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Flashcards in Digestive System Deck (77):
1

Where is the main site of absorption?

the small intestine

2

How is digestion in the small intestine aided?

secretion from the liver (bile salts) and secretions from the Pancreas (bicarbonate enzymes)

3

What are the four layers of the wall of the GI tract?

muscosa, submucosa, musclaris externa, serosa

4

What are Enteroendocrine cells?

they secrete hormones into the blood stream

5

What are exocrine cells?

secrete enzymes, mucus etc. Goblet cells secrete mucus and paneth cells secrete antimicrobial compounds

6

What is the Enteric Nervous System?

it is the neurons that are like the second brain

7

What does myenteric plexus do?

regulates motility via the enteric nervous system

8

what does the submucosal plexus do?

regulates secretion and absorption via the Enteric nervous system

9

What does the parasympathetic control do to ENS?

increase gut muscle activity, relx sphincters, increase secretion, secrete Ach

10

What does the sympathetic control do to ENS?

release noradrenaline, inhibit gut movements, constrict sphincters, reduce secretions

11

what vessesls bring blood to and from the digestive system?

splanchnic circulation

12

what artery supplies the stomach with blood?

celiac artery

13

artery for small intestine?

superior mesenteric artery

14

large intestine artery?

superior and inferior mesnteric arteries

15

Describe the activity of smooth muscles cells

they have pacemaker activity via interstitial cells of cajal, which generate slow ave potentials that do not always reach threshold and contract

16

Parasympathetic control ______ and therefore caus___ action potentials. While Sympathetic control _____ and has more ____ waves.

depoolarizes a more, hyperpolarizes

17

motilin is secreted by

m cells in the crypts in duodenum and jejunum

18

what is the duodenum and jejunum?

ebegning and end of small intestine

19

What does motilin do?

increase and regulates migrating motor complex

20

what is he difference between voluntary and involuntary swallowing?

voluntary involves the glossopharyngeal nerve and does not involve the faciel nerve

21

What is secondary peristalsis?

it happens when food gets stuck, it is the contraction to propel food through GI tract

22

what is the brain to stomach reflex called?

vagovagal reflex

23

What is the Ileocecal valve?

it controls emptying of small intestine to large intestine and prevents back flow

24

What happens during emesis from vagus, spinal nerves, phrenic nerve and stomach?

vagus - enhances salivation, relaxes esophagus, LES, body contract pylorus
spinal nervse - inspiration, contract abdominal muscles
phrenic nerve- diaphragm descends
stomach - undergoes reverse peristalsis

25

What increases surface area in the stomach?

rugae and gastric pits

26

what increases surface area in the small intestine?

villi and crypts of lieberkuhn

27

what increases surface area in the large intestine?

haustra, crypts of lieberkuhn

28

what does short microvilli mean?

malabsorption, immune disease allergy to gluten

29

where is saliva produced?

parotid gland, sublingual gland, submandibular gland

30

What is in saliva?

water, electrolytes, bicarbonate, mucus, IgA antibodies, lysozyme, defensins, enzymes

31

what is the function of saliva?

protection, lubrication, taste, digestion

32

What is the parasympathetic response in relation to saliva?

lots of watery saliva

33

What is the sympathetic response in relation to saliva?

small amount of thick saliva

34

What is secreted from the stomach?

mucous cell, parietal cells, chief cells, enterochromaffin-like cells, dcells, g cells

35

What are mucous cells?

mucus, bicarbonate

36

what are parietal cells?

HCL, intrinsic factor

37

what are chief cells?

pepsinogen, gastric lipase

38

what are enterochromaffin-like cells?

histamine

39

what are D cells?

somatostatin

40

what are G cells?

gastrin

41

What happens with people with Zollinger-ellison syndrome?

hyper-acidic stomach and damges stomach lining, release too much gastrin from a tumour in pancreas

42

What does HCI do?

kills bacteria, denatures proteins, activates pepsinogen

43

what does instrinsic factor due?

ensures the absorption of vitamin B12 in ileum

44

What does pepsinogen do?

it is the inactive form of pepsin that is activated by stimach acid, pepsin then breaks down proteins into peptides and or amino acids

45

What does gastrin do?

