Gastro & Hepatic Systems Flashcards
1
Q
What is function of mouth?
A
- To prepare food for swallowing
- Mixes food with amylase in the saliva to break down starch into sugars.
2
Q
What are salivary glands called?
A
Submandibular
Parotid
Sublingual
3
Q
How much saliva is produced daily in adults?
A
500ml
4
Q
What is oesophagus wall made of?
A
Mucosa,
submucosa
muscularis mucosa
5
Q
What is GOJ?
A
Gastro-oesphageal junction
physiological barrier which reduces reflux of gastric contents.
6
Q
What is at base of oesophagus?
A
Intrinsic lower oesophageal sphincter
7
Q
What causes food to move down oesophagus?
A
Peristalsis
8
Q
What is peristalsis regulated by?
A
Smooth muscles controlled by:
Enteric Nervous System
Peptide Hormones
Inherent timing of monocytes
9
Q
What does the stomach secrete to aid digestion?
A
Hydrochloric acid
Lipase
Pepsin
10
Q
What regulates stomach fluid secretions?
A
Central and enteric nervous system
Neuroendocrine cell networks
11
Q
How does mechanics of stomach work?
A
Very coordinated antropyloroduodenal contractions to titrate solid food
12
Q
What is titration of food?
A
Breaking it down
13
Q
What is purpose of gastric antrum?
A
Sieves liquid chyme through remaining solid matter in stomach and delivers slow rate of gastric contents into the duodenum.
14
Q
What is function of small intestine?
A
To absorb water, electrolytes and nutrients
15
Q
What is approximate length of duodenum?
A
30cm
16
Q
What is length of jejunum
A
2.5metres
17
Q
What is length of ileum?
A
4 metres
18
Q
Where does common bile duct enter small intestine?
A
Duodenum - about half way down.
19
Q
What is chyme?
A
Acidy pulpy fluid that passes from stomach to small intestine
20
Q
What happens as food passes from stomach to small intestine?
A
Chyme passes into small intestine which stimulates release of hormones secretin & CCK (cholecystokinin).
The stimulates release of bicarbonate and pancreatic enzymes and causes gallbladder to release bile.
21
Q
Where is CCK produced?
A
Cholecystokinin - produced in I cells in lining of duodenum
22
Q
What foods are broken down into different things in the small intestine?
A
Proteins/peptides - amino acids
Lips - fatty acids and glycerol
Triglycerides - free fatty acids and monoglycerides
Carbs - oligosaccharides
23
Q
What is water uptake driven by in s.intestine?
A
Absorption of Na and K
24
Q
How much fluid passes through small bowel each day?
A
9litres. Mixture of water and secretions
25
What is function of large bowel?
1. Propulsion of colonic contents towards rectum for expulsion
2. Absorption of water and electrolytes from remaining chyme
3. Absorption of short-chain fatty acids produced from microbiota
4. Defacation
26
What is function of short chain fatty acids the large bowel?
To keep microbiota of gut wall healthy
To help with remaining absorption of sodium
27
How long is typical transit of chyme in adult?
12-30 hours
28
What does wall of colon do?
Has role in production of vit k, vit b7 and B3
29
What does the stomach absorb?
Alcohol
30
What does duodenum absorb?
Cl, SO4, Iron, calcium, magnesium
31
What does Jejunum/ileum absorb?
```
glucose
vit c
thiamin
ribolfavin
folic acid
prtein
fat
cholesterol
Vit A & D
```
32
What does colon absorb?
Na
K
Vit K
H20
33
What is peristalsis?
Contraction and relaxation above and below a bolus of food to push food through gut
34
How does peristalsis work?
Pre bolus: circular contracts
longitudinal muscle relaxes,
Post bolus: circular muscle relaxes
longitudinal muscle contracts
35
How many lobes are in the liver?
2 main lobes with 4 lobes within that, and 8 segments altogether
36
which ligament divides the liver?
falciform ligament
37
How much weight does the liver contribute in adults and infants?
2.5% in adults
| 5% in infants
38
What is blood supply of liver?
25% hepatic artery
| 75% portal vein
39
Describe a liver lobule
Roughly hexagonal
Central vein with plates of hepatocytes radiating around
At the 6 corners there are branches of hepatic artery, hepatic portal vein and biles duct (the portal triad)
The hepatocytes are in close contact with blood filled sinusoids and are next to canaliculi that bile is secreted into.
