which fluid is secreted by the ciliary body and fills the anterior cavity of the eye?

Aqueous humor

The cochlea detects differences in the pitch of sound because different frequencies vibrate different areas along which of the following?

Basilar membrane

Which term refers to the comparison of signals from both the right and left ears to localize the source of a sound?

Binaural hearing

________ cells are first-order retinal neurons that synapse with photoreceptors.

Bipolar

Which type of retinal cell synapses with the photoreceptors and functions as a first order neuron in the visual pathway?

Bipolar cells

Which sensations result from activation of interoceptors?

Bladder pressure, visceral pain.

Which term refers to the transformation of cis-retinal to trans-retinal after absorption of light?

Bleaching

Which are examples of special senses?

Smell, Equilibrium, Vision

The is a highly vascular, deeply pigmented portion of the vascular tunic located behind the retina.

Choroid

What are olfactory hairs?

Cilia on olfactory cells that have receptors for odor molecules.

The suspensory ligament attaches the lens to which of the following structures?

Ciliary body

Which structure secretes the aqueous humor?

Ciliary body

Which genetic disorder is caused by a mutation in one or more photopsins?

Color blindness

Which type of photoreceptor is primarily responsible for photopic (day) vision and trichromatic (color) vision?

Cone cell

The anterior chamber of the eye is located between which two structures?

Cornea and iris

Which term refers to the mound of hair cells and supporting cells within the ampullae of the semicircular ducts?

Crista ampullaris

Which term refers to the gelatinous cap surrounding the stereocilia and kinocilium of the hair cells within the ampullae of the semicircular ducts?

Cupula

What occurs when outer hair cells of the spiral organ are stimulated by motor neurons from the pons?

Decreased mobility of the basilar membrane.

Which term refers specifically to the perception of acceleration?

Dynamic equilibrium

Vision is the perception of which of the following?

Electromagnetic radiation

____________ is a neuromodulator that blocks the conduction of pain signals by second-order spinal neurons.

Enkephalin

Which term refers to coordination, balance, and orientation in three-dimensional space?

Equilibrium

True or false: The auditory ossicles provide mechanical advantage and amplify the sound.

False Reason: Vibrations of the stapes against the the inner ear normally have the same amplitudes as vibrations of the tympanic membrane. Instead, they serve a protect function and actively muffle very loud noises.

Which term refers to the outermost layer of the eyeball?

Fibrous

Which type of lingual papillae is most abundant?

Filiform papillae

Which type of lingual papillae is responsible for giving cats' tongues their rough, sandpaper-like feel?

Filiform papillae

Which type of lingual papillae are weakly developed in humans and lose most of their taste buds by age 2 or 3 years?

Foliate papillae

Which type of lingual papillae form parallel ridges on the sides of the tongue?

Foliate papillae

Which portion of the retina produces the greatest visual acuity (sharpness of image)?

Fovea centralis

Which term refers to unencapsulated nerve endings that act as temperature receptors (warm and cold), and nociceptors (pain)?

Free nerve endings.

Which type of lingual papillae are most concentrated at the tip and sides of the tongue?

Fungiform Papillae

Which type of lingual papillae contain about three taste buds per papillae?

Fungiform papillae

The posterior chamber of the eye is located between which two structures?

Iris and lens

What happens when the retinal moiety of rhodopsin absorbs light?

It becomes all-trans retinal.

Which of the following statements about photopic vision is false? a. It is mediated by the cones. b. It has a low threshold. c. It produces fine resolution. d. It does not function in starlight. e. It does not employ rhodopsin.

It has low threshold.

What is the function of the tympanic reflex?

It muffles the transfer of vibrations to the oval window in order to protect the hair cells of the inner ear from very loud noises.

Which are functions of the vitreous body?

Keeps retina smooth. Maintains intraocular pressure.

Which structure focuses incoming light onto the retina?

Lens

The vitreous body, or humor, is a jelly-like substance located between what two structures of the eye?

Lens and retina

What are the visible bumps on the tongue called?

Lingual papillae

Which are examples of somatosensory (general) senses?

Pain, Pressure, Touch, Stretch.

Which type of receptor detects touch, pressure, stretch, or vibration?

Mechanoreceptor

Most encapsulated nerve endings are which of the following?

