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alimentary system > physiology > Flashcards

physiology Flashcards

1
Q

is the muscualris externa in the rectum/ anus thick or thin

A

thin

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2
Q

what happens to the micelle when it reaches the acid microclimate of the small intestine brush border

A

breakdown releasing its contents to diffuse across the plasma membrane

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3
Q

which 2 ducts join to form the common bile duct

A

common hepatic duct form the liver

cystic duct from the liver

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4
Q

How are amino acids transported into the cell

A

SAAT1
sodium coupled amino acid transporter
(Na/ K ATPase)

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5
Q

Once CO2 is inside a parietal cell, what chemical reaction takes place

A

CO2 + H20 –> H2CO3

carbonic anhydrase

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6
Q

what prevents gastric acid corrosion and pepsin digestion in the stomach

A

mucous

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7
Q

what are place circulares

A

folds in the mucous membrane of the small intestine

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8
Q

which vitamins are water soluble

A

B C folic acid

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9
Q

which vein does the interior mesenteric drain into

A

splenic

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10
Q

how are digestive enzymes stored in acinar cells

A

inactive form (zymogen)

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11
Q

How does sympathetic innervation effect secretion and motility

A

Decrease secretion

Decrease motility

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12
Q

what motility happens in the gut while food is being processed

A

Segmentation

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13
Q

what separates the right and left lobes of the liver

A

falciform ligament

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14
Q

which transporter transports glucose/ galactose into the cell

A

SGLT1 - coupled to sodium

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15
Q

what happens to the stomach contents that don’t leave the pyloric sphincter when it contracts

A

forced back into body for further mixing with pepsin and acid

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16
Q

what are enterogastrones released in response to

A

acid
hypertonic solutions
fatty acids
monoglycerides

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17
Q

which minor lobe of the liver is superior in your drawing

A

quadrate

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18
Q

where are the mucous glands in the oesophagus

A

submucosal

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19
Q

what happens to the bicarbonate made inside a parietal cell

A

transported out BL membrane in exchange with a Cl ion - which exits through Cl channel on apical membrane

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20
Q

Why does the stomach store food

A

constant energy supply between meals

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21
Q

What does the lamina propria contain

A

glands, blood vessels, lymph

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22
Q

what is the purpose of the backwards and forwards movements of segmentation

A

thorough mixing of contents with digestive enzymes

brings chyme into contact with absorbing substance

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23
Q

What enzymes hydrolyse peptide bonds

A

protease

peptidase

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24
Q

what is the max storage of glycogen

A

3 miles - after it is tired as fat

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25
Q

what does bile aid in

A

fat digestion and absorption in the small intestine

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26
Q

what muscles control chewing

A

skeletal muscles of mouth and jaw

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27
Q

in the pharyngeal phase of swallowing, what triggers the relax of contractions by the pharyngeal muscles

A

sense bolus

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28
Q

where are monosaccharides broken down

A

small intestine

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29
Q

where is NaCl absorbed in the intestine and what does this mean

A

ileum - chyme is dehydrated as water follows sodium out

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30
Q

what happens to fatty acids and monoglycerides that are not absorbed across the plasma membrane

A

released back into micelles (dynamic equilibrium - constant supply of free molecules)

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31
Q

what is silly about the production of gastrin

A

it is produced in the antrum but has to go through the full bloodstream to be utilised in the body

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32
Q

which anal sphincter is smooth muscle

A

internal anal - autonomic

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33
Q

How does parasympathetic innervation by the vagus nerve effect secretion and motility

A

Increase secretion

Increase motility

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34
Q

what type of muscle are the UOS and LOS

A

smooth

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35
Q

how does the stomachs receptive relaxation work

A

vagal reflex - thin elastic smooth muscle of gastric fundus/ body allowing it to balloon

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36
Q

which nerves innervate the salivary glands

A

glossopharyngeal

facial

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37
Q

why is secretin released in response to acid in the duodenum

A

increases bicarbonate

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38
Q

what is different about the muscularis externa in the stomach

A

has an oblique layer of muscle (inner)

