CHAPTER 15 THE SPECIAL SENSES - Warner Pacific …classpages.warnerpacific.edu/bdupriest/BIO 221/Chapter 15 Special... · CHAPTER 15 THE SPECIAL SENSES . ... Quiz Q4: Which nerve

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CHAPTER 15

THE SPECIAL SENSES


THE SPECIAL SENSES

Overview


Which of these is NOT a special sense?

1) touch

2) sight

3) taste

4) smell

5) hearing


THE SPECIAL SENSES

VISION


Figure 15.1b The eye and associated accessory structures.

(b) Lateral view; some structures shown in sagittal section

Levator palpebrae superioris muscle Orbicularis oculi muscle

Eyebrow

Tarsal plate

Palpebral conjunctiva

Tarsal glands

Cornea

Palpebral fissure

Eyelashes

Bulbar conjunctiva

Conjunctival sac

Orbicularis oculi muscle


Figure 15.2 The lacrimal apparatus.

Lacrimal gland

Excretory ducts of lacrimal glands

Lacrimal punctum

Lacrimal canaliculus

Nasolacrimal duct

Inferior meatus of nasal cavity

Nostril

Lacrimal sac


Figure 15.3a Extrinsic eye muscles.

Inferior rectus muscle

Inferior oblique muscle

Superior oblique

muscle

Superior oblique

tendon

Superior rectus

muscle

Lateral rectus

muscle

(a) Lateral view of the right eye


Figure 15.3b Extrinsic eye muscles.

Superior oblique

muscle

Common

tendinous ring

Trochlea

Superior oblique

tendon

Superior rectus

muscle

(b) Superior view of the right eye

Axis at center

of eye

Medial

rectus muscle

Inferior

rectus muscle

Lateral

rectus muscle


Figure 15.4a Internal structure of the eye (sagittal section).

Central artery

and vein of

the retina

Optic disc

(blind spot)

Optic nerve Posterior pole

Fovea centralis

Macula lutea

Retina Choroid

Sclera

Ora serrata

(a) Diagrammatic view. The vitreous

humor is illustrated only in the

bottom part of the eyeball.

Ciliary body Ciliary zonule (suspensory ligament)

Cornea

Iris

Anterior pole

Pupil

Anterior segment (contains aqueous humor)

Lens

Scleral venous sinus

Posterior segment (contains vitreous humor)


Figure 15.4b Internal structure of the eye (sagittal section).

(b) Photograph of the human eye.

Ciliary zonule (suspensory ligament)

Cornea

Lens

Anterior segment

Margin of pupil

Iris

Ciliary body Vitreous humor in posterior segment

Choroid

Fovea centralis

Optic disc

Optic nerve

Ciliary processes

Retina

Sclera


Which layer of the eye contains photoreceptors?

1) sclera

2) choroid

3) retina


Quiz Q4: Which nerve controls the muscles

that move the eyeball?

1) Vagus nerve

2) Phrenic nerve

3) Oculomotor nerve

4) Sciatic nerve


Quiz Q5: True or false: Tears are produced

In the medial corner of the eye.

1) True

2) False


Figure 15.5 Pupil dilation and constriction, anterior view.

Iris (two muscles)

• Sphincter pupillae

• Dilator pupillae

Sphincter pupillae

muscle contraction

decreases pupil size.

Dilator pupillae

muscle contraction

increases pupil size.

Sympathetic + Parasympathetic +


Figure 15.6a Microscopic anatomy of the retina.

(a) Posterior aspect of the eyeball

Neural layer of retina Pigmented

layer of

retina

Central artery

and vein of retina Optic

nerve

Sclera

Choroid

Optic disc

Pathway of light


Figure 15.6b Microscopic anatomy of the retina.

Pigmented

layer of retina Pathway of light

Pathway of signal output

(b) Cells of the neural layer of the retina

Amacrine cell Horizontal cell

• Rod

Photoreceptors

• Cone

Bipolar

cells Ganglion

cells


Figure 15.6c Microscopic anatomy of the retina.

