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The Special Senses-Hearing Smell Sight Taste and Balance PowerPoint Presentation

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Description : Check out this medical PowerPoint presentation titled "The Special Senses - Hearing, Smell, Sight, Taste and Balance" by A. BENNO SUSAI.

This medical PowerPoint presentation is about the special senses, the senses that involve specific organs and receptors dedicated to one particular type of stimulus. The five special senses are hearing, smell, sight, taste, and balance.

Hearing: Hearing is the ability to perceive sound. The ears are the organs responsible for hearing, and they consist of the outer ear, middle ear, and inner ear. Sound waves are collected by the outer ear, amplified by the middle ear, and transmitted to the inner ear, where they are converted into nerve impulses that are sent to the brain for interpretation.
Smell: Smell is the ability to perceive odors. The olfactory system, located in the nasal cavity, is responsible for smell. Olfactory receptors detect chemicals in the air, which are then transmitted to the brain for interpretation.
Sight: Sight is the ability to perceive light. The eyes are the organs responsible for sight, and they consist of the cornea, iris, lens, retina, and optic nerve. Light enters the eye through the cornea, is focused by the lens, and is converted into nerve impulses by the retina. The optic nerve then transmits these impulses to the brain for interpretation.
Taste: Taste is the ability to perceive flavors. Taste buds, located on the tongue and other parts of the mouth, are responsible for taste. Taste buds detect different types of molecules, which are then transmitted to the brain for interpretation.
Balance: Balance is the ability to maintain equilibrium. The vestibular system, located in the inner ear, is responsible for balance. It consists of three semicircular canals and two otolith organs. These organs detect changes in head position and movement, which are then transmitted to the brain for interpretation.

All of these special senses work together to provide us with a rich and varied sensory experience of the world around us.

Tags : Sense of Hearing, Sense of Smell, Sense of Sight, Sense of Taste,Sense of Balance, special senses

