Monogastric Stomach Motility Flashcards
What contributes to the mechanical breakdown of food particles?
Muscle contractions
Gastric contents are released at a controlled rate with the help of what kind of cells?
Specialized smooth muscle pacemaker cells
What initiates the contraction of intestinal and gastric muscles?
Ca++
When an animal eats a meal, the _____________ expands to accommodate large volumes of food
Fundus
This part of the stomach acts like a large mixing chamber
Body (corpus)
This part of the stomach acts like a pump
Pyloric antrum
Peristaltic contractions get progressively stronger as food moves towards where?
The pylorus
What 2 things do peristaltic movements do?
Fragment food into small particles
Influence rate of gastric emptying
When the peristaltic contraction reaches the pyloric sphincter it narrows preventing large particles from leaving the stomach and forces them back into the corpus (body). This is called what?
Retropulsion
The motility of the stomach is under _______________ control
Neurohumoral control
What is neurohumoral control?
Neurotransmitters and hormones affect motility of the stomach and rate of gastric emptying
The motility of the stomach _____________ when food enters it
Decreases
The motility of the stomach _____________ as food approaches the pyloric region
Increases
________________ is released in the pyloric region that increases peristaltic contractions
Acetylcholine
The hormonal control of gastric emptying is done by hormone?
Gastrin
The rate of gastric emptying is controlled by what 2 things?
Strength of pyloric antral muscle contractions
Degree of contraction of pyloric sphincter
What hormones released by the small intestine play a role in the delay of gastric emptying?
Secretin
Cholecystokinin (CCK)
Gastric inhibitory peptide (GIP)
Mechanical digestion is essential to what?
Increasing the amount of food surface area
What is responsible for chemical digestion?
Digestive enzymes
What are the two phases of chemical digestion?
Luminal digestion
Membranous chemical digestion
What happens during luminal chemical digestion?
Hydrolysis - large macromolecules are broken down into short chain polymers
What happens during membranous chemical digestion?
Hydrolysis is repeated - short chain polymers are completely broken down into their most basic component parts
What are the 5 components of a meal?
Carbohydrates
Proteins
Lipids
Vitamins
Minerals
What are carbohydrates made up of?
Repeating units of monosaccharides - starches, sugars, cellulose
What are proteins made up of?
Repeating units of amino acids
A chain of >50 amino acids is a _____________
Protein
A chain of <50 amino acids is a ______________
Peptide
What are lipids made up of?
Glycerol backbone and 3 fatty acids
How are carbohydrates digested?
Begins with amylase in the saliva and continues in the stomach and small intestine
How are proteins digested?
Pepsinogen released by chief cells is activated to pepsin by the acidic environment produced by HCl
