1. How Nutrients Become You!
TEKS 1A, 1B, 2A, 2B, 2C

3. You are what you eat! Food is your body’s fuel.
When you eat, your body breaks down food and the nutrients it contains into simpler elements.
Energy is released and nutrients are used to help build, repair, and maintain body cells.

4. 6 Nutrient Groups Carbohydrates Fats Proteins Vitamins Minerals Water
Each one has a specific job to perform in your body.

5. Nutrient Functions Build and repair body tissues
Regulate all body processes
Provide energy

6. Build & Repair Body Tissues
Your body is made up of billions of cells and these cells continually grow and change to help repair damaged body tissues and to replace old cells.
You need nutrients to do this job.

7. Regulate Body Process
The circulation of body fluids requires a balance of essential nutrients.
Maintaining the correct acid-base level in the blood is a function of nutrients.
Digestion, absorption, and metabolism rely on proper nutrients.

8. Provide Energy Food is to your body what gasoline is to a car.
It is the source of energy for performance.
Energy is necessary for all life processes to occur – to breathe, pump blood, move muscles, and provide heat.

9. Kilocalories
A kilocalorie is the amount of heat needed to raise one kilogram of water one degree Celsius.
We often refer to them as just calories.

10. The Process of Digestion
Digestion is the process by which your body breaks down food, and the nutrients in food, into simpler substances.
The blood can then carry these simple substances to cells for use in
growth, repair, and maintenance.

12. Digestion
It occurs through mechanical and chemical means throughout the digestive system.
Mechanical digestion happens as food is crushed and churned.
Chewing food is an observable form of mechanical digestion.

13. Digestion
In chemical digestion, food is mixed with powerful acids and enzymes.
Enzymes are a type of protein produced by cells that cause specific chemical reactions.
Digestive enzymes cause food particles to break apart into simpler substances.

14. Gastrointestinal (GI) Tract
As food is digested, it passes through a muscular tube leading from the mouth to the anus.
This tube is called the GI tract.
The GI tract is 25 to 30 feet in length.
Each section performs important functions.

16. The Mouth
Food enters the GI tract through the mouth.

17. Mastication
Mastication, or chewing, is the first step in the digestive process.
The teeth and tongue work together to move food and crush it into smaller pieces.
The process prepares food for swallowing.

18. The Tongue
You have about 9000 taste buds that cover the surface of the tongue.
They sense the flavor in food.
This triggers salivary glands in your mouth.

19. Saliva Saliva is a mixture of about 99% water plus a few chemicals.
One of these chemicals is an enzyme called salivary amylase.
This enzyme is only found in the mouth and helps chemically break down (digest) the starches in foods.

20. Saliva
It plays other important roles in the digestive process besides the breakdown of starches.
Without saliva, your mouth is dry and food seems to have little taste.
Saliva moistens, softens, and dissolves food.
It also helps clean the teeth and neutralize mouth acids.

21. The Esophagus
As you chew, the muscles of your mouth and tongue form the food into a small ball.
The tongue moves the food particles to the back of your mouth and you swallow.
As you swallow, food passes from the mouth to the stomach through the esophagus.

22. The Esophagus

23. The Esophagus The esophagus is a tube about 10 inches long.
It connects the mouth to the stomach

24. The Esophagus
The esophagus is one of two tubes in the throat, the other is the trachea (windpipe).
When you swallow food, a flap of skin called the epiglottis closes to keep food from entering the trachea.
Breathing automatically stops when you swallow food to help prevent choking.

25. Peristalsis
A series of squeezing actions by the muscles in the esophagus, known as peristalsis helps move food through the tube.
Peristalsis is involuntary – you have no control.
It occurs throughout the esophagus and intestine to help mechanically move and churn food.

27. In the Stomach
When you eat, the stomach produces gastric juices to prepare for digesting the food.
Gastric juices contain hydrochloric acid, digestive enzymes, & mucus.

28. Gastric Juices
The mixture of gastric juices with chewed and swallowed food combine in the stomach.
This mixture is called chyme.

29. Mucosa The stomach has a thick wall lining called the mucosa.
The mucosa secretes mucus.
This is a thick fluid that helps soften and lubricate food and it helps protect the stomach from its strong acidic juices.
The acid in the stomach is almost as strong as battery acid found in a car.

30. Protein Digestion Protein digestion begins in the stomach.
The major gastric enzyme that begins to chemically break down protein is pepsin.

31. Stomach Most people can hold about 1 quart of food in their stomachs.
Food generally remains in the stomach for 2 to 3 hours.
Liquids leave before solids.
Carbohydrates and proteins digest faster than fats.
Now we travel to the small intestine.

