Chapter 1 Flashcards
What is digestion?
Digestion is a complex body process in which the body breaks down food eaten into nutrients, which the body can absorb for fuel in order to survive. Digestion also involves eliminating waste.
Digestion include both mechanical and chemical.
What is mechanical digestion?
A physical action through which food is broken down for absorption. Chewing in the mouth and peristalsis in the oesophagus and stomach are both mechanical digestion.
What are macronutrients for?
Macronutrients are essential nutrients that the body needs in large amounts. These nutrients all supply the body with energy, promote growth and the repair of tissues, and regulate body processes.
What are the macronutrients, and what do they do?
Carbohydrates-Main source of energy
Protein-Used for tissue development and growth as well as hormone production
Lipids/Fats-Used for energy storage within the body.
What is chemical Digestion?
Enzymes or gastric juices that are released to break food down further, this allows the body to break down food into it’s most simple form. Saliva in the mouth, gastric juices in the stomach and enzymes in the small intestine are examples of chemical digestion.
What is metabolism?
All the chemical processes that use nutrients to make other substances required by the body. Metabolism has 2 categories.
What are the 2 categories?
Catabolism-The breaking down of nutrients into their components, usually for energy.
Anabolism-When a new substance is created from the components derived from catabolism. Anabolism is responsible for creating new tissue with proteins.
What are the parts of the digestive system?
Mouth-Chewing
Salivary Glands-Release saliva
Oesophagus-Peristalsis
Stomach-Churning and gastric juice release
Pancreas-Secretes enzymes into small intestine
Gall Bladder-Stores and releases bile
Small Intestine-Enzyme release and absorption
Large Intestine-Water absorption and bacteria feeding
How are lipids digested and absorbed?
Digestion of fats begins in the mouth, slowly, as the lipase present in the saliva starts to break down the lipids. Chewing also happens in the mouth, breaking food into smaller chunks, increasing the surface area for the enzymes to go to work.
In the stomach churning occurs which mixes the food with gastric juices, which contain acid and enzymes for the further breakdown of food.
When the food gets to the small intestine it is already started to be broken down, however the pancreas secretes more enzymes into the small intestine to break the food down the majority of the way into it’s simplest form, nutrients. The lipase from the pancreas breaks the complex fats into monoglycerides, fatty acids and glycerol. The glycerol etc are absorbed by the inner section of the villi (lacteal).
How is protein digested and absorbed?
Digestion of protein also begins in the mouth with the chewing and churning. Increasing the surface area for the enzymes later on to break it down.
The oesophagus, through peristalsis, pushes the bolus down to the stomach.
In the stomach the protein is mixed with gastric juices and enzymes. An acid in the stomach DENATURES the protein, in order for the enzyme pepsin to break down the protein into their simplest amino acid form.
Once the amino acids reach the small intestine, the pancreas secretes protease and peptidase to break down the protein into their simplest form. The villi absorb the protein and deliver it to the blood capillaries, where they are taken to the liver to be dissolved and stored for use.
How are carbohydrates digested and absorbed?
Saliva contains the enzyme amylase, which begins the digestion of carbohydrates in the mouth as a form of chemical digestion, along side the mechanical digestion of the chewing.
The stomach continues digestion by churning the food with acids to break it down into a watery substance called chyme.
Digestion continues in the small intestine where pancreatic amylase is released into the small intestine to break down the carbohydrates. It breaks down the poly- and di- saccharides into monosaccharides, which are mainly glucose molecules. Digestion of sugars and starches usually only take 1-4 hours.
Glucose is absorbed into the blood capillaries via the villi to be used as the body’s main source of energy. The pancreas also secretes a hormone called insulin, which helps regulate glucose within the blood stream, and the distribution of glucose to all the body’s cells.
What are probiotics?
Live microbial food supplements such as bifidobacterium and lactobacillus bacterial species, or foods that have naturally occurring live bacteria such as fermented food. Probiotics are often referred to as ‘good bacteria’ because they are said to restore balance of important bacteria or microflora in the intestinal tract.
What are prebiotics?
Compounds found in food products or those added to food products that are non-digestible. Prebiotic components feed bacteria by stimulating the growth or other activity of naturally occurring bacteria in the colon. To be considered prebiotic, the substance must not be broken down and absorbed by the small intestine. They act as a substrate to allow beneficial colonic bacteria to grow and improve the balance of microflora, thus improving health.
What is Gut Flora?
Microorganisms in your gut are called gut flora, found in the colon or large intestine. They perform many important health functions such as turning fibre into short-chain fats which feed your gut wall, and perform many important health functions.
What is unbalanced gut flora linked to?
Numerous diseases such as obesity, type 2 diabetes, heart disease and colorectal cancer.
