Outcome 2 - process required for the body to utilize the nutrients in foods Flashcards
What is digestion?
The process by which food are broken down into their nutrients.
Where does the digestive process begin?
Digestive process begins in the mouth with mastication (chewing), which consists of mixing the food with saliva and swallowing it. A digestive enzyme called salivary amylase begins the proces of breaking down carbohydrates into simpler forms that the body can use.
What is the digestive process once food is swallowed?
After the food is swallowed, the churning action of the stomach mixes it with gastric juice. The digestion of carbohydrates continues in the stomach, and the digestion of protein begins
Where does absorption of nutrients occur?
Nutritional elements in the gastrointestinal tract pass through its lining and into the bloodstream. Absorption of nutrients occurs mostly in the small intestines.
What is Metabolism?
The process by which cells convert nutrients into useful energy or into new compounds vital for cellular structure and function. It is all the changes that take place in the body.
What is Mechanical Digestion?
The rythmic contractions of the intestines are the chewing of food in the mouth, the churning of food in the stomach, and the peristalsis. These movements break the food into smaller particles, mix it with digestive juices, and move the food through the intestines.
What is Chemical Digestion?
Chemical digestion is the action of emzynes as they break foods into simpler forms that can be absorbed.
What are enzymes?
An enzyme is a substance that causes a chemical change or breakdown in another substance.
Enzymes are very specific in their action. For example, an enzyme that digests carbohydrates will not have an effect on protein. Many enzymes require coenzymes, which is produced by the body from vitamins and minerals.
What mechanical digestion takes place in the mouth?
Chewing breaks the food down and mixes it with saliva.
What chemical digestion takes place in the mouth?
Salivary amylase is the enzyme in saliva that acts on CHO and begins to break complex carbohydrates into simpler sugars.
What is the role of the stomach in digestion?
The stomach serves as a temporary storage depot for food. Partial digestion of protein occurs here, and the stomach prepares food for further digestion in the small intestine.
What mechanical digestion takes place in the stomach?
Food is constantly churned and mixed with gastric juice until it becomes a liquid known as chyme.
What does gastric juice contain?
-Hydrochloric Acid
-Pepsin
-Rennin
What is the role of hydrochloric acid in gastric juice?
-swells the proteins so they can more easily be attached to enzymes
-provides the acid medium necessary for the action of pepsin
-increases the solubililty of calcium and iron salts so they can be absorbed more readily
-reduces the activity of harmful bacteria that may be present in food
What is the role of Pepsin in gastric juice?
Splits protein into smaller molecules
What is the role of Rennin in gastric juice?
Acts on casein (a protein in milk) and breaks it down into calcium caseinate
What length of time does food stay in the stomach?
Food stays in the stomach for varying lengths of time. A high CHO meal or food leaves the stomach faster than high protein, which leaves more quickly than high fat.
Smaller amounts of food leave the stomach in less time than a large meal.
Fastest is CHO, then Protein, then high Fat
Digestion of CHO and fats in the stomach?
Very little digestion of CHO and fats occur in the stomach
Where does most digestive activity take place?
Most digestive activty takes place in the small intestine.
How does digestion occur in the small intestine?
A duct brings juices into the small intestine from the gallbladder and the pancreas. The walls of the small intestine also secrete additional juice.
Juices in the small intestine?
-Bile
-Pancreatic Juice
-Intestinal Juice
What is the purpose of bile?
Is essential for fat digestion. It is made by the liver, stored in the gallbladder, and released into the small intestine. Bile emulsifies fat, which is a process of dispersing fat in a water solution. Instead of having a large piece of fat in the intestine, bile breaks it into tiny globules that can more easily be attacked by the fat-splitting enzymes.
What is the purpose of Pancreatic Juice?
Contains, protein, fat, and CHO digesting enzymes. These are trypsin, lipase, and amylase respectively.
What is the purpose of Intestinal Juice?
Contains enzymes that have a further action on protein and CHO. These are pepitdases that complete the breakdown of protein into amino acids, sucrase, maltase, and lactase that break down sucrose, maltose, and lactose.
What is the role of the large intestine in digestion?
Digestion has been essentially completed by the time the food mass reaches the large intestine. Here bacteria synthesize Vitamin K. This vitamin and electrolytes, mainly sodium, are absorbed here. Water is also absorbed here, and gradually the intestinal contents take on a solid consistency. The solid wastes are eliminated through the rectum as feces
What does feces contain?
Feces contain fibres from food, small amounts of undigested foods, bile salts, cholesterol, mucus, bacteria and broken down cellular wastes.
Three important ways that saliva protects teeth are..
- Saliva physically clears cariogenic materials from the mouth.
- Buffers acid formation.
- Forms a protective coating on the teeth.
Rapid caries development is often a problem in individuals with little or no saliva. Certain medications can reduce saliva production.
What does Complex CHO break down into?
Disaccharides > Monosaccharides
ex) Starch > Maltose, Sucrose, Lactose > Glucose, Fructose, Galactose
What does Proteins break down into?
Amino Acids
What do Fats breakown into?
Gycerol, Phospholipids > Fatty Acids, Cholesterol, Monoglycerides
Where does absorption of nutrients occur>
No absorption of nutrients occurs in the mouth or stomache except for water.
Most nutrients are absorbed through the small intestine.
Nutrients are absorbed either into the blood (CHO, Pro, Water soluble vitamins) or into the lymph (fat and fat-soluble vitamins). Lymph fluid eventually empties into the blood and then all nutrients are made available to the body cells.
Nutrients can move through the intestinal wall by filtration, active transport, passive transport, diffusion, or pinocytosis.
What is Anabolism?
Small molecules are put together to form larger molecules. Examples include the formation of tissue to heal a wound, building hemoglobin from amino acids and iron, forming adipose tissue, etc. These require or consume energy.
What is Catabolism?
Large molecules are broken down into smaller ones. Examples include the breakdown of tissue as a in a burn or wound, weight losee, etc. These release energy.
What is Homeostasis?
Homeostasis is a balance between building up and breaking down. Examples include weight loss and weight gain.
