CH 7 :HUMAN NUTRITION
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Questions and Answers

What is the process of taking in substances like food and drink into the body called?

  • Egestion
  • Assimilation
  • Ingestion (correct)
  • Absorption

What is the primary function of digestion in the digestive system?

  • To transport nutrients into the blood
  • To remove undigested food from the body
  • To break down large insoluble food molecules (correct)
  • To store food for later use

Which mineral ion is specifically associated with the prevention of rickets?

  • Calcium (correct)
  • Sodium
  • Potassium
  • Iron

What describes the movement of nutrients from the intestines into the blood?

<p>Absorption (A)</p> Signup and view all the answers

Which of the following organs is NOT part of the alimentary canal?

<p>Liver (D)</p> Signup and view all the answers

The removal of undigested food is known as which process?

<p>Egestion (C)</p> Signup and view all the answers

Which vitamin deficiency is directly related to scurvy?

<p>Vitamin C (B)</p> Signup and view all the answers

What is one primary function of teeth in the digestive process?

<p>Bite off pieces of food (A)</p> Signup and view all the answers

What is the primary role of maltase in digestion?

<p>To digest maltose into glucose (A)</p> Signup and view all the answers

What role does saliva play in the digestion process?

<p>It helps soften food for easier chewing (B)</p> Signup and view all the answers

Which enzyme is responsible for breaking down starch into maltose in the mouth?

<p>Amylase (D)</p> Signup and view all the answers

Which process is responsible for the breakdown of excess amino acids in the liver?

<p>Deamination (A)</p> Signup and view all the answers

What action moves food through the esophagus?

<p>Peristalsis (D)</p> Signup and view all the answers

What is absorbed through the lacteal route during digestion?

<p>Fatty acids and glycerol (C)</p> Signup and view all the answers

What is the function of hydrochloric acid in gastric juice?

<p>To kill microbes and activate pepsinogen (A)</p> Signup and view all the answers

Which component of the large intestine is responsible for water absorption?

<p>Colon (B)</p> Signup and view all the answers

Which of the following statements accurately describes the differences between root hair cells and villi?

<p>Root hair cells are found in plants (A)</p> Signup and view all the answers

How does mucus function in the stomach?

<p>It protects the stomach wall from acid and enzymes (C)</p> Signup and view all the answers

Which statement is true regarding pepsin?

<p>It is secreted in an inactive form to prevent self-digestion (B)</p> Signup and view all the answers

What is physical digestion primarily achieved by in the stomach?

<p>Contraction and relaxation of stomach muscles (D)</p> Signup and view all the answers

Which function does saliva NOT serve in the mouth?

<p>Activating pepsin (B)</p> Signup and view all the answers

What is the primary role of pepsin in the stomach?

<p>To digest proteins (D)</p> Signup and view all the answers

Why are proteases secreted in an inactive form?

<p>To prevent digestion of their producing cells (A)</p> Signup and view all the answers

What is chyme?

<p>Food mixed with gastric juice leaving the stomach (B)</p> Signup and view all the answers

Which component of bile helps in the emulsification of fats?

<p>Bile salts (D)</p> Signup and view all the answers

What function does the duodenum serve in the small intestine?

<p>Emulsification of fat (C)</p> Signup and view all the answers

Which of the following correctly describes the pH change that occurs in the small intestine?

<p>From acidic to alkaline (D)</p> Signup and view all the answers

What is the role of hydrogen carbonate in the duodenum?

<p>To neutralize stomach acid (B)</p> Signup and view all the answers

Which part of the small intestine is primarily responsible for the absorption of digested food?

<p>Ileum (B)</p> Signup and view all the answers

What happens to salivary amylase when it reaches the stomach?

<p>It is deactivated due to pH changes (B)</p> Signup and view all the answers

What is the primary purpose of bile pigment in bile?

<p>To give color to urine and feces (D)</p> Signup and view all the answers

What is the primary function of amylase in pancreatic juice?

<p>Breaks carbohydrates into maltose (B)</p> Signup and view all the answers

How does the structure of villi enhance nutrient absorption in the ileum?

<p>Villi contain blood capillaries and lacteals (A)</p> Signup and view all the answers

What is the role of bicarbonate in pancreatic juice?

<p>To reduce acidity of chyme (A)</p> Signup and view all the answers

What is the primary function of lipase?

<p>To break down fats into fatty acids and glycerol (D)</p> Signup and view all the answers

Why is the wall of vilis only one cell thick?

