Digestive System: Digestion and Absorption

Question 1

is the breakdown of food to molecules small enough to be absorbed into the circulation.

Answer 1

Digestion

Question 2

breaks large food particles into smaller ones.

Answer 2

mechanical digestion

Question 3

breaking of covalent chemical bonds in organic molecules by digestive enzymes.

Answer 3

Chemical digestion

Question 4

side that faces the digestive tract lumen

Answer 4

apical membrane

Question 5

side that faces the circulation

Answer 5

basolateral membrane.

Question 6

products of lipid metabolism are coated with proteins and transported into lymphatic capillaries

Answer 6

lacteals

Question 7

consist primarily of polysaccharides, such as starches; disaccharides, such as sucrose (table sugar) and lactose (milk sugar); and monosaccharides, such as glucose and fructose (the sugar found in many fruits).

Answer 7

Ingested carbohydrates

Question 8

A minor amount of carbohydrate digestion begins in the oral cavity with the partial digestion of starches by ____________

Answer 8

salivary amylase

Question 9

Carbohydrate digestion is resumed in the small intestine by ____________

Answer 9

pancreatic amylase

Question 10

Carbohydrate digestion is resumed in the small intestine by _________

Answer 10

pancreatic amylase

Question 11

are bound to the microvilli of the intestinal epithelium digest disaccharides into monosaccharides.

Answer 11

disaccharidases

Question 12

located on the basolateral membrane.

Answer 12

sodium-potassium pump

Question 13

The rate of glucose transport into most types of cells is greatly influenced by________ and may increase 10-fold in its presence

Answer 13

insulin

Question 14

are molecules that are insoluble or only slightly soluble in water.

Answer 14

lipids

Question 15

digests lipid molecules

Answer 15

Lipase

Question 16

The vast majority of lipase is secreted by the pancreas and is referred to as ____________

Answer 16

pancreatic lipase

Question 17

which is secreted in the oral cavity and swallowed with food, digests a small amount (<10%) of lipid in the stomach. The

Answer 17

lingual lipase

Question 18

The stomach also produces very small amounts of

Answer 18

gastric lipase

Question 19

key step in lipid digestion which bile salts transform large lipid droplets into much smaller droplets.

Answer 19

emulsification

Question 20

Once lipids are digested in the intestine, bile salts aggregate around the small droplets to form_________

Answer 20

micells

Question 21

Proteins synthesized in the epithelial cells attach to droplets of triglycerides, phospholipids, and cholesterol to form______

Answer 21

chylomicrons

Question 22

major transport lipoproteins which is 92% lipid and 8% protein;

Answer 22

very low-density lipoprotein (VLDL),

Question 23

major transport lipoproteins which is 75% lipid and 25% protein;

Answer 23

low-density lipoprotein (LDL)

Question 24

major transport lipoproteins which is 55% lipid and 45% protein

Answer 24

high-density lipoprotein (HDL)

Question 25

LDL is delivered to cells of various tissues through the circulation.
Cells have __________ in “pits” on their surfaces, which bind the LDL. Once LDL is bound to the receptors, the pits on the cell surface become endocytotic vesicles, and the cell takes in LDL by receptor-mediated endocytosis.

Answer 25

LDL receptors

Question 26

are taken into the body from a number of dietary sources.

Answer 26

proteins

Question 27

secreted by the stomach catalyzes the cleavage of covalent bonds in proteins to produce smaller polypeptide chains.

Answer 27

pepsin

Question 28

These are broken down into tripeptides, dipeptides, and amino acids by______ bound to the microvilli of the small intestine.

Answer 28

peptidases

Question 29

(TRUE OR FALSE)
About 9 L of water enter the digestive tract each day as a combination of ingested and secreted fluids. Of this 9L, about 92% is absorbed in the small intestine, and another 6-7% is absorbed in the large intestine

Answer 29

true

Question 30

Active transport mechanisms for ______ ions are present within the epithelial cells of the small intestine.

Answer 30

sodium

Question 31

(TRUE OR FALSE)
Potassium, calcium, magnesium, and phosphate are also actively transported.

Answer 31

TRUE

Question 32

ions move passively through the intestinal wall of the duodenum and the jejunum following the positively charged sodium ions, but chloride ions are actively transported from the ileum.

Answer 32

chloride