Chapter 3 (unit 2)

Major organs of the gastrointestinal tract

mouth, esophagus, stomach, small intestine, and large intestine

accessory organs

pancreas, liver, salivary glands, and gallbladder

Salivary glands

secrete fluids to lubricate foods and digestive enzymes to begin the breakdown of food

Liver

largest of the accessory organs and produces bile

Gallbladder

stores bile and secretes it into the small intestine

Pancreas

produces enzymes for chemical digestion and bicarbonate to neutralize stomach acid

Ingestion

Involves the intake of food through the mouth, where it is chewed and mixed with saliva. Although this is mostly physical breakdown, some chemical digestion begins here, breaking down starch with the enzyme amylase

Mechanical Digestion

involves the physical breakdown of food into smaller pieces into chyme by the churning action of the stomach

Chemical Digestion

Involves the enzymatic breakdown of macromolecules into smaller molecules, such as carbohydrates, proteins, and lipids, that can be absorbed in the small intestine later. In the stomach, gastric juices containing enzymes and acid further break down food

Absorption

takes place primarily in the small intestine, where nutrients are absorbed through the intestinal wall with the help of microvilli into the bloodstream for distribution to cells throughout the body.

Excretion

the expulsion of the undigested food and waste products from the body through the rectum and anus as feces. Takes place in the large intestine and anus.

Villi

finger-like projections that protrude from the absorptive mucosal cells of the small intestine into the lumen of the GI tract, which are responsible for increasing the available surface area for absorption

Nutrients

_______ (carbs, amino acids, mineral and water-soluble vitamins) enter blood vessels to liver then organs

Fat-soluble nutrients

_______ first enter the lymph before being distributed to tissues in the blood

Lipase

enzyme that starts breaking down fats. Present in mouth, stomach, and small intestine

Amylase

an enzyme that starts digesting the carbohydrates

Proteases

Digests protiens in stomach and SI

Peristalsis

generated by muscle contractions that propel contents forward

Segmentation

effectively mixes the contents of the small intestine but does not have a significant impact on forward movement.

Acid Reflux

Condition caused by occasional reguritation of stomach contents, inluding acid, back into the esophagus. Categorized by a burning feeling in the esophagus

Gastroesophageal reflux disease (GERD)

Recurrent and more serious form of acid reflux that is accompanied by inflammation and/or erosion of the esophageal lining along with pain

Gallstones

Small, pebblelike substances that develop in the gallbladder. They form when substances in bile harden into pieces of stonelike material

Hemorroids

Swollen and inflamed veins in the anus and lower rectum. Can be related to low-fiber diets and chronic constipation or diarrhea

Gastritis

Inflammation of the stomach, often causing nausea and/or pain. Can be caused by alcohol, medications, or other factors

Ulcer

Irrittion or perforation of the mucosal wall caused primarily by infection. Often causes pain and bleeding in stomach or SI

Diverticular Disease

Condition in which there are small pouches or pockets in the wall or lining of any portion of the digestive tract. These pockets occur when the inner layer of the digestive tract pushes through weak spots in the outer layer.

Celiac disease

An autoimmune disease that can be managed with dietary restrictions to avoid the protein gluten found in wheat