Copyright 2009, John Wiley & Sons, Inc.

The Special Senses

Videos

Bozeman senses: https://youtu.be/TAzTFgPSPiU

How hearing works: https://youtu.be/flIAxGsV1q0

How does the ear work: https://youtu.be/qgdqp-oPb1Q

Khan, smell: https://youtu.be/5-McqAO8_Qw

Khan, taste: https://youtu.be/-vp1X7_u3KU

TedEd, smell: https://youtu.be/snJnO6OpjCs

Vsauce, why two nostrils: https://youtu.be/eiAx2kqmUpQ

Handwritten, the eye: https://youtu.be/MJxxFwVu1OM

Its okay to be smart, how many smells?: https://youtu.be/-yEtBps-BnI

Is your red the same as mine? https://youtu.be/evQsOFQju08

How the eye works: https://youtu.be/RE1MvRmWg7I

TedEd how we see color: https://youtu.be/l8_fZPHasdo

Ted Ed, Why we cry: https://youtu.be/keMF8YzQoRM

Copyright 2009, John Wiley & Sons, Inc.

Comparison of General and Special Senses

General Senses

Include somatic sensations (heat,

pain).

Sensors are scattered throughout

the body.

Simple structures.

Special Senses

Include smell, taste, vision, hearing

and equilibrium.

Concentrated in specific locations

in the head.

Complex.

Copyright 2009, John Wiley & Sons, Inc.

Copyright 2009, John Wiley & Sons, Inc.

Olfaction: Sense of Smell Olfactory epithelium contains 10-100

million receptors.

Can detect about 10,000 different

odors.

Olfactory receptor- a neuron with

olfactory hairs that respond to chemical

stimulation of odorants.

Supporting cells- provide support and

nourishment.

Basal cells- replace olfactory receptors.

Copyright 2009, John Wiley & Sons, Inc.

Olfaction: Sense of Smell Olfactory epithelium contains 10-100

million receptors.

Can detect about 10,000 different

odors.

Olfactory receptor- a neuron with

olfactory hairs that respond to chemical

stimulation of odorants.

Supporting cells- provide support and

nourishment.

Basal cells- replace olfactory receptors.

Copyright 2009, John Wiley & Sons, Inc.

Olfaction: Sense of Smell Odorant binds to the receptor of an

olfactory hair→

nerve impulse through olfactory nerves

(using Na+ channels)→

olfactory bulbs→

olfactory tract→

primary olfactory area of the cerebral

cortex.

Olfactory Epithelium and

Olfactory Receptors

continued…

Anatomy of Taste Buds and Papillae

Taste bud- made of three types of

epithelial cells: supporting cells, gustatory

receptor cells and basal cells.

About 50 gustatory cells per taste bud.

Each one has a gustatory hair that projects

through the taste pore.

Taste buds are found in the papillae.

Three types of papillae: vallate

(circumvallate), fungiform and foliate.

Copyright 2009, John Wiley & Sons, Inc.

Physiology of Gustation

Five types of taste:

Sour: It is mostly acidic solutions

like lemon juice. This sensation is

caused by hydrogen ions (H+).

Sweet: Caused by sugar and its

derivatives such as fructose or

lactose.

Copyright 2009, John Wiley & Sons, Inc.

Physiology of Gustation

Bitter: There are a wide range of

sensory cells that respond to bitter

substances. From an evolutionary

standpoint, this can be explained by

the many different bitter species of

plants, some of which were

poisonous.

Salty: Food containing table salt.

Which consists of sodium and

chloride.

Umami: ????

Copyright 2009, John Wiley & Sons, Inc.

Physiology of Gustation

Savory or Umami: The “umami”

taste, which is similar to the taste of

meat broth, is usually caused by

glutamic acid or aspartic acid.

Glutamic acid – ripe tomatoes or

cheese.

Aspartic acid – asparagus and other

plants.

Chinese cuisine uses glutamate as

flavor enhancers.

Info from: U.S. national library of

Medicine

Copyright 2009, John Wiley & Sons, Inc.

Gustatory Pathway

Vision or Sight

Visible light:

400-700 nm.

Copyright 2009, John Wiley & Sons, Inc.

Accessory Structures of the Eye

Copyright 2009, John Wiley & Sons, Inc.

Accessory Structures of the Eye

Anatomy of the Eyeball

Copyright 2009, John Wiley & Sons, Inc.

Fibrous tunic - outer layer

Sclera: The white outer coat

of the eye, surrounding the

iris.

Cornea: The clear front

window of the eye which

focuses light into the eye.

Corrective laser surgery

reshapes the cornea,

changing the focus.

Anatomy of the Eyeball

Copyright 2009, John Wiley & Sons, Inc.

Fibrous tunic - outer layer

Sclera: The white outer coat

of the eye, surrounding the

iris.

Cornea: The clear front

window of the eye which

focuses light into the eye.

Corrective laser surgery

reshapes the cornea,

changing the focus.

Anatomy of the Eyeball

Copyright 2009, John Wiley & Sons, Inc.

Vascular tunic or uvea- middle

layer

Ciliary body: Structure

containing muscle, located

behind the iris, which

focuses the lens.

Iris: The colored part of the

eye which helps regulate the

amount of light entering the

eye.

