Eating and Human Digestion Quiz

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Questions and Answers

What is the primary function of the digestive system?

To convert large molecules into smaller, absorbable nutrients. (correct)

To eliminate waste products from the kidneys.

To regulate hormone production throughout the body.

To synthesize new complex molecules for the body.

During digestion, carbohydrates are broken down into which of the following?

Glycerol and Fatty acids

Amino acids

Triglycerides

Monosaccharides (correct)

What are the end products of fat (lipid) digestion?

Nucleotides and Bases

Peptides and Amino Acids

Glucose and Fructose

Glycerol and Fatty acids (correct)

What are the final products of protein digestion?

Amino acids Signup and view all the answers

Which of the following is NOT considered a nutrient that must be broken down during digestion?

Vitamins Signup and view all the answers

Which body system is primarily responsible for the process of digestion?

The digestive system Signup and view all the answers

What is the significance of breaking down nutrients into their smallest parts?

To make the nutrients easier to absorb into the bloodstream. Signup and view all the answers

Why is it important for complex carbohydrates to be broken down into monosaccharides during digestion?

Monosaccharides are small enough to be absorbed into the bloodstream. Signup and view all the answers

During digestion, what happens to proteins?

They are broken down into amino acids. Signup and view all the answers

What happens to fats during digestion to allow for them to be absorbed?

They are broken down into fatty acids and glycerol. Signup and view all the answers

What is the primary function of the liver in relation to blood?

Filtering and removing toxic substances from the blood Signup and view all the answers

Which of the following best describes the role of the lymphatic system?

Removing fluid from tissues and aiding in immune response Signup and view all the answers

What are the main waste products removed by the kidneys?

Water and small molecules filtered from the blood Signup and view all the answers

What is the correct order of processes involved in nutrients once consumed from food?

Digestion, Absorption, Metabolism Signup and view all the answers

What is the main purpose of the stomach in the digestive system?

Food storage and beginning the breakdown of protein Signup and view all the answers

Which of the following is an example of 'metabolism' within the body?

Using absorbed nutrients for energy production or building new structures Signup and view all the answers

What is the role of amylase in the initial stages of digestion?

Initiating the digestion of starches Signup and view all the answers

What is one of the main functions of the large intestine?

Storing and eliminating feces Signup and view all the answers

What happens to nutrients that are absorbed into the body?

They are converted into substances the body can use as energy or for building larger structures. Signup and view all the answers

What is the role of bile in digestion?

Breaking down fats Signup and view all the answers

What is the primary role of bile in digestion?

To emulsify fats into smaller particles. Signup and view all the answers

Which of the following best describes the movement of fat-soluble nutrients after they are absorbed in the small intestine?

Into the lymph system, bypassing the liver initially, then into the bloodstream through the neck area. Signup and view all the answers

The stomach lining is protected from the effects of pepsin and hydrochloric acid by:

Mucus. Signup and view all the answers

What is the semi-liquid mixture of food and gastric secretions called?

Chyme Signup and view all the answers

Which of the following organs produces bicarbonate, pancreatic amylase, protease, and lipase?

Pancreas Signup and view all the answers

Which of the following has the longest transit time through the digestive system?

Meat Signup and view all the answers

Which of the following is NOT a method of nutrient absorption in the small intestine?

Reverse osmosis Signup and view all the answers

Which of the following best describes passive/simple diffusion in the context of nutrient absorption?

Movement of nutrients from a high concentration to a low concentration, without the need for a protein carrier or energy. Signup and view all the answers

What is the approximate transit time from the mouth to the large intestine?

40 hours Signup and view all the answers

After absorption in the small intestine, water-soluble nutrients are transported directly to the liver via the:

Hepatic portal vein Signup and view all the answers

What is the primary function of the epiglottis?

To prevent food from entering the trachea. Signup and view all the answers

Which of the following best describes peristalsis?

The rhythmic muscle contractions that move food along the digestive tract. Signup and view all the answers

In which part of the digestive system does the majority of mechanical digestion take place?

Mouth and stomach Signup and view all the answers

What is the function of the muscular ring located at the end of the esophagus?

