Digestion and Nutrition Lecture 8

Flashcards covering key concepts from the 'Digestion and Nutrition' lecture, including digestive system overview, human digestive system components, digestion processes, and nutrient requirements.

What is the common goal of the digestive system?

To provide organic molecules to the body, which are then broken down in cellular respiration.

What are the four stages of food processing?

Ingestion, Digestion, Absorption, and Elimination.

What is ingestion?

The intake of food.

What is digestion?

The breakdown of food molecules.

What is absorption in the context of digestion?

The uptake of nutrient molecules into cells.

What is elimination?

The removal of undigested waste material.

What key biological molecules are required for digestion?

Digestive enzymes.

What is the role of enzymes in digestion?

They decrease the activation energy for chemical reactions, breaking polymers into monomers.

What are the two forms of digestion?

Mechanical and Chemical digestion.

Describe mechanical digestion.

Physical breakdown of food, such as chewing or churning, without chemical reactions.

Describe chemical digestion.

The breaking of polymers into monomers through hydrolysis reactions, requiring enzymes.

What kind of chemical reaction is involved when breaking down food molecules using enzymes?

Hydrolysis.

What are the two types of digestive systems in animals?

Incomplete and Complete digestive systems.

What is an incomplete digestive system?

A one-way, sac-like cavity with a single opening (like in a hydra).

What is a complete digestive system?

A tube with an opening at each end (mouth and anus).

What does the specialization of a digestive system reflect?

The feeding behavior of the animal.

Name two main organs of the human digestive tract.

Mouth, Esophagus, Stomach, Small intestine, Large intestine, Rectum, or Anus (any two).

Name two accessory organs of the human digestive system.

Salivary glands, Liver, Gallbladder, or Pancreas (any two).

What is the primary function of the salivary glands?

To secrete saliva, which contains enzymes and aids in forming food into a paste.

What is the main digestive function of the liver?

It secretes bile, which helps break up fats.

What is the function of the gallbladder?

It stores and concentrates bile.

What is the primary digestive function of the pancreas?

It secretes digestive enzymes.

Where is bile produced?

In the liver.

Where is bile stored?

In the gallbladder.

What digestive processes begin in the mouth?

Mechanical and chemical digestion.

What enzyme in saliva begins carbohydrate digestion?

Salivary amylase.

What is the function of mucins in saliva?

They are gel-like proteins that help bind food together, making it easier to swallow.

What is the role of the epiglottis during swallowing?

It closes the airway to prevent food from entering.

What is peristalsis?

Waves of muscle contractions that move food through the digestive tract.

What are the primary functions of the stomach?

Mixing and storing food, secreting acid and enzymes, and controlling passage to the small intestine.

What components make up gastric fluid in the stomach?

Hydrochloric acid (HCl), pepsin, and protective mucus.

What is the function of hydrochloric acid (HCl) in the stomach?

It denatures proteins, unfolds them, and helps pepsin bind to them for digestion. It also contributes to the stomach's very acidic pH.

Which organ is the primary location for chemical digestion and nutrient absorption?

The small intestine.

Besides liver and gallbladder, what other accessory organ sends secretions to the small intestine?

The pancreas.

What types of molecules do disaccharidases break down?

Disaccharides (into monosaccharides).

What types of molecules do peptidases break down?

Polypeptides (unfolded proteins) into amino acids.

What is the function of bile when it enters the small intestine?

It emulsifies fats, breaking them into smaller droplets to increase surface area for enzyme action.

What structural features increase the surface area of the small intestine for absorption?

Folds, villi, and microvilli.

How are monosaccharides and amino acids absorbed into the cells lining the small intestine?

They are actively transported into the cells and directly enter the bloodstream.

How are fats primarily transported into the body after digestion in the small intestine?

They are transported into lymph vessels, which eventually drain into the blood.

What are the main functions of the large intestine (colon)?

Water absorption and waste concentration (storing feces).

What beneficial role do bacteria play in the colon?

They produce ions and vitamins that can be absorbed by the body.

What are the main fates of organic molecules from digested food in the body?

They can be burned as fuel, stored as fat, converted into other molecules, or used as building blocks.

What is the major use of carbohydrates in the body?

Providing an immediate source of energy (glucose).

How is excess glucose stored in the body?

As glycogen or fat tissue.

What is a key benefit of consuming complex carbohydrates?

They provide fiber, which promotes colon health and reduces cholesterol.

What are two major uses of lipids (fats) in the body?

Longer-term energy storage and as components of cell membranes (phospholipids).

What are essential fatty acids?

Fats that the body needs but cannot produce, which must be obtained from food (e.g., linoleic acid).

What is the primary role of proteins in nutrition?

To provide amino acids needed to build more proteins in the body.

What is the difference between "complete" and "incomplete" proteins?

Animal proteins are "complete" as they supply all essential amino acids, while plant proteins are "incomplete" and must be combined to provide all of them.