Cholecystokinin

Definition

Cholecystokinin (CCK) is a hormone produced by the cells of the small intestine that plays a crucial role in digestion and appetite regulation. It is released in response to the presence of fats and proteins in the duodenum, stimulating the gallbladder to release bile and the pancreas to secrete digestive enzymes. CCK also sends signals to the brain to promote feelings of satiety, connecting it to both digestive processes and the regulation of gastrointestinal function.

5 Must Know Facts For Your Next Test

1. CCK is secreted when fatty acids and amino acids enter the small intestine, signaling that food is present.
2. One of CCK's primary functions is to stimulate the contraction of the gallbladder, leading to the release of bile that helps digest fats.
3. CCK also enhances pancreatic enzyme secretion, which is vital for breaking down macronutrients.
4. In addition to its digestive roles, CCK has important effects on appetite regulation by acting on receptors in the brain.
5. Cholecystokinin levels can influence overall energy balance and body weight by affecting both hunger and digestion.

Review Questions

• How does cholecystokinin contribute to the digestive process once food enters the small intestine?
  • Cholecystokinin plays a key role in digestion by being released when fats and proteins enter the small intestine. It stimulates the gallbladder to contract, releasing bile which emulsifies fats, making them easier to digest. Additionally, CCK prompts the pancreas to secrete digestive enzymes that further break down macronutrients, facilitating nutrient absorption.
• Discuss how cholecystokinin affects appetite regulation and what implications this has for energy balance.
  • Cholecystokinin influences appetite regulation by sending signals to the brain indicating that enough food has been consumed. This promotes feelings of fullness or satiety, which helps prevent overeating. The balance between CCK secretion and appetite can impact overall energy intake, contributing to weight management and obesity prevention.
• Evaluate the potential clinical implications of altered cholecystokinin levels in individuals with gastrointestinal disorders.
  • Altered levels of cholecystokinin can have significant clinical implications for individuals with gastrointestinal disorders such as pancreatitis or gallbladder disease. In these cases, inadequate CCK release may lead to poor fat digestion and nutrient malabsorption. Conversely, excessive CCK may cause digestive discomfort or inhibit appetite, complicating management strategies for these patients. Understanding CCK's role can help tailor dietary interventions and pharmacological treatments aimed at restoring normal digestive function.

Related terms

Bile: A digestive fluid produced by the liver and stored in the gallbladder, essential for emulsifying fats and aiding in their digestion.

Pancreatic Enzymes: Enzymes secreted by the pancreas that aid in the digestion of carbohydrates, proteins, and fats within the small intestine.

Satiety: The feeling of fullness that inhibits further eating, which can be influenced by hormones like cholecystokinin.