To regulate the passage of food into the stomach. Signup and view all the answers

What is the name of the enzyme contained in saliva and what does it break down?

Amylase, breaks down starches Signup and view all the answers

What is the purpose of hydrochloric acid in gastric juice?

To kill microorganisms, unfold proteins, and activate pepsinogen. Signup and view all the answers

How does the GI tract supply the body with water and nutrients?

Via a combination of food passage, secretion, digestion, absorption and circulation. Signup and view all the answers

What is the inactive form of the protein-digesting enzyme found in the stomach?

Pepsinogen Signup and view all the answers

What best describes the lumen of the GI tract?

The inside space of the GI tract. Signup and view all the answers

What is the name given to the ball of food after it is chewed and mixed with saliva, which is then swallowed?

Bolus Signup and view all the answers

Study Notes

Course Information

Course title: Eating and Human Digestion
Course code: NUTR 1100
Instructor: Stephanie Gladman, MHSc, RD (Registered Dietitian)
Institution: Langara College

Learning Outcomes

Recall the anatomy and function of the gastrointestinal tract, and the role of its major structures.
Describe nutrition-related physiological processes, including digestion, absorption, transport, and elimination, and their role in delivering and using energy and nutrients in the body.
Differentiate between water-soluble and fat-soluble absorption, including the systems used and reasoning.
Describe metabolism processes and the role of energy and nutrients in the body.

Digestion

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Digestive System - Where does food travel?

Diagram showing the path of food through the digestive system

Digestive System - Accessory Organs

Diagram showing the accessory organs of the digestive system.

Human Digestion

Food is broken down into its smallest parts, which are the nutrients:
- Carbohydrates
- Fats (lipids)
- Proteins
- Vitamins
- Minerals
- Water

Human Digestion - Mechanical Digestion

Food is broken down into smaller parts through:
- Teeth (chewing)
- Stomach (smooth muscles)
- Muscular contractions (peristalsis)

Human Digestion - Chemical Digestion

Enzymes speed up the chemical breakdown of food.
Acids (hydrochloric acid - gastric juice) break down chemical bonds.

Digestive System

Gastrointestinal (GI) tract: a 30-foot long hollow tube, with a lumen (inside space) lined by mucosal cells.
The GI tract constantly supplies the body with water and nutrients.
- Secretion of digestive juices and enzymes
- Passage of food through the tract
- Digestion of food
- Absorption of water and nutrients
- Circulating blood to distribute absorbed nutrients
Each part of the digestive tract has specific functions:
- Passage of food
- Temporary storage
- Digestion of food
- Absorption of food
- Elimination of waste

Structure, Enzymes, and Secretions - Mouth

Teeth
Taste buds
Saliva (1-1.5 liters produced daily)
- Moistens
- Contains enzymes (salivary amylase) which break down starch.
- Protects teeth.
- Forms a protective layer.

Structure, Enzymes, and Secretions - Throat (Pharynx)

Trachea → lungs
Esophagus → stomach
Epiglottis: prevents food from going down the wrong tube

Structure, Enzymes, and Secretions - Esophagus

Connects pharynx to stomach
Bolus of food is moved by rhythmic muscle contractions (called peristalsis).
Food passes through a muscular ring (sphincter) to enter the stomach.
No digestion takes place in the esophagus.

Structure, Enzymes, and Secretions - Stomach

Temporary storage until processed.
Mechanical + chemical digestion.
Gastric glands produce gastric juices containing:
- Water
- Pepsin (inactive protein-digesting enzyme)
- Kills microorganisms, unfolds proteins, and activates pepsinogen to pepsin. Also inhibits amylase (breaks down starch).
Chyme: a semi-liquid blend of foods and gastric secretions.
It leaves the stomach through the pyloric sphincter to enter the small intestine.
Protects stomach lining from pepsin and hydrochloric acid

Structure, Enzymes, and Secretions - Stomach Emptying

Regulated by chyme and signals from nerves and hormones.
Affected by:
- Meal size (large > small > liquid)
- Meal composition (fat > fiber > carbohydrates and sugars)
- Affects satiety; importance of a balanced meal.