Choroid

Pigmented

layer of retina

Axons of

ganglion

cells

Outer segments

of rods and cones Nuclei of

ganglion

cells

Nuclei of

rods and

cones

Nuclei

of bipolar

cells

(c) Photomicrograph of retina


A neuron which receives information from a

rod or cone and passes it to another neuron

is called a…

1) Photoreceptor

2) Retina cell

3) Bipolar cell

4) Ganglion cell

5) Optic nerve cell


Figure 15.7 Part of the posterior wall (fundus) of the right eye as seen with an ophthalmoscope.

Macula lutea

Central artery and vein emerging from the optic disc

Optic disc

Retina


Figure 15.8 Circulation of aqueous humor.

Sclera

Bulbar

conjunctiva

Scleral venous

sinus

Posterior

chamber

Anterior

chamber Anterior

segment

(contains

aqueous humor)

Corneal-

scleral junction

Cornea

Cornea

Corneal epithelium

Corneal endothelium

Aqueous humor

Iris

Lens

Lens

epithelium

Lens

Posterior

segment

(contains vitreous

humor)

Ciliary zonule

(suspensory

ligament)

Ciliary

processes

Ciliary

muscle

Ciliary

body

Aqueous humor is

formed by filtration

from the capillaries in

the ciliary processes. Aqueous humor flows from the

posterior chamber through the pupil

into the anterior chamber. Some also

flows through the vitreous humor

(not shown). Aqueous humor is reabsorbed into the

venous blood by the scleral venous sinus.

1

1

2

3

2

3


Figure 15.9 Photograph of a cataract.


Figure 15.10 The electromagnetic spectrum and photoreceptor sensitivities.

Wavelength (nm)

Visible light

(b)

(a)

Blue

cones

(420 nm) Rods

(500 nm)

Green

cones

(530 nm)

Red

cones

(560 nm)

X rays UV Infrared Micro-

waves Radio waves

Gamma

rays

Light absorp

tion (p

ervent of m

axim

um

)


Figure 15.11 Refraction.


Figure 15.12 Bending of light by a convex lens.

Point sources

(a) Focusing of two points of light.

(b) The image is inverted—upside down and reversed.

Focal points


Figure 15.13a Focusing for distant and close vision.

Lens

Inverted

image

Ciliary zonule

Ciliary muscle

Nearly parallel rays from distant object

(a) Lens is flattened for distant vision. Sympathetic

input relaxes the ciliary muscle, tightening the ciliary

zonule, and flattening the lens.

Sympathetic activation


Figure 15.13c Focusing for distant and close vision.

Ciliary muscle

View

Lens

Ciliary zonule

(suspensory ligament)

(c) The ciliary muscle and ciliary zonule are

arranged sphincterlike around the lens.

(Anterior segment as viewed from within the eye.)


Figure 15.13b Focusing for distant and close vision.

Divergent rays from close object

(b) Lens bulges for close vision. Parasympathetic

input contracts the ciliary muscle, loosening the

ciliary zonule, allowing the lens to bulge.

Inverted image

Parasympathetic activation


Figure 15.14 Problems of refraction (1 of 3).

Focal

plane

Focal point is on retina.

Emmetropic eye (normal)



Concave lens moves focal

point further back.

Eyeball too long

Uncorrected

Focal point is in front of retina.

Corrected

Myopic eye (nearsighted)



Eyeball

too short

Uncorrected

Focal point is behind retina.

Corrected

Convex lens moves focal

point forward.

Hyperopic eye (farsighted)


An image of an object is presented ________

on the retina.

1) Upside down and mirror image

2) Upside down and reversed

3) Right side up and mirror image

4) Right side up and reversed


A myopic person cannot see distant images

well because…

1) Their eyeball is too long

2) Their eyeball is too short

3) Their eyeball is too wide

4) Their eyeball is too narrow


Figure 15.15a Photoreceptors of the retina.

Process of bipolar cell

Outer fiber

Apical microvillus

Discs containing visual pigments

Melanin granules

Discs being phagocytized

Pigment cell nucleus

Inner fibers

Rod cell body

Cone cell body

Synaptic terminals

Rod cell body

Nuclei

Mitochondria

Connecting cilia

Basal lamina (border with choroid)

(a) The outer segments

of rods and cones

are embedded in the

pigmented layer of

the retina.

