What is the Difference Between Carotid Sinus and Carotid Body

The key difference between carotid sinus and carotid body is that the carotid sinus is a baroreceptor located at the proximal end of the internal carotid artery, while the carotid body is a chemoreceptor located in the adventitia of the bifurcation of the common carotid artery.

Sensory receptors occur in specialized organs such as eyes, ears, nose, mouth, and internal organs. They are primarily classified as chemoreceptors, thermoreceptors, mechanoreceptors, or photoreceptors. The carotid sinus and carotid body are two sensory receptors in the human body.

CONTENTS

1. Overview and Key Difference
2. What is a Carotid Sinus 
3. What is a Carotid Body
4. Similarities – Carotid Sinus and Carotid Body
5. Carotid Sinus vs. Carotid Body in Tabular Form
6. Summary – Carotid Sinus vs. Carotid Body

What is a Carotid Sinus?

Carotid sinus is a baroreceptor. It usually senses changes in systemic blood pressure in the body. The carotid sinus is located in the adventitia of the carotid bulb of the internal carotid artery. The carotid arteries are the major blood vessels that provide blood to the brain. Both right and left common carotid arteries bifurcate in the neck at the level of the carotid sinus into the internal carotid artery and the external carotid artery. The internal carotid artery supplies blood to the brain, while the external carotid artery supplies blood to the neck and face. Therefore, the carotid sinus has many types of receptors that play a vital role in the control of blood pressure in the body.

Besides, the carotid sinus is intimately related to the carotid body due to its location, but it performs different functions. However, the function of the carotid sinus can be affected by carotid body tumor resection and carotid sinus syndrome.

What is a Carotid Body?

The carotid body is a chemoreceptor. It is located in the adventitia of the bifurcation of the common carotid artery. Carotid bodies monitor the pH, pCO₂, and pO₂ of the blood and thereby primarily regulate the cardiovascular and respiratory function. The function of the carotid body can be complemented by other chemoreceptors, such as the aortic body located in the aortic arch. The average size of a carotid body is 3-5 mm in diameter, and the average weight of the carotid body is 12 mg.

The carotid body is composed of two receptor cell types: chief cells (derived from the neural crest and release acetylcholine, ATP, and dopamine in response to activation) and sustentacular cells (supporting cells). Furthermore, the function of the carotid body is affected by carotid body tumors such as chemodectoma.

What are the Similarities Between Carotid Sinus and Carotid Body?

• The carotid sinus and carotid body are two sensory receptors in the human body.
• The carotid sinus is intimately related to the carotid body due to its location.
• Both perform important sensory functions in the boy.
• Their function can be affected by different disorders.

What is the Difference Between Carotid Sinus and Carotid Body?

The carotid sinus is a baroreceptor located at the proximal end of the internal carotid artery, while the carotid body is a chemoreceptor located in the adventitia of the bifurcation of the common carotid artery. Thus, this is the key difference between carotid sinus and carotid body. Furthermore, the carotid sinus controls blood pressure in the body, while the carotid body controls cardiovascular and respiratory functions.

The infographic below presents the differences between carotid sinus and carotid body in tabular form for side-by-side comparison.

Summary – Carotid Sinus vs. Carotid Body

A major function of the sensory receptors is to help people learn about the external environment or about the state of their internal environment. Carotid sinus and carotid body are two sensory receptors in the human body. The carotid sinus is a neurovascular structure that appears as a dilation at the beginning of the internal carotid artery. On the other hand, the carotid body is a small mass of cells and nerve endings located in the adventitia of the bifurcation of the common carotid artery. So, this is the basic difference between carotid sinus and carotid body.

Reference:

1. “Anatomy, Head and Neck: Carotid Bodies.” Statpearls – NCBI Bookshelf.
2. “Carotid Sinus – An Overview.” ScienceDirect Topics.

Image Courtesy:

1. “2122 Common Carotid Artery” By OpenStax College – Anatomy & Physiology, Connexions Web site, Jun 19, 2013. (CC BY 3.0) via Commons Wikimedia
2. “Carotid body tumour 2 high mag” By Nephron – Own work (CC BY-SA 3.0) via Commons Wikimedia