The alimentary or gastrointestinal tract

& the accessory organs

The digestive system is a collection of organs that can be divided into two

parts:

List, in order, the eight parts of the digestive tract.

1. Oral cavity

2. Pharynx

3. Esophagus

4. Stomach

5. Small Intestine

6. Large Intestine

7. Rectum

8. Anus

The functions of the alimentary tract, overall, would be to:

• Take in food.• Break down the food into

simpler components.• Absorb the nutrients.• Discard the waste.

The three accessory organs found in or near the oral cavity are the

TongueTeeth

Salivary glands

The three accessory organs found in the abdominal cavity are the

LiverGall bladder

Pancreas

The functions of the pharynx, with respect to the digestive system, are to:

• receive partially digested food from the oral cavity

• pass the partially digested food on to the esophagus.

Cutting, grinding, lubricating, tasting, manipulating, and moving food are all examples of ____________ digestion.

mechanical

Converting large, complicated food molecules into glucose, amino acids, and

fatty acids so they can be absorbed is ____________ digestion.

chemical

What is the general name given to substances which perform chemical

digestion in the digestive tract?

enzymes

A common tube shared by the respiratory and digestive systems.

pharynx

Subdivision of the pharynx located behind the nasal cavity is the:

nasopharynx

oropharynx

Subdivision of the pharynx located behind the oral cavity is the:

laryngopharynx

Subdivision of the pharynx located behind the larynx is the:

These act as “first line” defenders, screening out microorganisms from the air,

food, and liquids that enter the body:

tonsils

Tonsils found in the nasopharynx are called:

pharyngeal tonsils

Tonsils located in the laryngopharynx, at the base of the tongue, are called:

Lingual tonsils

Tonsils located at the back of the nasal cavity are called the:

pharyngeal tonsils

What is the main purpose of mechanical digestion?

To increase the surface area of the food for enzymes to

act.

A straight, collapsible muscular tube which lies behind (posterior to) the trachea and is

about 1 inch in diameter and 10 inches long.

Esophagus

The functions of the esophagus are to:

• receive partially digested food from the pharynx

• pass the partially digested food on to the stomach.

Rhythmic contractions of the smooth muscle layers which propel food through

the digestive tract are called:

Peristalsis or Peristaltic waves

The smooth muscle valve located at the end of the esophagus which controls the

entrance to the stomach is called:

Gastroesophageal or cardiac sphincter

The uppermost portion of the stomach is called the:

Fundus or fundic region

A small region of the stomach very near the cardiac sphincter where the esophagus

meets the stomach is the

Cardia or cardiac region

The middle and largest portion of the stomach is called the ___________ of the

stomach.

body

This is the “cone-shaped,” terminal portion of the stomach.

Pylorus or pyloric region

The smooth muscle valve that prevents back flow of material from the small intestine to the stomach is called the

pyloric sphincter

The term used to describe the partially digested food once it has been mixed with the digestive secretions of the stomach.

chyme

Five functions of the stomach, as listed in class, are:

1. Receives bolus from the esophagus.2. Mixes bolus with gastric juices, and

mechanically breaks up the food.3. Begins the chemical breakdown of

proteins.4. Begins the process of absorption.5. Passes the chyme on to the small

intestine.

A collapsible, muscular tube that extends from the pyloric sphincter of the stomach to

the large intestine.

Small intestine

The small intestine is the site where the majority of the _________ digestion of food and _________ of nutrients takes

place.

chemical absorption

The first 10 – 12 inches of the small intestine is called the

duodenum

The middle section of the small intestine representing about 40% of its length is

called the

jejunum

The final portion of the small intestine, which represents about 60% of its length is

called the

ileum

_______________ project into the lumen of the small intestine where they are bathed in the intestinal contents. They function to increase _____________ of the intestinal

lining for absorption.

Intestinal villisurface area

A five foot long collapsible tube that is divided into two parts and is located

between the small intestine and the rectum.

Large intestine

The entrance to the large intestine is called the

cecum

A vestigial structure located off the cecum of the large intestine is the

vermiform appendix

The major portion of the large intestine which is divided into 4 parts is the

colon

The four sections of the colon, in order, are the

AscendingTransverseDescending

Sigmoid

Four functions of the large intestine were discussed. These were:

1. Receives nutrient depleted chyme from the small intestine.

2. Reabsorbs the rest of the water and electrolytes from chyme.

3. Forms and stores feces until defecation.

4. Passes feces on to the rectum.

Final storage area for feces.

When the rectum fills with feces it is stimulated to contract. This is called the

rectum

Defecation reflex

The last section of the digestive tract is called the ______________. It is made up of three

_________________ muscles.

anussphincter