the digestive system Flashcards

1
Q

the mouth

A

mobility: mastication of food by teeth and tongue
digestion–> amylase produced by salivary glands breaks down starch
absorption: non
secretion: amylase

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2
Q

osephagus

A

mobility- peristalsis
digestion- null
secretion: of mucosa (lube)
absorption: null

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3
Q

stomach

A

motility: contraction beings in the funds where s.muscle is stimulated- 3 sub units of the stomach fire APs; either tonic or phasic
absorption- some e.g. water
digestion- pepsin hydrolyses proteins and contraction produces chyme

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4
Q

s.intestine

A

motility: peristalsis
secretion: proteases, carbhohdrases and lipase
absorption: sugars, amino acids and fatty acids by villi
digestion- secretion, peristalsis, absorption

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5
Q

l.intestine

A

motility: segmentation contractions, antiperistalric and mass movement
secretion: mucosa and bicarbonate
absorption: water
digestion: removes waste product

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6
Q

accessory organs

A
liver- bile an blood processor
gall bladder-storage of bile
pancreas- enzymes
appendix stores healthy bacteria
salivary glands
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7
Q

polysaccharides digestion

A

broken down to disaccharides and other smaller sugars e.g. maltose by amylase in the saliva.
-then further broken down by enzymes found on the brush boarder to monosaccharides

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8
Q

monosaccharides

A

galactose
glucose
fructose

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9
Q

fat molecule

A

3 fatty acids 1 glycerol

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10
Q

fat present in s intestine..

A

stimulates the pancreas to release lipase and the gall bladder to release bile

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11
Q

pro enzyme of pepsin

A

pepsinogens–> acid content of the stomach activates pepsinogens to pepsins

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12
Q

functions of the appendix

A
  • protect good bacteria
    e. g. when an individual has diarrhoea and loses lots of bacteria, the appendix can store good bacteria that can help re-populate the digestive system to keep you healthy
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13
Q

patients who have had their appendix removed are..

A

4x more likely to have irritation in their l intestine

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14
Q

where interstitial cells of canal located

A

fundus (pacemaker cells)

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15
Q

BER

A

basic electrical rhythm 3 per min

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16
Q

where are enzymes and acid produced in the stomach

A

cardia

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17
Q

what character of the stomach means that its capacity can increase so much

A

the rugae

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18
Q

where does most mixing and churning occur in the stomach

A

antrum

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19
Q

pyloric antrum

A

nearer body

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20
Q

pyloric canal

A

empties into the duodenum

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21
Q

mains parts of s.intestine

A

duodenum
jejunum
iieum

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22
Q

main parts of large intestine

A

cecum, appendix, ascending transverse and descending colon, sigmoid and anus and rectum

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23
Q

how can too much fatty foods cause acid reflux

A

not due to an excess of acid but due to a malfunction of the gastrosphogeal sphincter- e.g. if it loses tone it won’t fully close.

fatty foods causes heartburn due to two reasons:

1) lipids cause the LEA to relax, easier for reflux to occur
2) lipids cause pyloric valve to contract tighter, so food is held in the stretch for longer- higher chance of reflux

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24
Q

coeliac disease

A

an autoimmune disease- immune system mistake gluten for a pathogen and attack it.
This causes villi to be broken down and they lose their important surface area (flattened)

-can cause rapid weight loss due to less nutrient being absorbed

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25
Q

symptoms of eating too much fatty food

A

bloating
acid reflux and heartburn
increased risk of heart disease

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26
Q

to alleviate symptoms of coeliac disease

A

no gluten must be eaten

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27
Q

gastric emptying is largely controlled by factors in the…

A

duodenum

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28
Q

factors in the stomach that influence gastric emptying

A
  • amount of chyme being stored
  • stomach distention
  • fluidity of the chyme
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29
Q

factors in the s.intestine that influence gastric emptying

A

-if fat, acid, hypertonicity, distention is in the s.intestine then it won’t signal to the stomach to empty

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30
Q

what causes diarrhoea

A

when water can not be absorbed by the bowels:
-bacteria, viruses may effect ion channels which mean water potential causes water to leave the blood and enter in lumen and not be absorbed.

