Digestive System Physiology + GI investigations Flashcards
(186 cards)
1
Q
What are the four main functions of the GI tract?
A
digestion
secretion
absorption
motility
2
Q
what are the four main histological layers of the gut tube? what are their sublayers?
A
mucosa - epithelium, lamina propria, muscularis mucosae
submucosa
muscularis externa - concentric + longitudinal
serosa/adventitia
3
Q
what is the Enteric Nervous System and where in the gut lining is it found?
A
nervous system without any brain input, controls GI tract.
made up of submucosal plexus (under submucosa) + myenteric plexus (between muscle layers of muscularis externa)
4
Q
where in the GI tract is stratified squamous epithelium found?
A
mouth
oesophagus
anal canal
5
Q
where in the GI tract is simple columnar epithelium found?
A
stomach
small intestine
large intestine
6
Q
what is the arterial blood supply to the GI tract in the abdomen?
A
celiac trunk
superior mesenteric artery
inferior mesenteric artery
7
Q
what are the main branches of the celiac trunk?
A
left gastric artery
splenic artery
hepatic artery
8
Q
what is the venous drainage from the GI tract, and where does it lead to?
A
gastric veins
splenic veins
superior and inferior mesenteric veins
drain into the hepatic portal vein and into the liver
9
Q
what is the parasympathetic action on the GI tract, and from which nerves?
A
increased salivation - CNVII (facial) and CNIX (glossopharyngeal)
increased motility - CNX (vagus)
increased secretion - CNX (vagus)
10
Q
what is the sympathetic action on the GI tract, and from which nerves?
A
decreased motility - splanchnic nerves
decreased secretion - splanchnic nerves
some salivation
11
Q
what are the main functions of the submucosa in the gut tube?
A
support of the mucosa
contain glands in oesophagus and duodenum
12
Q
what is the reason behind the change in term between serosa and adventitia?
A
serosa - lined by peritoneum
adventitia - not lined by peritoneum (not in abdomen)
13
Q
what is the function of the muscularis mucosae?
A
slight contraction to help glands secrete their contents
14
Q
what is the function of the muscularis externa layers?
A
concentric layer - segmentation
longitudinal layer - peristalsis
15
Q
what is dumping syndrome and how is it avoided in nature?
A
- food entering the small intestine too fast and water entering the gut lumen through osmosis creating a huge load on the gut
- avoided through the gradual breakdown of polimerised nutrients rather than intake of simple monomers of carbs/fats/proteins
16
Q
what are three kinds of carbohydrate monosaccharides?
A
glucose
galactose
fructose
17
Q
what are the three kinds of carbohydrate disaccharides, and what are they made up of?
A
lactose = glucose + galactose maltose = glucose + glucose sucrose = glucose + fructose
18
Q
what are the three kinds of carbohydrate polysaccharides? which one(s) can the GI tract not digest and why?
A
starch
glycogen
cellulose (not digested by GI tract because made up of beta1-4 glycosidic bonds)
19
Q
how is cellulose broken down by the GI tract?
A
digested by the bacteria colonising the colon
20
Q
what are the two main types of starch and their differences?
A
alpha-amylose - unbranched alpha1-4 glycosidic bonds
amylopectin - branched alpha1-6 glycosidic bonds
21
Q
which transport proteins carry which monosaccharides into enterocytes, and what other molecules do they co-transport?
A
glucose and galactose = SGLT1 transporter. co-transport of Na
fructose = GLUT5 transporter. no co-transport
22
Q
what transport protein transports monosaccharides out of the enterocytes and into the bloodstream?
A
GLUT2 transporter
23
Q
is there a movement of water from the gut lumen into the gut wall in monosaccharide absorption? be specific
A
glucose - yes, water enters the gut wall
galactose - yes, water enters the gut wall
fructose - no water movement
24
Q
why is there no movement of water in fructose absorption?
