Unit 7 - Human Diet & Digestion

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Questions and Answers

What is the primary role of chemical digestion in the digestive process?

To digest food mechanically into smaller pieces

To convert large, insoluble molecules into small, soluble molecules (correct)

To absorb nutrients directly into the bloodstream

To produce large, insoluble molecules for storage

What substance do amylases primarily break down?

Proteins

Starch (correct)

Sucrose

Lipids

Which enzyme is responsible for breaking down proteins in acidic conditions?

Lipase

Trypsin

Pepsin (correct)

Amylase

Where is lipase produced and secreted during digestion?

Pancreas and duodenum Signup and view all the answers

What is the main purpose of hydrochloric acid in the stomach?

To kill bacteria and activate digestive enzymes Signup and view all the answers

In which part of the digestive system does the absorption of small food molecules occur?

Small intestine Signup and view all the answers

Which enzyme digests maltose into glucose?

Maltase Signup and view all the answers

What is the final stage of food processing that involves the elimination of undigested material?

Egestion Signup and view all the answers

What is the primary function of bile in the digestive process?

To neutralize hydrochloric acid and emulsify fats Signup and view all the answers

Why does pepsin work efficiently in the stomach?

As a result of the low pH environment Signup and view all the answers

How are nutrients absorbed from the digestive system into the bloodstream?

Via diffusion and active transport Signup and view all the answers

What structural feature of the ileum enhances its absorption capabilities?

It is highly folded with numerous villi and microvilli Signup and view all the answers

What substance is primarily absorbed in the colon?

Water Signup and view all the answers

What is emulsification, as performed by bile?

The process of breaking fats into smaller drops Signup and view all the answers

What is the ideal pH range for enzymes in the small intestine compared to those in the stomach?

Small intestine enzymes prefer a more alkaline pH Signup and view all the answers

Which component runs through the center of the villus in the small intestine?

Lacteal Signup and view all the answers

What is a characteristic symptom of scurvy?

Gum ulcerations Signup and view all the answers

Which food group is crucial for the absorption of calcium in the body?

Vitamins Signup and view all the answers

What is the main function of bile in digestion?

To emulsify fats Signup and view all the answers

Which stage of digestion occurs when food is taken into the body?

Ingestion Signup and view all the answers

What type of teeth are specifically adapted for tearing and holding food?

Canines Signup and view all the answers

Which of the following is NOT a function of the digestive system?

Regulating body temperature Signup and view all the answers

Which of the following organs does NOT directly process food?

Pancreas Signup and view all the answers

What is the role of mechanical digestion in the digestive process?

To increase surface area for enzymes Signup and view all the answers

What condition is characterized by poor bone development in children?

Rickets Signup and view all the answers

Which aspect of the digestive system is primarily involved in the egestion process?

Rectum Signup and view all the answers

How long can food typically be digested within the stomach?

Several hours Signup and view all the answers

What type of digestion is primarily responsible for breaking down food into smaller pieces without changing its chemical structure?

Mechanical digestion Signup and view all the answers

Which nutrient deficiency is associated with symptoms like anemia and exhaustion?

Vitamin C Signup and view all the answers

What process follows the absorption of nutrients in the digestive system?

Assimilation Signup and view all the answers

Study Notes

Balanced Diet

A balanced diet includes all food groups in correct proportions
Necessary food groups include carbohydrates, proteins, lipids, vitamins, minerals, dietary fiber, and water

Food Groups and Functions

Carbohydrates: Source of energy
Proteins: Growth and repair
Lipids: Insulation and energy storage
Dietary Fiber: Provides bulk for intestinal movement
Vitamins: Needed in small quantities for maintaining health
Minerals: Needed in small quantities for maintaining health
Water: Needed for chemical reactions in cells

Food Sources

Carbohydrates: Bread, cereals, pasta, rice, potatoes
Proteins: Meat, fish, eggs, pulses, nuts
Lipids: Butter, oil, nuts
Dietary Fiber: Vegetables, whole grains, fruits
Vitamins & Minerals: Fruits, vegetables, meats, dairy products, water, juice, milk

Vitamin and Mineral Requirements

Vitamin C: Crucial part of collagen. Deficiency causes scurvy. Found in citrus fruit, strawberries, and green vegetables
Vitamin D: Aids calcium absorption, key for strong bones and teeth. Found in oily fish, eggs, liver, dairy products, sunlight.
Calcium: Needed for strong teeth and bones, blood clotting. Deficiency can lead to osteoporosis. Found in milk, cheese, eggs, leafy green vegetables
Iron: Essential for hemoglobin production (carrying oxygen). Found in red meat, liver, leafy green vegetables

Varying Dietary Needs

Age: Energy and protein needs vary with age (higher for growth)
Activity Levels: Higher energy needs for more active individuals
Pregnancy: Increased energy requirements for fetal growth, also higher calcium and iron needs
Breastfeeding: Increased energy and calcium needs for milk production

Scurvy

Severe Vitamin C deficiency
Symptoms: Anemia, exhaustion, spontaneous bleeding, limb pain, swelling, gum ulcerations, tooth loss
Caused by lack of Vitamin C in the diet over 3 months
Treatable with oral or intravenous Vitamin C

Rickets

Condition in children – poor bone development
Symptoms: Bone pain, lack of bone growth, weak bones, deformities
Caused by severe Vitamin D deficiency
Vitamin D helps absorb calcium. Calcium is critical for normal bone development.
Sources of Vitamin D are sunlight, oily fish, egg yolks

Digestive System (Organs)

Alimentary Canal: Food passes directly through these organs: Mouth, Oesophagus, Stomach, Small Intestine (duodenum and ileum), Large Intestine (colon, rectum, anus)
Accessory Organs: Salivary glands, Pancreas, Liver, Gallbladder

Digestive System Functions (Summary)

Ingestion: Taking food and drink into the body
Mechanical Digestion: Breaking food into smaller pieces (e.g., chewing, stomach churning)
Chemical Digestion: Breaking down complex food molecules into simpler absorbable molecules (e.g., enzymes breaking down proteins)
Absorption: Taking small molecules into the bloodstream
Assimilation: Using absorbed nutrients for bodily functions
Egestion: Removing undigested waste from the body

Enzymes in Digestion

Amylases: Break down starch to simpler sugars
Proteases: Break down proteins into amino acids
Lipases: Break down lipids into fatty acids and glycerol

Hydrochloric Acid (HCl)

Produced in the stomach
Low pH needed for enzymes (e.g., pepsin) to work optimally
Kills bacteria

Bile

Produced by the liver, stored in the gallbladder
Neutralises stomach acid, aiding small intestine enzymes
Emulsifies fats (breaks down large fat droplets into smaller ones, increasing surface area for enzyme action)

Absorption (Summary)

Occurs mainly in the small intestine (with villi and microvilli)
Nutrients (glucose, amino acids, fatty acids, glycerol) transported to blood or lymph.

Adaptations of the Small Intestine

Long, folded structure dramatically increases surface area for absorption.
Villi and microvilli increase surface area for faster absorption.

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Description

This quiz covers the essential components of a balanced diet, detailing each food group and its functions. Learn about the importance of carbohydrates, proteins, lipids, vitamins, minerals, dietary fiber, and water, along with their food sources and health implications.