Pig

me

nte

d la

ye

r

Ou

te

r se

gm

en

t

In

ne

r

se

gm

en

t


Figure 15.15b Photoreceptors of the retina.

Rod discs

Visual

pigment

consists of

• Retinal • Opsin

(b) Rhodopsin, the visual pigment in rods, is embedded in

the membrane that forms discs in the outer segment.


Figure 15.16 The formation and breakdown of rhodopsin.

11-cis-retinal

Bleaching of

the pigment:

Light absorption

by rhodopsin

triggers a rapid

series of steps

in which retinal changes shape

(11-cis to all-trans)

and eventually

releases from

opsin.

1

Rhodopsin

Opsin and

Regeneration

of the pigment:

Enzymes slowly

convert all-trans

retinal to its

11-cis form in the

pigmented

epithelium;

requires ATP.

Dark Light

All-trans-retinal

Oxidation

2H+

2H+

Reduction

Vitamin A

2

11-cis-retinal

All-trans-retinal


Figure 15.17 Events of phototransduction.

1

2

Light (photons) activates visual pigment.

Visual pigment activates transducin

(G protein).

3 Transducin activates phosphodiester

ase (PDE).

4 PDE converts cGMP into GMP, causing cGMP levels to fall.

5 As cGMP levels fall, cGMP-gated cation channels close, resulting in hyperpolarization.

Visual

pigment

Light

Transducin

(a G protein)

All-trans-retinal

11-cis-retinal

Open cGMP-gated cation channel

Phosphodiesterase (PDE)

Closed cGMP-gated cation channel


Figure 15.18 Signal transmission in the retina (1 of 2).

1 cGMP-gated channels open, allowing cation influx; the photoreceptor depolarizes.

Voltage-gated Ca2+ channels open in synaptic terminals.

2

Neurotransmitter is released continuously.

3

4

Hyperpolarization closes voltage-gated Ca2+ channels, inhibiting neurotransmitter release.

5

No EPSPs occur in ganglion cell.

6

No action potentials occur along the optic nerve.

7

Neurotransmitter causes IPSPs in bipolar cell; hyperpolarization results.

Na+

Ca2+

Ca2+

Photoreceptor

cell (rod)

Bipolar

cell

Ganglion

cell

In the dark


Figure 15.18 Signal transmission in the retina (2 of 2).

1 cGMP-gated channels are closed, so cation influx stops; the photoreceptor hyperpolarizes.

Voltage-gated Ca2+ channels close in synaptic terminals.

2

No neurotransmitter is released.

3

Lack of IPSPs in bipolar cell results in depolarization.

4

Depolarization opens voltage-gated Ca2+ channels; neurotransmitter is released.

5

EPSPs occur in ganglion cell.

6

Action potentials propagate along the optic nerve.

7

Photoreceptor

cell (rod)

Bipolar

cell

Ganglion

cell

Light

Ca2+

In the light


The protein responsible for detecting light

in rods is…

1) Vitamin A

2) photoreceptor

3) 11-cis-retinal

4) rhodopsin


True or False: Photoreceptors generate action

potentials when they are stimulated by light.

1) True

2) False


Figure 15.19a Visual pathway to the brain and visual fields, inferior view.

Pretectal nucleus

Right eye Left eye

Fixation point

Optic radiation

Optic tract

Optic chiasma

Uncrossed (ipsilateral) fiber Crossed (contralateral) fiber

Optic nerve

Lateral geniculate

nucleus of

thalamus

Superior colliculus Occipital lobe (primary visual cortex)

(a) The visual fields of the two eyes overlap considerably.

Note that fibers from the lateral portion of each retinal field do not cross at the optic chiasma.

Suprachiasmatic nucleus


Figure 15.19b Visual pathway to the brain and visual fields, inferior view.

Optic radiation

Superior colliculus

(sectioned)

Lateral geniculate

nucleus

Optic tract

Optic chiasma

Optic nerve

(b) Photograph of human brain, with the right side

dissected to reveal internal structures.

Corpus callosum


Which of the following structures is not involved

in the processing of visual information?

1) Retina

2) Thalamus

3) Medulla oblongata

4) Visual cortex in occipital lobe


THE SPECIAL SENSES

OLFACTION (SMELL)


Figure 15.21a Olfactory receptors.

