Lesson 6 (Chapter 2: Structures of the Digestive System) Flashcards
Mouth (Oral Cavity)
Food begins its journey through the digestive system in the mouth. Other organs of the oral cavity also aid in the digestion of food: lips, tongue, palate (roof of the mouth), teeth, and salivary glands. The lips hold the food in the mouth while the teeth chop it into small pieces. The food is moistened by saliva before the tongue pushes it into the throat. The soft palate prevents food and liquid from moving upward into the nasal cavity during swallowing.
Pharynx (Throat)
The pharynx allows the chewed food to pass from the mouth to the esophagus. A flap of tissue, known as the epiglottis, closes off the entrance to the trachea (windpipe) during swallowing.
Esophagus
The esophagus is a muscular tube that carries food and liquids from the pharynx to the stomach. The esophagus walls propel food to the stomach by rhythmic waves of muscular contractions called peristalsis.
Stomach
The stomach is a hollow sac that serves as a storage area for food. It also mixes the food with acid and enzymes, so it is more easily digested. Mucus coats the cells of the stomach lining to protect them from damage by the acid and enzymes.
Small Intestine
The stomach releases food into the small intestine. This coiled organ takes up most of the space in the abdominal cavity and consists of three sections: duodenum, jejunum, and ileum. Ultimately, by the time food leaves the small intestines, about 90% of the nutrients have been absorbed into the bloodstream.
Large Intestine
The large intestine wraps around the top and sides of the small intestine. Here, the waste products of digestion are processed in preparation for excretion from the body. The many bacteria that inhabit the large intestine can further digest some material. The major parts of the large intestine are the cecum, colon, rectum, and anus.
Liver
The liver is the largest internal organ in the body. The liver has many different functions, but its primary function in digestion is to produce bile and secrete it into the small intestine. Bile is a greenish-yellow fluid that is necessary for the digestion of fat.
Gallbladder
The gallbladder stores bile for later use.
Pancreas
The pancreas is a glandular organ in the upper abdomen. It secretes pancreatic juices (water, salt, sodium bicarbonate, and digestive enzymes) to aid in digestion and help neutralize stomach acids.
Ingestion
The intake of food provides the nutrients that the body uses to provide energy for all the functions of the body.
Secretion
The digestive system secretes saliva, mucus, hydrochloric acid, enzymes, and bile to aid in digestion, lubricate the GI tract, and protect the body from bacteria present in food.
Movement
Peristalsis is the wave-like motion that moves the digested food down the GI tract.
Digestion
Mechanical digestion is the physical breakdown of pieces of food into smaller pieces. Chemical digestion breaks down complex food molecules by the action of acid, enzymes, and pancreatic juice into smaller molecules that are easier to absorb.
Absorption
Most absorption of nutrients takes place in the small intestine, where blood and lymphatic vessels in the intestinal wall pick up the molecules and carry them to the rest of the body.
Excretion
The final function of the digestive system is the removal of indigestible substances and other waste products from the body in a process known as defecation.
Stomat/o
Mouth
Deglutition
Swallowing
Mastication
Chewing
Bucc/o
Cheeks
Cheil/o
Lips
Gloss/o or Lingu/o
Tongue
Pharyng/o
Pharynx
Peristalsis
The wavelike movement of the digestive tract
Cardiac Valve, Lower Esophageal Sphincter (LES)
Prevents gastric juice from splashing into the esophagus
