Olfaction

What structures are involved in our sense of smell?

olfactory bulb

olfactory epithelium

glomeruli

olfactory cortex

orbitofrontal cortex

amygdala

what are odors

molecules in the air dissolve in the mucus of the olfactory epithelium and bind odorant receptors embedded in cilia of olfactory sensory neurons

how many different types of receptors does one specific olfactory receptor neuron express

1

how are olfactory sensory neurons organized

scattered across the olfactory epithelium

describe how scent molecules are processed

molecules from the air dissolve in the mucus inside the nose, they bind to specific receptors on olfactory sensory neuron in olfactory epithelium

these sensory neurons send signals through the skull to the olfactory bulb, to process smel

areas in the olfactory bulb called glomeruli organize the signals, from here, signals go to…

• olfactory cortex (smell identification)

• hippocampus (linking to memory)

• amygdala (emotional processing)

how are sensory neurons organized in the olfactory epithelium

by receptor type: neurons with the same receptor are scattered within specific zones of the olfactory epithelium

axonal convergence onto glomeruli

How does convergence of olfactory neurons onto glomeruli aid in odor discrimination?

• Thousands of olfactory receptors respond to different chemical features.

• Neurons expressing the same receptor converge onto the same glomerulus, creating a combinatorial “smell code”.

• This allows the brain to detect and differentiate a vast number of odors based on these patterns.

what is vomeronasal organ

an organ that detects pheromones found in many animals: assess degree of relatedness to other animals

What is the evidence for and against pheromone-like communication in humans?

for

• pheromone-like communication: exposure to female tears claimed reduce testosterone and sexual arousal in males

against

• humans do not have vomeronasal organ