Published on : Jun 23, 2023 | Views : 1208 | Downloads : 1

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Slide 1-

The Special Senses(Hearing, Smell, Sight, Taste and Balance) CLASS: I M.Sc., UNIT: 4 PREPARED BY: A. BENNO SUSAI DEPARTMENT OF BIOCHEMISTRY, SJC, TRICHY
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The Special Senses Taste, smell, sight, hearing, and balance Special sensory receptors Localized – confined to the head region Receptors are not free endings of sensory neurons Special receptor cells DEPARTMENT OF BIOCHEMISTRY, SJC, TRICHY
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The Chemical Senses: Taste and Smell Taste – gustation Smell – olfaction Receptors – classified as chemoreceptors Respond to chemicals DEPARTMENT OF BIOCHEMISTRY, SJC, TRICHY
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Taste – Gustation Taste receptors Occur in taste buds Most are found on the surface of the tongue Located within tongue papillae DEPARTMENT OF BIOCHEMISTRY, SJC, TRICHY
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Taste Buds Collection of 50-100 epithelial cells Contain three major cell types Supporting cells Gustatory cells Basal cells Contain long microvilli – extend through a taste pore DEPARTMENT OF BIOCHEMISTRY, SJC, TRICHY
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Taste Buds Figure 16.1a, b DEPARTMENT OF BIOCHEMISTRY, SJC, TRICHY
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Taste Sensation and the Gustatory Pathway Four basic qualities of taste Sweet, sour, salty, and bitter A fifth taste – umami – “deliciousness” No structural difference among taste buds DEPARTMENT OF BIOCHEMISTRY, SJC, TRICHY
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Gustatory Pathway Taste information reaches the cerebral cortex Primarily through the facial (VII) and glossopharyngeal (IX) nerves Some taste information through the vagus nerve (X) Sensory neurons synapse in the medulla Located in the solitary nucleus DEPARTMENT OF BIOCHEMISTRY, SJC, TRICHY
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Gustatory Pathway from Taste Buds Figure 16.2 DEPARTMENT OF BIOCHEMISTRY, SJC, TRICHY
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Smell (Olfaction) Receptors are part of the olfactory epithelium Olfactory epithelium composed of: Cell bodies of olfactory receptor cells Supporting cells – columnar cells Basal cells – form new olfactory receptor cells DEPARTMENT OF BIOCHEMISTRY, SJC, TRICHY
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Smell (Olfaction) Axons of olfactory epithelium Gather into bundles – filaments of the olfactory nerve Pass through the cribriform plate of the ethmoid bone Attach to the olfactory bulbs DEPARTMENT OF BIOCHEMISTRY, SJC, TRICHY
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Olfactory Receptors Figure 16.3a, b DEPARTMENT OF BIOCHEMISTRY, SJC, TRICHY
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The Eye and Vision Visual organ – the eye 70% of all sensory receptors are in the eyes 40% of the cerebral cortex is involved in processing visual information DEPARTMENT OF BIOCHEMISTRY, SJC, TRICHY
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Figure 16.5b Accessory Structures of the Eye Lacrimal apparatus – keeps the surface of the eye moist Lacrimal gland – produces lacrimal fluid Lacrimal sac – fluid empties into nasal cavity DEPARTMENT OF BIOCHEMISTRY, SJC, TRICHY
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The Fibrous Tunic Most external layer of the eyeball Composed of two regions of connective tissue Sclera – posterior five-sixths of the tunic White, opaque region Provides shape and an anchor for eye muscles Cornea – anterior one-sixth of the fibrous tunic Limbus – junction between sclera and cornea Scleral venous sinus – allows aqueous humor to drain DEPARTMENT OF BIOCHEMISTRY, SJC, TRICHY
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Medial View of the Eye Figure 16.7a DEPARTMENT OF BIOCHEMISTRY, SJC, TRICHY
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The Vascular Tunic The middle coat of the eyeball Composed of choroid, ciliary body, and iris Choroid – vascular, darkly pigmented membrane Forms posterior five-sixths of the vascular tunic Brown color – from melanocytes Prevents scattering of light rays within the eye Choroid corresponds to the arachnoid and piamaters DEPARTMENT OF BIOCHEMISTRY, SJC, TRICHY
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Posterior View of the Anterior Half of the Eye Figure 16.9a DEPARTMENT OF BIOCHEMISTRY, SJC, TRICHY
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The Vascular Tunic Ciliary body – thickened ring of tissue – encircles the lens Composed of ciliary muscle Ciliary processes – posterior surface of the ciliary body Ciliary zonule (suspensory ligament) Attached around entire circumference of the lens DEPARTMENT OF BIOCHEMISTRY, SJC, TRICHY
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The Vascular Tunic Figure 16.8 DEPARTMENT OF BIOCHEMISTRY, SJC, TRICHY
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The Iris Visible colored part of the eye Attached to the ciliary body Composed of smooth muscle Pupil – the round, central opening Sphincter pupillae muscle (constrictor or circular) Dilator pupillae muscle (dilator or radial) Act to vary the size of the pupil DEPARTMENT OF BIOCHEMISTRY, SJC, TRICHY
Slide 22-

The Sensory Tunic (Retina) Retina – the deepest tunic Composed of two layers Pigmented layer – single layer of melanocytes Neural layer – sheet of nervous tissue Contains three main types of neurons Photoreceptor cells Bipolar cells Ganglion cells DEPARTMENT OF BIOCHEMISTRY, SJC, TRICHY
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Microscopic Anatomy of the Retina Figure 16.10a Ganglion cells DEPARTMENT OF BIOCHEMISTRY, SJC, TRICHY
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Photoreceptors Two main types Rod cells – more sensitive to light Allow vision in dim light Cone cells – operate best in bright light Enable high-acuity, color vision Considered neurons DEPARTMENT OF BIOCHEMISTRY, SJC, TRICHY
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Photoreceptors Figure 16.11 DEPARTMENT OF BIOCHEMISTRY, SJC, TRICHY
Slide 26-

Rhodopsin – Visual purple Rhodopsin Bathorhodopsin Lumirhodopsin Metarhodopsin I Metarhodopsin II All – trans retinal All – trans retinol (Vitamin A) Photoisomerization Scotopsin 11 – cis retinal 11 – cis retinol DEPARTMENT OF BIOCHEMISTRY, SJC, TRICHY
Slide 27-

