(continuation) Digestive System

Question 1

Cells of Gastric Glands:

Answer 1

1. Regenerative cells
2. Parietal cells
3. Chief cells
4. Enteroendocrine cells

Question 2

divide rapidly to produce new cells that migrate to surface

Answer 2

Regenerative cells

Question 3

secrete HCl acid and intrinsic factor

Answer 3

Parietal cells

Question 4

secrete pepsinogen

Answer 4

Chief cells

Question 5

secrete hormones and paracrine messengers

Answer 5

Enteroendocrine cells

Question 6

Gastric Secretions:

Answer 6

• 2 to 3 L of gastric juice/day (H2O, HCl and pepsin)
• Parietal cells contain carbonic anhydrase (CAH)

Question 7

Functions of Hydrochloric Acid:

Answer 7

• Activates pepsin and lingual lipase
• Breaks up connective tissues and plant cell walls
• Converts ingested ferric ions (Fe3+) to ferrous ions (Fe2+)
• Destroys ingested bacteria and pathogens

Question 8

essential for B12 absorption by the small intestine. RBC production (lack causes pernicious anemia)

Answer 8

Intrinsic factor

Question 9

secreted as pepsinogen (inactive). HCl converts it to pepsin (active)

Answer 9

Pepsin

Question 10

lipase digests the butterfat of milk in infants. chymosin curdles milk by coagulating proteins

Answer 10

Gastric lipase and chymosin

Question 11

hormones enter blood

Answer 11

distant cells

Question 12

paracrine secretions

Answer 12

neighboring cells

Question 13

signaling molecules produced in digestive tract and CNS

Answer 13

Gut-brain peptides

Question 14

Swallowing center signals stomach to relax

Answer 14

Gastric Motility

Question 15

when abdominal contraction forces upper esophageal sphincter to open

Answer 15

vomiting

Question 16

lower esophageal sphincter to relax

Answer 16

retching

Question 17

sight, smell, taste or thought of food; vagus nerve stimulates gastric secretion and motility

Answer 17

Cephalic phase

Question 18

activated by presence of food or semi-digested protein

Answer 18

Gastric phase

Question 19

duodenum regulates gastric activity through hormones and nervous reflexes

Answer 19

Intestinal phase

Question 20

duodenum inhibits stomach

Answer 20

enterogastric reflex

Question 21

Gross Anatomy of Liver:

Answer 21

• 3 lb. organ located inferior to the diaphragm
• 4 lobes - right, left, quadrate and caudate

Question 22

Tiny cylinders found in the liver

Answer 22

hepatic lobules

Question 23

________ and ________ bring blood to liver

Answer 23

hepatic portal vein and hepatic artery

Question 24

Pancreatic Acinar Cells:

Answer 24

• Zymogens = proteases
• trypsinogen
• chymotrypsinogen
• procarboxypeptidase
• Other enzymes
• amylase
• lipase
• ribonuclease and deoxyribonuclease

Question 25

* involve only mucosa and submucosa * chyme flows in a spiral path causing more contact

Answer 25

Circular folds (plicae circularis) up to 10 mm tall

Question 26

______ are fingerlike projections 1 mm tall

Answer 26

Villi

Question 27

Gradual movement of contents towards colon

Answer 27

Peristalsis

Question 28

Water is absorbed by ________ following the absorption of salts and organic nutrients

Answer 28

osmosis

Question 29

Gross Anatomy of Large Intestine:

Answer 29

5 feet long and 2.5 inches in diameter in cadaver Begins as cecum and appendix in lower right corner Ascending, transverse and descending colon frame the small intestine Sigmoid colon is S-shaped portion leading down into pelvis Rectum - straight portion ending at anal canal

Question 30

straight portion ending at anal canal

Answer 30

Rectum

Question 31

muscle tone in longitudinal muscle fibers (concentrated in taeniae coli) form pouches (haustra)

Answer 31

Muscularis externa

Question 32

Bacterial flora populate large intestine

Answer 32

* ferment cellulose and other undigested carbohydrates; we absorb resulting sugars * synthesize vitamins B and K

Question 33

* average person produces 500 mL per day * most is swallowed air but hydrogen sulfide, indole, and skatole produce odor

Answer 33

Flatus (gas)

Question 34

Absorption and Motility

Answer 34

Transit time is 12 to 24 hours

Question 35

Anatomy of Anal Canal:

Answer 35

* 3 cm total length * Anal columns are longitudinal ridges separated by mucus-secreting anal sinuses * Hemorrhoids are permanently distended veins

Question 36

Stretching of the rectum stimulates __________

Answer 36

defecation

Question 37

Neural Control of Defecation:

Answer 37

1. Filling of the rectum 2. Reflex contraction of rectum and relaxation of internal anal sphincter 3. Voluntary relaxation of external sphincter