Chemoreceptor trigger zone

Chemoreceptor Trigger Zone

The Chemoreceptor Trigger Zone (CTZ) is an area of the medulla oblongata that receives inputs from blood-borne drugs or hormones, and communicates with the vomiting center to induce vomiting. It is a significant part of the body's defense mechanism against toxins and harmful substances.

Anatomy

The CTZ is located in the area postrema of the medulla oblongata, near the fourth ventricle of the brain. It is outside the blood-brain barrier, which allows it to respond to substances present in the blood that cannot cross the barrier.

Function

The primary function of the CTZ is to detect toxins in the blood and send signals to the vomiting center in the brain to initiate the vomiting reflex. It does this through the use of chemoreceptors, which are specialized cells that can detect changes in the chemical composition of the body's fluids.

The CTZ is sensitive to a variety of substances, including drugs, toxins, and metabolic products. It can also be stimulated by certain medications, such as chemotherapy drugs, which can cause nausea and vomiting.

Clinical significance

Understanding the function of the CTZ has important implications for the treatment of nausea and vomiting. Antiemetic drugs, which are used to prevent or treat nausea and vomiting, often work by blocking the action of certain neurotransmitters in the CTZ.

In addition, the CTZ's location outside the blood-brain barrier means that it can be affected by substances that cannot cross the barrier. This makes it a target for the treatment of conditions such as motion sickness and morning sickness.

See also

• Area postrema
• Vomiting center
• Blood-brain barrier
• Chemoreceptor