Anatomy of the Eyeball

Copyright 2009, John Wiley & Sons, Inc.

Retina- inner layer

Optic nerve: A bundle of

more than a million nerve

fibers carrying visual

messages from the retina to

the brain.

Anatomy of the Eyeball

Copyright 2009, John Wiley & Sons, Inc.

Lens- Focuses light rays onto the

retina. The lens is transparent,

and can be replaced if necessary.

Lens divides the eyeball into two

cavities: anterior and posterior.

Anterior cavity- further divided

into anterior and posterior

chambers. Both are filled with

aqueous humor.

Posterior cavity (vitreous

chamber)-filled with vitreous

body.

Anatomy of the Eyeball

Copyright 2009, John Wiley & Sons, Inc.

Pupil is an opening in the center

of the iris.

Contraction of the circular

muscles of the iris causes

constriction of the pupil.

Contraction of the radial muscles

causes dilation of the pupil.

Cavities of the Eyeball

Copyright 2009, John Wiley & Sons, Inc.

The Lacrimal Apparatus

Copyright 2009, John Wiley & Sons, Inc.

Structure of Rod and Cone Photoreceptors

Rods: involved in non-colored and reduced light vision.

Cones: involved in color and acute vision.

Refraction Abnormalities and their Correction

Nearsightedness (myopia)-

close objects seen clearly.

Image is focused in front of the

retina. Correction- use of

concave lens.

Farsightedness (hyperopia)-

distant objects seen clearly.

Image is focused behind the

retina. Correction- use of

convex lens.

Copyright 2009, John Wiley & Sons, Inc.

The Ear

Anatomy of the Ear

Copyright 2009, John Wiley & Sons, Inc.

Anatomy of the Ear

External (outer) ear

Auricle or pinna: the outer part of

the ear, serves to "catch" the sound

waves.

Tympanic membrane: commonly

called the eardrum. It is positioned

between the ear canal and

the middle ear.

Copyright 2009, John Wiley & Sons, Inc.

Anatomy of the Ear

The eardrum is rigid, and very

sensitive. Even the slightest air-

pressure fluctuations will move it

back and forth.

The eardrum can also serve to

protect the inner ear from

prolonged exposure to loud, low-

pitch noises.

The eardrum is the entire sensory

element in your ear.

Copyright 2009, John Wiley & Sons, Inc.

Anatomy of the Ear

Middle ear

Malleus: When the

eardrum vibrates, it moves

the malleus from side to

side like a lever.

Incus: The malleus is

connected to the incus,

which is attached to the

stapes.

Stapes: The other end of

the stapes rests against

the cochlea, through

the oval window.

Anatomy of the Ear

Middle ear

Auditory (eustachian)

tube: Creates pressure

balance.

How hearing works:

http://www.youtube.com/w

atch?v=flIAxGsV1q0

Copyright 2009, John Wiley & Sons, Inc.

The Internal Ear

Copyright 2009, John Wiley & Sons, Inc.

The Internal Ear

Semicircular canals: sense

head rotations and balance.

Cochlea: contains the spiral

organ of Corti, the receptor

for hearing.

Organ of Corti: consists of

tiny hair cells that translate

the fluid vibration of sounds

into electrical impulses that

are carried to the brain.

Copyright 2009, John Wiley & Sons, Inc.

Physiology of Equilibrium

Two types of equilibrium:

Static - maintenance of the

body position relative to the

force of gravity.

Dynamic - maintenance of

body position (mainly head) in

response to rotational

acceleration and deceleration.

Physiology of Equilibrium

Tilting of the head forward→

sliding of the otolithic

membrane bending the hair

bundles→

receptor potential→

vestibular branch of the

vestibulocochlear nerve.

Physiology of Equilibrium

Tilting of the head forward→

sliding of the otolithic

membrane bending the hair

bundles→

receptor potential→

vestibular branch of the

vestibulocochlear nerve.

Test Review

The online quiz is here:

http://highered.mheducation.com/sites/0072351136/student_view

0/chapter15/chapter_quiz.html

Or you can google: Anatomy and Physiology online quiz.

Make sure you are on Chapter 15: The Special Senses

Questions to focus on: 24, 25, 26, 28, 31, 35, 41, 44, 45, 46, 58,

63, 64, 65, 66, 67, 68, 69, 70, 78, 80, 85, 86, 87, 88.

Copyright 2009, John Wiley & Sons, Inc.

The Senses Flowchart

Create a flowchart that explains

how each sense receives input and

how it relays that information to the

brain.

Properly use or label the key terms

in the diagrams or in the

explanations.

Each flowchart should include at

least four steps with each step

being at least one sentence.

Olfactory pathway: Olfactory tract, olfactory

nerve, olfactory epithelium, olfactory cilia,

olfactory bulb, and cribriform plate.

Gustatory pathway: Taste bud, taste pore,

gustatory cell, gustatory cortex, cranial

nerve fibers, and gustatory hair.

Visual pathway: Lens, pupil, iris, cornea,

retina, sclera, optic nerve, optic tract,

visual cortex, rods, and cones.

Auditory pathway: Auditory canal,

Tympanic membrane, Malleus, Incus,

Stapes, Cochlea, Organ of Corti, auditory

nerve, and auditory cortex.

Copyright 2009, John Wiley & Sons, Inc.