Body Systems - Introduction to Digestion

How does the digestive system protect itself from harmful toxins?

Vomiting and diarrhea

Vomiting

Protective mechanisms to remove toxins from the body, and involves a strong muscular contraction that forces the contents of the stomach up through the esophagus and through the mouth (and sometimes the nose as the oral and nasal cavities are connected)

Diarrhea

Occurs due to the inadequate absorption of water in the colon. Often caused by an infection, kills around 2 million children worldwide each year.

Why do we need to eat?

- Growth
- Maintenance (repairment of tissues)
- Energy
- Regulation of cellular respiration

Essential nutrients

The basic raw materials that the body systems need in order to build and maintain bodily structures, perform their functions, and obtain energy for survival (major components)

Macromolecules

Larger, more complex assemblies of organic molecules.

What do ORGANIC molecules contain?

Carbon bonded to hydrogen, as well as to other atoms, such as oxygen, sulfur, and nitrogen.

What is energy from macromolecules used for in the digestive system?

Metabolism

Metabolism

All of the chemical processes carried out by cells to maintain life-catabolism and anabolism.

Catabolism

The breaking down of big molecules to small molecules.

Anabolism

The conversion of small molecules to big molecules.

What are the four major categories of macromolecules?

1. Carbohydrates
2. Lipids
3. Nucleic acids
4. Proteins

Carbohydrates

- Macromolecules that always contain carbon, hydrogen, and oxygen.
- Almost always in the same proportion: 1H:2O:1C ratio
- Provide short-term or long-term energy storage for organisms.

What are the two main types of carbohydrates?

1. Simple sugars
2. Polysaccharides

Monosaccharides (simple sugars)

Carbohydrates molecules with 3 - 7 carbon atoms.
- Glucose (can be found in blood)
- Galactose (can be found in dairy)
- Fructose (can be found in fruit)

Disaccharides

Made up of two simple sugars (monosaccharides)
- Sucrose (glucose + fructose, table sugar)
- Lactose (glucose + galatose, sugar found in dairy products)