Small Intestine/Pancreatic Secretions Flashcards Preview

S&F IV: Exam One > Small Intestine/Pancreatic Secretions > Flashcards

Flashcards in Small Intestine/Pancreatic Secretions Deck (16):
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Enterocytes

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

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

1

Goblet Cells

Mucous secreting cells spread throughout villus

2

Crypt Cells

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

*Secrete fluids and electrolytes

3

Segmentation Contractions

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

4

Peristaltic Reflex

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

5

Intestinointesinal Reflex

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

*Prevents movement of material into already distended segment

6

Gastroileal reflex

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

7

Gastrocolic reflex

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

8

Pancreatic Acinar Cells

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

9

Centroacinar/Duct Cells

Secrete HCO3-

10

Changes in Ion Concentrations w/ Increased Pancreatic Flow

Na+ => Same

Cl- => Decreases

K+ => Same

HCO3- => Increases

*Fluid will remain isotonic to plasma

11

Formation of pancreatic fluid

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

12

Secretin Potentiation

CCK and Ach enhance effects of Secretin on ductal cells

=>Increased HCO3- secretion

13

Pancreatitis

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

*Caused by chronic alcohol consumption or possibly gallstones

14

Cystic Fibrosis

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

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

15

Pseudohypoparathyroidism

Characterized by tissue resistance to PTH