Regional Specializations of the Retina Macula lutea – contains mostly cones Fovea centralis – contains only cones Region of highest visual acuity Optic disc – blind spot DEPARTMENT OF BIOCHEMISTRY, SJC, TRICHY
Slide 28-

Figure 16.10c Blood Supply of the Retina Retina receives blood from two sources Outer third of the retina – supplied by capillaries in the choroid Inner two-thirds of the retina – supplied by central artery and vein of the retina DEPARTMENT OF BIOCHEMISTRY, SJC, TRICHY
Slide 29-

Internal Chambers and Fluids The lens and ciliary zonules divide the eye Posterior segment (cavity) Filled with vitreous humor Clear, jelly-like substance Transmits light Supports the posterior surface of the lens Helps maintain intraocular pressure DEPARTMENT OF BIOCHEMISTRY, SJC, TRICHY
Slide 30-

Internal Chambers and Fluids Anterior segment Divided into anterior and posterior chambers Anterior chamber – between the cornea and iris Posterior chamber – between the iris and lens Filled with aqueous humor Renewed continuously Formed as a blood filtrate Supplies nutrients to the lens and cornea DEPARTMENT OF BIOCHEMISTRY, SJC, TRICHY
Slide 31-

Internal Chambers and Fluids Figure 16.8 DEPARTMENT OF BIOCHEMISTRY, SJC, TRICHY
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The Lens A thick, transparent, biconvex disc Held in place by its ciliary zonule DEPARTMENT OF BIOCHEMISTRY, SJC, TRICHY
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Lens, Zonule Fibers, & Ciliary Muscles DEPARTMENT OF BIOCHEMISTRY, SJC, TRICHY
Slide 34-

Lens Epithelium capsule epithelium fibers DEPARTMENT OF BIOCHEMISTRY, SJC, TRICHY
Slide 35-

The Eye as an Optical Device Structures in the eye bend light rays Light rays converge on the retina at a single focal point Light bending structures (refractory media) The lens, cornea, and humors Accommodation – curvature of the lens is adjustable Allows for focusing on nearby objects DEPARTMENT OF BIOCHEMISTRY, SJC, TRICHY
Slide 36-

Visual Pathways Most visual information travels to the cerebral cortex Responsible for conscious “seeing” Other pathways travel to nuclei in the midbrain and diencephalon DEPARTMENT OF BIOCHEMISTRY, SJC, TRICHY
Slide 37-

Visual Pathways to the Cerebral Cortex Pathway begins at the retina Light activates photoreceptors Photoreceptors signal bipolar cells Bipolar cells signal ganglion cells Axons of ganglion cells exit eye as the optic nerve DEPARTMENT OF BIOCHEMISTRY, SJC, TRICHY
Slide 38-

Visual Pathways to the Cerebral Cortex Optic tracts send axons to: Lateral geniculate nucleus of the thalamus Synapse with thalamic neurons Fibers of the optic radiation reach the primary visual cortex DEPARTMENT OF BIOCHEMISTRY, SJC, TRICHY
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Visual Pathways to the Brain and Visual Fields Figure 16.15a DEPARTMENT OF BIOCHEMISTRY, SJC, TRICHY
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Visual Pathways to Other Parts of the Brain Some axons from the optic tracts Branch to midbrain Superior colliculi Pretectal nuclei Other branches from the optic tracts Branch to the suprachiasmatic nucleus DEPARTMENT OF BIOCHEMISTRY, SJC, TRICHY
Slide 41-

Normal Opthalmoscopic View of Eye DEPARTMENT OF BIOCHEMISTRY, SJC, TRICHY
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Disorders of the Eye and Vision: Macular Degeneration Age-related macular degeneration (AMD) Involves the buildup of visual pigments in the retina Dry Wet DEPARTMENT OF BIOCHEMISTRY, SJC, TRICHY
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Macular Degeneration Simulation DEPARTMENT OF BIOCHEMISTRY, SJC, TRICHY
Slide 44-

