Human Nutrition and Digestion Quiz
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Questions and Answers

Which of the following is NOT a function of lipids in the human body?

  • Cell membrane formation
  • Energy storage
  • Production of hormones
  • Transport of water-soluble vitamins (correct)

    • Why are linoleic acid (18:2 ɷ-6) and linolenic acid (18:3 ɷ-3) considered essential fatty acids for humans?

  • These fatty acids are required for the synthesis of other essential nutrients.
  • These fatty acids are only found in certain types of plant-based foods.
  • Humans lack the enzymes necessary to produce these fatty acids internally. (correct)
  • Humans can synthesize these fatty acids from other sources.

    • Which of the following is NOT a function of proteins in the human body?

  • Transportation of molecules
  • Structural support
  • Hormone regulation
  • Production of energy (correct)

    • Which of the following amino acids is NOT considered an essential amino acid for adults?

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

    Which of these is NOT a macromineral required in large amounts by the human body?

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

    What is the key characteristic that distinguishes vitamins from other nutrients?

    <p>Vitamins are organic compounds containing carbon, hydrogen, and often other elements. (A)</p> Signup and view all the answers

    Which of the following is NOT a function of the stomach?

    <p>Absorption of nutrients (D)</p> Signup and view all the answers

    What is the role of the pyloric sphincter?

    <p>To regulate the flow of chyme from the stomach into the duodenum. (D)</p> Signup and view all the answers

    Which of the following statements about the role of HCI in the stomach is TRUE?

    <p>HCI activates digestive enzymes for protein digestion, such as pepsin. (A)</p> Signup and view all the answers

    What is the primary function of the longitudinal, circular, and oblique layers of muscles in the stomach?

    <p>To facilitate the movement of food through the stomach. (D)</p> Signup and view all the answers

    Which of the following best defines the study of nutrition?

    <p>The science that studies the body's use of nutrients for energy, growth, and regulation. (B)</p> Signup and view all the answers

    What are the primary elements, in terms of percentage of total mass, that form the foundation of molecules in the human body?

    <p>Oxygen, Carbon, Hydrogen, Nitrogen (D)</p> Signup and view all the answers

    Why are carbohydrates, fats, and proteins classified as macronutrients?

    <p>Because the body requires them in large quantities. (C)</p> Signup and view all the answers

    What does the term 'essential nutrient' indicate?

    <p>A nutrient that must be obtained through diet. (D)</p> Signup and view all the answers

    What is the primary function of dietary fiber, a form of carbohydrate?

    <p>To support normal function of the gastrointestinal tract. (B)</p> Signup and view all the answers

    What is the main use of glucose derived from dietary carbohydrates?

    <p>Immediate energy or storage as glycogen. (A)</p> Signup and view all the answers

    Which characteristic of lipids requires specialized processing during digestion and absorption?

    <p>Their miscibility in water. (C)</p> Signup and view all the answers

    What constitutes the largest proportion of lipids that humans consume?

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

    What is the main function of the small intestine?

    <p>Absorption of nutrients (B)</p> Signup and view all the answers

    What is the role of bile acids in digestion?

    <p>Emulsification of fats (B)</p> Signup and view all the answers

    What are the three phases of gastric secretion, and what triggers each phase?

    <p>Cephalic: triggered by smell of food; Gastric: triggered by stomach distension; Intestinal: triggered by food entering the small intestine (A)</p> Signup and view all the answers

    What are the different types of cells involved in the formation of intestinal villi?

    <p>Enterocytes, goblet cells, enteroendocrine cells (C)</p> Signup and view all the answers

    What is the function of the crypts of Lieberkuhn?

    <p>Production of new intestinal cells (D)</p> Signup and view all the answers

    How does the pH of the stomach contribute to iron absorption?

    <p>The acidic pH converts ferric iron to ferrous iron, which is more readily absorbed. (D)</p> Signup and view all the answers

    What are the three main components of bile?

