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Flashcards in GI Deck (61):
1

What are the two enteric plexuses that innervate the GI

Submucosal (Meissner Plexus) and the Myenteric (Auerbach Plexus)

2

Myenteric plexus is responsible for:

GI movement/motility- increased tonicity, intensity, rate, velocity, and local blood flow
Inhibits sphincter tone (pylorus & ileocecal valve)

3

what does the meissner (submucosal) plexus do

GI secretion & local blood flow
-very small segments of GI wall, lead to various degrees of unfolding wall

4

what does the ptyalin secrete

salivary amylase, digest starch

5

parietal cells of the oxyntic gland in the mucosal layer of the stomach secrete:

HCL & intrinsic factor

6

What do chief cells secrete

pepsinogen

7

How does pepsinogen become activated?

HCl splits it into an active form of pepsin

8

D cells secrete:

somatostatin (inhibits gastric juices)

9

G cell

secrete gastrin increasing gastric juice

10

ECL cells in the Oxyntic gland secrete

histamine (stimulates gastric acid juice)

11

Where is the swallowing center located

medulla and pons

12

Splanchnic flow describes::

nutrients from the gut, spleen, and pancreas travel via portal vein to liver

13

Describe rhythmic slow waves

smooth muscle that shows undulating changes in resting membrane potential but don't cause contraction

14

What causes contaction of GI

Channels open allow for Ca++ along with Na+ to enter and cause long AP, contraction

15

What occurs in liver

removes bacteria/particles

16

what are the accessory organs of digestion

liver, gallbladder, and pancreas

17

what is saliva made up

water, mucus, amylase, bicarbonate, K+, and lingual lipase

18

Where and why would you see a apthous ulcer

"cold sore" disruption in mucousal surface from trauma infection, or inflammation

19

What two things occur in order to move the bolus from mouth into esophagus

pharynx muscles raise soft palate closing entry to nasopharynx, and epiglottis slides back to close off larynx & trachea

20

whats the main function of the UES

prevent air into esophagus during respiration

21

whats the main function of LES

prevents backflow from stomach

22

How do both Esophageal Sphincters perform there function

maintaining tonicity

23

Describe the muscularis propria in the esophagus

Proximal 1/3 smooth
middle 1/3 skeletal, smooth
Distal 1/3 smooth

24

what is achalasia

LES fails to relax preventing food from entering stomach

25

how would u tx achalasia

antispasmodics, balloon placement

26

Esophageal strictures are caused by

scar tissue, sometimes from GERD

27

Describe the gastroileal reflex

it increases ileal motility (emptying ileum, preparing for more chyme)

28

describe gastroenteric reflex

distension of the stomach triggers peristalsis

29

how do rugae help aid digestion

allow for increased volume without change in pressure, and increase surface area

30

Describe retropulsion in the stomach

as the pyloris contracts sending chyme to duodenum, the remaining gets propelled back away from sphincter for further mixing

31

what cells mediate the pace of peristalsis in stomach

Cajal cells

32

What two structures of the GI are retroperitoneal

esophagus and duodenum

33

what structures are intraperitoneal

jejunum, ileum, liver and stomach

34

What do the Brunner's Glands do in the duodenum

secrete alkaline mucus for protection via neutralizing acid

35

why does a patient become constipated with an inflamed appendix?

irritates the cecum (close in location) hence, sphincter spasms cause partial paralysis of ileum

36

what does the Crypt of Leiberkuhn do to contribute to the health of the SI

contains undifferentiated cells to replace the epithelial layer, secretes some digestive juices

37

how do gastrin, insulin, motilin, and serotonin act on peristalsis

increase

38

what acts to delay emptying of the stomach?

distension, irritation, acidity, CCK, GIP, & Secretin

39

Cholecystokinin CCK functions to:

stimulate release of bile & pancreatic juices to break down lipids & aa
Inhibits: gastric emptying & parietal cells secretion HCL

40

these two enzymes are secreted from the pancreas to aid with digestion of proteins

trypsinogen and chymotrypsin

41

why aren't trypsinogen and chymotrypsin able to act immediately on digestion

they are inactive forms to prevent them from destructing the pancreas... must be modified.

42

How are fats aided in digestion?

bile salts from the liver and lipase from the pancreas both facilitate fat breakdown.

43

what is the route of bile once it is ejected from the gallbladder to the SI

to cystic duct, common bile duct, and to the Sphincter of Oddi at the Ampulla of Vater at junction of the duodenum

44

what carries bile from hepatocytes to the bile ducts

bile canalculi

45

What does the liver store

fat, glycogen iron, copper, Vitamin B12, A, D, and E

46

what does the liver synthesize

fat, phospholipids, cholesterol, plasma proteins, non-essential aa, serum enzymes (AST, ALT, LDH, and alk phosp)

47

where is calcium primarily absorbed

ileum

48

how is calcium absorbed

via passive, active, and carrier proteins

49

what enhances calcium absorption

bile salts, which also enhances vitamin D

50

What does vitamin B12 bind to

intrinsic factor making it resistant to digestion

51

where does most absorption of vitB12 occur

ileum terminally

52

Whats vitamin B12 necessary for

erythrocyte maturation

53

why does a deficiency of vitB12 cause pernicious anemia

without B12, one wouldn't have RBC formatioin

54

what is pernicious anemia caused from

lack of B12 in order to have erythrocyte maturation

55

Secretin is stimulated to be secreted by what

low pH

56

GIP does what

secretes insulin, it also inhibits parietal/chief/paralysis

57

Iron and calcium have a special regulation in the body

amount absorbed dependent on amount needed

58

iron absorption is facilitated by

vitamin C

59

Describe the ileogastric reflex

when ileum is distended, it inhibits gastric motility

60

describe gastrocolic

distended gastric promotes propulsion through colon

61

What do the I cells in Small Intestine secrete

Cholecystokinin- responsible for ejecting bile (inhibits gastrin motility)