Cholecystokinin

Definition

Cholecystokinin (CCK) is a peptide hormone produced by the intestinal I cells that plays a crucial role in the regulation of various digestive processes. It is primarily responsible for stimulating the release of bile from the gallbladder and the secretion of digestive enzymes from the pancreas, thereby facilitating the breakdown and absorption of fats and proteins in the small intestine.

5 Must Know Facts For Your Next Test

1. Cholecystokinin is released in response to the presence of fats and proteins in the small intestine, stimulating the release of bile from the gallbladder and the secretion of digestive enzymes from the pancreas.
2. The release of cholecystokinin also triggers the feeling of satiety, or fullness, by signaling the brain to stop eating.
3. Cholecystokinin plays a role in the regulation of gastric emptying, slowing the rate at which food leaves the stomach and enters the small intestine.
4. Impaired cholecystokinin signaling has been linked to various gastrointestinal disorders, such as gallstones, pancreatitis, and irritable bowel syndrome.
5. Cholecystokinin is also involved in the stimulation of the vagus nerve, which connects the brain to the digestive system and can influence appetite and food intake.

Review Questions

• Describe the role of cholecystokinin in the digestive system, specifically in relation to the gallbladder and pancreas.
  • Cholecystokinin (CCK) is a peptide hormone produced by the intestinal I cells that plays a crucial role in the regulation of digestive processes. When fats and proteins are present in the small intestine, CCK is released, which stimulates the gallbladder to contract and release bile. This bile helps emulsify and break down the fats, aiding in their absorption. Additionally, CCK triggers the pancreas to secrete digestive enzymes, further facilitating the breakdown and digestion of nutrients in the small intestine.
• Explain how cholecystokinin is involved in the regulation of appetite and satiety.
  • In addition to its role in the digestive system, cholecystokinin (CCK) is also involved in the regulation of appetite and satiety. When CCK is released in response to the presence of food in the small intestine, it signals the brain to induce a feeling of fullness or satiety. This helps regulate food intake and prevents overeating. The release of CCK also triggers the vagus nerve, which connects the digestive system to the brain, further reinforcing the sensation of satiety and contributing to the overall regulation of appetite and food consumption.
• Discuss the potential implications of impaired cholecystokinin signaling and its association with various gastrointestinal disorders.
  • Impaired cholecystokinin (CCK) signaling has been linked to several gastrointestinal disorders. For example, a disruption in CCK-mediated gallbladder contraction and bile release can lead to the formation of gallstones. Additionally, dysregulation of CCK-stimulated pancreatic enzyme secretion may contribute to the development of pancreatitis. Furthermore, altered CCK signaling has been associated with irritable bowel syndrome, where it can influence intestinal motility and sensitivity, leading to symptoms such as abdominal pain, bloating, and altered bowel habits. Understanding the role of CCK in these gastrointestinal conditions is crucial for the development of targeted therapies and the management of these disorders.

Related terms

Gallbladder:

A small, pear-shaped organ located beneath the liver that stores and concentrates bile, a digestive fluid produced by the liver.

Pancreas:

An organ located behind the stomach that produces enzymes and hormones, including insulin and glucagon, which are essential for the digestion and regulation of blood sugar levels.

I Cells: Specialized endocrine cells found in the lining of the small intestine that are responsible for the production and secretion of cholecystokinin.