    <p>Bile acids, cholesterol, pigments (B)</p> Signup and view all the answers

    How does cholecystokinin (CCK) regulate bile release?

    <p>CCK stimulates the gallbladder to contract and release bile into the duodenum. (A)</p> Signup and view all the answers

    What is the role of the pancreas in digestion?

    <p>Secretion of digestive enzymes (A)</p> Signup and view all the answers

    Which of the following hormones stimulate pancreatic secretions?

    <p>Secretin, CCK, vasoactive intestinal polypeptide (VIP) (A)</p> Signup and view all the answers

    What is the role of the glycocalyx in the small intestine?

    <p>All of the above (D)</p> Signup and view all the answers

    Where are the majority of digested carbohydrates, fats, and proteins absorbed?

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

    What is the primary function of intrinsic factor?

    <p>Absorption of vitamin B12 (D)</p> Signup and view all the answers

    What hormone is responsible for stimulating the release of gastric acid during the gastric phase?

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

    What is the approximate length of the large intestine?

    <p>1.5 - 1.8 m (A)</p> Signup and view all the answers

    What is the main function of the liver in digestion?

    <p>Production of bile (C)</p> Signup and view all the answers

    What is the difference between a villus and a microvillus?

    <p>Villi are finger-like projections found in the small intestine, while microvilli are hair-like structures on the surface of enterocytes. (B)</p> Signup and view all the answers

    Which enzyme in pancreatic juice is primarily responsible for fat digestion?

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

    What is the primary function of the large intestine?

    <p>To absorb water and electrolytes (D)</p> Signup and view all the answers

    Which part is the first section of the large intestine?

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

    Which type of carbohydrates are made up of 3-10 monosaccharide units?

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

    What is a characteristic of the bacteria found in the large intestine?

    <p>More than 400 species exist (C)</p> Signup and view all the answers

    Which type of bond is found in amylose?

    <p>Only alpha (1,4) glycosidic bonds (A)</p> Signup and view all the answers

    What is the approximate composition of feces in terms of bacteria?

    <p>30% (C)</p> Signup and view all the answers

    Which of the following is a function of probiotics?

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

    Study Notes

    Human Nutrition and Digestion

    • Nutrition: The study of how the body uses nutrients for energy, tissue growth, and function. It involves food composition, ingestion, digestion, absorption, nutrient functions, and metabolic by-product disposal.

    • Basic Composition of the Human Body: Oxygen (O2), Carbon (C), Nitrogen (N), and Hydrogen (H) make up 63%, 18%, 3%, and 6% respectively of the body's molecules.

    • Macronutrients: Carbohydrates, fats, and proteins are needed in large amounts.

    • Micronutrients: Vitamins and minerals are needed in smaller amounts.

    • Essential Nutrients: Obtained from diet.

    • Non-essential Nutrients: Synthesized by the body.

    Carbohydrates

    • Structure: Composed of carbon, hydrogen, and oxygen (1:1 carbon-to-water ratio). "Carbohydrate" literally means "carbon with water."

    • Energy Source: Major fuel source; starches and sugars from grains, vegetables, legumes, and fruits. Dairy and meat contain little carbohydrate.

    • Dietary Fiber: A carbohydrate that provides no energy but is crucial for gut health.

    • Glucose: The simple sugar formed from most dietary carbohydrates. Used for energy or stored as glycogen.

    • Glycogen Storage: Stored in skeletal muscle and the liver for energy needs. The brain relies on glucose for energy, requiring a constant supply.

    Lipids

    • Definition: Compounds soluble in organic solvents (acetone, ether, chloroform). Include fats, oils, cholesterol, and phospholipids.

    • Triacylglycerols (TG): The largest type of lipid in human diets.

    • Digestion and Processing: Lipids require special processing during digestion, absorption, transport, storage, and utilization due to their insolubility in water.

