Assignment - Infographics - 155
A Note on What Makes This an Infographic
A diagram of a nose cross-section with “olfactory epithelium” labeled is not an infographic. An infographic about smell tells the journey: how does a molecule floating in the air become the smell of biryani or rain? What happens in the nose, what happens in the olfactory bulb, and why does a smell instantly bring back a childhood memory? These are the questions that make this a story worth telling.
Objective
Create a journey narrative infographic in Canva that follows a smell from airborne molecule to conscious experience, explaining each step and including what makes smell unique among the five senses.
The Journey to Follow
Stage 1: The Molecule Becomes Airborne Smells begin with volatile chemical compounds - molecules that evaporate easily and float in the air. Cooking food, a flower, petrol, rain on dry earth - all release thousands of different molecules. Different molecules have different shapes, and the shape determines the smell.
Stage 2: Entering the Nose When you breathe in, air carries these molecules through the nostrils. The nose has two pathways for smell:
- Orthonasal: breathing in through the nostrils (normal smelling).
- Retronasal: molecules from food in your mouth travel up through the back of the throat to the nose (this is why you “taste” flavor when you chew).
Stage 3: The Olfactory Epithelium High in the nasal cavity (about 5-7 cm inside), molecules reach the olfactory epithelium - a small patch of tissue (about 5 cm² in humans) containing approximately 6-10 million olfactory receptor neurons.
Each receptor neuron has hair-like cilia coated with receptor proteins. When a molecule of the right shape binds to a matching receptor protein, the neuron fires an electrical signal. Humans have about 400 different types of olfactory receptors, allowing us to detect an estimated 1 trillion different smells.
Stage 4: The Olfactory Bulb The electrical signals travel along the olfactory nerve (Cranial Nerve I) directly to the olfactory bulb - a small structure at the base of the brain. The olfactory bulb does preliminary processing: sorting signals, combining them, and beginning to identify the smell.
Stage 5: The Brain From the olfactory bulb, signals travel to:
- The olfactory cortex: identifies the smell.
- The amygdala: links the smell to an emotional response.
- The hippocampus: connects the smell to memory.
This direct pathway to the amygdala and hippocampus explains why smell triggers memories and emotions more powerfully than any other sense. All other senses are processed through the thalamus first - smell is not.
Stage 6: Conscious Perception The brain combines all these signals and produces the experience of a specific smell - the smell of your mother’s cooking, the sea, rain, or a classroom.
Why Smell is Linked to Memory
Add a dedicated panel: The olfactory system connects directly to the limbic system (which processes emotions and memory). This is why a smell can instantly recall a memory from years ago with vivid emotional detail - a phenomenon called the Proust effect.
Smell and Taste
Add a brief note: approximately 80% of what we perceive as “taste” is actually smell. When you have a blocked nose, food loses most of its flavor - only the five basic tastes (sweet, sour, salty, bitter, umami) remain, because these are detected on the tongue itself.
Design in Canva
- A cross-section of the nose and part of the brain, with the journey traced by an arrow from nostril to olfactory epithelium to olfactory bulb to brain.
- Each stage gets a numbered callout panel with name and explanation.
- A separate panel on smell and memory.
- A brief panel on smell vs. taste.
Required Elements
- All 6 stages in the journey, each explained.
- The memory connection explained.
- The smell-taste relationship noted.
- Title: “How the Nose Works: The Journey of Smell.”