[04] Regulation of Digestion Flashcards
What primarily regulates the digestive system?
The autonomic nervous system and hormones
What is the role of the autonomic nervous system in digestion?
It controls smooth muscle contraction (peristalsis) and secretion in the digestive system
What are the two divisions of the autonomic nervous system that regulate digestion?
- Sympathetic nervous system
- Parasympathetic nervous system
How does the sympathetic nervous system affect digestion?
It generally inhibits digestive activities
How does the parasympathetic nervous system affect digestion?
It stimulates digestive activities
What is the role of hormones in digestion regulation?
They control the secretion of digestive enzymes and regulate the movement of food through the digestive tract
What are the two main types of digestive hormones?
- Gastric hormones
- Intestinal hormones
Name three main gastric hormones and their roles
- Gastrin → stimulates gastric acid secretion
- Ghrelin → stimulates hunger
- Leptin → suppresses hunger
Name three main intestinal hormones and their roles
- Secretin → stimulates pancreatic juice secretion, inhibits gastric secretion, and promotes bile secretion
- Cholecystokinin (CCK) → stimulates pancreatic enzyme secretion, gallbladder contraction, and slows gastric emptying
- Gastric inhibitory peptide (GIP) → inhibits gastric secretion and motility
What is the ‘Enteric Nervous System’?
It is a complex system of about 100 million nerves that govern the function of the gastrointestinal system
What is the role of the ‘Enteric Nervous System’ in the regulation of digestion?
It can control digestive function independently of the brain and the spinal cord
How does the body regulate the speed of digestion?
It uses a feedback loop involving hormones and the nervous system to ensure that each segment of the digestive tract works at the right speed for optimal absorption
What role does the hormone Motilin play in digestive regulation?
It controls the pattern of smooth muscle contractions in the upper digestive tract, leading to the migrating motor complex
What is the Migrating Motor Complex (MMC)?
It’s a series of contractions in the digestive tract that occur approximately every 90 minutes, helping to clear undigested food
What signals the end of the MMC?
Eating food, which causes the release of gastrin and CCK
