Lab 22: Digestive System

Question 1

Starch Digestion

Answer 1

• polysaccharide composed of glucose
• digestion begins in the mouth with enzyme salivary amylase
• continues in the duodenum with enzyme pancreatic amylase

Question 2

Protein Digestion

Answer 2

• macromolecules constructed of one or more polypeptide chains
• digestion begins in the stomach
• continues in the duodenum
• enzyme pepsin breaks down proteins
• presence or absence is detected by biuret reagent

Question 3

Lipid Digestion

Answer 3

• digestion begins in the duodenum
• assisted by secretions of bile from the liver and lipase from the pancreas
• bile salts emulsify fats so lipids can react with lipase
• end result: lipolysis forms fatty acid and glycerol

Question 4

Layers of the Small Intestine

Answer 4

-mucosa, submucosa, muscle (muscularis), serosa

Question 5

Mucosa

Answer 5

• top layer of the small intestine
• outer layer of columnar epithelial cells
• contains lamina propria, venules, arterioles, and lacteals
• contain villi: fingerlike extensions projecting toward the lumen
• contain microvilli: brush border; enhance surface area and absorptive capabilities of the intestine
• goblet cells: secrete mucus
• lacteal: located in the center of the villi; blood vessels

Question 6

Submucosa

Answer 6

• second layer of the small intestine
• composed of connective tissue and blood vessels
• contains lymph duct
• nutrients pass through the blood vessels of the mucosa and submucosa
• nutrient-rich blood then flows to the liver for processing

Question 7

Muscle (Muscularis)

Answer 7

• third layer of the small intestine
• two layers of smooth muscle: circular and longitudinal

Question 8

Segmentation

Answer 8

• contraction of the circular muscle layer
• aids in mixing the partially digested food with enzymes

Question 9

Peristalsis

Answer 9

• contraction of the longitudinal muscle layer
• aids to propel food along the digestive tract

Question 10

Serosa

Answer 10

• fourth layer of the small intestine
• thin layer(peritoneum)
• composed of squamous epithelial cells
• protects intestinal surface

Question 11

Anatomy of the Human Digestive System

(Labeling)

Answer 11

Question 12

The digestion of food begins in the mouth by the action of the enzyme _________ secreted by the _________ __________

Answer 12

amylase, salivary glands

Question 13

This enzyme begins the breakdown of _____

Answer 13

starch

Question 14

When you swallow, the _____ blocks the entrance to the larynx

Answer 14

epiglottis

Question 15

The bolus of food moves down the esophagis by muscular contractions called _____

Answer 15

peristalsis

Question 16

In the stomach, the action of _____ and ____ aid in the breakdown of ______.

Answer 16

hydrochloric acid, pepsin, chyme

Question 17

After leaving the stomach, the acidc mixture of partially digested food, called ____, enters the _____

Answer 17

chyme, duodenum

Question 18

In the duodenum, digestion is completed by the action of enzymes and secretions from the two accessory organs, ______ and the ______

Answer 18

pancreas, liver

Question 19

Carbohydrate and protein digestion are completed by ____, ______, and ____, additional components of pancreas secretions

Answer 19

trypsin, chymotrypsin, bicarbonate

Question 20

Fats are first broken into smaller droplets by a process called _________

Answer 20

emulsification

Question 21

This is accomplished by the action of a substance called _____________, which is secreted by the ______ and stored in the ___________.

Answer 21

bile, liver, gall bladder

Question 22

The action of the enzyme ____________ which is secreted by the ________ hydrolyzes the fat molecules.

Answer 22

lipase, pancreas

Question 23

Nutrient absorption takes place in the remaining two poritions of the small intestine, the _______ and the _______.

Answer 23

jejunum, ileum

Question 24

The primary function of the large intestine is to reabsorb _________ , which is stored in the ___, until it leaves the body through the ________

Answer 24

water, rectum, anus