Mechanoreceptors

Proprioceptors respond to which type of stimuli?

Movements or changes in body position.

The olfactory _________ in the nasal cavity contains the olfactory receptors.

Mucosa

Olfactory cells are a type of what?

Neuron

Which are somesthetic senses?

Pain, Touch, Stretch, Pressure.

The sense of smell is also known as ______.

Olfaction

Olfactory neurons synapse with mitral cells and tufted cells in the ________ , which lies inferior to the frontal lobe.

Olfactory bulb.

When olfactory fibers pass through the roof of the nose, they directly enter the ______.

Olfactory bulbs

What are the two moieties of rhodopsin?

Opsin and Retinal

Which area of the retina lacks photoreceptors and is therefore referred to as the "blind spot"?

Optic disc

The area of the brain responsible for creating an overall impression of food by integrating taste, smell and visual input is the area of the cerebral cortex called the ________ cortex.

Orbitofrontal

Equilibrium refers to perception of which of the following? Choose three of the options below.

Orientation in space, Coordination, Balance

Which membrane is found in the maculae of the saccule and utricle?

Otolithic

While hearing is primarily a function of the inner hair cells, cochlear tuning is a function of the _________ hair cells.

Outer

Three rows of _________ in the cochlea have V-shaped arrays of stereocilia and tune the frequency sensitivity of the cochlea.

Outer hair cells.

Which can be defined as discomfort resulting from tissue damage or exposure to noxious stimuli?

Pain

______ is a sensory modality mediated by specialized receptors called nociceptors.

Pain

Which describe the choroid?

Part of the vascular tunic (layer), Contains numerous capillaries, Highly pigmented

The visual pigment of a cone cell is ___________.

Photopsin

Which type of receptor responds to light?

Photoreceptor

Rhodopsin is an example of a visual _________, a molecule that plays a crucial role in visual transduction by changing shape when it absorbs certain wavelengths of light.

Pigment

The vestibular nerves lead to four vestibular nuclei that are located in which regions of the brainstem? Select two of the following structures.

Pons and Medulla oblongata

The taste hairs of taste cells project into small openings in the epithelium of the tongue where they come into contact with saliva mixed with bits of dissolved food. These small pits are called taste _________.

Pores

The bending of a tip link protein leads to depolarization of the hair cell by allowing _______ ions to diffuse across the membrane into the cell.

Potassium (K+)

The position and movements of body parts is detected by receptors called ______.

Proprioceptors.

Where are free nerve endings most abundant?

Skin and mucous membranes.

Which term refers to any structure specialized to detect a stimulus?

Receptor Reason not sense organ: A sense organ contains receptors along with other accessory structures.

As light passes through different mediums, its path will bend. What is this called?

Refraction

Which term refers to the bending of light rays as they pass through objects of different density?

Refraction

The ora serrata is the scalloped margin of which structure?

Retina

Which part of the eye forms from a cup-shaped outgrowth of the diencephalon and is actually considered part of the brain?Which part of the eye forms from a cup-shaped outgrowth of the diencephalon and is actually considered part of the brain?

Retina

Match each photopigment to the type of retinal cell that produces it. Rhodopsin --> ________ Photopsin --> ________ Melanopsin --> ________

Rhodopsin: Rods Photopsin: Cones Melanopsin: Ganglion cells.

Which are the photoreceptor cells responsible for night vision?

Rods

Which type of photoreceptor cells demonstrate extensive neural convergence resulting in spatial summation, useful for low light vision?

Rods

Which are types of photoreceptor cells?

Rods and cones

Which sensory modalities depend on the activation of chemoreceptors?

Smell and Taste

Which type of stimulus will maximally activate the sensory receptors within the semicircular ducts?

Rotational motion

Which term refers to the posterior, white portion of the fibrous layer?

Sclera

Aqueous humor is reabsorbed from the anterior chamber into the blood by which of the following?

Scleral venous sinus

Rod cells are primarily responsible for which type of vision?

Scotopic (night vision)

What is gustation?

Sense of taste.

Which term refers to sensory receptors accompanied by accessory tissues that facilitate transduction of a stimulus?

Sense organ Reason: A sense organ is composed of sensory receptors along with acessory tissues.