Olfactory tract

Olfactory bulb

(a)

Nasal

conchae

Route of

inhaled air

Olfactory

epithelium


Figure 15.21b Olfactory receptors.

Mitral cell (output cell)

Olfactory

gland

Olfactory

tract

Olfactory

epithelium

Filaments of olfactory nerve

Cribriform plate of ethmoid bone

Lamina propria connective tissue

Basal cell

Supporting cell

Dendrite

Olfactory cilia

Olfactory bulb

Glomeruli

Axon

Olfactory receptor cell

Mucus

Route of inhaled air

containing odor molecules (b)


Figure 15.22 Olfactory transduction process.

1

2

Odorant binds to its receptor.

Receptor activates G protein (Golf).

3 G protein activates

adenylate cyclase.

4 Adenylate cyclase converts

ATP to cAMP.

5 cAMP opens a cation channel allowing Na+ and Ca2+ influx and causing depolarization.

Odorant

G protein (Golf)

Receptor

Adenylate cyclase

Open

cAMP-gated

cation channel

GDP


THE SPECIAL SENSES

GUSTATION (TASTE)


Figure 15.23 Location and structure of taste buds on the tongue.

(a) Taste buds are

associated with

fungiform, foliate,

and circumvallate

(vallate) papillae.

(b) Enlarged section

of a circumvallate

papilla.

Fungiform

papillae Taste bud

Circumvallate

papilla

Epiglottis

Palatine tonsil

Foliate papillae

Lingual tonsil

Taste fibers of cranial nerve

Connective tissue

Gustatory (taste) cells

Taste pore

Gustatory hair

Stratified squamous

epithelium

of tongue

(c) Enlarged view of a taste bud.

Basal cells


Figure 15.23a Location and structure of taste buds on the tongue.

(a) Taste buds are associated with fungiform,

foliate, and circumvallate (vallate) papillae.

Fungiform papillae

Epiglottis

Palatine tonsil

Foliate papillae

Lingual tonsil


Figure 15.23b Location and structure of taste buds on the tongue.

(b) Enlarged section of a

circumvallate papilla.

Taste bud

Circumvallate papilla


Figure 15.23c Location and structure of taste buds on the tongue.

Taste fibers of cranial nerve

Connective

tissue

Gustatory (taste) cells

Taste pore

Gustatory

hair

Stratified squamous epithelium of tongue

(c) Enlarged view of a taste bud.

Basal cells


Figure 15.24 The gustatory pathway.

Gustatory cortex

(in insula)

Thalamic nucleus

(ventral posteromedial

nucleus) Pons

Solitary nucleus in

medulla oblongata

Facial nerve (VII)

Glossopharyngeal

nerve (IX)

Vagus nerve (X)


Gustation and olfaction use what kind of

sensory receptors?

1) Mechanoreceptors

2) Chemoreceptors

3) Photoreceptors

4) Nociceptors

5) Thermoreceptors


THE SPECIAL SENSES

HEARING & EQUILIBRIUM (BALANCE)


Figure 15.25a Structure of the ear.

External acoustic meatus

Auricle

(pinna)

(a) The three regions of the ear

Helix

Lobule

Pharyngotympanic (auditory) tube

Tympanic membrane

External

ear

Middle

ear Internal ear

(labyrinth)


Figure 15.25b Structure of the ear.

Pharyngotympanic

(auditory) tube

Auditory ossicles

Entrance to mastoid antrum in the epitympanic recess

Tympanic membrane

Semicircular canals

Cochlea

Cochlear nerve

Vestibular nerve

Oval window (deep to stapes)

Round window

Incu (anvil)

Malleus (hammer)

Stapes (stirrup)

(b) Middle and internal ear

Vestibule


Figure 15.26 The three auditory ossicles and associated skeletal muscles.

Pharyngotym-

panic tube

Tensor

tympani

muscle

Tympanic

membrane

(medial view)

Stapes

Malleus

View

Superior

Anterior

Lateral

Incus Epitympanic

recess

Stapedius

muscle


The separation between the outer ear and

inner ear is the…

1) Auricle

2) Incus

3) Oval window

4) Tympanic membrane


The spiral-shaped structure in the inner ear

which contains receptors for hearing is the…

1) vestibule

2) macula

3) cochlea

4) pharyngotympanic tube


Figure 15.27 Membranous labyrinth of the internal ear.

