1. Anthony J Greene1 Smell: Olfactory System

2. Anthony J Greene2 Olfactory Senses Taste and smell go hand-in-hand Plugging your nose and eating is not the same as unplugging it and eating the same food Brain relies on both senses to receive the message

3. Anthony J Greene3 Why do we need to smell? Smells help us to enhance the taste of our foods Helps us to distinguish between what is undesirable or lethal to us from what is pleasant or nutritious

4. Anthony J Greene4 Where does it take place? Nose or mouth Superior area of Nasal Cavity Cribriform plate of ethmoid bone-consists of many holes

5. Anthony J Greene5 Scent molecule

6. Anthony J Greene6 Structure of the cell Cilia- hair like structures that receive molecules from the inhaled air and interact with the mucus in our nose Dendrite – part of the nerve cell that receives the incoming signal of the detection of a specific odorant Olfactory receptor cell- is what receives the signal and continues to pass the message along to the Olfactory bulb

7. Anthony J Greene7 An odorant is a molecule that is either water or lipid soluble from the environment Then it travels to the nasal cavity where it attaches to the olfactory nerve receptors where a series of biochemical signals take place

8. Anthony J Greene8 The long ends of the Olfactory nerve cells must carry the signal and extend through the cribriform plate to synapse with other nerves of the Olfactory bulbs http://www.youtube.com/watch?v= 9qdor5V0SDk

9. Anthony J Greene9 What part of the brain receives the signal? Once the Olfactory bulb receives the nerve impulse it sends it to Cranial Nerve I Cranial Nerve I is the nerve which carries the nerve impulse to the Limbic system of the brain. Then it tells you what you are smelling!

10. Anthony J Greene10 What happens when you get sick? Your sense of smell is affected because the nasal membranes are inflamed This causes much fluid and mucus build up Mucus is then drained to the external nares or to the oropharynx to be digested or disposed of orally (cough or spit)

11. Anthony J Greene11 Abnormalities of Olfaction Anosmia- absence of smell that can be temporary or permanent Hyposmia-diminished olfactory sensitivity; may be early sign of Parkinson’s Disease, Alzheimer’s and Dementia Dysosmia-Altered sense of smell; wrongly interpreted smells or hallucinations of smells Epitaxis- a.k.a. nosebleeds due to dry membrane or broken blood vessels