SMELL, HUNGER AND THIRST

Smell

A hemical sense, meaning it detects molecules in the air.

Smell

It plays a huge role in taste, memory, and emotions-that's why certain scents can bring back strong memories.

Olfactory Receptors

Located in the upper nasal cavity, near the roof of the nose.

Olfactory Receptors

These specialized nerve cells detect airborne odor molecules

400; 10,000

Humans have around _____ types of olfactory receptors, allowing us to detect up to ______ different scents

Mucus Lining (inside the nasal cavity)

Where does the “Odor molecules from the air dissolve” ?

Olfactory Receptors

The molecules bind to _____ ____, triggering electrical signals.

Olfactory Bulb

Signals travel through the olfactory nerve to the _______ _____ in the brain

Olfactory Nerve

Carries smell signals from the nose to the brain. Unlike other nerves, it regenerates throughout life (but weakens with age)

Olfactory Bulb

Located just above the nasal cavity, sitting on the bottom of the brain.

Olfactory Bulb

Acts like a filter and relay station, processing smell signals before sending them to the brain

Olfactory Bulb

It is connected to the limbic system, which controls emotions and memory-this is why smells trigger strong memories and feelings

Olfactory receptors get "tired" quickly-this is called sensory adaptation.

• After continuous exposure to a smell, the receptors stop sending strong signals to the brain.

Why we stop noticing odors?

Sensory adaptation

Olfactory receptors get "tired" quickly-this is called _____ _____.

It is linked to taste, without smell, food tastes bland

Why smell is important?

It triggers memories & emotions Scents are processed in the limbic system, which is tied to emotions

Why smell is important?

It warns of danger - Smell helps detect smoke, gas leaks, spoiled food, and other hazards

Why smell is important?

Hunger and Thirst

These are visceral sensations, meaning they come from inside the body and help maintain balance (homeostasis).

Controlled by the Hypothalamus

In this part, hunger and thirst, if the brain monitors nutrient levels, salt balance, and hydration.

Hunger

Low glucose (sugar), fats, or amino acids signal the need for food.

Thirst

High salt levels or low water levels signal dehydration.

The brain creates the sensation of hunger or thirst to make you eat or drink

Hunger + Thirst =