haistmisnärvi

The term "haistmisnärvi" is Finnish and translates to "olfactory nerve" in English. It is the first cranial nerve, responsible for the sense of smell, or olfaction. This nerve is unique among cranial nerves as it is not a true nerve but rather a collection of nerve fibers that extend directly from the olfactory bulb in the brain to the olfactory epithelium located in the nasal cavity.

The olfactory epithelium contains specialized sensory cells called olfactory receptor neurons. These neurons have cilia that project into the nasal mucus. When odor molecules dissolve in the mucus, they bind to specific receptors on these cilia. This binding triggers an electrical signal that travels along the axon of the olfactory receptor neuron. These axons then pass through tiny openings in the cribriform plate of the ethmoid bone and synapse within the olfactory bulb, which is located just above the nasal cavity.

From the olfactory bulb, signals are processed and then transmitted to various parts of the brain, including the piriform cortex, amygdala, and entorhinal cortex. This processing allows for the identification and interpretation of smells, as well as their connection to emotions and memories. Damage to the olfactory nerve can result in anosmia, the loss of the sense of smell, or hyposmia, a reduced sense of smell. These conditions can arise from head trauma, infections, or neurodegenerative diseases.