Disorders of the Eye and Vision: Retinopathy Retinopathy in diabetes Vessels have weak walls – causes hemorrhaging and blindness DEPARTMENT OF BIOCHEMISTRY, SJC, TRICHY
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Disorders of the Eye and Vision: Trachoma Trachoma – contagious infection of the conjunctiva DEPARTMENT OF BIOCHEMISTRY, SJC, TRICHY
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The Ear: Hearing and Equilibrium The ear – receptor organ for hearing and equilibrium Composed of three main regions Outer ear – functions in hearing Middle ear – functions in hearing Inner ear – functions in both hearing and equilibrium DEPARTMENT OF BIOCHEMISTRY, SJC, TRICHY
Slide 47-

The Outer (External) Ear Composed of: The auricle (pinna) Helps direct sounds External acoustic meatus Lined with skin Contains hairs, sebaceous glands, and ceruminous glands Tympanic membrane Forms the boundary between the external and middle ear DEPARTMENT OF BIOCHEMISTRY, SJC, TRICHY
Slide 48-

The Outer (External) Ear Figure 16.17a DEPARTMENT OF BIOCHEMISTRY, SJC, TRICHY
Slide 49-

The Middle Ear The tympanic cavity A small, air-filled space Located within the petrous portion of the temporal bone Medial wall is penetrated by: Oval window Round window Pharyngotympanic tube (auditory or eustachian tube) Links the middle ear and pharynx DEPARTMENT OF BIOCHEMISTRY, SJC, TRICHY
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Structures of the Middle Ear Figure 16.17b DEPARTMENT OF BIOCHEMISTRY, SJC, TRICHY
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Figure 16.19 The Middle Ear Ear ossicles – smallest bones in the body Malleus – attaches to the eardrum Incus – between the malleus and stapes Stapes – vibrates against the oval window DEPARTMENT OF BIOCHEMISTRY, SJC, TRICHY
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DEPARTMENT OF BIOCHEMISTRY, SJC, TRICHY
Slide 53-

The Inner (Internal) Ear Inner ear – also called the labyrinth Lies within the petrous portion of the temporal bone Bony labyrinth – a cavity consisting of three parts Semicircular canals Vestibule Cochlea DEPARTMENT OF BIOCHEMISTRY, SJC, TRICHY
Slide 54-

The Inner (Internal) Ear Figure 16.17b DEPARTMENT OF BIOCHEMISTRY, SJC, TRICHY
Slide 55-

The Inner (Internal) Ear Membranous labyrinth Series of membrane-walled sacs and ducts Fit within the bony labyrinth Consists of three main parts Semicircular ducts Utricle and saccule Cochlear duct DEPARTMENT OF BIOCHEMISTRY, SJC, TRICHY
Slide 56-

The Inner (Internal) Ear Membranous labyrinth (continued) Filled with a clear fluid – endolymph Confined to the membranous labyrinth Bony labyrinth is filled with perilymph Continuous with cerebrospinal fluid DEPARTMENT OF BIOCHEMISTRY, SJC, TRICHY
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The Membranous Labyrinth Figure 16.20 DEPARTMENT OF BIOCHEMISTRY, SJC, TRICHY
Slide 58-

The Vestibule The central part of the bony labyrinth Lies medial to the middle ear Utricle and saccule – suspended in perilymph Two egg-shaped parts of the membranous labyrinth House the macula – a spot of sensory epithelium DEPARTMENT OF BIOCHEMISTRY, SJC, TRICHY
Slide 59-

The Vestibule Macula – contains receptor cells Monitor the position of the head when the head is still Contains columnar supporting cells Receptor cells – called hair cells Synapse with the vestibular nerve DEPARTMENT OF BIOCHEMISTRY, SJC, TRICHY
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Anatomy and Function of the Maculae Figure 16.21a DEPARTMENT OF BIOCHEMISTRY, SJC, TRICHY
Slide 61-

Anatomy and Function of the Maculae Figure 16.21b DEPARTMENT OF BIOCHEMISTRY, SJC, TRICHY
Slide 62-

