SPECIAL SENSES

Exploring Gustation, Olfaction, and Auditory Systems

Presented by: Cassandra Acuña

Sarah BuddOrnita Bouie

Jada BrownB.Valerie Bastien

Presented by: Ornita BouieGroup A

Gustation

Sources:1. Http://emedicine.Medscape.Com/article/1948599-overview#aw2aab6b52. Http://www-psych.Stanford.Edu/~lera/psych115s/notes/lecture11/3. Http://www.Sensorysociety.Org/ssp/wiki/taste_anatomy/

Why is Taste Important? Taste is a gate-keeper sensory mechanism

designed to test food and other substances before they enter the body.

Things that are potentially useful for the body tend to taste good, and things that are potentially harmful taste bad.

The Anatomy of Taste

The tongue contains many ridges and valleys called papillae. There are four types of papillae.

Filiform papillae: cone shaped & found all over the tongue Fungiform papillae: mushroom shaped & found at the tip

and sides of the tongue. Foliate papillae: a series of folds along the sides of the

tongue. Circumvallate papillae: shaped like flat mounds surrounded

by a trench & found at the back of the tongue. All papillae except filiform contain taste buds (so the very center of

your tongue which only has filiform papillae is "taste-blind”)

Anatomy of Taste

Pathways of Taste Transduction occurs when different taste substances cause a change in the flow of

ions across the membrane of a taste cell. Different substances affect the membrane in different ways.

Bitter and sweet substances bind into receptor sites which release other substances into the cell.

Sour substances contain H+ ions that block channels in the membrane. Salty substances break up into Na+ ions which flow through the

membrane directly into the cell. Electrical signals generated in the taste cells are transmitted in three pathways:

1. The chorda tympani nerve-conducts signals from the front and sides of the tongue.

2. The glosso-pharyngeal nerve-conducts signals from the back of the tongue.

3. The vagus nerve-conducts taste signals from the mouth and the larynx. These three nerves make connections in the brain stem in the nucleus of the solitary

tract (NST) before going on to the thalamus and then to two regions of the frontal lobe.

The Experience of Taste Your experience of taste depends on

your internal state, past experiences, and your genes.

Our sensation of taste also depends heavily on smell and texture.

Taste Assessment Saltiness: is a taste produced by the presence of sodium ions.

(sodium chloride) Bitterness: is the most sensitive of the tastes, many perceive

it as unpleasant, sharp, or disagreeable. (quinine hydrochloride or quinine sulfate)

Sweetness: usually regarded as a pleasurable sensation, is produced by the presence of sugars and a few other substances. (sucrose)

Sourness: is the taste that detects acidity. (citric acid) Umami (旨味 ): is an appetitive taste and is described as a

savory or meaty taste. (Monosodium Glutamate)

Presented by: Sarah BuddGroup A

Aural Senses

Sources: http://www.biographixmedia.com/human/ear-anatomy.html Human Anatomy &Physiology, 8eElaine Marieb &Katja Hoehn

Ear Anatomy

Anatomy of the Auditory System

The Auditory System is divided into three subsystems.

Outer Ear

Middle Ear

Inner Ear

The Outer Ear Anatomy

Outer Ear Auricle: Directs Sound Into The Ear Auditory Canal: Passage That Leads To The Tympanic

Membrane Through The Temporal Bone External Acoustic Meatus: Opening Of The Auditory

Canal Guard Hairs: Protect The Outer End Of The Auditory Canal Cerumen: Also Known As Earwax, This Coats The Guard

Hairs Which Helps Block Foreign Particles

The Middle Ear Anatomy Middle Ear: located in the tympanic cavity of the

temporal bone tympanic membrane: also known as the eardrum, closes the inner ear and seperates it from

The Middle Ear Auditory (Eustachian) Tube: the passageway to the nasopharynx, it allows air to enter or leave the tympanic cavity which equalizes air pressure on both sides of the tympanic membrane

Auditory Ossicles: bones located within the tympanic cavity include the malleus, incus, and stapes