increases HCI, histamine, pepsinogen, mucus, stomach motility and mass movements

46

What pancreatic secretion enter the small intestine?

acinar and duct cells

47

what are acinar cells?

release by pancreas to small intestine, they include pancreatic amylase, pancreatic lipase, inactive proteases (trypsinogen, chymotrypsinogen, procarboxypeptidase, proelastase)

48

what are duct cells?

pancreatic secretions to the small intestine that release sodium, bicarbonate and water

49

What activates pancreatic enzymes in the small intestine?

enterokinase

50

What facilitates the transfer of water and bicarbonate in the small intestine?

cystic fibrosis transmembrane regulator

51

Why do people with cystic fibrosis have to ingest pancreatic enzymes?

because there no luminal bicarbonate to break down the thick mucus, so the enzymes can't travel to the small intestine

52

What is secreted from the liver into the small intestine via the gall bladder?

bile salts, lecithin, cholesterol, bilirubin, bicarbonate

53

What hormones are released from the small intestine?

Secretin, CCK, GIP, motilin, GLP-1

54

What does secretin do?

to decrease stomach acidity by increasing the release of pancreatic bicarbonate, and decreasing gastric acid secretion/gastric emptying

55

What does CCK do?

contraction of the gall bladder, increases the release of pancreatic enzymes, and decrease gastric acid secretion

56

what does does glucagon-like peptide 1 (GLP-1) do?

fatty acids and carbs in small intestine, helps to feel satieted, increases insulin, and beta cell growth,, decreases glucagon and gastric acid secretion and emptying

57

Why is pancreatic amylase more effeective?

because it can withstand the acidity in the small intestne and it has more mre brush broader enzymes

58

what is the order to carb absrption?

galactose, glucose and fructose

59

When does the digestion of protein begin?

in the stomach - with pepsinogen, acid pepsin to break them down

60

What do brush border enzymes do?

facilitates the transfer of carbs and proteins and fat

61

Why do people with zolinger- syndrome have malnutrition?

becaus e high acidity kills everything even fat, so no nutrients get absorbed to the rest of the body

62

What breaksdown fat in the mouthy and stomach?

lingual lipase and gastric lipase

63

What breaksdown fat in the small intestine?

bile salts from cholesterol, create larger surface area for enzymes to access the fat, along with pancreatic lipase and colipase it turns them into micells

64

What are chylomicrons?

triglycerides assemble with proteins, that are delievered out of cells to get absorbed in the lymphatic system, store energy and can be taken up by the liver

65

What are fat soluble vitamines?

A, D, E, K

66

What are water soluble vitamins?

C and B

67

What increases calcium absorption?

calbindin, this is increased by calcitriol and vit d

68

what increases iron absorption?

ferroportin - levels DEcreased by hepcidin from the liver

69

What is the cephalic phase?

seeing, smelling, tasting or thinking about food. Vagus stimulates stomach secretion and then pancreatic secretion

70

What is GERD? what aggravates it and how to change it?

Acid-reflex, causes by fatty meal, alcohol, caffeine, chocolate, peppermint all increase relaxation of LES. Treated with lifestyle changes like weight loss, eat small meals, eat earlier in the day, stop smoking, reduce acid secretion or enhance stomach emptying via drugs

71

What is the gastric phase?

when food is in the stomach

72

What is the regulation of stomach secretions?

gastrin stimulates stomach acid directly though direct action and histamine, acid stimulates short reflex secretion or pepsinogen, somatostatin release H+ to decrease stomach acid and pepsin

73

What are gastric ulcers?

from H. pylori, secondary causes: drugs, excess acid (zollinger Ellison) organ stress

74

How do h. pylori survive in the stomach?

they make bicarbonate to surround themselves to protect from stomach acid

75

How do you test for H. Pylori?

A breath test, by drinking urea with 14C isotope, and the measure 14CO2 in breath, if it's in the breath than it is a yes

76

How do you treat H. Pylori?

you can give an antibiotic but need something else to decrease the pH

77

What is the intestinal phase?

there is a presence of chyme, distension of the small intestne, secretin from S cells stimulates fluid and bicarbonate secretion. CCK from I cells stimulates secretion of pancreatic enzymes