UNIT 2: (FOOD/FEED COMPOSITION ANALYSIS) AND DIGESTIVE SYSTEMS Flashcards
Mechanical, chemical, enzymatic breakdown of complex food matrix is called…
digestion
Ability of molecules to pass through mucosal cells, blood stream, tissues is called…
absorption
The percentage of a compound from food matrix that moves into blood stream is the…
bioavailability or digestibility.
- effective digestion and absorption combined
A specialized neural net around the digestive tract is called the…
Enteric Nervous System or second brain.
- complete reflexes (does not require brain or spinal cord CNS)
What is the role of the Second Brain?
- control secretion, motility, absorption, control of gut microbiome and gut immunity
What is the difference between the digestive system and GI tract?
Digestive system = GI tract + associated organs
Humans, pigs, cats, dogs have what type of digestive system?
- simple system with non-functional caecum
What does a non-functional caecum mean?
- not significant fermentation and VFA production
High fibre and low nutrient diets are suitable for simple, non-functional caecums.
True/false.
False
- nutrient dense
- low fibre
What are the two enzymes secreted in the oral cavity?
- a- amylase
- lingual lipase
What is chronic heartburn called?
GERD - gastro-esophageal reflux disease
- due to excess acid secretion and impairment of closing the lower esophageal sphincter
- leading to inflammation (chronically)
What do the gastric glands secrete?
- H2O
- mucus
- electrolytes
- HCl
- enzymes
What is the first step of break down of the food matrix?
- break down proteins via stomach acid
- denatured and partially degraded
- release fat droplets to move down to GI tract
What are impeding waves and how do they work?
- alternate regular motility sending digestive contents back in small intestine
- intestinal receptors sense digestion is not complete
- send message to Second Brain (Enteric Nervous System)
- food sent backwards for more complete digestion
The small intestine is 40 square metres. The large surface area adaptations include intestinal surface folds. What are these folds called?
Kerckring folds
Where are villi located?
sits on surface of folds
What does each villi have associated with it?
- central lacteal
- arteriole
- venule
- capillary bed (to hepatic circulation)
What are the components of villi?
maintained by
- ECM proteins
- intestinal epithelial
- intestinal mucosal
- enterocytes (epithelial cells of villi)
- crypts are stem cells that replace enterocytes every 3 days
Microvilli are …
the tiny finger like projections that cover each enterocyte from outer surface of the mucosal cell
What acts as a site for binding of digestive enzymes?
Mesh of glycoproteins anchored in membrane and reach into lumen
- allows for enzyme products to be formed near transporters of cell membrane
What is recovered in the colon?
- water
- electrolytes (sodium and chloride)
What is absorbed in the colon?
- absorption in the colon is reduced greatly
- lipid soluble nutrients and VFAs can be absorbed slowly
Colonic biodiversity increases/decreases as the human body ages or enters chronic disease states
Decreases
What is the role of the microbiome?
Ferment:
- undigested fibre
- resistant starch
- some protein