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39
Q

which vitamins are fat soluble

A

A D E K

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40
Q

what do the serous and mucous glands in saliva excrete

A

serous - protein (amylase)
mucous - mucous
mixed - both

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41
Q

What is the animal storage of glucose

A

glycogen

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42
Q

what do pancreatic duct cells secrete to keep enzymes at optimum pH

A

HCO3

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43
Q

what is muslin in saliva

A

protein

mucin + water = mucus - lubricant

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44
Q

what are chylomicrons

A

extracellular fat droplets containing phospholipids, cholesterol & fat soluble vitamins

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45
Q

how does unabsorbed iron travel in the blood

A

bound to transferrin

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46
Q

are micelles absorbed across the small intestine epithelium

A

no

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47
Q

what produces oscillations in the membrane potential of pacemaker cells that causes depolarisation

A

BER - basic electrical rhythm

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48
Q

what kind of saliva does the parasympathetic nervous system produce

A

lots of watery saliva

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49
Q

Which electrolyte does a rise in gastrin produce that increases the action of the proton pump to make more acid

A

Calcium

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50
Q

what 4 things are contained in a micelle

A

monoglyceride
fatty acid
bile salt/ phospholipid (emulsifying agents)

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51
Q

how is bilirubin added to bile

A

extracted from blood by hepatocytes and secreted into bile

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52
Q

What are disaccharides

A

2 monosaccharides linked by glycosidic bonds

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53
Q

what section of the liver is not covered by visceral peritoneum

A

bare area

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54
Q

what is a crypt of lieberkuhn

A

villi that extend into the lamina propia

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55
Q

how does ferritin leave the body

A

black faeces

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56
Q

What are the contents of saliva

A

water, mucin, alpha-amylase, electrolytes, lysozyme

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57
Q

What are the endocrine glands of the pancreas called

A

islets of langerhans

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58
Q

what does the ileocal sphincter do in response to distension of the colon by a bolus

A

contracts to prevent reflux

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59
Q

How are the glucose linked in cellulose

A

unbranched linear chains linked by beta- 1,4 glycosidic bonds

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60
Q

where is gastrin produced

A

the antrum of the stomach

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61
Q

what does alpha amylase do in saliva

A

catalyses breakdown of polysaccharides (starch, amylase) into disaccharides

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62
Q

what neutralises acid in the duodenum

A

HCO3

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63
Q

What is the law of the intestine

A

If intestinal smooth muscle is distended - muscle on the oral side contracts and muscle on the anal side relaxes
mediated by neurones in the myenteric plexus

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64
Q

what does the UOS do once food has entered the oesophagus

A

contracts to prevent reflux

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65
Q

What are the 3 pairs of salivary glands

A

Parotid
Sublingual
Submandibular

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66
Q

Which organs does the superior mesenteric artery supply

A

small intestine, caecum, ascending colon, transverse colon

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67
Q

How does histamine increase the action of the protein pump (make more HCl)

A

stomach has unique receptor with Gs coupled to AC which converts ATP –> cAMP which acts on the pump

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68
Q

Which membrane does CO2 in the blood diffuse over to get inside the parietal cell

A

Basolateral

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69
Q

what stimulates the cephalic phase of gastric acid production

A

sight, smell and taste of food

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70
Q

what circulation recycles secreted bile salts

A

enterohepatic (liver –> bile duct –> duodenum –> ileum (5% lost) –> portal vein –> liver (5% synthesis)

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71
Q

what are hepatic sinusoids

A

spaces beween hepatic chords with a blood channel for dead cells

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72
Q

when is GIP released (gastric inhibitory peptide)

A

fat in the duodenum

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73
Q

What muscle makes up the muscularis externa

A

2 concentric thick layers of smooth muscle

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74
Q

What tissue is the submucosa made up of

A

Thick, irregular connective tissue

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75
Q

what do the electrolytes in saliva do (ions in solution)

