Torus Aoicus is present in
**Core Concept**
Torus Aorticus, also known as the aortic body or aortic ridge, is a small mass of tissue located in the aortic arch. It is part of the aortic body system, which is involved in the regulation of blood pressure and the detection of changes in blood composition.
**Why the Correct Answer is Right**
The Torus Aorticus contains chemoreceptors that detect changes in the pH, oxygen, and carbon dioxide levels in the blood. These chemoreceptors are sensitive to hypoxia (low oxygen levels) and are responsible for stimulating the chemoreceptor reflex, which increases ventilation and heart rate in response to low oxygen levels. The Torus Aorticus is also involved in the regulation of blood pressure by detecting changes in blood pressure and sending signals to the brain to adjust heart rate and vascular tone accordingly.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because the Torus Aorticus is not located in the pulmonary artery. The pulmonary artery is a separate vessel that carries deoxygenated blood from the heart to the lungs.
* **Option B:** This option is incorrect because the Torus Aorticus is not a part of the carotid body system. The carotid body system is involved in the regulation of blood pressure and the detection of changes in blood composition, but it is located in the carotid arteries, not the aortic arch.
**Clinical Pearl / High-Yield Fact**
The aortic body system is an important component of the autonomic nervous system, and dysfunction of this system can lead to a variety of clinical disorders, including hypertension, hypotension, and respiratory failure.
**Correct Answer:** D