Carotid body

Carotid Body

The carotid body is a small cluster of chemoreceptors and supporting cells located near the fork (bifurcation) of the carotid artery (which takes oxygenated blood from the heart to the brain). The carotid body detects changes in the composition of arterial blood flowing through it, mainly the partial pressure of oxygen, but also of carbon dioxide. The carotid body is one of the peripheral chemoreceptors of the respiratory system, assisting in the regulation of respiration.

Structure

The carotid body is located in the neck on either side of the trachea, and is approximately 2 mm in size. It is located at the bifurcation of the common carotid artery, between the internal carotid artery and the external carotid artery. The carotid body is composed of clusters of cells known as glomus cells, which are connected by a thin connective tissue. These cells are surrounded by a dense network of capillaries and nerve endings.

Function

The primary function of the carotid body is to monitor the levels of oxygen and carbon dioxide in the blood. When oxygen levels are low (hypoxia), or carbon dioxide levels are high (hypercapnia), the carotid body sends signals to the respiratory center in the brainstem, which in turn increases the rate and depth of breathing. This response is a key component of the body's homeostatic control of its blood gases.

Clinical significance

Dysfunction of the carotid body can lead to conditions such as sleep apnea, hypertension, and heart failure. In addition, tumors of the carotid body, although rare, can occur. These are typically benign and slow-growing, but can cause symptoms such as difficulty swallowing, hoarseness, and a pulsating mass in the neck.

See also

• Peripheral chemoreceptors
• Respiratory system
• Carotid artery