A

control tonicity and pH by selectively releasing NaCl/ bicarbonate

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76
Q

why does peristalsis need neural and hormonal control to induce an AP

A

depolarisation is sub threshold

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77
Q

What breaks down disaccharides

A

brush border enzymes in small enzymes

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78
Q

what are the constituents of triaglycerol

A

glycerol + 3 fatty acids

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79
Q

what neural response helps increase the frequency of APs in peristalsis (PNS/ENS)

A

reflex from distension of stomach wall

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80
Q

where does the bulk of digestion are place

A

duodenum

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81
Q

Which two plexus make up the enteric nervous system

A

Myenteric and submucosal

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82
Q

what do the enterogastrones act together to do

A

prevent further acid build up - maintain pH for pancreatic enzymes

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83
Q

which transporter transports fructose into the cell

A

GLUT 5

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84
Q

where is secretin released from in response to acid in the duodenum

A

S cells in duodenum

pancreas and liver

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85
Q

What is the epithelium in the stomach, small intestine and large intestine

A

simple columnar

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86
Q

What turns off the protein pump that helps to make gastric acid

A

prostaglandins - receptor coupled to inhibitor G protein (Gi) that turns off AC

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87
Q

why does emulsification speed up fat digestion

A

increases surface area of the lipids and accessibility to lipase action

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88
Q

what percentage of saliva is water

A

99%

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89
Q

what initiates segemntation

A

depolarisation from pacemaker cells in longitudinal muscle layer

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90
Q

list some enterotoxigenic bacteria

A

vibrio cholera

escherichia coli

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91
Q

Describe the process of emulsification

A

large lipid droplets broken into smaller droplets by mechanical disruption from contraction of the smooth muscle in the muscularis externa - grinds and mixes lumenal contents

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92
Q

how are water soluble vitamins absorbed

A

passive diffusion or carrier mediated transport

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93
Q

where is iron absorbed

A

duodenum

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94
Q

what channel does Cl pass out of the cell into the intestinal lumen

A

CFTR - cystic fibrosis transmembrane conductance regulator

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95
Q

what kind of saliva does the sympathetic nervous system produce

A

small volume
viscous saliva (dry mouth)
alpha 1 - high mucous beta 2 - high amylase

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96
Q

Where in the GI tract is water absorbed

A

large intestine

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97
Q

what is the surface area of the small intestine

A

200m2

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98
Q

What type of blood is carried via the portal system

A

venous - rich in nutrients

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99
Q

in the gastric phase, what causes the vagal and enteric reflexes to fire ACh

A

distension of the stomach by the arrival of food

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100
Q

how is the absorption of fatty acids and monoglycerides enhanced

A

micelles

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101
Q

list the 4 functions of the stomach

A

temporary store of ingested food
dissolve food particles (initiate digestion)
control delivery of contents to small intestine
Produce intrinsic factor (vit B12 absorption)

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102
Q

are large lipid droplets soluble in water

A

no

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103
Q

what attaches the small intestine epithelial cells

A

tight junction complex

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104
Q

Which nerve is used for sympathetic innervation of the gut

A

splanchnic

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105
Q

Where are bile salts produced

A

the liver

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106
Q

how is there voluntary delay of defaecation

A

descending pathways to external sphincter – grow with age

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107
Q

what happens in the chewing phase of swallowing

A

molecule size reduced (bolus)

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108
Q

what is in the centre of each hexagonal lobule in the liver

A

central veins –> hepatic veins –> IVC

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109
Q

Where does the inferior mesenteric artery leave the abdominal aorta

A

L3

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110
Q

which transporter transports glucose out of the cell

A

GLUT 5

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111
Q

Which is the inner layer of the muscular external and what does it do

A

Circular - constricts the lumen

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112
Q

which receptors counteract saliva

A

chemoreceptors - chemicals in food

pressure receptors - distension of mouth/ tongue

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113
Q

how is water important for normal digestion

A

maintains contents in liquid state
promotes mixing with enzymes
aids nutrient presentation to absorbing surface
dilutes and washes away potentially harmful substances

