A P II EXAM II Power Point 1 The Chemical Senses Define and identify the anatomy of the olfaction receptor cells and epithelium Olfactory Epithelium layer Pseudostratified epithelium 1 layer of cells giving the false impression of multi Known as Olfactory Epithelium located on the roof of the nasal cavity Three types of cells Olfactory Receptor Millions on each side of nasal septum Supporting Surround Olfactory Cells This type of cell produces a thick mucus layer Mucus and cilia provide molecules in air Afferent neurons then send a signal up to the Glomeruli The Glomeruli is where the receptor cell and olfactory tract synapse to capture chemicals and surface area Basal Base of epithelium Olfactory Receptor Cells Bipolar Neurons thin dendrite that ends with a knob giving way to olfactory cilia Olfactory Cilia Serve to increase receptive surface area These lie flat on epithelium and are covered by mucus that is produced by the supporting cells 1 The mucus captures airborne chemicals A P II EXAM II Filaments of the Olfactory Nerve run superior to inferior through the cribriform plate Replaced every 30 60 days by differentiation of basal cells These cells can distinguish about 10 000 different odors Glutamate is the MAJOR transmitter for this system Serotonin and Dopamine are also involved but to a lesser extent Receptors are stimulated by a minimum of 1 000 smell genes being activated Unique receptor protein Each cell has only 1 TYPE of receptor protein Each protein responds to some odorants more than others to capture specific odor Some receptor proteins respond to a few organs some receptor proteins respond to many This is all due to threshold sensitivity Nasal cavity contains pain receptors that respond to irritants Explain in detail the transduction of smell and its process and adaptation through the somatosenstory system Smell Transduction How communication is shaped by a chemical 1 Odor binds to a receptor 2 G protein signaling molecule is activated which activates the enzyme adenylate cyclase to synthesize cAMP cAMP is a secondary messenger 3 cAMP binds to 4 This allows a cation membrane channel to open from the extracellular to intracellular Cation channel space 5 Na and Ca2 flow in causing depolarization Olfactory receptors send the AP to the second order neurons Mitral Cells inside glomeruli Different glomeruli respond to different odors Glomeruli are specific all the same information gathers in it s labeled glomeruli so all of the same communication signals are in one place Once this information bundles together it moves toward the MITRAL cell then the BRAIN 2 Mitral cells send information down olfactory tract to either the Thalamus or past the Thalamus to the Hypothalamus amygdala or limbic system sympathetic emotional responses to odors A P II EXAM II Describe and locate the types of taste buds associated with gustation Taste buds primarily on the tongue housed in papillae Abrasive Feel o Fungiform Papillae Top 0 9 tastebuds o Foliate Papillae Lateral foliate A AT T THE E EDGE o Circumvallate Papillae Back Largest in size Least in o Filliform Papillae Fill over tongue 150 tastebuds Describe the gustatory cells Cells Stratified Squamous Each bud has 50 100 cells of which there are 2 types of cells Gustatory Replaced 30 60 days or Basal replaced 7010 days Like stem cells o Gustatory Cells Gustatory Hairs Hair projects through at taste pore into saliva The chemical is captured by hair sticking up taste pore Like Olfactory Cilia and Mucus o Dendrites in each cell take signal from receptor cell to the brain 2 Types of Gustatory cells one release its neurotransmitter serotonin the other uses ATP 3 A P II EXAM II 1st cell Serotonin carried by synaptic vesicles 2nd cell uses ATP as NT b c they can t use synaptic vesicles Name the major types of taste stimuli and where they most commonly occur Taste Location o Sweet Receptors Tip of Tongue o Salty and Sour Sides o Bitter Back o Umami Pharynx However all taste can come from all areas these are just primary regions Describe the physiology and transduction of gustation including the afferent fibers that are involved Gustation Physiology 1 Chemicals dissolved in saliva contact gustatory hairs 2 Binding of chemical to gustatory cell induces depolarization 3 At highest change in membrane voltage neurotransmitter released from synapse 4 Binding of NT to the associated afferent fiber dendrite moves information to the 1st order neurons Afferent Fiber Origination 1 Facial Nerve VII 4 A P II EXAM II a Anterior 2 3 of tongue 2 Glossopharyngeal Nerve IX a Posterior 1 3 of tongue and the oropharynx 3 Vagus Nerve X a Throat region Epiglottis Lower Pharynx 4 Solitary Nucleus of Medulla 2nd order neurons 5 Thalamus 3rd order neurons 6 Taste Gustatory Cortex a Elicit digestive reflexes through PNS on the way saliva into mouth Define the disorders of the chemical senses Smell Taste Anosmias Absence of smell Hyposmia Impaired sense of smell Dysosmia Distorted sense of smell Ageusia Absence of taste Hypogeusia Decreased sensitivity Hypergeusia Increased sensitivity Dysgeusia Distorted sense of taste Power Point 2 Vision The Eye Part I Locate and describe the accessory structures of the eye in detail along with the path through the lacrimal apparatus Accessory Structures 1 Eyebrows Overlie supra orbital margins of skull Shade the eyes from sunlight and prevent perspiration from reaching eyes a Contraction of Orbicularis Oculi is what closes our eye 2 Eyelids Palpebrae Separated by the palpebral fissure meet at the medial and lateral commissures of the eye a Function Protect the eyes Blink 3 7 sec prevent drying through blinking 3 Lacrimal caruncle In medial commissure fleshy elevation that contains sweat glands These sebaceous glands provide oil and secretions for lubrication of our eyes so it doesn t dry out 4 Tarsal Plates Connective Tissue Sheets support eyelid 5 Eyelashes Projecting follicles unencapsulated free nerve ending of which a touch prevents reflex blinking a Has tarsal glands in tarsal plates to secret oily lubrication contains sebaceous gland and Ciliary gland for oily secretions 6 Conjunctiva transparent mucous membrane covering the eyelid Provides an anchor for muscle Orbicularis Oculi to close eyelid and Levator Palpebrae superioris to raise eyelid 5 A P II EXAM II Lacrimal Apparatus Lacrimal Gland and ducts that drain secretions Lacrimal Gland In orbit above lateral end of the eye Releases lacrimal secretion tears as a saline
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