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31
Q

how many layers does the GI tract have

A

4 layers

32
Q

4 layers of the GI tract

A

mucosa
sub mucosa
muscular propria
adventitia

33
Q

3 layers of mucosa

A
  1. lining of epithelium (including glandular tissue)
  2. lamina propria (vascularised loose connective tissue)
  3. muscular mucosal (thin layer of smooth muscle)
34
Q

sub mucose

A

loose connective layer–> large blood vessels, lymphatics, nerves and muscuos secreting glands

35
Q

muscular propria (2 layers)

A

inner layer is circular
outer layer is longitudinal
–> for peristalsis

36
Q

adventitia

A

outer most layer

  • loos connective tissue, covered by visceral peritoneum
  • blood vessels lymphatics and nerves
37
Q

mucosa folds into deep pits

A

1) enzymes (acids from pits)

2) mucus from necks

38
Q

4 types of cells within gastric pits

A

mucous secreting surface and neck cells

parietal cells

chief cells

g cells

D cells

39
Q

parietal cells

A

HCL and intrinsic factors (FUNDUS)

40
Q

chief cells

A

pepsinogen (FUNDUS)

41
Q

G cells

A

gastrin (ANTRUM)

42
Q

D cells

A

somatostatin (ANTRUM)

43
Q

production of stomach acid

A

(first all receptors must be full on outside of parietal cell- histamine, AcH, CCK)

  • co2 enters parietal cell form blood forming H2CO3 with water
  • H2CO3 dissociate to form H+ and HCO3-
  • H+ (ATP dependent pump) pumps out H+ into the gastric lumen and K+ are pumped in, in exchanged
  • HCO3- is pumped out into the blood and Cl- is pumped in
  • cl- passively diffuses out, as well as K+
  • Cl- and H+ covalently bond in the lumen to form HCL
44
Q

control of HCL production

A
  • -distension protein attaches to G cell, this causes GASTRIN to be released
  • GASTRIN causes 2 responses: stimulates paras NS to release AcH (which attaches to receptor on parietal cell membrane). It also causes the blood to release CCK which causes ECL cells to release histamine. Then both histamine and CCK attach to their receptors on the parietal cells.
  • when all receptors are full this triggers CO2 to enter the cell and production of HCL is started.
45
Q

uses of HCL

A

-kills bacteria
-denatures proteins
helps gastric lipase
-converts pepsinogen to pepsin

46
Q

regulation (3)

A

cephalic
gastric
intestinal

47
Q

mucus cells secrete a protective coat of

A

bicarbonate mucus- alkaline

48
Q

what mark the entry of gastric glands

A

gastric pits

49
Q

cells found in funds and body which produce most gastric secretions

A

parietal, chief, mucous neck cells, enteroendocrine (G cells

50
Q

what is released in pyloric antrum

A

gastrin and mucus

51
Q

parietal cells

A

HCL and intrinsic factor

52
Q

hcl

A

denatures proteins, kills bacteria, needed to activate pepsin

53
Q

chief cells

A

secrete pepsinogen –> the inactive version of pepsin

54
Q

pepsin is activated by

A

HCL released by parietal cells

55
Q

mucous neck cells

A

thin, acidic mucus —> diff from mucous secreted by goblet cells

56
Q

G cells (enteroendocrine)

A

gastrin

57
Q

gastrin

A

promotes gastric emptying and increases secretion by gastric glands

58
Q

histamine

A

stimulates parietal cells to release HCL

59
Q

cephalic phase

A

sight/smell of food, causes the vagus nerve to be stimulated and therefore and increase in gastric motility

60
Q

gastric phase

A

stomach distention causes local reflexes and vagovagel reflexes which stimulates the vagus nerve. Food chemicals increase the pH and activates chemoreceptors–> G cell secretion of gastrin. Stimulates stomach secretory activity

61
Q

intestinal phase

A

low pH and partially digested food in duodenum. stomach empties and increase in intestinal gastrin

62
Q

enteric

A

controls sooth muscle contraction and G1 secretions and blood flow

63
Q

autonomic

A

parasympathetic -vagus nerve–> rest and digest

sympathetic –> fight or flight

64
Q

pancreas

A

chief factory for digestive enzymes that are secreted into the duodenum e..g proteases, lipase, carbohydrases

65
Q

liver

A

produces and secretes bile

66
Q

gall bladder

A

storage of bile

67
Q

bile

A

helps absorb fats –> emulsification. carries waste from the liver which cannot go through the kidney

68
Q

mouth, stomach, s.intestine

A

mouth–> amylase
stomach–> protease
s.intestine –> amylase, protease, lipases

69
Q

protein molecules get broken down into

A

amino acid molecules

70
Q

liver and gall bladder secretes

A
bile
phospholipids
bicarbonate ions
cholesterol
bile pigments
71
Q

pernicious anaemia

A

caused by impaired absorption of B12 within the s.intestine

  • -> malabsorption
  • -> atrophic gastritis
  • -> intestinal disease
  • -> acid suppressant
72
Q

B12 needed for

A

nervous system function and red blood cell formation

73
Q

what is needed for b12 absorption

A

intrinsic factor released by parietal cells

74
Q

bad cholesterol

A

low density lipoprotein

75
Q

LDL

A

makes up the majority of the bodies cholesterol. having high levels can lead to plaque build-up in your arteries and result in heart disease and strokes

76
Q

HDL

A

good cholesterol–> absorbs cholesterol and takes