The Power of Smell. Dakota Aulds, Theresa VanSchyndel, Molly Hibbler

Transcription

1 The Power of Smell Dakota Aulds, Theresa VanSchyndel, Molly Hibbler

2 Key Terms -Olfactory epithelium is a specialized epithelial tissue inside the nasal cavity that is involved in smell -Olfactory receptor neuron is a transduction cell within the olfactory system -Olfactory bulb is a neural structure of the vertebrate forebrain involved in the sense of smell. Flow of olfactory information from receptors to glomeruli layer. -Glomerulus (glomeruli plural) is a spherical structure located in the olfactory bulb of the brain where synapses form between the terminals of the olfactory nerve and the dendrites of mitral, periglomerular and tufted cells.

3 Physiology of Smell 1. Odorant molecules (scents) floating in the air reach the nostrils and dissolve in the mucus (which is on the roof of each nostril). 2. Underneath the mucus, in the olfactory epithelium, specialized receptor cells called olfactory receptor neurons detect the odor. These neurons are capable of detecting thousands of different odors. 3. The olfactory receptor neurons transmit the information to the olfactory bulbs, which are located in the ethmoid bone. 4. The olfactory bulbs has sensory receptors that are actually part of the brain which send messages directly to: The most primitive brain centers where they influence emotions and memories (limbic system structures), and Higher centers where they modify conscious thought (neo-cortex). 5. These brain centers perceive odors and access memories to remind us about people, places, or events associated with these olfactory sensations.

4 Anatomy of Smell

5 Anatomy of Smell

6 I Smell Trouble *Total Anosmia: inability to smell all odorants on both sides of the nose *Partial Anosmia: inability to smell certain odorants *Specific Anosmia: lack of ability to smell one or a few odorants Hyperosmia: abnormally acute smell function and often interpreted as hypersensitivity to odors Dysosmia: distorted or perverted smell perception Parosmia/Cacosmia: change in quality of an olfactory cue Phantosmia: odor sensations in absence of an olfactory stimulus *Olfactory agnosia: inability to recognize odor sensations despite olfactory processing, language, and intellectual function intact Seen in certain stroke and postencephalitic patients Presbyosmia: smell loss due to aging

7 Why are my Spidey-Senses Tingling? Aging -Younger people have thousands of glomeruli(nerve endings) arranged in single or double layers -Decrease with aging Head trauma Upper respiratory infections Dementia-related Diseases (Alzheimer s) Parkinson s Disease Congenital Dysfunction Kallmann Syndrome Toxic Exposure

8 Treatment: Differs between conductive loss and receptive loss Receptive Vitamin A necessary in repair of epithelium Zinc improvements in anosmia Aminophylline Conductive Therapy camp role in transduction

9 Fun Facts! The sense of smell is the first of all our senses to develop. Even before we are born, our sense of smell is fully formed and functioning. A woman s sense of smell is much stronger than a man s. It is heightened even more in the first half of the menstrual cycle and reaches its peak when she is most fertile Your sense of smell accounts for 75-95% of the impact a flavour has. Without being able to smell the difference between onion and potato, it d be difficult to tell them apart. Smell is 10,000 times more sensitive than any of the other senses The olfactory response is immediate, extending directly to the brain. This is the only place where the central nervous system is directly exposed to the environment

10 Mini Review- Steps 1) Volatile, or gaseous state, molecules are sniffed into the nostril itself while being filtered through protected nose hairs 2) Travel to the back of the nose, called the Olfactory Epithelium, where they attach on and dissolve in mucus 3) Within Olfactory Epithelium are Olfactory Sensory Neurons, they send action potential through the Ethmoid Bone 4) Olfactory Bulbs are located there, which is the pathway to the brain COOL SIDE NOTE!! Each Olfactory receptor only can smell one kind of smell 5) All of these different smells combine together in the Glomerulus, then send it to the Mitral Cell which sends the signal to the brain

11 More Steps 6) Message travels along the Olfactory Tract to the Olfactory Cortex 7) The Cortex sends the information to Two different parts of the brain a. The Frontal Lobe > Understands what it is b. Limbic System such as the Hypothalamus and the Amygdala > Memories/ past experiences

12 Works Cited "Neuroscience for Kids - Chemical Senses." Neuroscience for Kids - Chemical Senses. N.p., n.d. Web. 10 Mar Cruickshanks), (Photo: David. "20 Fascinating Facts about Our Sense of Smell." Mirror. N.p., 25 Aug Web. 10 Mar "The Sense of Smell: A Powerful Sense." The Sense of Smell: A Powerful Sense. N.p., n.d. Web. 10 Mar