A
because there is no co-transport of charged molecules into the enterocytes with fructose absorption
25
how does Na leave the enterocyte after being pumped into the cell through SGLT1 and GLUT5?
through the Na-K-ATPase pump (sodium potassium pump)
26
where in the epithelial cells of the GI tract are the sodium potassium pumps located?
all along the basolateral membrane
27
what are the membranes in enterocytes relevant for absorption barriers?
apical membrane
| basolateral membrane
28
which enzymes breaks down which carbohydrates and where?
alpha-amylase - breakdown of polysaccharides in mouth and small intestine
sucrase/lactase/maltase - breakdown of disaccharides (sucrose/lactose/maltose) in small intestine
29
which types of alpha-amylase are there?
salivary amylase
| pancreatic amylase
30
how are monosaccharides distributed around the body?
through the bloodstream
31
what enzymes break down proteins? what are the two classifications and their properties?
enzymes: peptidases or proteases
endopeptidases/endoproteases - cleave protein/peptide anywhere along peptide chain and split it in two or more peptides
exopeptidases/exoproteases - cleave one amino acid at a time from each end of the peptide chain
32
with what chemical process do proteases/peptisases break down peptide chains?
hydrolysis of peptide bonds
33
what is PepT1 and why is it important?
proton (H) coupled transporter which transports peptides into the epithelial cells
it's important because it proves proteins aren't only absorbed as amino acids, but as di/tripeptides
34
what percentage of proteins are absorbed as polypeptides through the PepT1 transporter?
~70%
35
what are the membrane transporters which allow proteins into epithelial cells, and what are they coupled to?
SAAT1 (coupled with Na transport) - carry amino acids
| PepT1 (coupled with H transport) - carry di/tripeptides
36
how is H recycled after the use in the proton pump PepT1?
```
through NHE3 (sodium hydrogen exchanger 3)
allows Na into the cell and pumps H back out into lumen
```
37
where along the GI tract are proteins digested?
stomach and small intestine
38
does amino acid transport across the gut epithelium trigger water absorption?
yes
39
what lumen environment does PepT1 require to function and what explains it?
acidic environment, because it needs H ions to be able to transport peptides
40
what are the membrane transporters involved in protein absorption from the gut?
SAAT1
PepT1
NHE3 (indirectly involved with PepT1)
41
what are the membrane transporters involved in carbohydrate absorption from the gut?
GLUT2
GLUT5
SGLT1
42
what is the main structure of lipids which enter our digestive tract?
triacylglycerides
43
how are fats globules reduced in size for absorption? what structure is responsible?
separated in smaller fat globules by oesophageal smooth muscle
44
how are small fat globules prepared for digestion, after separation by the oesophageal motility?
separated fat globules surrounded by emulsifiers (bile salts)
45
what enzyme breaks down fats once emulsified?
pancreatic lipase
46
which organs are responsible for the digestion of fats from the gut, and by what action?
pancreas - secretes pancreatic lipase
| liver - secretes bile
47
what is the role of bile salts in the digestion of fats?
it emulsifies fat globules to keep them separate
48
how is absorption of fats maximised once fat globules are emulsified?
- lipase breaks down fat globules into monoglycerides and free fatty acids
- micelles formed which carry fats across the mucous layer to the epithelial brush border
49
what is the function or micelles?
they carry monoglycerides and free fatty acids through the mucous layer of the small intestine for absorption into the gut cells
50
what happens to the fatty acids once absorbed by gut cells? (4 stages)
- reassembled into TAG in smooth endoplastic reticulum
- processed in the Golgi body
- exocitosed from cell to extracellular space
- TAG picked up by lacteals in form of chylomicrons
51
how are fats distributed around the body from the gut, and in what form?
fats take form of chylomicrons which enter lymphatic system through lacteals
52
what makes micelles break down at the gut brush border?
the acidic microenvironment on the surface of the brush border
53
what are the possible ways vitamins can be absorbed from the gut? what is the exception?
```
fat soluble (A,D,E,K) - same as lipids
water soluble (B, C) - diffusion or carrier mediated
exception: Vitamin B12 - needs intrinsic factor
```
54
what are the molecules responsible for fat emulsification?
bile salts
| phospholipids
55
where are lipids digested in the gut?
small intestine
56
where is vitamin B12 absorbed?
distal ileum
57
what are molecules responsible for iron absorption and storage, and where are they found?
ferritin - in gut cells
| transferrin - in blood
58
why is ferritin important? explain how it works
it regulates the amount of iron absorbed by the body:
low iron in body - less ferritin so more free iron
high iron in body - more ferritin so more iron trapped in gut cell
59
what does ferritin do?
it captures absorbed iron from the gut when there is no need for it
60
how much ingested iron is actually absorbed by the body?
