Cholecystokinin (CCK)

Definition

Cholecystokinin (CCK) is a hormone produced by the cells in the lining of the small intestine, primarily in response to the presence of fats and proteins in the digestive tract. It plays a crucial role in the regulation of appetite and digestion by signaling the gallbladder to release bile and stimulating the pancreas to secrete digestive enzymes. CCK also acts on the brain to promote feelings of satiety, helping to control food intake.

5 Must Know Facts For Your Next Test

1. CCK is released into the bloodstream when food enters the small intestine, particularly when fats and proteins are present.
2. In addition to its role in digestion, CCK has been shown to have an impact on reducing hunger and increasing the sensation of fullness after meals.
3. CCK also slows down gastric emptying, which prolongs the time food stays in the stomach, contributing to feelings of satiety.
4. This hormone may also influence pancreatic function by stimulating the secretion of digestive enzymes that aid in nutrient absorption.
5. Abnormal CCK levels have been linked to various gastrointestinal disorders and obesity, highlighting its importance in appetite regulation.

Review Questions

• How does cholecystokinin (CCK) interact with other hormones to regulate appetite and digestion?
  • Cholecystokinin (CCK) works alongside other hormones like ghrelin and leptin to maintain a balance in appetite regulation. While ghrelin promotes hunger, CCK signals satiety by releasing bile and digestive enzymes. This interplay ensures that when food enters the small intestine, CCK is released, promoting fullness and slowing gastric emptying, while leptin sends signals from fat stores to suppress further eating. Together, these hormones create a feedback loop that helps regulate food intake and energy balance.
• What effects does cholecystokinin have on gastrointestinal function beyond its role in appetite regulation?
  • Cholecystokinin (CCK) not only helps control appetite but also plays a vital role in gastrointestinal function. It stimulates the gallbladder to release bile, which is necessary for fat digestion and absorption. CCK also promotes pancreatic enzyme secretion, facilitating nutrient breakdown in the small intestine. Additionally, CCK slows gastric emptying, ensuring that food is processed efficiently while enhancing nutrient absorption over time.
• Evaluate how abnormalities in cholecystokinin levels could contribute to obesity or eating disorders.
  • Abnormalities in cholecystokinin (CCK) levels can significantly impact eating behaviors and potentially contribute to conditions like obesity or eating disorders. For example, low levels of CCK may lead to inadequate signaling of fullness, resulting in overeating due to a lack of satiety cues. Conversely, excessive CCK might cause discomfort or aversion to food, potentially leading to restrictive eating patterns. These dysregulations highlight CCK's critical role in maintaining a healthy relationship with food and energy balance.

Related terms

Ghrelin: A hormone produced in the stomach that stimulates appetite, often referred to as the 'hunger hormone.'

Leptin:

A hormone secreted by adipose (fat) tissue that helps regulate energy balance by inhibiting hunger, thus promoting weight loss.

Peptide YY (PYY): A hormone released from the intestine after eating that reduces appetite and inhibits gastric motility.