Small Intestine/Pancreatic Secretions

Question 0

Goblet Cells

Answer 0

Mucous secreting cells spread throughout villus

Question 1

Enterocytes

Answer 1

Columnar epithelial cells in a villus that fnxn to digest, absorb, and secrete fluids

*Cells at tip of villus more active than those @ base

Question 2

Crypt Cells

Answer 2

Found at the base of a villus and serve as the stem cells for the intestines

*Secrete fluids and electrolytes

Question 3

Segmentation Contractions

Answer 3

Circular smooth muscle around segments of intestine contract forcing chyme in both directions; after relaxation, chyme mixes w/ digestive juices

*Net direction is towards the colon due to more contractions occurring in proximal SI

Question 4

Peristaltic Reflex

Answer 4

Moves contents along intestine; initiated by chyme that distends the intestinal wall

Question 5

Intestinointesinal Reflex

Answer 5

Overdistension of an SI segment inhibits contractile activity in the rest of the intestine

*Prevents movement of material into already distended segment

Question 6

Gastroileal reflex

Answer 6

Gastric secretion and emptying triggers peristalsis in ileum causing relaxation of the ileocecal sphincter

Question 7

Gastrocolic reflex

Answer 7

Urge to defecate after eating; food presence causes increased colic motility

Question 8

Pancreatic Acinar Cells

Answer 8

Secrete peptidases, lipases, and amylases; found in the acinus

Question 9

Centroacinar/Duct Cells

Answer 9

Secrete HCO3-

Question 10

Changes in Ion Concentrations w/ Increased Pancreatic Flow

Answer 10

Na+ => Same

Cl- => Decreases

K+ => Same

HCO3- => Increases

*Fluid will remain isotonic to plasma

Question 11

Formation of pancreatic fluid

Answer 11

HCO3- is secreted thru HCO3-/Cl- antiporter; Cl- returns to lumen via facilitated diffusion

Na+ diffuses in b/w cells to the lumen and also enters the ductal cell via Na+/H+ ATPase

Question 12

Secretin Potentiation

Answer 12

CCK and Ach enhance effects of Secretin on ductal cells

=>Increased HCO3- secretion

Question 13

Pancreatitis

Answer 13

Activated enzymes and decreased trypsin inhibitors digest pancreatic tissue causing: abdominal pain, nausea, vomiting, fever

*Caused by chronic alcohol consumption or possibly gallstones

Question 14

Cystic Fibrosis

Answer 14

Defective Cl- channels lead to decreased secretion of aqueous pancreatic component

=>Enzymatic secretion blocked by supersaturation of protein leading to malabsorption and steatorrhea

Question 15

Pseudohypoparathyroidism

Answer 15

Characterized by tissue resistance to PTH