Structure, Enzymes, and Secretions - Small Intestine

Main site of chemical digestion and absorption.
Has three parts.
Accessory organs play a role:
Bicarbonate
Pancreatic amylase
Protease
Lipase
Makes bile
Stores bile

Structure, Enzymes, and Secretions - Bile

Emulsifies lipids (fats) - a type of mechanical digestion.
Makes fat particles small enough for enzymes to break down chemical bonds.
Lipases (enzymes) break down those bonds, releasing glycerol and fatty acids – chemical digestion.

Structure, Enzymes, and Secretions - Large Intestine

Things not absorbed.
Some absorption happens:
- Water
- Vitamins (e.g., vitamin K)
- Fiber
- Prebiotics
- Probiotics

Structure, Enzymes, and Secretions - Rectum

Storage area
Packs waste, expels through anus.

Transit Time

Time from mouth to anus varies.
Mouth to small intestine: 6-8 hours
Mouth to large intestine: ~40 hours
Diet, physical activity, emotional state, health status, and laxative use affect transit time.
- Shorter time = healthier intestinal wall
- Longer time = more harmful bacteria produced.

Absorption

Most absorption happens in the small intestine.
Digested food (nutrients) must cross the gastrointestinal wall into the circulatory system.
Small intestine has folds, villi, and microvilli for maximum nutrient absorption.
Diagrams show structure of the small intestine (folds, villi, microvilli, capillaries, lacteals, etc.)
Three methods of absorption:
- Passive/Simple diffusion
- Facilitated diffusion
- Active transport

Passive/Simple Diffusion

Nutrients absorbed due to a concentration gradient.
No energy required.
Concentration greater in GI tract than inside intestinal wall.

Facilitated Diffusion

Similar to passive diffusion (high to low concentration).
No energy required.
Requires special protein carriers to transport nutrients.

Active Transport

Absorbs nutrients from low to high concentration.
Requires energy and a carrier.

Post Absorption

Circulatory/cardiovascular system
Urinary system
Waste removal

Movement of Nutrients

Water-soluble nutrients: transported through capillaries in the villi to the hepatic portal vein, then to the liver.
Fat-soluble nutrients packaged in protein vehicles into the lymph system.

Circulatory/Cardiovascular System

Transports nutrients to cells and waste away from cells.
Consists of heart, blood, and blood vessels.
Nutrients absorbed in small intestine, travel to liver, then to the heart, lungs, and then all body cells.

Liver

Collects nutrients absorbed in the digestive tract.
Stores nutrients.
Converts nutrients into substances usable by the body.
Filters blood and removes harmful substances.

Lymphatic System

Removes fluid from tissues.
Filters fluid before returning to blood.
Involved in immunity (contains immune cells to fight antigens).
Transports and absorbs fat-soluble nutrients.

Waste Removal

Undigested/unabsorbed materials (feces): removed through the GI tract.
Metabolic wastes removed through:
- Kidneys (filter water and small molecules, excretes excess as urine).
- Lungs (remove CO2 and water).
- Skin (removes water, minerals, and N-containing wastes through sweat)

Excretion and Waste

Urine color chart
Bristol stool chart

Review Differences

Digestion: Breaking down food into simple nutrients.
Absorption: Nutrients enter the body by crossing the gastrointestinal wall and entering the circulatory system.
Metabolism: What happens to nutrients once inside the body.

Metabolism

Nutrients used for energy.
Larger structures are built (requires energy).
Larger structures broken down (creates energy).

Digestive System Summary

Diagram summarizing major structures and functions of the digestive system.

Student Independent Activities

Review Allergies and Intolerances section.

Outcome Reviews

Outcomes of the class
Summarized knowledge learned in the lecture.

Participation Activity

Instructions to join a Kahoot! quiz.
Kahoot! instructions

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Description

Test your knowledge on the anatomy and function of the gastrointestinal tract. This quiz covers digestion, absorption, and metabolism processes essential for delivering energy and nutrients in the body. Differentiate between water-soluble and fat-soluble absorption along the way.