    • Functions: Energy storage, insulation, padding, cell signaling, membrane formation, hormone synthesis, and transport of fat-soluble vitamins (A, D, E, K).

    • Essential Fatty Acids: Humans lack certain enzymes to produce omega-3 and omega-6 polyunsaturated fatty acids (PUFAs), making them essential.

      • Linoleic acid (omega-6)
      • Linolenic acid (omega-3)

    Proteins

    • Structure: Organic compounds made of amino acids (small building blocks). Contain carbon, hydrogen, oxygen, nitrogen, and sulfur.

    • Importance: Essential for structural components, contractile filaments, antibodies, transporters, neurotransmitters, hormones, and enzymes.

    • Amino Acids: About 20 amino acids are incorporated into proteins via mRNA. Humans can't produce (or produce enough) some amino acids (essential amino acids), requiring intake through diet:

      • Lysine
      • Tryptophan
      • Methionine
      • Valine
      • Phenylalanine
      • Leucine
      • Isoleucine
      • Threonine
      • Histidine (infants only)

    Minerals

    • Definition: Inorganic substances crucial for health.

    • Macrominerals (needed in large amounts): Calcium, sodium, chloride, potassium, phosphorus, magnesium.

    • Trace Minerals (needed in smaller amounts): Iron, zinc, copper, selenium, iodine, fluoride.

    Vitamins

    • Definition: Organic compounds containing carbon, hydrogen, and sometimes oxygen, nitrogen, phosphorus, sulfur, and other elements.

    • Initially identified as a "vital amine," but now known to not always contain nitrogen.

    • Types: Water-soluble and fat-soluble.

    • Function: Essential for chemical reactions in the human body.

    • Essential: Vitamins cannot be made by the body in sufficient amounts.

      • Exceptions: Vitamin D (can be produced from cholesterol with UV light), Vitamin K, and biotin (made in large intestine).

    Water (H₂O)

    • Crucial Nutrient: The most vital nutrient; essential for survival.

    Digestion: Overview

    • Mouth: Mechanical breakdown, and amylase and lingual lipase action.

    • Esophagus: (25 cm) Transports food to the stomach.

    • Stomach: Muscular organ (cardiac, fundus, body, antrum) with three layers of muscles.

      • Mixes and grinds food (chyme).

      • Releases gastric juice containing HCl and pepsin.

      • Protects itself with alkaline mucus.

      • Stores approximately 4 liters of food.

      • Releases chyme in small portions to the duodenum.

    • Small Intestine: (duodenum, jejunum, ileum)

      • Site of most digestion and absorption.

      • Increased surface area due to villi and microvilli.

    • Large Intestine: (cecum, colon, rectum, anal canal)

      • Absorbs water and electrolytes.

      • Stores and eliminates undigested material (feces).

      • Contains trillions of bacteria that produce vitamins K, biotin, and short-chain fatty acids.

    Accessory Organs:

    • Liver: Produces bile, important for fat digestion.

    • Gallbladder: Concentrates and stores bile.

    • Pancreas: Secretes pancreatic juice containing bicarbonate and digestive enzymes (proteases, amylase, lipase), critical for digesting carbs, proteins and fats.

    Digestive Processes

    • Bile and Bile Salts: Emulsify fats into smaller droplets.

    • Pancreatic Enzymes: Aid in the digestion of carbohydrates, proteins, and fats.

    • Large Intestine Bacteria: Synthesize vitamins and other substances.

    • Absorptive Processes: Nutrients absorbed across the small intestine's wall, into the bloodstream or lymphatic system.

    • Digestive phases of the stomach: Cephalic, Gastric and Intestinal.

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    Description

    Test your knowledge on human nutrition, digestion, and the roles of macronutrients and micronutrients in the body. This quiz covers the basic composition of the human body and the significance of carbohydrates as an energy source. Challenge yourself to see how well you understand essential and non-essential nutrients.

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