Flashcards in Digestion Deck (27):
What is the digestive system made up of?
The digestive system is made up of the alimentary canal (a muscular tube through which food passes from mouth to anus), liver and pancreas.
What part does the mouth play in the digestive system?
The mouth is where food is taken in (ingestion), chewed into smaller pieces and mixed with saliva. This begins the breakdown of food.
What part does the oesophagus play in the digestive system?
The oesophagus is a muscular tube which pushes food into the stomach.
What part does the stomach play in the digestive system?
Muscles in the stomach wall contract and relax to mix food with digestive juices.
What part does the pancreas play in the digestive system?
The pancreas produces pancreatic juice containing digestive enzymes that pass to the small intestine.
What part does the small intestine play in the digestive system?
The small intestine is where digestion (breaking food down into soluble products) and absorption (diffusion of soluble products into the blood) takes place.
What part does the liver play in the digestive system?
The liver processes the nutrients from the small intestine and produces bile, which helps digest fat.
What part does the large intestine play in the digestive system?
The large intestine absorbs water from the remaining indigestible food matter.
What part does the anus play in the digestive system?
In the anus, undigested food is removed as faeces (egestion)
What is the peristalsis?
Contraction and relaxation of the muscle layers in the wall of the alimentary canal moves food through the digestive system. This is a muscular action.
What is the gall bladder?
The gall bladder is a small sac-like structure connected to the small intestine by the bile duct. It stores the greenish alkaline liquid called bile produced by the river.
What are the enzymes job?
Enzymes break down large, insoluble molecules of carbohydrates, fats and proteins into smaller molecules which the body can absorb.
Give an example, the location, the food component acted on and the substance produced by the enzyme group; carbohydrases digest carbohydrates
Location: mouth and small intestine
Food component acted on: starch
Substance produced: glucose
Give an example, the location, the food component acted on and the substance produced by the enzyme group; proteases digest proteins
Food component acted on: proteins
Substance produced: amino acids
Give an example, the location, the food component acted on and the substance produced by the enzyme group; lipases digest fats and oils
Location: small intestine
Food component acted on: fats and oils
Substance produced: fatty acids and glycerol
How can you detect the presence of the soluble products of digestion in the water?
Add a mix of enzyme(s) and large food molecule(s) into the tubing and suspend it in warm water (which acts like the blood supply).
What does bile do?
- Bile breaks down fats into small droplets (emulsification), which increases the surface area, speeding up the action of lipase.
- Bile also neutralises the stomach acid present in the food, which enters the small intestine to allow enzymes to work at their optimum pH of around 8.
What do ville do?
Tiny projections called ville (singular villus) line the small intestine. They increase its surface area, allowing more efficient absorption of the soluble products of digestion.
What are functional foods?
Functional foods are foods that have health-promoting benefits over and above their basic nutritional value.
What are probiotic foods?
Probiotic foods contain bacteria such as Bifidobacteric and lactic acid bacteria Lactobacillus that are believed to maintain a healthy digestive system.
What are prebiotic food?
Prebiotic foods contain added sugars called oligosaccharides. These cannot be digested, but act as a food supply to the "good" bactera in the alimentary canal.
What are plant stanol esters?
Plant stanol esters have been clinically proven to reduce the absorption of harmful cholesterol.
What can bacteria we carry in our digestive system be divided into?
- "bad" bacteria
- "good" bacteria
What do prebiotics and probiotics do?
Prebiotics and probiotics are foods which aim to boost the numbers of "good" bacteria that suppress the activity of the "bad" bacteria,
What does lowering blood cholesterol do?
Lowering blood cholesterol reduces a person's risk of heart disease.
What are some concerns that there is about the effectiveness of functional foods?
- How well the bacteria survive the manufacture and storage of probiotics before sale
- Their passage through the digestive system
- Competition with the trillions of other microorganisms already in the gut.