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114
Q

which 3 mechanisms control gastric acid secretion

A

neurocrine - Ach vagus
endocrine - gastrin
paracrine - histamine

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115
Q

what do intestine crypts secrete

A

Cl and H20

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116
Q

what is the only essential (non - compensated for) function of the stomach

A

produce intrinsic factor for Vit B12 absorption

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117
Q

What tissue is the lamina propria

A

smooth connective tissue sheath

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118
Q

what are the 3 hormones released from gland cells in the duodenal mucosa (enterogastrones)

A

secretin
GIP
CCK

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119
Q

which hormone initiates the MMC

A

motilin

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120
Q

what is the predominant pigment of bile pigments

A

bilirubin (yellow)

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121
Q

which anal sphincter is skeletal muscle

A

external anal - voluntary

122
Q

What does the gall bladder do to bile

A

stores and concentrates it

123
Q

what is the only nutrient that the gut regulates

A

iron

124
Q

what is a micelle

A

extracellular structure that encapsulates the fat to keep it away from water (fat taxi)

125
Q

what causes MMC to sop

A

arrival of food in the stomach (segmentation begins)

126
Q

how does the body respond to anaemia

A

decrease in ferritin level - more iron in good

127
Q

how is pepsin stored and what is this method of storage called

A

pepsinogen in chief cells

zymogen storing

128
Q

what response does the sight, smell and taste of food have

A

vagus nerve fires - ACh on parietal cells, stimulates G cells to produce gastrin which acts on parietal cells

129
Q

what condition is caused by a Vit b12 deficiency

A

pernicious anaemia

130
Q

describe the transportation of pancreatic enzymes to the duodenum

A

acinar cells –> lobules –> intercalated ducts –> interlobular ducts –> main pancreatic duct (meets with common bile duct) –> sphincter of oddi

131
Q

how is paracellular movement described

A

down leaky channels

132
Q

what do stomach chief cells secrete

A

pepsinogens

133
Q

What motility happens in the gut after finishing food

A

peristalsis

134
Q

what is the blood level of glycogen

A

5 mmol/L

135
Q

Where is the majority of bacteria in the GI tract

A

large intestine

136
Q

which receptors does acetylcholine act on

A

muscarinic cholinergic

137
Q

what do stomach mucous neck cells secrete

A

mucous

138
Q

How does ACh act to increase the action of the protein pump on parietal cells and produce more HCL

A

intracellular Ca

139
Q

what so the lysozyme is saliva do

A

bacteriocidal- cleave polysaccharide component of bacterial wall to sterilise

140
Q

How does the vagus nerve effect salivation

A

it doesn’t

141
Q

How long is the gut tube

A

8m

142
Q

what muscles layer produces haustra in the large intestine

A

circular layer

143
Q

Which 2 veins make the portal vein

A

splenic

superior mesenteric

144
Q

what happens to the soft palate and nasopharynx during the pharyngeal phase of swallowing

A

soft palate - reflected back and up

nasopharynx - closed to prevent regurgitation

145
Q

where is the swallowing centre located

A

medulla - next to respiratory

146
Q

what generates the peristaltic rhythm in the stomach

A

pacemaker cells in longitudinal muscle layer near oesophageal opening

147
Q

how does the gall bladder concentrate bile by 5-20 times

A

absorbs Na so H2O follows

148
Q

What 3 monosaccharides can be absorbed

A

Glucose
Galactose
Fructose

149
Q

which 2 ducts join to make the common hepatic duct

A

right and left hepatic

150
Q

what pH do intestinal enzyme work at

A

neutral

151
Q

When does the motilin hormone rise to start the MMC

A

when nutrient content in the blood lows

152
Q

which section of the gut has the fastest segmentation and what does this allow

A

intestine –> rectum

slow migration of chyme toward rectum

153
Q

What are the 3 sections of the small intestine called

A

duodenum
jejunum
ileum

154
Q

how does the dehydration of chyme occur to form solid faecal pellets

A

active transport of Na from lumen into blood causes the osmotic absorption of water