Anterior

Semicircular

ducts in

semicircular

canals

Posterior

Lateral

Cristae ampullares in the membranous ampullae

Utricle in

vestibule

Saccule in

vestibule Stapes in

oval window

Temporal bone

Facial nerve

Vestibular

nerve

Superior vestibular ganglion

Inferior vestibular ganglion

Cochlear

nerve

Maculae

Spiral organ (of Corti)

Cochlear

duct

in cochlea

Round

window


Figure 15.28a Anatomy of the cochlea.

(a) Helicotrema

Modiolus Cochlear nerve, division of the vestibulocochlear nerve (VIII)

Cochlear duct

(scala media)

Spiral ganglion

Osseous spiral lamina

Vestibular membrane


Figure 15.28b Anatomy of the cochlea.

(b)

Cochlear duct (scala media; contains endolymph)

Tectorial membrane

Vestibular membrane

Scala vestibuli (contains perilymph)

Scala tympani

(contains

perilymph) Basilar

membrane

Spiral organ

(of Corti)

Stria

vascularis

Spiral

ganglion

Osseous spiral lamina


Figure 15.28c Anatomy of the cochlea.

(c)

Tectorial membrane Inner hair cell

Outer hair cells

Hairs (stereocilia) Afferent nerve

fibers

Basilar

membrane

Fibers of cochlear nerve

Supporting cells


Figure 15.28d Anatomy of the cochlea.

Inner

hair

cell

Outer

hair

cell

(d)


True or false: The organ of Corti senses

sound waves when the tectorial membrane

vibrates.

1) True

2) False


The actual sensory receptor of hearing is the…

1) the cochlea

2) hair cell

3) the basilar membrane

4) the tympanic membrane


Figure 15.29 Sound: source and propagation.

Area of high pressure

(compressed

molecules)

Crest

Trough

Distance Amplitude

Area of low pressure

(rarefaction)

(a) A struck tuning fork alternately compresses

and rarefies the air molecules around it,

creating alternate zones of high and

low pressure.

(b) Sound waves

radiate outward

in all directions.

Wavelength A

ir p

re

ssu

re


Figure 15.30 Frequency and amplitude of sound waves.

Time (s)

(a) Frequency is perceived as pitch.

High frequency (short wavelength) = high pitch Low frequency (long wavelength) = low pitch

(b) Amplitude (size or intensity) is perceived as loudness.

High amplitude = loud Low amplitude = soft

Time (s)

Pre

ssu

re

P

re

ssu

re


Figure 15.30a Frequency and amplitude of sound waves.

Time (s)

(a) Frequency is perceived as pitch.

High frequency (short wavelength) = high pitch

Low frequency (long wavelength) = low pitch

Pre

ssu

re


Figure 15.30b Frequency and amplitude of sound waves.

(b) Amplitude (size or intensity) is perceived

as loudness.

High amplitude = loud

Low amplitude = soft

Time (s)

Pre

ssu

re


The “pitch” of a sound is determined by…

1) amplitude of a sound wave

2) frequency of a sound wave


Figure 15.31a Pathway of sound waves and resonance of the basilar membrane.

Scala tympani

Cochlear duct

Basilar membrane

1 Sound waves vibrate the tympanic membrane.

2 Auditory ossicles vibrate. Pressure is amplified.

3 Pressure waves created by the stapes pushing on the oval window move through fluid in the scala vestibuli.

Sounds with frequencies below hearing travel through the helicotrema and do not excite hair cells.

Sounds in the hearing range go through the cochlear duct, vibrating the basilar membrane and deflecting hairs on inner hair cells.

Malleus Incus

Auditory ossicles

Stapes

Oval window

Scala vestibuli

Helicotrema

Cochlear nerve

3 2

1

Round window

Tympanic membrane

(a) Route of sound waves through the ear


Figure 15.31b Pathway of sound waves and resonance of the basilar membrane.

Fibers of basilar membrane

(b) Different sound frequencies cross the

basilar membrane at different locations.

