8. Hunger and the Chemical Senses

Digestion

The process of breaking food down into its component molecules.

Hunger

An unpleasant psychological state designed to motivate an animal to seek and consume food.

Satiety

A psychological state in which an animal does not feel a desire to eat food.

Glycogen

Our body’s main way of storing the energy from food short-term. It’s made of glucose molecules stuck together in a branching pattern.

Fat

Our body’s preferred way of storing the energy from food for prolonged periods of time.

Hypothalamus

The part of the brain responsible for producing feelings of hunger and satiety.

Ghrelin

A hormone produced by cells lining the stomach that stimulates hunger.

Neuropeptide Y (NPY)

A neurotransmitter, released by neurons in the hypothalamus, that is essential for generating the feeling of hunger.

Leptin

A hormone secreted by fat cells. Leptin inhibits hunger somewhat, but only up to a certain point, beyond which further increases in leptin do not cause notable decreases in hunger.

Taste buds

Spherical structures on the tongue, as well as parts of soft palate and throat, that house taste cells.

Taste cells

Cells responsible for detecting taste molecules in our saliva.

Gustatory neurons

Neurons that generate action potentials in response to neurotransmitters release by taste cells, and carry this taste information to the medulla.

Gustatory cortex

The part of the brain dedicated to processing taste information.

Orbital cortex

The part of the brain where taste and smell information is integrated to produce flavour.

Flavour

The rich experience of food created when taste and smell information is combined.

Olfactory epithelium

The part of the nasal cavity dedicated to processing smell.

Olfactory sensory neurons

Neurons in the olfactory epithelium that detect odourants in the air, and generate action potentials in response.

Olfactory bulb

The part of the brain that receives information from the olfactory receptor cells which synapses with the glomeruli contained in the olfactory bulb.

Glomeruli

A set of cells found in the olfactory bulb that receive and encode smell signals from olfactory receptor cells.