155
Q

what causes the release of secretin

A

acid in the duodenum

156
Q

What is lactose broken down to and by what

A

glucose + galactose

lactase

157
Q

what happens to fatty acids and monogycerides after they enter epithelial cells

A

enter smooth ER for enzymes to reform them to triacylglycerol
transported through cells in vesicles
processed in golgi apparatus
exocytosed into extracellular fluid at basolateral membrane (as chylomicrons)

158
Q

what is cellulose a constituent of

A

plant cell walls

159
Q

What is exopeptidase

A

Break peptide ponds at terminal end, one amino acid at a time
aminopeptidase - amyl end
carboxypeptidase - carboy end

160
Q

How are the glucose arranged in glycogen

A

alpha- 1,4 glycosidic bonds

161
Q

what do pancreatic islets produce (endocrine)

A

insulin (alpha cells)
glucagon (beta cells)
somatostatin

162
Q

What does the longitudinal layer (outer) do

A

shortens tube

163
Q

Where are the digestive enzymes stored

A

pancreas

164
Q

what does GIP do

A

inhibit gastrin secretion / stop stimulation of parietal cells/ decrease secretion of Hal

165
Q

What are the 4 functions of the alimentary system

A

Digestion
Secretion
Absorption
Motility

166
Q

where are 95% nutrients absorbed

A

jejunum

167
Q

What direction doe segmentation move

A

backwards and forwards

168
Q

what cells make up the exocrine portion of the pancreas

A

acinar cells

169
Q

what happens to bile when the sphincter of Oddi is contracted

A

bile forced back into gallbladder where it is concentrated

170
Q

what divides the liver into hexagonal lobules

A

septa (vessels, ducts and nerves follow)

171
Q

What prevents bacterial colonisation of the small intestine

A

MMC - migrating motility complex

172
Q

what is the alimentary role of the liver

A

production of bile

173
Q

what is the outer connective tissue layer of the gut tube called outwith the peritoneal cavity

A

Adventitia

174
Q

what cells produce intrinsic factor

A

parietal cells

175
Q

What muscle is the muscular mucosae and what is its function

A

smooth - insignificant

176
Q

what are the 2 phases of gastric acid production

A

cephalic phase

gastric phase

177
Q

why is pepsin stored as an inactive precursor

A

prevent cellular digestion

178
Q

How is the gut maintained at an acidic environment to create a constant supply of hydrogen ions

A

NHE3 pumps them out the cell - coupled to sodium

Na/ K ATPase

179
Q

what are bile acids synthesised from

A

cholesterol in liver

180
Q

how do you treat enterotoxigenic bacteria

A

sodium glucose solution

drives water absorption = rehydration

181
Q

How often are the MMC waves

A

as one ends in terminal ileum another begins

182
Q

Which 2 organs contain submucosal glands

A

oesophagus - saliva

duodenum - bicarbonate

183
Q

how does the H/K ATPase pump work

A

1 for 1 exchange - keeps cell neutral

184
Q

where is food reduced to liquid form

A

stomach

185
Q

how are dipeptides transported into the cell

A

PEPT1 - hydrogen coupled

186
Q

which membrane is the proton pump that makes gastric acid

A

apical - into lumen

187
Q

Where does the superior mesenteric artery leave the abdominal aorta

A

L1

188
Q

what are the main functions of hepatocytes

A

bile synthesis
nutrient storage
conversion of nutrients (when required)
detoxification

189
Q

which movement occurs in the oesophagus during the oesophageal phase of swallowing

