INGESTION: the Taking in of Food and Liquids Into the Body

DIGESTIVE SYSTEM

INGESTION: The taking in of food and liquids into the body.

TEETH: to break the food into smaller pieces.

SALIVARY GLANDS:produces saliva (moistens the food and

contains enzymes) 1st line of chemical digestion.

Mechanical digestion- your teeth ex: chewing up tiny pieces of apple

SALVIA: contains ptyalin which is an enzyme that digests starch

ESOPHAGUS:“food pipe” transports food and liquids from the

mouth to the stomach (smooth muscle)

PERISTALSIS: a muscle contraction to help move the food along the

digestive system

PEPSIN: an enzyme found in the stomach to digest proteins

STOMACH: involuntary muscle, muscular contractions

(peristalsis) churn the food while gastric juices and

hydrochloric acid chemically break down food.

SMALL INTESTINE: (long) where absorption of nutrients into

the bloodstream occurs (at capillaries surrounding the villi)

villi= fingers in the small intestine.

LIVER: produces bile  breaks apart fat molecules, regulates

(controls) sugar levels.

GALL BLADDER: stores bile and releases it into the small

intestine.

PANCREAS: produces pancreatic juices (enzymes) which aid

digestion in the small intestine, produces insulin – regulates

the amount of sugar in the body.

LARGE INTESTINE: (big around in size) where water is reabsorbed,

contains bacteria which produce vitamins (B & K), forms solid waste

(feces)

APPENDIX: no particular function

RECTUM: stores solid waste (feces)

ANUS: opening at end of the rectum where solid waste passes out of the

body

A TRIP THROUGH THE DIGESTION SYSTEM

~digestion is the process by which food is broken down into useable substances by the body (nutrients the body can use)

~ the two kinds of digestion are MECHANICAL and CHEMICAL.

MECHANICAL- physically breaking food into smaller pieces

CHEMICAL- breaking down food into useable substances using enzymes

and acids.

LET’S START WITH THE MOUTH

A person takes food into his/her body by eating. This is called ingestion. The food is broken down by using the various teeth in the mouth. Chewing helps to break the food down into smaller pieces. Saliva is produced by the salivary glands (makes food slippery so it goes through the digestive system). Saliva contains enzymes (ptyalin) which helps to break down starches into sugars. The tongue helps to push the food around the mouth and also helps to swallow the food. Thus begins the process of digestion.

THE ESOPHAGUS

Peristalsis is the muscular contractions of the digestive system which push food through the system. Food passes through the esophagus and enters into the stomach. Food doe not enter the trachea (wind pipe) because of the flap of preventive tissue called the epiglottis.

THE STOMACH

The stomach secretes a substance called gastric juice. The gastric juice contains enzymes and hydrochloric acid. In particular, the enzyme pepsin is secreted and used to break down proteins. In addition to chemical digestion, the stomach continues to mash and grind the food. Muscular contractions mix the food with the gastric juice as peristalsis pushes the food towards the small intestine. When full, your stomach can contain approximately 1.5 liters (16 oz) of food.

THE SMALL INTESTINE

After spending 3-6 hours in the stomach, the food enters the small intestine. The small intestine is about 2.5cm around and 6 meters long. Food continues to move through the small intestine by the process known as peristalsis. Most digestion occurs in the first 30cm of the small intestine. The cells that line the walls of the small intestine release enzymes to help

break down the food. In addition, the small intestine gets help from two other organs, the liver and the pancreas. The pancreas releases pancreatic juice which contains several enzymes to help break down the food. The pancreas also produces insulin, which helps to regulate the amount of sugar in your blood. The liver produces bile which is then stored in the gall bladder. Bile helps to break down fats.

The inner lining of the small intestine walls is lined with millions of tiny finger-like projections called villi. Here, digested food is absorbed into the bloodstream through the capillary walls which surround the villi.

THE LARGE INTESTINE

Although most of the food you eat is digested in the small intestine, some substances cannot be digested. An example of this is cellulose (plant stuff), which is commonly referred to as roughage. The undigested food along with water makes its way into the large intestine. Here, water is reabsorbed into the bloodstream. If too little water is reabsorbed, diarrhea occurs. If too much water is reabsorbed, constipation occurs. Also, helpful bacteria living, inside the large intestine feed on the “leftovers” and make essential vitamins such as vitamin B and vitamin K (helps the red blood cells). These vitamins are absorbed into the bloodstream.

The large intestine is 6.5cm around but only 1.5 meters long. The material not absorbed in the large intestine forms the solid waste feces. The solid waste passes through the large intestine and is stored in the rectum before exiting the body through the anus.

NUTRITION--Nutrients are the parts of food your body can use.

The four basic food groups and several examples:

DAIRY / MEAT & PROTEINS / GRAINS
(CARBOHYDRATES) / FRUIT &
VEGETABLES
Milk / Beef- pork / Potatoes / Apples- celery
Cheese / Poultry- nuts / breads / Oranges
butter / Fish- beans / rice / corn
Yogurt / Seafood / Pasta / cucumbers
Ice cream / Eggs / Cereals / carrots

PROTEINS- Make up all the cells in your body (most important)

The proteins are used to build and repair your body cells. The building blocks of proteins are the amino acids. Your body obtains proteins from meats, eggs, fish, and poultry.

CARBOHYDRATES- are a quick energy source. The two types of carbohydrates are starches (big one) and sugars (smaller one). The faster fuel source is the sugar. Your body can obtain carbohydrates from grains (bread, pasta, and rice), fruits, vegetables, and sugars.

FATS- slow, long term sources of energy stored in the body. Fats have more energy than carbohydrates, but fats last longer. Fats and oils are used for a long term energy supply (stored energy). Fats support and cushion the organs in the body. They also insulate against the cold. Good sources of obtaining fats are meats, butter, dairy, vegetable oils, animal fats, salad dressing, and fried foods.

VITAMINS and MINERALS- control normal growth and body functions. Vitamins and minerals play at important role in your body, they help to regulate (control) growth and control normal body functions. Your body needs vitamin K to help with blood clotting and vitamin D for strong bones and teeth. It also needs the minerals iron (Fe) to help carry oxygen in the blood and calcium (Ca) for strong bones and teeth.

Calorie: amount of heat needed to raise 1 gram of water 1 degree Celsius. It is also known as the energy value of food.

Water: Necessary to life. 55%-75% of your body is made up of water.