<p>To allow easy crossing of digested nutrients (B)</p> Signup and view all the answers

What type of nutrients are absorbed into the lacteals?

<p>Fats (C)</p> Signup and view all the answers

What is the length of the human ileum approximately?

<p>5 meters (D)</p> Signup and view all the answers

What is the role of peptidase in digestion?

<p>To digest polypeptides into amino acids (A)</p> Signup and view all the answers

What adaptation in villi increases its surface area for absorption?

<p>Microvilli on the surface (C)</p> Signup and view all the answers

Which enzyme is primarily responsible for digesting carbohydrates?

<p>Amylase (C)</p> Signup and view all the answers

Flashcards

What is a balanced diet?

A balanced diet provides all the essential nutrients in the correct proportions to maintain good health, growth, and development.

What is the importance of carbohydrates?

Carbohydrates are the body's main energy source, providing fuel for physical activity and basic bodily functions.

What is the importance of fats and oils?

Fats and oils provide essential fatty acids, energy storage, insulation for organs, and hormone production.

What is the importance of proteins?

Proteins are building blocks for tissues, enzymes, hormones, and antibodies. They're essential for growth and repair.

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What is the importance of vitamins C and D?

Vitamins C and D are vital for maintaining a healthy immune system and strengthening bones. Vitamin C prevents scurvy, and Vitamin D prevents rickets.

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What is the importance of calcium and iron?

Calcium is essential for strong bones and teeth, and iron is vital for carrying oxygen in red blood cells.

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What is the importance of fiber?

Dietary fiber, or roughage, aids digestion by adding bulk to stools, preventing constipation, and regulating blood sugar levels.

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What is digestion?

The process of breaking down food into smaller molecules that the body can absorb and use for energy.

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What is physical digestion?

The process of physically breaking down food into smaller pieces using teeth and the muscles of the digestive system.

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What is chemical digestion?

The process of chemically breaking down food molecules through the action of enzymes.

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How do teeth aid digestion?

Teeth help with the physical digestion of food by biting off pieces and chewing them into smaller particles. This increases the surface area of the food, making it easier for the enzymes to work.

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What is the role of saliva in digestion?

Saliva, produced in the mouth, contains enzymes like amylase that begin the chemical breakdown of food.

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What does the esophagus do in digestion?

The esophagus is a muscular tube that connects the mouth to the stomach. It helps to move food down to the stomach using peristalsis - a wave-like muscular contraction.

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What happens in the stomach during digestion?

The stomach is where physical and chemical digestion happen. Muscles churn food, and gastric juice containing acids and enzymes (like pepsin) break down food further.

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What is the role of pepsin in digestion?

Pepsin is an enzyme that is activated in the stomach. It helps break down proteins into smaller molecules called polypeptides.

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What is the purpose of mucus in the stomach?

Mucus protects the lining of the stomach from the corrosive effects of hydrochloric acid and digestive enzymes like pepsin.

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Stomach Mucus

A protective layer of mucus secreted by the stomach lining, acting as a barrier against stomach acid and digestive enzymes.

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Pepsin

A protease enzyme found in the stomach, breaking down proteins into smaller polypeptide chains.

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Trypsin

A protease enzyme found in the small intestine, further breaking down polypeptides into even smaller fragments.

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What are proteases?

Enzymes responsible for breaking down proteins into smaller units.

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Why are proteases secreted in inactive forms?

Proteases are initially secreted in inactive forms to prevent them from digesting the cells producing them.

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What is chyme?

The mixture of food and gastric juice that leaves the stomach, characterized by its acidic nature.

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What is the duodenum?

The first part of the small intestine, where bile emulsifies fats and the pH of the food is adjusted to be more alkaline.

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What is the ileum?

The final part of the small intestine, where the complete digestion of all food types takes place, and the digested nutrients are absorbed.

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What is bile?

A fluid produced by the liver and stored in the gallbladder, containing bile salts and bile pigments.

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How do bile salts work?

Bile salts break down large fat droplets into smaller droplets, increasing their surface area for digestion.

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What is pancreatic juice?

A digestive fluid produced by the pancreas, containing enzymes and bicarbonate, that helps neutralize stomach acid and digest food in the small intestine.

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What is the function of bicarbonate in pancreatic juice?

A component of pancreatic juice that neutralizes the acidic chyme from the stomach, creating an alkaline environment for optimal enzyme activity in the small intestine.

