Injection of hypeonic saline in which region of hypothalamus produces intense thirst:
**Core Concept**
The hypothalamus is a crucial region in the brain that regulates body temperature, hunger, thirst, and other vital functions. The hypothalamic region involved in the regulation of thirst is the lateral hypothalamus, which responds to changes in the body's hydration status by stimulating the sensation of thirst.
**Why the Correct Answer is Right**
The correct region involved in the sensation of thirst is the **lateral hypothalamus**. This area contains osmoreceptors that detect changes in the concentration of solutes in the blood, particularly sodium. When hyperosmolality is detected, the lateral hypothalamus is stimulated, leading to the sensation of intense thirst. This mechanism is mediated by the **AV3V region**, a specific area in the lateral hypothalamus that contains osmoreceptors sensitive to changes in blood osmolality.
**Why Each Wrong Option is Incorrect**
* **Option A:** The **suprachiasmatic nucleus** (SCN) is primarily involved in regulating circadian rhythms and is not directly responsible for the sensation of thirst.
* **Option B:** The **ventromedial hypothalamus** is involved in the regulation of appetite and satiety, but not the sensation of thirst.
* **Option C:** The **dorsomedial hypothalamus** is involved in the regulation of body temperature and is not directly responsible for the sensation of thirst.
**Clinical Pearl / High-Yield Fact**
Remember that the sensation of thirst is a protective mechanism that helps maintain proper hydration status in the body. The lateral hypothalamus's response to hyperosmolality is essential for regulating fluid balance and preventing dehydration.
**Correct Answer:** C.