Blood flows out the sinusoids into the central vein and is transported out of liver by hepatic vein.
40
What are sinusoids in the liver lined with?
1. endothelial cells
2. phagocytic Kupfer cells
3. hepatic stellate cells
41
What is function of kupfer cells in liver?
eradicate bacteria from the gut
42
What is function of hepatic stellate cells in the liver?
store fat and vitamin A
43
How many functions does the liver perform?
Over 400
44
Name the main functions of the liver
1. Secretory
Synthesis and excretion of bile
2. Storage:
of glycogen, iron, vitamins A, D, E, K and B12, blood
3. Metabolism
- of fat protein and carbs
- synthesis of blood-clotting factors and inhibitors
- synthesis of albumin
- detoxification of hormones, drugs and other substances like ammonia
45
What is albumin?
Main plasma protein - maintains oncotic pressure and transportation of substances in blood
46
What is bile made of?
Excretory pathway for bilirubin - breakdown product of haemoglobin.
Also contains bile salts, cholesterol, electrolytes, copper, water, lecithin, mucus
47
Describe bilrubin metabolism
Erthrocyte
120 days
macrophages engulf
releases Hb
broken into: globin - the protein, further broken down into amino acids and reused by body
and haem - broken into Fe2+ which is reused
and unconugated bilirubin (LIPID soluble)
carried by albumin to the liver
CONJUGATION by combining with gluceronic acid
is now CONJUGATED BILIRUBIN (water soluble)
excreted in bile to s.intestine via common bile duct
in terminal ileum/early colon
bacteria remove glucoronic acid
makes urobilinogen
90% of it oxyidised by bacteria
makes stercobilinogen - comes out in faeces. has brown colour
10% is absorbed back to liver by portal vein - 5% desecrated, 5% to kidney, converted to yellow urogilngen = yellow urine colour.
48
What is role of bile acids?
emulsify fats
49
What is an imperforate anus?
Absence of normal anal opening - can range from full rectal atresia to recto-bladder neck fistula.
Congenital abnormality
50
What is occurrence of imperforate anus?
1 in 5000 births. cause unknown
50% of children born with T21 will have anal defect at birth.
51
What happens if imperforate anus noted on newborn physical exam?
Ultrasound to rule out cardiac or urological defects
Observe for 18-24 hours to see if pas meconium
May need colostomy surgery
52
What is duodenal atresia?
The duodenum is closed off. Nothing can pass as it is disconnected from rest of intestine
53
When in foetal growth does duodenal atresia occur?
About 6 weeks embryo stomach starts to rotate.
| Then atresia happens between 6-10 weeks for no known reason
54
What is oeosphageal atresia?
Short section at top of oesophagus not formed properly and so is not connected to stomach.
55
When in embryo growth does oesophageal atresia occur?
Within first 6 weeks
56
How do they repair oesophageal atresia?
Depends on the distance between the ends of the oesophagus. There are 5 broad types of OA including TOF-OA with oesophagus connected to airway.
57
What is Hirschsprungs?
The failure of parasympathetic ganglion cells to form in all or lower part of large intestine.
This causes lack of nerve innervation and therefore the absence or alteration of peristalsis.
Means waste cannot pass through colon and normal colon swells with blocked still
58
What is incidence of Hirschsprungs and cause?
Has genetic component
1 in 5000 live births
59
What is gastroschisis?
Abdomen wall does not form completely so intestines develop outside body and are open to air.
60
What is difference between omphalocele and gastroschisis?
Omphalocele = SEAL = intestines outside but in protective sac
Gastroschisis = completely out - no sac
61
When is gastroschisis identified?
12 weeks scan - see bowel loops in amniotic fluid
62
Are there any occurrence links for gastroschisis?
Interesting higher occurrence link between premature births and young mothers.
63
What is intussusception?
Telescoping of the bowel wall in itself. Can be fatal as blood supply can block off and cause necrosis.
64
Where is most common site for intussusception to occur?
Ileocaecal valve
65
What is common age and presenting factors for intussusception?
6 months - 3 years
Boys > girls
Children with CF
66
What is treatment of intussusception?
