The receptor cells of the olfactory epithelium are
**Core Concept**
The olfactory epithelium is a specialized mucosa in the nasal cavity responsible for detecting odorants. The receptor cells in this epithelium are a unique type of sensory neurons that play a crucial role in our sense of smell.
**Why the Correct Answer is Right**
The correct answer is **B. Bipolar neurons with microvilli**. These receptor cells have a specialized structure consisting of a bipolar cell body with microvilli on their apical surface. The microvilli increase the surface area, allowing the receptor cells to bind odorant molecules. These odorant molecules bind to specific olfactory receptors on the surface of the microvilli, triggering a signaling cascade that ultimately leads to the perception of a particular smell.
**Why Each Wrong Option is Incorrect**
- **Option A:** is incorrect because the olfactory receptor cells are not pseudounipolar neurons, which are typically found in the peripheral nervous system.
- **Option C:** is incorrect because the olfactory receptor cells do not have a unipolar structure, which is characteristic of sensory neurons in other parts of the body.
**Clinical Pearl / High-Yield Fact**
The loss of olfactory receptor cells can lead to a reduced sense of smell, which is a common symptom in various neurological disorders, including Alzheimer's disease and Parkinson's disease.
**Correct Answer: B. Bipolar neurons with microvilli**