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Digestive System Overview
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Digestive System Overview
Digestive System
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1
Question
What is the digestive system made up of?
Answer
The digestive tube and digestive glands.
2
Question
What is the digestive tract and what organs does it include?
Answer
It is the pathway through which food passes and undergoes mechanical and chemical digestion. It includes: - Mouth - Pharynx - Esophagus - Stomach - Small intestine - Large intestine - Anus
3
Question
What digestive glands secrete digestive juices?
Answer
- Salivary glands - Liver - Pancreas - Microscopic glands in the walls of the stomach and small intestine
4
Question
Define digestion.
Answer
Digestion is the breakdown of food using chemical and mechanical processes that change complex food into small particles called nutrients able to pass into the blood and reach every cell in the body.
5
Question
What is mechanical digestion?
Answer
Mechanical digestion is a process of physical breakdown of complex food into small parts or fragments.
6
Question
What organs are responsible for mechanical digestion?
Answer
- The mouth (chewing) - Pharynx (swallowing) - Esophagus (peristaltic movement) - Stomach (churning) - Small intestine (churning and peristaltic movement) - Large intestine (progression, transit, and elimination)
7
Question
What is chemical digestion?
Answer
The process of breakdown of complex food into nutrients under the action of enzymes found in digestive juices.
8
Question
What organs are responsible for chemical digestion?
Answer
- Mouth (Salivary amylase found in saliva) - Stomach (Pepsin found in gastric juice) - Small intestine (Pancreatic juice and intestinal juice)
9
Question
How does mechanical digestion facilitate chemical digestion?
Answer
By breaking down food into smaller particles, making it easier for enzymes to act on them.
10
Question
What are the two main categories of substances in food?
Answer
Food consists of inorganic and organic substances.
11
Question
What are inorganic substances found in food?
Answer
- Water - Mineral salts
12
Question
What are organic substances found in food?
Answer
- Carbohydrates - Proteins - Lipids - Vitamins
13
Question
What are carbohydrates and their main groups?
Answer
Carbohydrates are called saccharides or compounds of sugar. The three main groups of carbohydrates are: 1. Monosaccharides 2. Disaccharides 3. Polysaccharides.
14
Question
What are monosaccharides?
Answer
The simplest sugar molecules with the same chemical formula C6H12O6. Examples: - Glucose - Fructose - Galactose
15
Question
What are disaccharides?
Answer
Disaccharides are sugars made up of 2 molecules of monosaccharides. Examples: - Maltose (malt sugar) - Lactose (milk sugar) - Sucrose (table sugar)
16
Question
What are polysaccharides?
Answer
Polysaccharides are complex sugars, nonsoluble in water, made up of a long chain of monosaccharides. Examples include starch and cellulose.
17
Question
What is cellulose and its significance?
Answer
Cellulose is a plant sugar that makes up the cell wall of plant cells and is not digested by our body due to a lack of specific enzymes. It helps in the transit of food and prevents constipation and colon cancer.
18
Question
What is the lipid family and its importance?
Answer
Lipids are important as an energy source, components in the cell membrane, and in the formation of some hormones and vitamins. They are insoluble in water.
19
Question
What are examples of lipids?
Answer
- Fats - Waxes - Vitamins - Cholesterol
20
Question
How do lipids pass into the blood?
Answer
Lipids are complex molecules that cannot pass into the blood unless digested into their simplest forms: fatty acids and glycerol.
21
Question
What is bile and its role in digestion?
Answer
- Is a greenish alkaline liquid made of minerals, water, and pigments - Manufactured by the liver - Stored in the gall bladder - Poured into the small intestine. It renders the medium alkaline in the small intestine and facilitates the digestion of fats by emulsification.
22
Question
What is the difference between one protein molecule and another?
Answer
- Type of amino acids - Number of amino acids - Sequence of amino acids
23
Question
What defines enzymes in the context of digestion?
Answer
Enzymes are biological catalysts that speed up digestion and remain intact at the end of digestion.
24
Question
What suffix is used in the naming of enzymes?
Answer
The suffix 'ase' is used in the naming of enzymes. For example, maltose is acted upon by maltase.
25
Question
What is the specificity of enzymes?
Answer
Enzymes are specific in their action according to the key-lock theory, meaning each enzyme acts on one substrate.
26
Question
What are some examples of enzymes and their substrates?
Answer
Examples: - Salivary amylase acts on starch - Lipase acts on lipids - Maltase acts on maltose - Sucrase acts on sucrose - Lactase acts on lactose - Pepsin acts on proteins
27
Question
What are the optimal pH levels for different enzymes?
Answer
- Salivary amylase: neutral medium (pH 7) - Pepsin: acidic medium (pH 2) - All other enzymes: basic medium (pH 8)
28
Question
What is the ideal temperature for enzyme activity?
Answer
Enzymes react optimally at a temperature of 37°C (body temperature). They become inactive at 0°C and can be destroyed at high temperatures (e.g., 60°C).
29
Question
What is the difference between digestive juices and enzymes?
Answer
Digestive juices are secretions from glands into the digestive tube that contain enzymes. While each enzyme targets a specific food, digestive juices can act on various foods because they contain multiple enzymes.
30
Question
What are the digestive juices produced in the mouth, stomach, and small intestine?
Answer
- Mouth: Saliva contains amylase that acts on cooked starch to produce maltose in a neutral medium. - Stomach: Gastric juice contains pepsin that acts on proteins to produce peptides in an acidic medium. - Small intestine: Pancreatic juice and intestinal juice contain various enzymes that act on different substrates in a basic medium.