~10%
61
what are micelles made up of?
bile salts
phospholipids
fatty acids
monoglycerides
62
why is emulsification of fats necessary?
because it would take lipase too long to break down fat globule otherwise
63
what are the main components of saliva and their respective functions? (5)
water - soften food
mucins - create mucous with addition of water
alpha-amylase - to break down complex carbs
electrolytes - maintain pH
lysozyme - break down bacteria
64
name the salivary glands
parotid gland
submandibular gland
sublingual gland
65
what are the types of glands in the salivary glands, and what are their functions? (2)
mucous glands - produce mucins
| serous glands - produce amylase
66
how is salivation controlled?
parasympathetic system - facial and glossopharyngeal nerves (CN 7 and 9)
sympathetic system - adrenergic fibres (apha1 for mucins and alpha2 for serous)
reflex from chemoreceptors in wall of mouth and tongue - salivary secretion when food enters mouth
67
what type of muscle innervates the oesophagus?
upper third - skeletal
middle third - skeletal and smooth
lower third - smooth
68
what are the stages of swallowing and what happens during each? (4)
1. oral phase - food moved back to soft palate by tongue
2. pharyngeal phase - reflex contraction of pharyngeal muscles (controlled by medulla): nasopharynx and epiglottis close, upper oesophageal sphincter relaxes
2. oesophageal phase - bolus moves down through peristalsis
3. gastric phase - lower oesophageal sphincter relaxes, bolus enters stomach, stomach relaxes
69
what is the type of epithelium that lines the oesophagus and why?
non-keratinised stratified squamous epithelium
- non-keratinised because if keratinised it would be too rigid
- stratified squamous to provide enough thickness to withstand sharp bits of food
70
what is the histological structure of the gut tube wall?
- mucosa (epithelium, lamina propria, muscularis mucosae)
- submucosa
- muscularis mucosae (circular, longitudinal, oblique in stomach)
- adventitia (oesophagus)/serosa (in peritoneum)
71
what is the function of rugae in the stomach?
prevent the stomach lining to become too thin when it stretches in response to food entering the stomach
72
what are the main functions of the stomach? (5)
- storage of food
- control of gastric emptying
- break down food and begin digestion (pepsin)
- produce gastric acid to destroy pathogens - sterilisation
- produce intrinsic factor
73
what are the three layers of the stomach muscle and what are their individual actions on the stomach?
inner oblique layer - wringing motion
circular layer - contraction
longitudinal layer - shortening
74
how is chewing controlled? (2)
voluntary control - skeletal muscle
| reflexes
75
what are the three mechanisms that control gastric secretion?
neuroendocrine (ACh through vagus nerve)
endocrine (gastrin)
paracrine (histamine/prostaglandins)
76
which mechanism has an inhibitory effect on gastric secretion?
paracrine through prostaglandins
77
which mechanism causes a rise in intracellular calcium to trigger gastric secretion and how?
gastrin and ACh
| they cause an increase in calcium, which activates Protein Kinase C and activates the H-K ATPase (proton pump)
78
which intracellular mechanism steps are essential for maintaining a low pH in the stomach lumen? (4)
- CO2 and H2O combining to form carbonic acid
- carbonic acid dissociation into bicarbonate + H
- H pumped out to lumen through proton pump
- chloride pumped out to lumen as a result of H-K pump action
79
which cells produce gastric acid, and what else do they produce?
parietal cells. also produce intrinsic factor
80
what is the purpose of intrinsic factor?
it is essential for the absorption of vitamin B12 in the distal ileum
81
what is gastrin, where is it secreted and how does it work?
- gastrin is a hormone which promotes gastric acid secretion
- gastrin is secreted by G-cells in the stomach antrum
- gastrin is secreted into the circulation and goes to act on parietal cells which will produce HCl as a result
82
what is produced in parallel with gastric acid, from which cells?
pepsinogen. produced from chief cells
83
what is pepsinogen and how does it work?
it's a zymogen secreted and stored by chief cells
| when hydrolised by gastric acid at low pH it turns into active pepsin, which digests peptides
84
how does the stomach protect itself from gastric acid and pepsin, and how is this different from the small intestine?
through secreting a layer of mucous on its epithelial surface
the mucous in the stomach has neutral pH, whereas the small intestine has an acidic mucous with low pH
85
how are parietal cells stimulated?
through vagal input directly to parietal cells
through vagal input into G-cells --> gastrin acting on parietal cells
through ACh and gastrin input into ECL cells --> histamine production --> act on parietal cells
86
what is histamine secreted by in the stomach, what triggers its secretion and what does it do?