Hydrostatic reduction. If fails then has to have theatre.
67
What is volvulus?
When part of the intestine becomes twisted at least 180 degrees and cuts off blood supply resulting in gut ischaemia
68
What is presentation of volvulus?
Bilious vomiting
Abdominal pain
Distended Abdo
Absent Bowel Sounds
69
What is treatment of volvulus?
Surgery:
Untwisting in viable
Resection and end to end anastomosis if bowel nectrotic
70
What is pyloric stenosis?
Increased mass size of circular muscle of pylorus. Narrows the pyloric canal and prevents stomach from emptying properly..
71
What is presentation of pyloric stenosis?
Projectile vomiting
Poor weight
Palpitation reveals olive shaped bulge below right costal margin and distended upper abdo
Derranged blood electrolytes
72
What is treatment of pyloric stenosis?
NBM
NG on free drainage
IV's to correct electrolytes
Surgery - pyloromyotomy
73
What is inflammatory bowel disease?
Importantly NOT irritable bowel syndrome
IBD includes Crohns, Ulcerative colitis and indeterminiate colitis.
74
What is Crohn's disease?
Inflammation of mucosa in any part of digestive tract from mouth to anus.
Can affect all layers of the bowel, and result in granulomas
75
What is ulcerative colitis?
inflammation of mucosa affecting only the colon, and only the inner lining of the bowel.
76
What is indeterminate colitis?
Histologically shows characteristics of both crowns and UC so cannot be categorised.
77
What is jaundice?
Raised level of bilirubin in the blood
78
What is bilirubin?
By product of break down of haemoglobin.
79
What is life span of RBC?
Children & adults = 120 days
Neonate 60-80 days
Preterms maybe only 20-30 days
80
How are RBCs removed from system?
The reticuloendothelial system removes them through phagocytosis
81
What is reticuloendothelial system?
Heterogenous population of phagocytic cells that are fixed in tissues that play important role in clearance of particles and substances
82
What is presentation of Crohn's diease?
```
Abdo pain that pain relief won't help
Nausea/vomiting
Loss of appetite
Diarrhoea
Constipation
Nocturnal bowel movemets
Weight loss (due to small bowel involvement)
PR bleeding/mucus
Peri-anal disease like fissures, fistulas, skin tags or abscesses
Lethargy
Mouth ulcers
Arthrtitis (joint pains)
Uveitis (inflamed eyes)
Erythema nodosom (fatty lumps under skin)
Pyoderma gangrenous (painful pustules)
```
83
What is presentation of ulcerative colitis?
```
Abdo pain
PR bleeding (bright red)
Diarrhoea
Painful bowel motion
Poor appetite
Lethargy
```
84
How many babies have jaundice?
30-50% of term neonates have jaundice after birth. More in pre-term neonates
85
Why do babies have jaundice?
Normal factors such as liver take up to 2 weeks to become efficient in conjugating bilirubin
86
What is baby jaundice called?
Physiological jaundice "normal".
87
What are symptoms of prolonged jaundice?
```
Pale chalky stool
Dark urine that stains nappy
Measure conjugated bilirubin
Need full blood count and urine culture
Need routine metabolic screening
```
88
What are most common causes of unconjugated hyperbilirubinaemia?
Physiological
Breast milk jaundice
haemolysis
congenital defects of conjugation or Gilbert syndrome
89
What is biliary atresia?
End result of destructive idiopathic inflammatory process.
Affects both intra and extra hepatic bile ducts
Leads to fibrosis and obliteration of biliary tract
Eventually leads to biliary cirrhosis
Most common surgically correctable liver disorder in infancy. Most common cause for liver transplant in children.
90
What happens if biliary atresia is left untreated?
symptoms of chronic liver disease
| Death by 2 years of age
91
What is incidence of biliary atresia?
In Northern Europe - 1 in 20,000
| In Taiwan 1 in 5000
92
What is cause of biliary atresia?
Definitive unknown but thought to be 4 main types:
Syndromic
Cystic
CMV associated
Isolated
93
What is presentation of biliary atresia?
```
Conjugated jaundice
Pale chalky stools
Dark urine
Hepatomegaly/splenomegaly
Signs of liver failure:
Hypoglycaemia
Ascites
Acid-Base imbalance
Coagulopathy
```