The Semicircular Canals Lie posterior and lateral to the vestibule Anterior and posterior semicircular canals Lie in the vertical plane at right angles Lateral semicircular canal Lies in the horizontal plane DEPARTMENT OF BIOCHEMISTRY, SJC, TRICHY
Slide 63-

The Semicircular Canals Figure 16.20 DEPARTMENT OF BIOCHEMISTRY, SJC, TRICHY
Slide 64-

The Semicircular Canals Semicircular duct – snakes through each semicircular canal Membranous ampulla – located within bony ampulla Houses a structure called a crista ampullaris Cristae contain receptor cells of rotational acceleration Epithelium contains supporting cells and receptor hair cells DEPARTMENT OF BIOCHEMISTRY, SJC, TRICHY
Slide 65-

Structure and Function of the Crista Ampullaris Figure 16.22 DEPARTMENT OF BIOCHEMISTRY, SJC, TRICHY
Slide 66-

The Cochlea A spiraling chamber in the bony labyrinth DEPARTMENT OF BIOCHEMISTRY, SJC, TRICHY
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The Cochlea Figure 16.23a–c DEPARTMENT OF BIOCHEMISTRY, SJC, TRICHY
Slide 68-

The Cochlea The cochlear duct (scala media) – contains receptors for hearing Lies between two chambers The scala vestibuli The scala tympani The vestibular membrane – the roof of the cochlear duct The basilar membrane – the floor of the cochlear duct DEPARTMENT OF BIOCHEMISTRY, SJC, TRICHY
Slide 69-

The Cochlea The cochlear duct (scala media) – contains receptors for hearing Organ of Corti – the receptor epithelium for hearing Consists of: Supporting cells Inner and outer hair cells (receptor cells) DEPARTMENT OF BIOCHEMISTRY, SJC, TRICHY
Slide 70-

The Role of the Cochlea in Hearing Figure 16.24 DEPARTMENT OF BIOCHEMISTRY, SJC, TRICHY
Slide 71-

Equilibrium and Auditory Pathways The equilibrium pathway Transmits information on the position and movement of the head Most information goes to lower brain centers (reflex centers) The ascending auditory pathway Transmits information from cochlear receptors to the cerebral cortex DEPARTMENT OF BIOCHEMISTRY, SJC, TRICHY
Slide 72-

Auditory Pathway from the Organ of Corti Figure 16.25 DEPARTMENT OF BIOCHEMISTRY, SJC, TRICHY
Slide 73-

Disorders of Equilibrium and Hearing: Motion Sickness Motion sickness (Kinetosis ) – carsickness, seasickness Popular theory for a cause – a mismatch of sensory inputs DEPARTMENT OF BIOCHEMISTRY, SJC, TRICHY
Slide 74-

Disorders of Equilibrium and Hearing: Meniere’s Syndrome Meniere’s syndrome – equilibrium is greatly disturbed Excessive amounts of endolymph in the membranous labyrinth Normal Meniere’s DEPARTMENT OF BIOCHEMISTRY, SJC, TRICHY
Slide 75-

Disorders of Equilibrium and Hearing: Conduction Deafness Deafness Conduction deafness Sound vibrations cannot be conducted to the inner ear Ruptured tympanic membrane, otitis media, otosclerosis Normal tympanic membrane Otitis media Ruptured tympanic membrane DEPARTMENT OF BIOCHEMISTRY, SJC, TRICHY
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Disorders of Equilibrium and Hearing: Sensorineural Deafness Deafness Sensorineural deafness Results from damage to any part of the auditory pathway mild severe DEPARTMENT OF BIOCHEMISTRY, SJC, TRICHY
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REFERNCES Arthur C. Guyton, 2005, Text Book of Medical Physiology, WB Saunders’s, USA. Gerald J. Tortora and Sandra Reynolds. 2003. Principles of Anatomy and Physiology. (10th Edition). John Wiley and Sons. Inc. Pub. New York. DEPARTMENT OF BIOCHEMISTRY, SJC, TRICHY