Medium-frequency sounds displace the basilar membrane near the middle.

Low-frequency sounds displace the basilar membrane near the apex.

Base

(short,

stiff

fibers)

Frequency (Hz)

Apex

(long,

floppy

fibers)

Basilar membrane

High-frequency sounds displace the basilar membrane near the base.


Figure 15.32 Photo of cochlear hair cell with its precise array of stereocilia.


“Resonance” refers to…

1) Something really making sense

2) The vestibule and cochlea vibrating at the

same time and same frequency

3) The response of fibers of a particular

length vibration with sound waves of a

particular frequency.

4) Fibers of a particular length vibrating with

sound waves of a particular amplitude.


Figure 15.33 The auditory pathway.

Medial geniculate nucleus of thalamus

Primary auditory cortex in temporal lobe

Inferior colliculus

Lateral lemniscus

Superior olivary nucleus (pons-medulla junction)

Spiral organ (of Corti)

Bipolar cell

Spiral ganglion of cochlear nerve

Vestibulocochlear nerve

Medulla

Midbrain

Cochlear nuclei

Vibrations

Vibrations


Which of these structures is NOT involved in

carrying information from the vestibulocochlear

nerve?

1) thalamus

2) Auditory cortex

3) pons

4) Medulla oblongata


Figure 15.34 Structure of a macula.

Macula of saccule

Otoliths

Hair bundle

Kinocilium

Stereocilia

Otolithic membrane

Vestibular nerve fibers

Hair cells

Supporting cells

Macula of utricle


Figure 15.35 The effect of gravitational pull on a macula receptor cell in the utricle.

Otolithic membrane

Kinocilium

Stereocilia

Receptor potential

Nerve impulses generated in vestibular fiber

When hairs bend toward the kinocilium, the hair cell depolarizes, exciting the nerve fiber, which generates more frequent action potentials.

When hairs bend away from the kinocilium, the hair cell hyperpolarizes, inhibiting the nerve fiber, and decreasing the action potential frequency.

Depolarization

Hyperpolarization


Figure 15.36a–b Location, structure, and function of a crista ampullaris in the internal ear.

Fibers of vestibular nerve

Hair bundle (kinocilium

plus stereocilia)

Hair cell

Supporting

cell

Membranous

labyrinth

Crista

ampullaris

Crista ampullaris

Endolymph

Cupula

Cupula

(a) Anatomy of a crista ampullaris in a

semicircular canal

(b) Scanning electron

micrograph of a

crista ampullaris

(200x)


Figure 15.36c Location, structure, and function of a crista ampullaris in the internal ear.

Fibers of vestibular nerve

At rest, the cupula stands

upright.

Section of ampulla, filled with endolymph

(c) Movement of the

cupula during

rotational

acceleration

and deceleration

Cupula Flow of endolymph

During rotational acceleration, endolymph moves inside the semicircular canals in the direction opposite the rotation (it lags behind due to inertia). Endolymph flow bends the cupula and excites the hair cells.

As rotational movement slows, endolymph keeps moving in the direction of the rotation, bending the cupula in the opposite direction from acceleration and inhibiting the hair cells.


Rotational movement is detected by…

1) Macula in utricle

2) Macula in saccule

3) Cupula & crista ampullaris attached to

semicircular canals

4) All of the above


Figure 15.37 Pathways of the balance and orientation system.

Cerebellum

Oculomotor control (cranial nerve nuclei

III, IV, VI)

(eye movements)

Spinal motor control (cranial nerve XI nuclei

and vestibulospinal tracts)

(neck movements)

Visual

receptors

Somatic receptors

(from skin, muscle

and joints)

Vestibular

nuclei

(in brain stem)

Input: Information about the body’s position in space comes

from three main sources and is fed into two major processing

areas in the central nervous system.

Output: Fast reflexive control of the muscles serving the eye

and neck, limb, and trunk are provided by the outputs of the

central nervous system.

Vestibular

receptors

Central nervous

system processing

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CHAPTER 15 THE SPECIAL SENSES - Warner Pacific …classpages.warnerpacific.edu/bdupriest/BIO 221/Chapter 15 Special... · CHAPTER 15 THE SPECIAL SENSES . ... Quiz Q4: Which nerve