A

peristalsis - open in front and contract behind

190
Q

what lies between cells in the hepatic cords that radiate form the central veins

A

bile canaliculi

191
Q

how does emulsification prevent reformation of droplets

A

polar tails repel each other

192
Q

where is enterokinase found and why

A

brush border of duodenal cells - so digestive enzymes can only be active there

193
Q

What neurones does the submucosa contain

A

submucosal plexus - parasympathetic

194
Q

what does vit B12 do to blood cells

A

allows them to mature to concave shape - optimum for carrying oxygen

195
Q

What are the 3 layers of the mucosa

A

Epithelium
Lamina propria
Muscularis mucosal

196
Q

describe the epithelium of the anus

A

Junctional - simple columnar –> stratified squamos

197
Q

what are some associated symptoms of constipation

A

headaches
nausea
loss of appetite
abdominal distension

198
Q

what causes diarrhoea

A 
pathogenic bacteria
protozoans
viruses/ toxins
food - e.g. lactose intolerance
stress
199
Q

What transporter is essential for the transportation of monosaccharides

A

Na/K ATPase

200
Q

what happens in the voluntary oral phase of swallowing

A

bolus pushed to back of mouth by tongue

201
Q

what is contained in each portal triad

A

hepatic portal vein
hepatic artsy
hepatic duct

202
Q

what causes haustra appear in the large intestine

A

contractions of teniae coli

203
Q

why determines the frequency of segmentation

A

BER

204
Q

what happens to bile once it is modified by bacterial enzymes in the large intestine

A

turns brown - faeces

205
Q

how does water move through parietal cells

A

paracellular transport

206
Q

why is the epithelium of the oesophagus

A

stratified non keratinised squamous

207
Q

What acts as an emulsifying agent during emulsification

A

bile salts and phospholipids - secreted from bile in liver

208
Q

what does the ileocal sphincter do in response to increased segmentation in the ileum

A

opens to allow chyme to enter the large intestine

209
Q

how much water does the small intestine secrete per day (crypts of lieberkun)

A

1.5 L water

210
Q

Which organs does the inferior mesenteric artery supply

A

descending colon, sigmoid colon, rectum

211
Q

what does bacterial fermentation of undigested carbohydrates make

A

short chain fatty acids - energy source
vitamin K - blood clotting
Gas - flatulence

212
Q

how is the secretion of water in the small intestine from cryptos lieberkuhn passive

A

osmotic gradient of the active secretion of Cl into intestinal lumen

213
Q

how is the gastric phase of gastric acid production inhibited

A

decrease in pH from the increase in HCl turns off the production of gastrin (which turns of the production of more gastrin)

214
Q

what environment does pancreatic lease act in

A

aqueous only- at surface of droplet

215
Q

which phase prepares the stomach for any food by inducing the parietal cells to make more HCl

A

Cephalic phase

216
Q

which nerves innervate the liver

A

hepatic plexus on inferior surface

217
Q

What converts trypsinogen to its active form trypsin

A

enterokinase - CCK

218
Q

what are the functional cells of the gut called

A

interocytes

219
Q

roughly how much bacteria is in the large intestine

A

1 x 10^14

220
Q

what happens to the LOS when the bolus reaches the stomach

A

relaxes

221
Q

which transportation method do most crypts use to absorb nutrients

A

Na coupled secondary active transport

222
Q

Why are the peristaltic waves in the stomach slow

A

basic electrical rhythm - spontaneous depolarisation and repolarisation through gap junctions

223
Q

in what circumstances is pepsinogen made into pepsin by acid hydrolyses

A

pH < 3

224
Q

what are the 2 monomers of starch and how are they different

A

alpha-amylase - straight chains

amylopectin - highly branched structure

225
Q

Where is the apical membrane on the small intestine epithelial cells

A

outside

basolateral inside

226
Q

where are the gastric pits of the stomach

A

surface epithelial mucus cells

227
Q

describe the epithelium of the large intestine and what does it not have

A

simple columnar epithelium
no villi or folds
flat and smooth

228
Q

where are the portal triads

A

each corner of hexagonal lobule

229
Q

What is located in between the longitudinal and circular layers of the muscularis externa