secreted by enterochromaffin-like (ECL) cells
secretion triggered by ACh and gastric action
causes activation of parietal cells
87
what is the function of parietal cells, chief cells and mucous cells in the stomach?
parietal cells - secrete HCl and intrinsic factor
chief cells - secrete pepsinogen
mucous cells - secrete neutral pH mucous for protection
88
what inhibits gastric acid secretion?
inhibition of vagal input (stop eating)
lower pH, higher HCl levels in stomach
release of enterogastrones from the small intestine (CCK, secretin)
89
what are enterogastrones?
they are hormones which inhibit gastric acid secretion and reduce gastric emptying
90
what triggers release of enterogastrones?
the presence of acid/fat/carbs in the duodenum
91
what is the purpose of enterogastrones?
reducing the amount of acid in the duodenum
92
what are the two phases during which parietal cells are activated for gastric acid secretion?
cephalic phase
| gastric phase
93
where are G-cells found?
in antrum of stomach
94
where are parietal cells and chief cells found?
in gastric glands of stomach epithelium
95
how do histamines trigger production of gastric acid from parietal cells?
through G-protein coupled receptor (adenylyl cyclase) which turns ATP into cAMP --> activates Protein Kinase C -->activates proton pump
96
how do ACh and gastrin trigger production of gastric acid from parietal cells?
through an increase in intracellular calcium, which activates Protein Kinase C and stimulates proton pump
97
what triggers parietal cells during the gastric phase of gastric acid secretion?
distension of stomach (food arriving) - causes vagal reflex --> stimulates parietal cells
presence of peptides in stomach - stimulates G-cells --> act on parietal cells
98
explain why pepsin creates a positive feedback loop
because once activated by low pH it can trigger more pepsinogen secretion from chief cells, which due to the low pH are in turn activated to pepsin
99
what is a zymogen?
it's an inactive form of an enzyme
100
why is pepsin secreted by chief cells as a zymogen?
because the activated form of pepsinogen would digest the stomach itself, as it's made of proteins
101
what is a disease related to a lack of intrinsic factor, and why?
pernicious anaemia
because it impairs RBC maturation, but it takes long to show symptoms as even though a lack of intrinsic factor stops vitamin B12 absorption, the liver still has a 3 year supply of vitamin B12 before it runs out
102
what is the electrical underlying current which controls peristaltic movement in the stomach?
base eletrical rhythm (BER)
103
why does the BER not always cause contractions?
because it is normally sub-threshold, and needs neuronal or hormonal input to reach threshold and create an action potential
104
what does the strength of gastric peristaltic contractions depend on?
the number of action potentials fired through neuronal and hormonal input
105
what neuronal and hormonal input promotes peristaltic contractions of the stomach?
hormonal - gastrin
| neuronal - vagal input/reflexes from stomach stretching
106
where in the stomach is the muscle layer thickest and why?
antrum. because bolus gets churned and mixed here before gastric emptying
107
what happens in the duodenum as soon as bolus has passed the pyloric sphincter into the duodenum itself? (3)
release of secretin from S-cells
release of bicarbonate from Brunner's glands
release of cholecystokinin (CCK)
108
what is the purpose of secretin being secreted on arrival of bolus into the duodenum? (3)
it promotes the secretion of bicarbonate from pancreatic duct cells
it decreases gastrin secretion
it reduces peristaltic movement in the stomach
109
what is the point of pancreatic duct cells secreting bicarbonate?
it helps to neutralise the gastric acid which has entered the duodenum from the stomach
110
what is the purpose of CCK being secreted on arrival of bolus into the duodenum? (3)
it promotes zymogen secretion from the pancreatic acinar cells
it promotes relaxation of Sphincter of Oddi
it promotes contraction of gallbladder --> bile release
111
what happens to pancreatic enzymes (zymogens) when they reach the duodenum through the pancreatic duct?
they are activated by trypsin into active enzymes
112
what allows active trypsin to activate pancreatic enzymes?
the membrane-bound enterokinase, which turns trypsinogen into trypsin
113
what reduces the peristaltic movement of the stomach?
secretin secretion, in response to acid entering the duodenum
114
what are Brunner's glands, where are they located and what is their purpose?
they are glands in the duodenal submucosa which produce bicarbonate
115
what are the names of the channels in the liver which hold 1. bile, 2. blood?