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What does pancreatic amylase do?

An enzyme found in pancreatic juice that breaks down carbohydrates (starches) into simpler sugars (maltose).

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What does trypsin do?

An enzyme in pancreatic juice that breaks down proteins into smaller peptides.

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What does lipase do?

An enzyme in pancreatic juice that breaks down fats (lipids) into fatty acids and glycerol.

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Where does pancreatic juice work?

The first part of the small intestine, where pancreatic juice and bile enter to aid in digestion.

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What are villi?

Finger-like projections found in the ileum that increase surface area for efficient nutrient absorption.

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What are microvilli?

Even smaller projections on the surface of villi cells, further increasing surface area for absorption.

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What are blood capillaries in the villi?

Tiny blood vessels found within villi, transporting absorbed nutrients to the liver and rest of the body.

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What does Maltase do?

Maltase is an enzyme that breaks down maltose into glucose.

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What is the hepatic portal vein?

The hepatic portal vein carries absorbed nutrients from the small intestine directly to the liver.

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What are the main functions of the liver?

The liver stores excess glucose as glycogen, breaks down toxins, and breaks down excess amino acids producing urea.

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What is a lacteal?

The lacteal is a lymphatic vessel within the villi that absorbs fatty acids and glycerol.

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Study Notes

Human Nutrition

  • Human nutrition encompasses the process of consuming and absorbing nutrients for growth, repair, and energy.
  • A balanced diet includes carbohydrates, fats, proteins, vitamins (like C and D), minerals (like calcium and iron), fiber, and water.
  • Key dietary sources of nutrients vary.

Digestive System

  • The human digestive system encompasses organs like the mouth, esophagus, stomach, small intestine, large intestine, salivary glands, pancreas, liver, and gall bladder.
  • These organs work in various stages of digestion
  • Ingestion: Intake of food and drink.
  • Digestion: Breaking down large food molecules into smaller, absorbable molecules.
  • Absorption: Uptake of these smaller molecules into the bloodstream.
  • Assimilation: Use of these absorbed molecules by body cells.
  • Egestion: Removal of undigested food.

Digestion in Mouth

  • Physical digestion involves mechanical breakdown of food through chewing by teeth.
  • Chemical digestion in the mouth involves saliva.
  • Saliva contains water, mucus, and amylase.
  • Water helps dissolve food, mucus lubricates, while amylase initiates starch digestion.

Digestion in Stomach

  • Physical digestion occurs through contractions of the stomach muscles.
  • Chemical digestion involves gastric juice containing hydrochloric acid and pepsinogen.
  • Hydrochloric acid kills bacteria, pepsinogen converts to pepsin to digest proteins.
  • Mucus protects the stomach lining from acid.

Digestion in Small Intestine

  • The small intestine comprises the duodenum and ileum.
  • The duodenum receives bile from the liver and gallbladder, and pancreatic juice from the pancreas to further digest fats, proteins, and carbohydrates. – Bile: produced by liver, stored in gallbladder, emulsifies fats. – Pancreatic juice: contains enzymes to complete digestion of proteins, carbohydrates, and fats
  • The ileum absorbs digested food molecules into the bloodstream via villi and lacteals, which are important for nutrient absorption

Intestinal Enzymes

  • Intestinal enzymes include lipase, peptidase, and maltase, that work inside the intestines to breakdown fats, proteins and carbohydrates

Absorption

  • Nutrients are absorbed into the blood or lymphatic system in the small intestine. – Blood: absorbs amino acids, monosaccharides etc – Lymphatic system: absorbs fats

Liver Function

  • Liver performs various functions, including detoxification, protein synthesis, and glucose regulation.

Hepatic Portal Vein

  • Connects intestines to liver
  • Carries absorbed nutrients to liver

Hepatic Vein

  • Carries blood away from the liver
  • Carries substances from liver to heart and general circulation

Diseases

  • Cholera: A bacterial infection causing severe diarrhea, caused by bacteria attached to the wall of the intestines and releasing toxins stimulating chloride ions which in turn increases the fluid in the lumen lowering water potential and causing osmosis

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Related Documents

Human Nutrition IGCSE Biology Past Paper PDF 2024

Description

Test your knowledge on the digestive system with this quiz. From the functions of various organs to the importance of nutrients, this quiz covers key concepts in human digestion. Ideal for students learning about biology and the digestive process.

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