Alimentary secretory functions

Question 1

What effect does parasympathetic stimulation have on the alimentary tract glandular rate?

Answer 1

Increases.

Question 2

What effect does sympathetic stimulation have the the alimentary tract glandular secretion rate?

Answer 2

Dual effect. Alone usually increases secretion, but if in the presence of parasympathetic stimulation usually reduces secretion.

Question 3

What are the two major types of protein secretion in saliva?

Answer 3

serous secretion- ptyalin (a-amylase) for digesting starches and mucus secretion- mucin, for lubricating and protective purposes.

Question 4

Saliva predominately contains what ions?

Answer 4

Potassium and bicarbonate

Question 5

What factors are in saliva that help destroy bacteria?

Answer 5

thiocyanate ions; proteolytic enzymes (lysozyme)

Question 6

What controls nervous regulation of salivary secretion

Answer 6

parasympathetic pathways- from superior and inferior salivatory nuclei in the brain stem

Question 7

What are the two important tubular glands of the stomach?

Answer 7

Oxyntic (gastric) and pyloric

Question 8

What three cell types make up oxyntic (gastric) glands?

Answer 8

mucous neck cells- secrete mucus, peptic (chief) cells-pepsinogen, parietal (oxyntic) cells- HCl, intrinsic factor.

Question 9

What three basic factors stimulate gastric acid secretion?

Answer 9

Ach, gastrin, histamine

Question 10

Ach stimulation excites secretion of

Answer 10

pepsinogen by peptic cells, Hcl bu parietal cells, mucous by mucous cells.

Question 11

Gastrin and histmaine excite secretion of

Answer 11

acid by parietal cells

Question 12

Intrinsic factor is secreted by _____ and essential for absorption of_____

Answer 12

parietal cells (along with hcl); Vit B12 in the ileum

Question 13

What are the three phases of gastric secretion?

Answer 13

cephalic (neurogenic signals from brain transmitted to stomach by vagus nerve- 30% of gastric secretion), gastric (excites vagovagal reflexes from stomach to rain and back, local enteric reflexes, gastrin mechanism- 60% of gastric secretions), intestinal (food in upper SI causes stomach secretion-10% of acid response to meal).

Question 14

The pancreas secretes multiple enzymes for digesting proteins, carbs and fats. Which are important for protein digestion?

Answer 14

TRYPSIN, chymotrypsin, carboxypolypeptidase.

Question 15

Which pancreatic enzyme is important for digesting carbs?

Answer 15

Pancreatic amylase

Question 16

Which pancreatic enzymes are important for fat digestion?

Answer 16

pancreatic lipase, cholesterol esterase, phospholipase

Question 17

Proteolytic digestive enzymes are created in an inactive form in the pancrease and activated after secretion into the intestinal tract. (Trypsinogen, chymotrypsinogen, procarboxypolypeptidase). Trypsinogen is activated by what enzyme?

Answer 17

Enterokinase. It can also be autocatalytically activated by trypsin.
Trypsin activates chymotrypsinogen

Question 18

What are the three stimuli that cause pancreatic secretion?

Answer 18

Ach, CCK, secretin

Question 19

What are the three phases of pancreatic secretion?

Answer 19

Cephalic (20% of secretion), gastric (5-10% of secretion), intestinal (causes copious secretion in response to secretin after chyme enters SI 80% of secretion)).
Secretin causes large amount of bicarb secretion to neutralize acidic chyme. CCK stimulates digestive enzymes