1. bile canaliculi
| 2. hepatic sinusoids
116
what is the characteristic of the blood in the liver sinusoids?
carry both arterial and venous blood
117
what are the main alimentary functions of the liver? (2)
- production of bile
| - storage of nutrients from hepatic circulation
118
what are the contents of bile? (6)
- cholesterol
- lecithin
- bile acids
- toxic metals
- bile pigments (bilirubin)
- bicarbonate
119
which of the bile contents is produced by the hepatic duct cells?
bicarbonate
120
what is bilirubin?
breakdown product of heme group from recycled RBC's.
121
what is the porta hepatis?
it's the area of liver which allows access to the hepatic ducts, the hepatic artery and the hepatic portal vein
122
list the 4 main functions of hepatocytes in the liver
- store nutrients
- nutrient interconversion (glucose to glycogen)
- production of bile
- detoxification
123
what are the individual actions of CCK in response to fats/proteins in the duodenum? (3)
- relaxation of Sphincter of Oddi
- contraction of gallbladder
- release of zymogens from pancreatic acinar cells
124
what is the generic function of secretin and CCK?
secretin - neutralisation of acid through promotion of bicarbonate
CCK - digestion through bile and pancreatic acid secretion
125
how are bile acids rendered more soluble?
through addition of glycine or taurine
126
what are the three layers of the gallbladder wall?
mucosa
muscularis
serosa
127
what are the fat emulsifying elements of bile? (3)
cholesterol
lecithin
bile acids
128
what is the function of villi and crypts in the small intestine?
villi - absorption
| crypts - secretion
129
what do crypts of Lieberkuhn secrete in the small intestine?
chloride and water
130
how is cystic fibrosis related to the secretion of chloride in the small intestine?
water follows osmotic gradient of chloride into the gut lumen. if the chloride channel isn't working (CFRT) no chloride exits cell, so no water is secreted
131
why is sodium absorption important in the small intestine?
because sodium transport is coupled to transport of other nutritional molecules (glucose, peptides etc)
132
what is the purpose of microvilli?
increase surface area for absorption
133
what is the difference between peristalsis and segmentation, and what are their functions?
segmentation - moves chyme back and forth - promotes mixing
peristalsis - sweeps chyme down small bowel towards large bowel - ensures nothing is left in small intestine and reduces risk of bacterial colonisation of small bowel
134
when does segmentation start?
when chyme enters the small intestine
135
when does peristalsis start?
when absorption is complete
136
what is the gastro-ileal reflex?
closure of the ileocaecal sphincter in response to distension of colon, when chyme has entered large bowel
137
in what parts of small intestine epithelium is water secreted and absorbed?
secreted - crypts of Lieberkuhn
| absorbed - villi
138
how is concentration of bile controlled?
absorption of water by gallbladder epithelium
lots of fatty food - lots of dilute bile
small amount of food - a little, concentrated bile
139
what electrical mechanism controls small intestine peristalsis and segmentation?
peristalsis - BER and stimulation through action potentials
| segmentation - Migrating Motility Complex (MMC)
140
how does the small gut ensure that chyme only travels towards large bowel and not in the other direction?
because the BER contractions are stronger at the top of the small intestine, and tail down towards the rectum
141
what is the pH of the mucous layer lining the small intestine?
acidic microclimate
142
what is the pH of the mucous layer lining the stomach?
neutral pH - mucous containing bicarbonate
143
what hormone initiates the action of the Migration Motility Complex (MMC) in the small intestine?
motilin
144
where is the majority of nutrients absorbed in the small intestine?
in the jejunum
145
during which phase of eating does segmentation occur?
when there is food in the stomach
146
what's the histological appearance of the colonic epithelium?
flat, deep crypts containing goblet cells
147
what characteristics of the muscularis externa differentiate the colon from the small intestine?
incomplete longitudinal layer - teniae coli
| circular layer bunched up - haustra
148
what are the main functions of the colon? (2)
- absorb water
| - allow undigestible molecules to be broken down by gut flora
149
how is water absorbed from the colon?
through the sodium-potassium ATPase which pulls in Na, driving passive water movement into epithelial cells
150
what are the three breakdown products of cellulose by gut flora in the colon?
- gas
- vitamin K
- short chain fatty acids
151
what drives the movement of chyme through the colon?