A

myenteric plexus

230
Q

What is triacylglycerol broken down into and by what

A

monoglyceride and 2 fatty acids

pancreatic lipase

231
Q

What is endopeptidase

A

Break bonds of middle amino acids, leaving 2 chains

232
Q

where is the peristaltic wave in the stomach most powerful

A

antrum - thick muscle

233
Q

how is cellulose digested

A

dietary fibre - no digestion enzymes

234
Q

Which two nerves innervate salivation

A

Facial (VII)

Glossopharyngeal (IX)

235
Q

Which organs does the celiac trunk supply

A

stomach, small intestine, pancreas, liver

236
Q

what do stomach parietal cells secrete

A

HCl, intrinsic factor

237
Q

where is bicarbonate secreted in the duodenum

A

Brunner’s glands in submucosa

238
Q

What is the purpose of producing saliva

A

acts as a lubricant

239
Q

how are fat soluble vitamins absorbed

A

same as fat

240
Q

what type of muscle is present in the top 1/3 of the oesophagus

A

skeletal (voluntary - swallowing reflex)

241
Q

Where does the coeliac trunk leave the abdominal aorta

A

T12

242
Q

how do the enterogastrones prevent acid build up in the duodenum

A

inhibit gastric acid secretion

reduce gastric emptying (reduce motility/ contract pyloric sphincter)

243
Q

how do enterotoxigenic bacteria cause profuse watery diarrhoea

A

produce protein enterotoxins which elevate intracellular secondary messengers to turn on Cl production from crypt cells which increases water secretion
(swamps absorptive capacity of villas cells)

244
Q

what nutrients are stored in hepatocytes

A

glycogen
fat
vit B12, A, D, E, K
Cu and Fe

245
Q

what are the effects of an increase of CCK in the circulation

A

delayed gastric emptying
increased pancreatic enzymes
Sphincter of oddi relaxes
increased gallbladder contraction

246
Q

how does the self limiting negative feedback of secretin work

A

neutralisation of the duodenum inhibits production

247
Q

what cells do gastrin/ Ach stimulate to produce histamine in the cephalic phase

A

ECL cells

248
Q

what converts all inactive digestive enzymes to their active form

A

trypsin

249
Q

where are the goblet cells in the large intestine

A

crypts

250
Q

What is the epithelium in the mouth, oesophagus and anal canal

A

stratified squamous (non keritonised)

251
Q

where are gut stem cells found

A

crypts of lieberkuhn

252
Q

what are the components of bile

A 
bile acids
Lecithin
cholesterol
bile pigments (bilirubin) 
toxic metals
bicarbonate
253
Q

What do the lymphatics in the submucosa do

A

Take away fat as it doesn’t mix with water

254
Q

during constipation is there absorption of toxins form faecal material

A

NO

255
Q

what is a lacteal

A

lymphatic capillary that removes dietary fats

256
Q

what does somatostatin do

A

controls insulin and glucagon levels

257
Q

what is CCK released in response to

A

fatty and amino acids in the duodenum

258
Q

how long is a peptide

A

3-10 amino acids

259
Q

what does the sphincter of Oddi control

A

the delivery of bile and digestive enzymes to the duodenum

260
Q

What is sucrose broken down to and by what

A

glucose + fructose

sucrase

261
Q

What stimulates G cells to produce gastrin

A

peptides in the lumen

262
Q

where is the HCl made in the stomach and where do the components come from

A

stomach lumen
H - dissociation of HCO3 from CO2
Cl - exchange transport with bicarbonate, exits through Cl channel

