Term
| What structures is the gastrointestinal tract made of? |
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Definition
- mouth
- esophagus
- stomach
- small intestine
- large intestine
- cecum
- rectum |
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Term
| How is the digestive system different from the gastrointestinal tract? |
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Definition
| The digestive system is made up of the GI tract and associated organs (liver, pancreas, gallbladder) |
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Term
| What type of diet is a simple system suited for? |
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Definition
| a nutrient dense, low fibre diet |
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Term
| What happens in the oral cavity in digestion? |
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Definition
- food is chewed
- mixed with saliva (a-amylase and lingual lipase) |
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Term
| What substances do a-amylase and lipase work on respectively? |
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Definition
a-amylase works on carbs
lipase works on certain lipids |
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Term
| What happens in the simple stomach during digestion? |
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Definition
- glands secrete gastric juice, water, electrolytes, HCL and enzymes
- food becomes chyme |
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Term
| What is the pH of the stomach acid? |
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Definition
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Term
| How long does it take for gastric emptying? |
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Definition
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Term
| What are the three regions of the small intestine? |
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Definition
- duodenum
- jejunum
- ileum |
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Term
| What happens in the small intestine during digestion? |
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Definition
nutrient digestion and absorption
chyme acidity neutralized by pancreatic juices |
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Term
| What happens in the large intestine during digestion? |
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Definition
- site of fermentation of undigested CHO, protein, alcohols and fibres
- production of short chain fatty acids (SCFA) and volatile fatty acids (VFA) |
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Term
| What does the fermentation of CHO generate? |
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Definition
| Lactate and SCFA (short chain fatty acids) |
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Term
| What structures increase surface area in the small intestine? |
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Definition
| kercking folds -> villi -> microvilli |
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Term
| What are the two types of nutrient transport? |
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Definition
1. passive transport = diffusion and facilitated diffusion
2. active transport (requires ATP) |
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Term
| What diet is a simple system with a functional cecum suited for? |
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Definition
| a diet with large amounts of forage |
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Term
| What substances does the small intestine absorb? |
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Definition
- glucose
- amino acids
- fatty acids |
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Term
| What are the four sections of a ruminant stomach? |
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Definition
1. rumen
2. reticulum
3. omasum
4. abomasum |
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Term
| What diet is a ruminant system suited for? |
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Definition
| highly suited for high quantity of roughages |
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Term
| What happens in the reticulum? |
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Definition
| region of microbial fermentation |
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Term
| What happens in the rumen? |
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Definition
| food is mixed, partially broken down and stored temporarily |
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Term
| What structure in the rumen increases surface area and why? |
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Definition
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Term
| What happens in the omasum? |
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Definition
Reabsorption of water and some electrolytes
filters large particles |
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Term
| What happens in the abomasum? |
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Definition
| digestive enzymes secreted from glands (HCL, mucin, pepsinogen, lipase etc) |
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Term
| Which region of a ruminant stomach is most like a mono gastric stomach? |
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Definition
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Term
| What are the advantages to a ruminant digestive system? |
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Definition
- vitamin synthesis
- non-protein nitrogen utilization |
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Term
| What are the disadvantages to a ruminant digestive system? |
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Definition
- carbohydrate utilization
- heat production |
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Term
| What is the crop used for in an avian digestive system? |
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Definition
- temporary storage location for food
- food is softened |
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Term
| What are the two chambers of an avian stomach? |
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Definition
1. glandular portion - proventriculus
2. muscular portion - gizzard |
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Term
| What occurs in the cecum of a bird? |
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Definition
| minor site of bacterial fermentation |
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Term
| What is the function of the cloaca? |
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Definition
| to connect the digestive, urinary and reproductive systems |
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Term
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Definition
| The measure of the fraction of a specific nutrient or of energy that is extracted by the GI tract |
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Term
| How is digestibility calculated? |
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Definition
| The amount of nutrient in the diet and the amount appearing in the faces |
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Term
| What are the steps to the total collection method? |
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Definition
1. allow animal to adapt to diet over a 7-12 day period
2. isolate animal for quantitative analysis
3. measure intake over a 3-10 day period
4. collect and weigh all faces
5. analyze for nutrient of interest |
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Term
| How do you calculate the apparent digestibility coefficient according to the total collection method? |
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Definition
| (total intake-total feces)/total intake |
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Term
| What does the indicator method require? |
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Definition
| either an internal (natural component in diet) or external (component added to diet) marker |
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Term
| What are the criteria for a marker? |
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Definition
- non-absorbable
- must not affect or be affected by the GIT
- must mix easily with the food
- easy and accurately measured in samples |
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Term
| What are the steps to the indicator method? |
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Definition
1. adapt animal to test diet (including marker)
2. collect a feed and fecal sample
3. analyze each for marker and nutrient of interest |
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Term
| What are the steps to the true digestibility method? |
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Definition
1. perform digestibility study using test diet with nutrient of interest
2. switch diet containing none of the nutrient of interest
3. analyze faces after previous diet is cleared
4. subtract level of nutrient in feces of animals fed the zero nutrient diet from the test diet |
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Term
| What are the factors that affect digestibility? |
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Definition
1. feed intake
2. particle size
3. chemical composition
4. climate
5. age |
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