digestion + metabolism

Question 1

what is mechanical digestion?

Answer 1

physical breakdown of food into smaller particles

Question 2

what is chemical digestion?

Answer 2

hydrolysis reactions that break down macros into monomers

Question 3

what is included in saliva?

Answer 3

Salivary amylase (starch)
lingual lipase (fats)
mucous (binding and lubrication)
lysozyme (kills bacteria)
immunoglobin (inhibits bacterial growth)
electrolytes

Question 4

what are parietal cells?

Answer 4

these are cells in the gastric pits that secrete HCl and a hunger hormone called ghrelin

Question 5

what are chief cells?

Answer 5

these are cells in the gastric pits that are the most common they secrete lipase and pepsinogen

Question 6

what is HCl in the stomach

Answer 6

this is CO2 +H2O -> H2CO3 -> HCO3 + H
this is to digest things as it is extremely acidic (>0.8 pH), this activated pepsin and lingual lipase, this breaks up connective tissues and plant cell walls, converts ferric to ferrous

Question 7

what is are zymogens

Answer 7

coverts to active enzyme by removing amino acids

Question 8

what is pepsinogen?

Answer 8

this is the active form of zymogens activated by pepsin its autocatalytic.

Question 9

what is the main function of pepsin?

Answer 9

digestion of dietary proteins into shorter peptides completed in the small intestine.

Question 10

what is the intrinsic factor?

Answer 10

secreted by parietal cells it absorbed vitamin B12 and binds it, this is needed to make hemoglobin

Question 11

what is gastric lipase

Answer 11

produced by chief cells minor role in digesting fats.

Question 12

what is gastric secretion stimulated by?

Answer 12

acetylcholine (parasympathetic nerve fibers)
histamine (enteroendocrine)
gastrine (enteroendocrine G cells in pyloric gland)

Question 13

what is the cephalic phase?

Answer 13

Brain -> stomach

Question 14

what is the gastric phase

Answer 14

stomach -> stomach

Question 15

what is the intestinal phase

Answer 15

small intestine -> stomach

Question 16

what are bile acids

Answer 16

steroids synthesized by cholesterol
aid in fat digestion

Question 17

what are the major pancreatic enzymes

Answer 17

trypsinogen (converted to trypsin by enterokinase)
chymotrypsinogen (converted to chymotrypsin by trypsin)
procarboxypeptidase (converted to carboxy peptidase by trypsin)

Question 18

what regulates pancreatic juice secretion?

Answer 18

acetylcholine (via vagus nerve and enteric nerves stimulates cephalic phase)
cholecystokinin (via duodenum in response to fats, stimulates intestinal phase and pancreatic enzyme secretion and bile secretion)
secretin (via duodenum stimulates liver and pancreas to make NaCO3)

Question 19

what is peristalsis?

Answer 19

moves the contents of the small intestine towards the colon.