Food Composition and Digestion: Nutrients and Enzymes
What is Food? What Substances is it Composed of?
Food processing involves natural products, which provide substances that our cells need to live.
Organic Constituents of Food: Types and Characteristics
Carbohydrates (2 types):
- Simple: Small molecules with a sweet taste, like maltose, formed by two glucose molecules.
- Complex: Very large molecules, like starch and cellulose. Cellulose contains a lot of fiber, which cannot be digested by humans but is very beneficial for intestinal function.
Lipids:
There are two types:
- Oils: Liquid at room temperature, usually vegetable-based, and often unsaturated fat.
- Tallow: Solid at room temperature, animal-based, and typically saturated fat.
Proteins:
Formed by the union of amino acids, such as hemoglobin and gluten.
Vitamins:
Cells are unable to manufacture them; we need to obtain them from food. Humans need them in very small quantities, but they are essential.
Functioning of the Digestive System
The digestive system transforms food into nutrients.
What are Digestive Enzymes?
Proteins that are part of the digestive juices. Their operation accelerates the decomposition of nutrients.
Accessory Glands: Types and Description
There are three: salivary glands, pancreas, and liver.
- Salivary glands: Flow to the interior of the mouth, producing saliva.
- Pancreas: Beneath the stomach, produces insulin and pancreatic juice, and empties into the duodenum.
- Liver: Located next to the stomach, secretes bile, and releases it into the duodenum when high-fat foods are circulating.
What Secretion Does Not Contain a Digestive Enzyme? What is its Role?
Bile. Its function is to emulsify fats, fragmenting fat into droplets and thereby facilitating the action of digestive juices on fats.
Definition of Digestion and its Types
Digestion is the process of transformation of food as it passes through the digestive tract. It can be mechanical or chemical.
Mechanical Digestion: Definition and Types
The set of physical actions that reduce the size of the food and move it along the digestive tube.
- Crushing: Done by the teeth.
- Swallowing: The passage of food from the mouth to the esophagus, through the larynx.
- Movements: Contraction of the digestive tube wall. There are two types:
- Mixing food with digestive juices.
- Peristaltic: They move the food.
Chemical Digestion: Definition and Types
Transformation of food into smaller, more soluble substances (nutrients).
Takes place in three places:
- Mouth: Saliva contains the enzyme amylase, which initiates the digestion of carbohydrates.
- Stomach: The gastric glands secrete a juice containing hydrochloric acid and the enzyme pepsin, which initiates protein digestion.
- Small intestine: Intestinal and pancreatic juices, and bile are poured here.
What are Amylase, Pepsin, and Lipase? What are their Roles?
- Amylase: Breaks down carbohydrates into simple sugars.
- Pepsin: Breaks down proteins into smaller amino acid chains.
- Lipase: Breaks down fats.
In What Areas of the Gastrointestinal Tract Does the Absorption of Nutrients into the Blood Occur?
- Small intestine: Through the intestinal villi, which absorb the bulk of organic nutrients.
- Large intestine: Where most of the water and minerals are absorbed.
Definition of a Balanced Diet
A diet that provides all types of nutrients in adequate amounts to keep our body in good condition and ensure correct development.
Name the Three Different Functions of Food
- Structural: Building and replenishing our own body matter.
- Energy: Releasing energy used for movement or maintaining body temperature.
- Regulatory: Ensuring that the body’s processes develop normally.