SPECIAL SENSES Presented by: Cassandra Acuña Sarah Budd Ornita Bouie Jada Brown B.Valerie Bastien Exploring Gustation, Olfaction, and Auditory Systems
GustationPresented by: Ornita Bouie Group A Sources: 1. Http://emedicine.Medscape.Com/article/1948599-overview#aw2aab6b5 2. 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-
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)
Aural SensesPresented by: Sarah Budd Sources: Group A http://www.biographixmedia.co m/human/ear-anatomy.html Human Anatomy & Physiology, 8e Elaine Marieb & Katja Hoehn
Anatomy of the Auditory System The Auditory System is divided into three subsystems. Outer Ear Middle Ear Inner Ear
The Outer Ear AnatomyOuter 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
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 MembranousLabyrinthEndolymph: Fluid Located In The Membranous LabyrinthVestibule: 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 DuctSpiral Organ: The Device That Converts Vibrations Into Nerve Impulses. It Has AnEpithelium Composed Of Hair Cells (Which Is Where Everything That We Hear ComeFrom) And Supporting Cells
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
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.
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.
MultimediaThe CNS, Sense of SmellHow the Body Works : The Olfactory Pathway
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, conjunc tiva, lacrimal apparatus, and extrinsic eye muscles.
Accessory Structures of EyeEyebrows Eyebrow Help shade the eye from sunlight and prevent perspiration trickling down the forehead from reaching the eyes.
Accessory StructuresEyelids the eyelidmusclescauseblinking every3-7 secondsand to protectthe eye whenit isthreatened byforeignobjects.
Accessory StructuresLacrimalApparatus(tears)- thestructures thatsecrete anddrain tearsfrom the eye. Itconsists of thelacrimal glandand the ductsthat drainexcess lacrimalsecretions intothe nasalcavity.
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.