Cholecystokinin

Definition

Cholecystokinin (CCK) is a peptide hormone produced by the cells in the intestinal mucosa, primarily in response to the presence of fats and proteins in the small intestine. This hormone plays a crucial role in digestion by stimulating the gallbladder to contract and release bile, which aids in fat emulsification, and promoting the secretion of digestive enzymes from the pancreas, enhancing nutrient breakdown. Additionally, CCK acts on the brain to induce satiety, helping regulate appetite.

5 Must Know Facts For Your Next Test

1. Cholecystokinin is released into the bloodstream when fatty acids and amino acids enter the small intestine, primarily after a meal.
2. One of CCK's main functions is to stimulate gallbladder contraction, which releases bile into the small intestine for fat digestion.
3. CCK also encourages the pancreas to secrete digestive enzymes like lipases and proteases, further aiding in nutrient absorption.
4. Beyond its digestive roles, CCK is involved in signaling to the brain to reduce hunger and increase feelings of fullness after eating.
5. The presence of cholecystokinin can also slow gastric emptying, allowing for better digestion and nutrient absorption.

Review Questions

• How does cholecystokinin contribute to the digestion of dietary fats?
  • Cholecystokinin plays a vital role in fat digestion by stimulating the gallbladder to contract and release bile into the small intestine. Bile emulsifies fats, making them easier for digestive enzymes to break down. Additionally, CCK promotes the secretion of pancreatic enzymes that further aid in digesting dietary fats. Together, these actions enhance the body's ability to absorb essential nutrients from fat-containing foods.
• What mechanisms does cholecystokinin use to regulate appetite and satiety?
  • Cholecystokinin regulates appetite and satiety by acting on receptors in the brain after being released in response to food intake. When CCK levels rise following a meal, it signals to the brain that enough food has been consumed, promoting a sense of fullness. This hormonal feedback loop helps reduce further eating and maintains energy balance within the body. The role of CCK in appetite regulation highlights its importance beyond just digestion.
• Evaluate the overall impact of cholecystokinin on digestive health and nutritional absorption in individuals with gastrointestinal disorders.
  • In individuals with gastrointestinal disorders, cholecystokinin's role can be significantly affected. If CCK secretion is impaired, it can lead to inadequate bile release and reduced pancreatic enzyme activity, negatively impacting fat digestion and nutrient absorption. This may result in malabsorption syndromes or nutrient deficiencies. Understanding CCK's function can help healthcare providers develop strategies to manage digestive health effectively for those with such disorders, ensuring that patients receive adequate nutrition despite their conditions.

Related terms

Bile: A digestive fluid produced by the liver and stored in the gallbladder, essential for the emulsification and absorption of fats.

Pancreatic Enzymes: Digestive enzymes produced by the pancreas that break down carbohydrates, proteins, and fats in the small intestine.

Satiety: The feeling of fullness that signals the end of eating, regulated by hormones such as cholecystokinin.