Dig

Question 1

What is digestion?

Answer 1

“Chemical breakdown of food within the GI tract; distinct from absorption.”

Question 2

What is absorption?

Answer 2

“Uptake of nutrients into the body.”

Question 3

What is feeding?

Answer 3

“Endocrine control of food intake.”

Question 4

What are the three main GI divisions?

Answer 4

“Foregut, Midgut, Hindgut.”

Question 5

Where does most absorption occur?

Answer 5

“Midgut (small intestine).”

Question 6

Where does most digestion occur?

Answer 6

“Midgut.”

Question 7

What increases surface area for absorption?

Answer 7

“Villi and microvilli.”

Question 8

What are the two key GI functional themes?

Answer 8

“Secretion + Motility.”

Question 9

What organs produce major secretions into the gut?

Answer 9

“Pancreas + biliary system (liver + gallbladder).”

Question 10

What is peristalsis?

Answer 10

“Muscle-driven forward movement of food along the GI tract.”

Question 11

What is segmentation?

Answer 11

“Muscle contractions that mix food back-and-forth.”

Question 12

What regulates GI function?

Answer 12

“Neural + endocrine regulation.”

Question 13

What is the ENS?

Answer 13

“Enteric nervous system; regulates motility + secretion.”

Question 14

What stimulates ENS activity?

Answer 14

“Distension, osmolarity changes, chemical signals.”

Question 15

What are the three main gut hormones?

Answer 15

“Gastrin, CCK, Secretin.”

Question 16

Where is Gastrin secreted?

Answer 16

“Stomach/foregut.”

Question 17

Where are CCK and Secretin secreted?

Answer 17

“Small intestine/midgut.”

Question 18

What are the three homeostatic phases of digestion?

Answer 18

“Cephalic, Gastric, Intestinal.”

Question 19

What happens during the cephalic phase?

Answer 19

“Perception of food stimulates secretion.”

Question 20

What triggers the gastric phase?

Answer 20

“Arrival of food in foregut.”

Question 21

What triggers the intestinal phase?

Answer 21

“Arrival of food in midgut.”

Question 22

What stimulates H+ secretion in the stomach?

Answer 22

“Parasympathetic ACh + Gastrin.”

Question 23

What is secreted into blood as H+ enters the lumen?

Answer 23

“HCO₃⁻.”

Question 24

What are zymogens?

Answer 24

“Inactive enzymes secreted to avoid self-digestion.”

Question 25

What activates zymogens?

Answer 25

"Low pH in stomach."

Question 26

What % of protein digestion occurs in foregut?

Answer 26

"<20%."

Question 27

What is the state of nutrients leaving the foregut?

Answer 27

"Transformed but mostly undigested/unabsorbed."

Question 28

What does intestinal phase do to stomach?

Answer 28

"Inhibits gastric secretion + motility."

Question 29

What stimulates Secretin & CCK release?

Answer 29

"Low pH, stretch, food-borne chemicals in intestine."

Question 30

What does Secretin do?

Answer 30

"Stimulates pancreas + liver to release HCO₃⁻, neutralizing acid."

Question 31

What does CCK do?

Answer 31

"Stimulates pancreatic enzymes + bile secretion; contracts gallbladder; relaxes sphincter of Oddi."

Question 32

What is an exocrine secretion?

Answer 32

"Released into ducts/outside body rather than bloodstream."

Question 33

How are carbohydrates and proteins absorbed?

Answer 33

"Facilitated diffusion + secondary active transport via Na+/K+ pump gradients."

Question 34

How are lipids absorbed?

Answer 34

"Simple diffusion after emulsification + breakdown."

Question 35

What problem does lipid digestion face?

Answer 35

"Lipids aggregate and repel water, limiting enzyme access."

Question 36

What solves lipid aggregation problem?

Answer 36

"Bile salts emulsify fat droplets."

Question 37

What are bile salts?

Answer 37

"Amphipathic detergents that break up lipids."

Question 38

What happens to lipids after uptake into cells?

Answer 38

"Reassembled into triglycerides + packed into chylomicrons."

Question 39

What are chylomicrons?

Answer 39

"Large lipoproteins with lipid core & amphipathic outer coating; only ones made after meals in intestines."

Question 40

Where do chylomicrons go?

Answer 40

"Enter lymphatic system → blood."

Question 41

How do most nutrients travel after absorption?

Answer 41

"Hepatic portal vein → liver."

Question 42

What happens to bile salts after use?

Answer 42

"Reabsorbed → liver → recycled."

Question 43

What happens in hindgut?

Answer 43

"Reabsorbs remaining water."

Question 44

How much water enters gut/day?

Answer 44

"Up to 7 L/day."

Question 45

How much water remains to absorb in hindgut?

Answer 45

">1 L normally."

Question 46

How is hindgut water absorbed?

Answer 46

"Na+ active reabsorption → osmotic water uptake."

Question 47

Water content of normal feces?

Answer 47

"~100 mL/day."

Question 48

Purpose of sphincter of Oddi?

Answer 48

"Controls bile + pancreatic secretions entering intestine."

Question 49

Do midgut signals inhibit or stimulate foregut?

Answer 49

"Inhibit foregut secretion + motility."

Question 50

What stimulates pancreatic enzyme secretion?

Answer 50

"CCK."

Question 51

What neutralizes gastric acid in intestine?

Answer 51

"HCO₃⁻ from pancreas + liver."

Question 52

What are lipoproteins?

Answer 52

"Particles with hydrophobic core + amphipathic coating."

Question 53

What is the only lipoprotein made in intestines?

Answer 53

"Chylomicrons."

Question 54

When are chylomicrons produced?

Answer 54

"After a meal."

Question 55

What transport mechanism creates gradient for nutrient uptake?

Answer 55

"Na+/K+ ATPase."

Question 56

What hormone increases stomach motility?

Answer 56

"Gastrin."

Question 57

What causes foregut muscle contraction?

Answer 57

"NS stimulation + Gastrin."

Question 58

Define peristalsis vs segmentation.

Answer 58

"Peristalsis = forward propulsion; segmentation = mixing."

Question 59

What sensory stage begins swallowing + secretions?

Answer 59

"Cephalic phase."

Question 60

Is carbohydrate digestion significant in stomach?

Answer 60

"No, very little occurs."

Question 61

What stimulates bile release?

Answer 61

"CCK."

Question 62

Where are bile salts stored?

Answer 62

Gallbladder.