An electrical signal generated in the retina travels along a specific pathway in the nervous system to reach the visual cortex in the brain. Which term describes that pathway?

Sensory projection pathway. Reason: A sensory projection pathway is the anatomical pathway (nerves, tracts, etc) along which a sensory signal travels on its way to the brain. Not receptor potential: The receptor potential is the local change in membrane potential that occurs when a sensory cell detects a stimulus. It is the result of sensory transduction.

Which would be true about a person with only one eye?

She would have impaired stereoscopic vision.

Which term refers to any audible vibration of molecules?

Sound

Senses in which of the following categories utilize receptors that are specific to a particular area of the body?

Special senses.

The cochlear nerve is formed by the axons of which of the following?

Spiral ganglion neurons

Which term refers to the perception of the orientation of the head when the body is stationary?

Static equilibrium

Having two eyes with overlapping visual fields is necessary for which of the following?

Stereoscopic vision

What is the function of the middle ear?

Transmit sound waves to the inner ear.

_________ is a neurotransmitter that transmits pain sensations to second-order spinal neurons.

Substance P

Which of the following plays the largest role in binaural hearing?

Superior olivary nuclei of the pons.

Which types of sensory receptors are encapsulated nerve endings?

Tactile (Meissner) corpuscles, End bulbs, Lamellar (Pacinian), corpuscles, Bulbous (Ruffini) corpuscles

Match each structure to its description. Taste cells --> ________ Taste pore --> _________ Basal cells --> _________ Supporting cells --> __________ Taste buds --> ___________ Lingual papillae --> __________

Taste Cells: Sensory cells that detect tastants. Taste pore: Small pits in the epithelium of the tongue into which taste hairs project. Basal cells: Stem cells that give rise to new taste cells. Supporting cells: Mature cells within a taste bud that do not play a role in gustation. Taste buds: Clusters of taste cells, supporting cells, and basal cells. Lingual papillae: Visible bumps on the tongue, some of which contain taste buds.

Which structure in the gustatory pathway relays signals to the primary gustatory cortex?

Thalamus

What is the primary function of the outer ear?

Transmitting sound vibrations to the tympanic membrane.

Relative to high frequency vibrations, lower frequency vibrations cause which of the following?

The distal end of the basilar membrane to vibrate more than the proximal end.

The higher the frequency of sound,

The higher its pitch.

The acceleration you feel when an elevator begins to rise is sensed by

The macula sacculi

What is a sensory projection pathway?

The neural pathway followed by sensory signals on their way to the brain.

A _________ is a receptor that responds to temperature (heat and cold).

Thermoreceptor

What role do odorant binding proteins play in olfaction?

They transport hydrophobic odorants through the mucus that coats the olfactory epithelium.

What types of stimuli activate nociceptors?

Tissue damage, potentially damaging stimuli.

What is the function of the lacrimal apparatus?

To produce and drain tears

________ is the conversion of one form of energy to another. In biology, it is used to describe the conversion of stimulus energy into an electrical signal in the nervous system.

Transduction Not Perception: Perception is the conscious awareness of stimuli. Not Sensation: Sensation is the conscious perception of a stimulus; pain, taste, and color, for example, are not stimuli but sensations resulting from stimuli. Not Transformation: Transformation is to change, and is just a general term.

What is the primary function of a sensory receptor?

Transduction Not Propagation: An action potential is propagated along an axon, meaning that the action potential is "recreated" as it spreads down the length of the axon. Not Amplification: Amplification refers to increasing something. The primary function of a sensory receptor is transduction - to convert stimulus energy into a bioelectrical signal (the receptor potential). Not Perception: Perception is the conscious awareness of a stimulus and is a function of the brain.

True or false: Molecules must first be dissolved in the saliva to be tasted.

True

True or false: The macula utriculi are oriented horizontally on the floor of the utricle.

True

True or false: Inverted images are focused onto the retina by the lens.

True Reason: Images get inverted as they pass through the lens before being projected onto the retina.

True or false: Olfactory cells become activated through a second messenger system.

True Reason: Olfaction uses the cAMP system.

True or false: Most somatosensory projection pathways decussate.

True Reason: Most of these pathways decussate so that the primary somatosensory cortex in each hemisphere receives signals from the contralateral side of the body.