32. Small Intestine About 95% of digestion occurs in the small intestine.
The small intestine is coiled in the abdomen in circular folds
It has 3 sections
Duodenum
Jejunum
ileum

33. Duodenum
The first section of the small intestine and about 12 inches long

34. Jejunum
The middle section and about 4 feet long.

35. Ileum
The last section which is about 5 feet in length

36. Food Travel
It takes 5 to 14 hours for food to travel from the mouth through the small intestine.
Peristalsis helps move food through this process.
The small intestine needs less acid than the stomach to break down food.

37. The Pancreas
The pancreas, an elongated gland behind the stomach, helps create the correct environment.
It secretes bicarbonate, which neutralizes hydrochloric acid that has come from the stomach with the partially digested food.

39. The Pancreas
It also produces digestive enzymes that aid in the chemical digestion that takes place in the small intestine.
These enzymes break down proteins, fats, and carbohydrates into their most basic parts so your body can use them.

40. The Pancreas Breaks down proteins into amino acids
Breaks down carbohydrates into monosaccharides
Breaks down fats into fatty acids, glycerol, and monoglycerides

41. Proteases
The enzyme that breaks down proteins into amino acids

42. Lipases
Fat digesting enzymes which break down fats into fatty acids, glycerol, and monoglycerides

43. Saccharidases
Breaks down carbohydrates into monosaccharides (also known as simple sugars)

44. The Liver Also involved in chemical digestion
It produces a digestive juice called bile
Bile aids in fat digestion and it helps disperse fat in the water-based digestive fluids
Bile gives these fluid access to fats so they can break it down
Bile is stored in the gallbladder and secreted into the first part of the small intestine

45. Large Intestine Sometimes called the colon
Measures about 3 ½ feet in length in your body but about 5 or 6 feet if stretched out
Its main job is to reabsorb water

46. Absorption of Nutrients
Absorption is the passage of nutrients from the digestive tract into the circulatory or lymphatic system.
We will learn more about nutrients later in this study.
Most nutrients pass through the walls of the small intestine. Hoever, alcohol and a few other drugs can be absorbed in the stomach. Alcohol can actually be absorbed in the mouth.
The inside surface area of the small intestine is about 600 times larger than that of a smooth tube. This is because the wall of the small intestine is pleated with thousands of folds. The folds are covered with villi.
Villi are tiny, fingerlike projections that give the lining of the small intestine a velvetlike texture. Each cell of every villus is covered with miccrovilli which are like microscopic hairs that help catch nutrient particles.

47. Metabolism
Once nutrients are digested and absorbed, the circulatory system takes over.
It carries nutrients and oxygen to individual cells.
All the chemical changes that occur as cells produce energy and materials needed to sustain life are known as metabolism.

48. Metabolism
Through metabolism, cells break down some nutrients to release energy.
The body stores this energy as ATP(adenosine triphosphate).
ATP is the source of immediate energy found in muscle tissue
When the body needs energy, chemical reactions break down ATP to release energy.

49. Waste Products
Waste products leave the body through the kidneys, lungs, and skin

50. Factors Affecting Digestion and Absorption
Eating habits
Emotions
Food allergies
Physical activity
Lifestyle choices

51. Food Allergies
A food allergy is a reaction of the immune system to certain proteins found in food.
The protein that stimulates the immune system to produce antibodies is called an allergen.
Food allergies should not be confused with food sensitivities. These are reactions to food that do not involve the production of antibodies by the immune system. For example some people are sensitive to milk because they lack the enzyme needed to digest the sugar in milk they are not allergic to it.

52. Digestive Disorders Diarrhea Constipation Indigestion Heartburn Ulcer
Gallstones
diverticulosis

53. Diarrhea Diarrhea is frequent expulsion of watery feces.
Food sensitivity, harmful bacteria, and stress are just a few of the factors that can cause diarrhea.

54. Constipation
Constipation occurs when chyme moves very slowly through the large intestine.
When this happens, too much water is reabsorbed from the chyme and this causes the feces to become hard.
Constipation can result from erratic eating habits, low fiber intake, lack of physical activity and drinking too little water.

55. Indigestion Indigestion is a difficulty in digesting food.
It may be caused by stress, eating too much or too fast, or eating particular foods.

56. Heartburn
Heartburn is a burning pain in the middle of the chest but it has nothing to do with the heart.
It is caused by stomach acid flowing back into the esophagus, known as reflux.
A more serious condition is called gastroesophageal reflux.

57. Ulcer
An ulcer is an open sore in the lining of the stomach or small intestine.
It is caused by bacterium

58. Gallstones
Gallstones are small crystals that form bile in the gallbladder.
The presence of gallstones may slow fat digestions and cause fluids to pool and back up in the liver.

59. Diverticulosis
Diverticulosis is a disorder in which many abnormal pouches form in the intestinal wall.
When these pouches become inflamed, the condition is called diverticulitis.
The best prevention is a high fiber diet