Absorption

Question 1

nervous innervation of absorption occurs via the ____

Answer 1

Meissner’s Plexus (Submucosal plexus)

Question 2

function of Meissner’s Plexus (submucosal plexus)

Answer 2

allow for secretion of digestive enzymes required for absorption of nutrients

Question 3

innervations of mouth

Answer 3

CN V, VII, IX, X

Question 4

primary function of mouth

Answer 4

mechanical breakdown (mastication/chewing)

Question 5

surface area of food in the mouth will be ____

Answer 5

increased

Question 6

what nutrients are digested in the mouth?

Answer 6

carbohydrates
fats

Question 7

what is the function of amylase?

Answer 7

digests starch (amylose) to maltose in the mouth

Question 8

what is the function of salivary lipase?

Answer 8

digests triacylglycerols to glycerol + FAs in the mouth

Question 9

what foods require chewing for digestion?

Answer 9

vegetables (plants)

Question 10

what are the 3 phases of swallowing?

Answer 10

voluntary
pharyngeal
esophageal

Question 11

voluntary stage of swallowing

Answer 11

starts the swallowing process

Question 12

pharyngeal phase of swallowing

Answer 12

• close off trachea: inhibit breathing and approximate vocal cords
• upper sphincter relaxes, peristalsis begins: pass food further down esophagus

Question 13

esophageal phase of swallowing

Answer 13

final movement of food before stomach

Question 14

patients with CN injury will have an extremely hard time completing what phase of swallowing?

Answer 14

pharyngeal
(IX + X swallowing reflex)

Question 15

the upper 1/3 of the esophagus contains ____ muscle and has a ____ contraction

Answer 15

striated skeletal
strong

Question 16

the lower 2/3 of the esophagus contains ____ muscle and has a ____ contraction

Answer 16

smooth
weaker

Question 17

what are the 2 major types of peristalsis?

Answer 17

primary & secondary

Question 18

primary peristalsis

Answer 18

• initiated by medulla
• affects striated muscle (upper 1/3)

Question 19

secondary peristalsis

Answer 19

• initiated by enteric system
• affects smooth muscle (lower 2/3 & upper esophageal sphincter)

Question 20

the general anatomy of the stomach allows for ____ movements by the ____

Answer 20

mixing movements by the high pressure antral pump

Question 21

what nutrients are digested in the stomach?

Answer 21

proteins
fats

Question 22

function of pepsin

Answer 22

converts proteins to peptides in the stomach (active at pH2)

Question 23

function of gastric lipase

Answer 23

digests triacylglycerols to glycerol + FAs in the stomach

Question 24

directly after a meal, the volume of food in the stomach ____

Answer 24

increases

Question 25

what stimulates the myenteric reflex?

Answer 25

- increased gastric volume reduces available space for additional food - outward pressure of food stimulates myenteric reflex

Question 26

what is the function of the myenteric reflex?

Answer 26

- increase rate of emptying in the stomach - release gastrin

Question 27

the common bile duct enters the ____ of the small intestine through the ____

Answer 27

duododenum sphincter of Oddi

Question 28

function of sphincter of Oddi

Answer 28

allows both **bile & pancreatic enzymes** into duodenum

Question 29

when fatty chyme and amino acids from the stomach enter the duodenum, the hormone ____ is released

Answer 29

cholecystokinin (CCK)

Question 30

actions of cholecystokinin

Answer 30

1. relax (opens) **sphincter of Oddi** 2. cause release of **pancreatic enzymes** 3. contract gallbladder to release **bile**, necessary for action of pancreatic lipase 4. Decrease gastric emptying 5. cause brain to feel **satiated**

Question 31

nutrients absorbed in the jejunum

Answer 31

proteins, carbohydrates, lipids

Question 32

proteins enter the portal blood as ____

Answer 32

amino acids

Question 33

carbohydrates enter the portal blood as ____

Answer 33

monosaccharides

Question 34

fats enter the ____ as ____

Answer 34

lymph chylomicrons containing TAGs

Question 35

function of dipeptidase & tripeptidase

Answer 35

proteins in jejunum -> AAs in portal blood

Question 36

function of disaccharidases

Answer 36

carbohydrates in jejunum -> monosaccharides in portal blood

Question 37

surface area of the jejunum is increased by ____

Answer 37

villi and microvilli

Question 38

what happens to blood flow to the villi of the small intestine when food arrives?

Answer 38

increases (8x)

Question 39

what happens when blood flow to the villi of the small intestine is increased?

Answer 39

increased absorption and contraction of smooth muscle at appropriate rate

Question 40

what 2 factors could increase blood flow to villi of the small intestine?

Answer 40

1. arrival of food 2. increased GI secretions

Question 41

decrease in blood flow to the GI tract is usually associated with ____

Answer 41

sympathetic stimulation

Question 42

what is ischemia?

Answer 42

reduced blood flow to an area of the body

Question 43

what part of the GI tract is particularly sensitive to ischemia?

Answer 43

villi of SI

Question 44

what is the effect of ischemia on the GI tract?

Answer 44

decreased rate of absorption in that area of the gut

Question 45

where is vitamin B12 absorbed, and what is required for its absorption?

Answer 45

ileum & ileocecal valve intrinsic factor

Question 46

function of ileocecal valve

Answer 46

- prevent backflow from LI to SI - promote emptying into colon when stimulated (backup = pathOLogy)

Question 47

primary function of large intestine

Answer 47

absorption of water & electrolytes (some vitamins produced by bacteria & absorbed: vitamin K, biotin)

Question 48

what is the surface specialization of the large intestine?

Answer 48

crypts of Lieberkuhn (no villi)

Question 49

mucus secretion mostly occurs in the ____

Answer 49

large intestine

Question 50

what is the goal of mass movements?

Answer 50

push food through the LI, from transverse colon to rectum

Question 51

what reflexes initiate mass movements?

Answer 51

gastrocolic duodenocolic (ENS and ANS both involved)

Question 52

function of mixing movements in the Large intestine?

Answer 52

mix chyme -> helps with electrolyte absorption

Question 53

what are the 3 levels of control of the rectum & anus?

Answer 53

1. intrinsic 2. spinal cord reflex 3. high center (medulla)

Question 54

intrinsic control of rectum & anus

Answer 54

enteric nervous system which is activated by presence of feces entering rectum

Question 55

spinal cord innervation of rectum & anus

Answer 55

S2, S3, S4

Question 56

control of rectum & anus by medulla

Answer 56

efferent signals from brain down spinal cord to local level of innervation

Question 57

internal anal sphincter is under ____ control, while the external anal sphincter is under ____ control

Answer 57

autonomic voluntary