Haistmisepiteeli

Haistmisepiteeli, also known as olfactory epithelium, is a specialized tissue located in the nasal cavity responsible for the sense of smell. It lines a small area of the upper nasal passages, typically measuring a few square centimeters in humans. This epithelium is characterized by its distinct cellular composition and arrangement, which are crucial for detecting and processing airborne odor molecules.

The primary cells within the haistmisepiteeli are olfactory receptor neurons. These neurons are unique in that they are continually regenerated throughout an individual's life, a remarkable feat of tissue maintenance. Each olfactory receptor neuron extends a dendrite to the surface of the epithelium, which terminates in a knob bearing several cilia. These cilia are studded with olfactory receptors, proteins that bind to specific odorant molecules.

In addition to olfactory receptor neurons, the haistmisepiteeli contains supporting cells, also known as sustentacular cells, which provide metabolic and physical support to the neurons. Also present are basal cells, located at the base of the epithelium, which are stem cells responsible for generating new olfactory receptor neurons and supporting cells.

When odor molecules enter the nasal cavity, they dissolve in the mucus layer covering the haistmisepiteeli. They then bind to the olfactory receptors on the cilia of the olfactory receptor neurons. This binding triggers a signaling cascade within the neuron, leading to the generation of an electrical impulse. These impulses are then transmitted along the axons of the olfactory receptor neurons, which form the olfactory nerve, to the olfactory bulb in the brain. The olfactory bulb further processes this information, allowing for the perception of smell.