MMC - Mass Movement Contraction
152
what causes the urge to defecate?
the relaxation of the rectum wall
153
what are the two checkpoints faeces have to go through prior to defecation, and what controls them?
internal anal sphincter - involuntary (pelvic splanchnic nerves)
external anal sphincter - voluntary (descending pathways)
154
what are four common symptoms of constipation?
nausea
headaches
abdominal distension
loss of appetite
155
what is the main reason for constipation?
distension of the rectum
156
what causes diarrhoea?
increased secretion of chloride from crypts, causes passive movement of water into the colon lumen
157
what is the main treatment for diarrhoea?
sodium and glucose infusion to promote water absorption
158
what is the purpose of the bacterial colonisation in the colon?
to break down undigestable material (cellulose)
159
how much of our body weight is derived from colonic bacteria?
about 1kg
160
how much does a normal liver weigh?
~1.4kg
161
how much does a normal spleen weigh?
~150g
162
what are the sections of the large bowel? (5)
```
ascending colon
transverse colon
descending colon
sigmoid colon
rectum
```
163
what are the sections of the small bowel? (3)
duodenum
jejunum
ileum
164
what kind of epithelium is found in the anal canal?
junctional epithelium - simple columnar to stratified squamous
165
where is the thickest layer of muscularis externa found?
rectum and anal canal
166
what neuronal mechanism controls the defecation reflex?
parasympathetic - pelvic splanchnic nerves
167
what is the role of enterotoxins in diarrhoea, and which organisms are responsible for them?
organisms: vibrio cholerae; Escherichia coli
| turn up the chloride secretion from crypts in colon through upregulation of cAMP, cGMP and calcium
168
what is a significant complication of diarrhoea, and in which age groups?
dehydration in the elderly and very young
169
where in the gut lining are immune cells found?
in the lamina propria, under the epithelium
170
what are the lymphoid aggregations in the gut lining called?
Peyer's Patches
171
what is the importance of macrophages in the digestive tract?
effective at picking up and phagocytosing pathogenic organisms
172
what is the position of dendritic cells, and what is their importance in the digestive tract?
sit in the lamina propria and in Peyer's patches,with parts sticking through epithelium and into the lumen
they sample organisms in the lumen and present them to T cells for an appropriate response
173
what are mature dendritic cells also known as?
antigen presenting cell (APC)
174
what are M cells and what is their role?
specialised cells in the gut epithelium
| responsible for sampling the gut lumen contents and present particles for analysis in Peyer's Patches
175
what are two examples of an imbalance of the immune system in the gut?
inflammatory bowel disease
| coeliac disease
176
what is the general pathology behind IBD?
leaky epithelial layer allowing pathogenic organisms to get through to lamina propria, causing an inflammatory response
177
which immune cells are responsible for maintaining homeostasis in gut?
T reg cells
178
what is the function of cytokines in the gut immune response?
they regulate the differentiation of T cells to act as pro-inflammatory or anti-inflammatory
179
what is the general pathology behind coeliac disease?
exaggerated immune response to an indigestible particle derived from gluten
180
what is the role ot Th1 cells in the gut?
trigger an appropriate response to pathogens
181
what is the role of TReg cells in the gut?
maintain homeostasis and promote tolerance to self/benign antigens
182
list some of the features to be picked up at the bedside for GI investigations
- BMI changes
- pulse
- BP
- ECG
- temperature
- urinalysis
- capillary glucose
183
list some tests done with stool samples for GI investigations, and what they look for
- FOB (fecal occult blood)/FIT (fecal immunochemical test) - look for microscopic traces of blood in faeces
- faecal calprotectin - detects/rules out inflammation
- faecal elastase - measures pancreatic function
- faecal culture - looks for bacteria
184
name some examples of blood tests specifically carried out for GI investigations
```
FBC, U&E, creatinine, CRP, ESR
LFT's, TFT's
haematinics: vit B12, folate, ferritin
calcium/magnesium/phosphate
serology (autoantibodies)
alpha-1 antitrypsin
alpha fetoprotein
glucose/HbA1c
lipid profile
```
185
list some of the endoscopic imaging tests carried out for GI investigations
- endoscopy
- colonoscopy/sigmoidoscopy
- ERCP
- EUS
- enteroscopy (+/- capsule)
186
what are haematinics, and what are the most important ones?
haematinics are compounds found in diet that are important for RBC formation
the main ones are vitamin B12, folate and iron