263
Q

which nerves control the defaecation reflex

A

parasympathetic

264
Q

How do chylomicrons pass through endothelial cells

A

through lacteals and then through lymphatic system

265
Q

what is the primary role of the duodenum

A

gastric acid neutralisation

266
Q

What is maltose broken down to and by what

A

Glucose + glucose

maltase

267
Q

when is the production of pepsin inhibited

A

neutral pH - raise to stop

268
Q

describe starch

A

glucose storage in plants

Glucose monomers linked by alpha-1,4-glycosidic bonds hydrolysed by amylases

269
Q

what is the migrating motility complex

A

Pattern of peristaltic activity starting in antrum and travelling down small intestine

270
Q

what is the pH of the blood

A

7.4

271
Q

what neural response controls the pancreatic function

A

vagal/ local reflex triggered by arrival of nutrients in duodenum

272
Q

List 3 polysaccharides

A

Starch, Glycogen, Cellulose

273
Q

What would happen to the gut if the stomach didn’t store food

A

water influx

274
Q

what type of muscle is present in the middle 1/3 of the oesophagus

A

skeletal and smooth

275
Q

what does the enterogastric reflex do in response to acid in the duodenum

A

inhibit gastrin secretion / stop stimulation of parietal cells/ decrease secretion of Hal

276
Q

does the autonomic nervous system have any effect on the gut

A

no - constant movement when processing food

277
Q

What are the 4 layers of the gut tube

A

Mucosa
Submucosa
Muscular externa
Serosa (below diaphragm) / Adventitia

278
Q

What links the amino acids in proteins

A

peptide bonds

279
Q

if the main pancreatic duct is obstructed , how will digestive enzymes reach the duodenum?

A

accessory pancreatic duct

280
Q

define diarrhoea

A

too frequent passing of faeces which are too liquid

281
Q

what is the purpose of chewing

A

defence against respiratory failure

prolong taste experience

282
Q

why do parietal cells only produce Hal when necessary

A

Very energy dependent - K/ H pump

283
Q

where is glycogen stored

A

liver

284
Q

how does the body respond to hyperaemia

A

increase in ferritin level - more iron stored

285
Q

what happens to the cephalic phase of gastric acid production when you stop eating

A

decrease vagal activity - inhibit acid production

286
Q

how is gastric mucus cytoprotective

A

protects mucosal surface from mechanical injury and neutralised pH (HCO3)

287
Q

how is iron stored in a cell

A

ferritin - ions can’t leave

288
Q

where is mucous produced in the stomach

A

surface epithelial cells and mucus neck cells

289
Q

what 3 cells are contained in a gastric pit

A

neck, parietal, chief

290
Q

describe the epithelium of the rectum

A

simple columnar

291
Q

how are phospholipids amphiphatic

A

polar tail (water soluble) and non-polar head (fat soluble)

292
Q

what is the pH of the stomach of the stomach lumen

A

<2

293
Q

how long is the oesophagus

A

about 25cm

294
Q

how is Vit B12 absorbed

A

binds to intrinsic factor from the stomach

specific transport mediated system in distal ileum and moved to liver for storage

295
Q

what hormone helps increase the frequency of APs in peristalsis

A

gastrin

296
Q

describe the reflex of chewing

A 
contraction of jaw muscles
increase pressure food against gums, hard palate and tongue
mechanoreceptors fore
inhibit jaw receptors
decrease pressure
297
Q

what type of muscle is present in the lower 1/3 of the oesophagus

A

smooth

298
Q

what is a feature of the submucosa of the stomach

A

folded rugae

299
Q

Once it is produced, what does carbonic acid immediately dissociate to once its inside the cell?

A

H and HCO3

300
Q

what happens during swallowing when the bolus reaches the oesophagus

A

UOS relaxes and epiglottis covers opening to larynx (stops food entering teaches/ inhibits breathing)

301
Q

which muscle layer in the muscularis externa is incomplete in the large intestine

A

Longitudinal

302
Q

what molecules can’t pass the membrane

A

polar - water soluble

charged

alimentary system (2 decks)

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