Lesson 2 Check Off List Describe the components of the different special senses Five Special Senses 1 Olfaction Olfactory Organs provide sense of smell Located in nasal cavity on either side of nasal septum Made up of 2 Layers o Olfactory epithelium contains olfactory receptor cells supporting cells basal stem cells to regenerate olfactory receptor cells o Lamina propria contains areolar connective tissue blood vessels nerves olfactory glands produces mucus Olfactory Glands secretions coat surfaces of olfactory organs Olfactory Receptors highly modified neurons Olfactory reception involves detecting dissolved chemicals as they interact with odorant binding proteins o Odorant binding proteins located on the cell membrane of olfactory receptor cell Olfactory Pathways Axons leaving olfactory epithelium collected into 20 or more bundles o Penetrate cribriform plate of ethmoid bone o Reach olfactory bulbs of cerebrum where first synapse occurs Axons leading olfactory bulb o Travel along olfactory tract to reach olfactory cortex hypothalamus and portions of limbic system Arriving information reaches information centers without first synapsing in thalamus Olfactory Discrimination Can distinguish thousands of chemical stimuli CNS interprets smells by the pattern of receptor activity Olfactory Receptor Population Considerable turnover receptor cells replaced by basal cells Number of olfactory receptors and sense of smell declines with age 2 Gustation provides information about the foods and liquids consumed chemoreceptors Taste Receptors Gustatory Receptors o Are distributed on tongue and portions of pharynx and larynx o Clustered into taste buds Associated with epithelial projections lingual papillae on superior surface of tongue o Taste Buds Contain Four Types of Lingual Papillae 1 Filiform papillae Do not contain taste buds provide friction 2 Fungiform papillae contain about five taste buds 3 Vallate papillae contain 100 taste buds each 4 Foliate papillae folds located at lateral margins of each tongue o Basal Cells continuously dividing to produce new gustatory receptor cells o Gustatory receptor cells Extend taste hairs through taste pore Survive only 10 days before replacement o Monitored by cranial nerves VII IX X that synapse within solitary nucleus of medulla oblongata Then on to thalamus and primary sensory cortex 3 Vision 4 Equilibrium 5 Hearing Which one s of these depend on chemoreceptors first two olfaction and gustation Which one s of these depend upon mechanoreceptors last two equilibrium and hearing Describe the sensory transduction pathway of each sense how are the neurons connected to each other to reach the brain which part of the brain do they terminate Explain how olfaction and gustation are similar Describe the way that chemicals are detected by both systems Describe the different taste sensations Gustatory Discrimination o Four primary taste sensations 1 Sweet 2 Salty involve sodium 3 Sour involve hydrogen ions 4 Bitter o Additional Human Taste Sensations 1 Umami o Characteristic of beef chicken broths and parmesan o Receptors sensitive to amino acids small peptides cheese and nucleotides 2 Water detected by water receptors in the pharynx o Dissolved chemicals contact taste hairs o Bind to receptor proteins of gustatory cell o Salt and sour receptors Use chemically gated ion channels Na of H enter through Na or H leak channels Stimulation produces depolarization of cell o Sweet bitter and umami stimuli Activate G proteins Gustducins o End Result of Taste Receptor Stimulation Release of neurotransmitters by receptor cell o Dendrites of sensory afferents wrapped by receptor o Neurotransmitters generation action potentials in membrane afferent fiber Taste Sensitivity o Exhibits significant individual differences 1000 times more sensitive to acids sour taste than sweet salty 100 more times more sensitive to bitter than acids why o Poisons a lot of poisons are bigger to the taste So it is a mechanism for us to detect something that may be dangerous o Some conditions are inherited For example phenylthiocarbamide PTC o 70 of Caucasians taste it but 30 do not o Number of taste buds begins declining rapidly at age 50 Describe the structures of the eye Eyeball o Is hollow o Is divided into 2 cavities Large posterior vitreous cavity filled with vitreous humor Smaller anterior cavity filled with aqueous humor Consists of the anterior chamber anterior to iris and posterior chamber posterior to iris Note aqueous and vitreous humor help stabilize shape of eye o Optic Disc Circular region just medial to fovea Origin of optic nerve Blind spot located here why o There are no photo receptors located there Scotomas abnormal blind spots located in other areas other than optic disc May be caused by compression of optic disc damage to photoreceptors damage to visual pathway Which are the accessory structures of the eye What are their functions Accessory Structures of the Eye o Provide protection lubrication and support o Include The palpebrae eyelids continuation of skin Blinking keeps surface of eye lubricated free of dust debris Tarsal glands secrete lipid rich product that helps keep eyelids from sticking together The superficial epithelium of eye The lacrimal apparatus Superficial Epithelium of Eye o Lacrimal caruncle Mass of soft tissue containing glands producing thick secretions Contributes to gritty deposits that appear after good night s sleep o Conjunctiva epithelium covering inner surfaces of eyelids palpebral conjunctiva and outer surface of eye ocular conjunctiva Conjunctivitis pinkeye inflammation redness caused by allergy chemical irritation Lacrimal apparatus produces distributes and removes tears o Lacrimal gland tear gland Secretions contain lysozyme an antibacterial enzyme and antibodies Slightly alkaline Tears o Collect in the lacrimal lake o Pass through Lacrimal puncta Lacrimal canaliculi Lacrimal sac Nasolacrimal duct Three Layers of the Eye 1 Outer fibrous Layer The Fibrous Layer Describe and explain the function of the different eye layers tunics To reach inferior meatus of nose Sclera white of the eye Cornea transparent anterior region Corneal limbus border between cornea and sclera 2 Intermediate vascular layer Vascular Layer Uvea Functions Provides route for blood vessels and lumphatics that supply tissues of eye Regulates amount of light entering eye Secretes and reabsorbs aqueous humor that circulates within chambers of eye Controls shape of lens which is
View Full Document
Unlocking...