EATING AND DIGESTION

A. Why do we eat?Food contains sources of energy that the body needs to stay alive and to repair itself. Food is the fuel that provides energy, just like gas is the fuel that provides a car with energy.

B. What happens when I swallow my food?When a mouthful of chewed food is soft and pliable, your tongue squeezes off a portion and pushes it to the back of your mouth and down into your throat to the top of the esophagus. When you swallow, muscular waves, peristalsis, push the food along the digestive tract, from the mouth, down the esophagus to the stomach. From the stomach, it moves on to the small and large intestines.

C. What is a balanced diet?Ask your Wellness teacher and let me know.

D. So, what happens in my mouth while I’m chewing my food?Food in the mouth is mixed with a water-like substance called saliva or spit. Did you know that your salivary glands produce about 1.5 liters of saliva every day? As soon as you smell or look at food, saliva flows along tubes called salivary ducts into your mouth. This lubricates your food for easier chewing and swallowing. Your tongue pushes food around for thorough mastication.

E. What happens to the food in my stomach and small intestine?Your stomach is a muscular machine that churns the food in an acid-and-enzyme bath. Now the semifluid substance in your stomach is called chyme [pronounced kime]. Chyme passes from your stomach into your small intestine, where chemical digestion continues and most nutrients are absorbed. Food molecules pass through finger-shaped villi into the blood. Villi provide a large surface area for absorption of nutrients.

F. What else can you tell me about digestion?Well, through the process of digestion starches and carbohydrates are turned into glucose. Glucose is “burned” to release energy. Some of this is released as heat energy and some of it is changed by muscle cells into energy of movement. Did you know that bacteria live in your intestine? Don’t worry; these are healthy bacteria which make vitamin K.

G. What are the chemicals called that break down food?Enzymes.

How long does it take food to pass through my body?THE PASSAGE OF DIGESTION

MOUTH0 secondschewing

a mixture of fats (e.g. butter), proteins (e.g. meat), carbohydrates (e.g. rice) and water

ESOPHAGUS 10 seconds

food mixed with saliva passes down the esophagus into the stomach (peristalsis)

STOMACH 4 hours

food is mixed with chemical juices and churned in the stomachLIVERthe liver produces a green liquid, bile, to help break down fats

SMALL INTESTINE 4.5

hours

digestive juices (e.g. bile) break down foodthe mixture passes through the intestine wall into the blood

LARGE INTESTINE 7-

16 hours

water and undigested food pass into the large intestine water is absorbed into the blood

RECTUM 12-14 hours

solid waste from the large intestine is stored

ANUSmuscles push the solid waste out of the anus as feces