True or false: Sensitivity differences during light and dark adaptation result, at least in part, from the difference in bleaching and regeneration rates of photopsin and rhodopsin.

True. Reason: It takes 5 minutes to regenerate one-half of the rhodopsin, whereas to regenerate one-half of the cone pigments (photopsin) takes only 90 seconds.

True or false: Lower firing rates of inner hair cells in narrower bands of the cochlea will be interpret by the brain as a softer sound.

True. Reason: The amplitude of the vibration determines the loudness of the sounds. Airborne pressure waves with smaller amplitudes will cause lower levels of IHC activation and softer sounds.

Match each tunic of the eyeball to its components. Tunica Fibrosa --> _______ Tunica Vasculosa --> _______ Tunica interna --> _______

Tunica Fibrosa: Sclera and cornea. Tunica vasculosa: Choroid, ciliary body, and iris. Tunica interna: Retina and beginning of the optic nerve.

Where are the olfactory tracts located?

Underneath the frontal lobe.

Where is the olfactory mucosa located?

Upper region of the nasal cavity.

Which cranial nerves are involved in collecting sensory information from taste buds? Choose three from the list below.

Vagus (cranial nerve X), Glossopharyngeal (cranial nerve IX), Facial (cranial nerve VII)

Most taste buds occur in the ________

Vallate papillae

Which type of lingual papillae contain up to half of all taste buds and are arranged in a V towards the rear of the tongue?

Vallate papillae

Rank the types of lingual papillae according to how many taste buds they contain. Start with those that contain the highest number of taste buds per papillae, and end with those that do not contain any taste buds.

Vallate papillae, Fungiform papillae, Foliate papillae, Filiform papillae

The ______ nerve carries information to the vestibular nuclei of the pons and medulla oblongata.

Vestibular

Together, the utricle, saccule, and semicircular ducts comprise which of the following?

Vestibular apparatus

The cochlear nerve and the vestibular nerve come together to form which cranial nerve?

Vestibulocochlear (VIII)

Sound is produced by which of the following?

Vibrating objects pushing against air molecules.

Which types of sensation depend on the activation of mechanoreceptors?

Vibration, Touch, Hearing, Balance.

Which term refers to a molecule that plays a crucial role in visual transduction by changing shape when it absorbs certain wavelengths of light?

Visual pigment

The duplicity theory of vision holds that a single receptor system cannot produce both high sensitivity and high resolution. What does this theory explain?

Why we have both rods and cones

The function of the _________ in a taste bud is to replace dead taste cells.

basal cells.

Cochlear hair cells rest on

basilar membrane

The _________ body is an extension of the choroid that supports the iris and lens of the eye.

ciliary

The _________ is the translucent anterior section of the fibrous layer (tunic) of the eye.

cornea

The ________ ampullaris is a mound of hair cells and supporting cells within the ampulla of a semicircular canal.

crista

The most finely detailed vision occurs when an image falls on a pit in the retina called the __________.

fovea centralis

Hot and cold stimuli are detected by:

free nerve endings

The only cells of the retina that generate action potentials are the __________ cells.

ganglion

The _________ of the midbrain receives auditory input and triggers the head-turning auditory reflex.

inferior colliculi

The colored portion of the eye surrounding the pupil is called the ______.

iris

The visual adjustment that is made when you go from a dark or dimly lit area to a brighter area is called ________ adaptation.

light

The lacrimal apparatus drains tears into the ______.

nasal cavity

________ is the visual pigment present in cones.

photopsin

The ________ epithelium of the retina absorbs stray light.

pigment

The ________ is the opening within the iris of the eye.

pupil

In the phenomenon of __________ , pain from the viscera is perceived as coming from an area of the skin.

referred pain.

What are the neural components of the eye?

retina and optic disc

The ______ ducts of the inner ear are specialized to detect rotational head movements (angular acceleration).

semicircular

The retina is attached to the eye at the optic disc and at the ora _________

serrata

The __________ is a tiny bone that vibrates in the oval window and thereby transfers sound vibrations to the inner ear.

stapes

The _________ ligament attaches the lens of the eye to the ciliary body.

suspensory

What are the five primary taste sensations?

sweet, sour, salty, bitter, umami

The retina receives its oxygen supply from

the choroid.

The choroid is ______.

very vascular.