Oval Window: where the inner ear begins

Inner Ear AnatomyBony (Osseous) Labyrinth: Temporal Bone Passageways That House The Inner EarMembranous Labyrinth: Fleshy Tubes That Line The Bony LabyrinthPerilymph: Fluid That Is A Layer Of Cushion Between The Bony And Membranous LabyrinthEndolymph: Fluid Located In The Membranous Labyrinth Vestibule: Chamber That Begins The Labyrinths Which Contain Organs Of EquilibriumCochlea: The Actual Organ Of Hearing

Contains Three Fluid Filled Chambers: • The Scala Vestiguli,• The Scala Tympani• And The Cochlear Duct

Spiral Organ: The Device That Converts Vibrations Into Nerve Impulses. It Has An Epithelium Composed Of Hair Cells (Which Is Where Everything That We Hear Come From) And Supporting CellsModiolus: The Bone That The Cochlea Winds Around

Multimedia

Equilibrium equilibrium: coordination,

balance, and orientation in three-dimensional space

static equilibrium: the perception of the orientation of the head when the body is stationary

dynamic equilibrium: the perception of motion or acceleration

Presented By: B.Valerie Bastien

Olfaction

Source:

Anatomy of Olfaction Receptors involved:

Chemoreceptors (airborne) The location:

Found in the roof of nasal cavity. Structure:

Olfactory epithelium or yellow patch of pseudostratified epithelium What are olfactory receptor cells?

Unusual bipolar neurons with each having a thin apical dendrite, which terminates and give rise to radiating olfactory cilia. Olfactory cilia is also covered in a thin layer of mucus whose function is to act as a solvent to contain and dissolve airborne odors.

What makes olfactory receptor cells unusual? Very few cells like that of the neurons of the olfactory cells continuously undergo

turnover all throughout adult life; its location at the superficial level causes it to be at risk to be exposed to damage. These cells last from 30-60 days then basal cells replace them within the olfactory epithelium.

Anatomy of Olfaction (con’t)

Physiology of Olfaction How is the olfactory receptors activated?:

Odors bind to receptor proteins in the olfactory cilium membranes; this results in cation channels being opened and generating of receptor potentials.

What is smell transduction?: Olfactory transduction starts when an odorant binds to a receptor.

Fun Facts: Humans sense of smell is capable of differentiating between 10,000 or more odors. There are 1000 smell genes located in the nose. In odor for the nose to detect a particular odorant it must be in a gaseous state

and dissolve in the mucus in the olfactory epithelium. A portion of what is known as smell is actually considered pain; pain receptors are

located in the nasal cavities which react to irritants chili peppers, menthol, and jarring scent of ammonia.

Multimedia

The CNS, Sense of Smell

How the Body Works : The Olfactory Pathway

Presented By: Jada Brown

Vision

Vision Vision is our dominant sense: Some 70%

of all the sensory receptors in the body are in the eyes, and nearly half of the cerebral cortex is involved in some aspect of visual processing.

Anatomy of Eye

The adult eye is a sphere with a diameter of about 2.5 cm. (1 inch)

The accessory structures of the eye include the eyebrows, eyelids, conjunctiva, lacrimal apparatus, and extrinsic eye muscles.

Accessory Structures of Eye

Help shade the eye from sunlight and prevent perspiration trickling down the forehead from reaching the eyes.

Eyebrows Eyebrow

Accessory Structures

Eyelids

the eyelid muscles cause blinking every 3-7 seconds and to protect the eye when it is threatened by foreign objects.

Accessory Structures

Lacrimal Apparatus (tears)- the structures that secrete and drain tears from the eye. It consists of the lacrimal gland and the ducts that drain excess lacrimal secretions into the nasal cavity.

Accessory Structures

Extrinsic eye muscles- Six extrinsic eye muscles control the movement of each eyeball. They are among the most precisely and rapidly controlled skeletal muscles in the entire body. They allow the eyes to follow moving objects and help maintain the shape of the eyeball and hold it in the orbit.

Optical Illusions

Optical Illusions

Optical Illusion

Optical Illusion