Gastro-Intestinal Flashcards
(120 cards)
0
Q
What are the main functions of the stomach?
A
Store food
Mix and disrupt
Secrete acid and enzymes
1
Q
What are the 4 main processes of the digestive tract?
A
Secretion, digestion, motility and absorption
2
Q
What are the 4 parts of the stomach?
A
Cardiac, fundus, body, pyloric antrum
3
Q
How is reflux prevented?
A
Acute angle
Lower oesophageal sphincter
Positive intra abdominal pressure compresses the walls
4
Q
What are the cell layers that make up the alimentary canal?
A
Mucosa - epithelium, connective tissue and smooth muscle
Sub mucosa
Muscularis external
Serosa/adventitia
5
Q
What is the muscle and nerve supply for mastication?
A
Masseter
Trigeminal nerve
6
Q
What are the functions of saliva?
A
Lubricate
Start digesting carbohydrates
Protection - moist, wash teeth and alkaline
7
Q
What are the components of saliva?
A
Water, alkali, electrolytes, enzymes, mucus, bacteriostats
8
Q
What is xerostomia and the consequences of it?
A
Low saliva production
Can only eat moist food and teeth/mucosa degrades very quickly
9
Q
What are the 3 salivary glands and the type of saliva they produce?
A
Parotid - serous - high enzymes low mucus
Sub-lingual - mucous - high mucus no enzymes
Submandibular - mixed - produce 70% of saliva
10
Q
What do the acinar cells and ductal cells do?
A
Acinar secretes saliva and ductal cells modify the composition
11
Q
What is the effect of increased saliva production?
A
More produced = less modified so
Higher volume, alkalinity and enzyme levels
Less hypotonic
12
Q
Outline the process of swallowing
A
Voluntary phase - bolus formed and moved to pharynx
Reflex - pressure receptors stimulated causing: respiration inhibited, raise larynx, close glottis, open upper oesophageal sphincter, rapid peristaltic wave and opening of lower oesophageal sphincter
13
Q
What are some potential causes of dysphagia
A
Motility problems - achalasia
Obstruction - tumor
14
Q
What does lateral folding and craniocaudal folding accomplish?
A
Lateral - ventral body wall and tubular primitive gut
Craniocaudal - creates pockets
15
Q
What are the derivatives of the foregut? What is its blood supply?
A
Oesophagus, stomach, pancreas, liver, gall bladder and duodenum
Celiac trunk
16
Q
What are the derivatives of the midgut? What is its blood and nerve supply?
A
Duodenum, jejunum, ileum, cecum, ascending colon and transverse colon
Superior mesenteric artery/vein
Vagus nerve/superior mesenteric ganglion and plexus
17
Q
What are the derivatives of the hind gut? What is its blood and nerve supply?
A
Transverse colon, descending colon, sigmoid colon, rectum, upper anal canal, lining of bladder and urethra
Inferior mesenteric artery/vein
Pelvic nerve/inferior mesenteric ganglion and plexus
18
Q
What does the splanchnic and somatic mesoderm become?
A
Somatic - muscle and fasciae of the abdominal wall
Splanchnic - smooth muscle of the gut wall
19
Q
Describe the muscle and fascia of the abdominal wall
A
Lateral folding creates linea alba in the middle
External oblique, internal oblique and transversus abdominis. Rectus abdominis anteriorly.
Deep is transversalis fascia. Superficial is superficial fascia and skin
20
Q
What do the dorsal and ventral mesenteries do?
A
Dorsal - attach entire gut to roof of abdominal cavity
Ventral - attach foregut to the floor
21
Q
What do the left and right sac become?
A
Greater peritoneal sac
Lesser peritoneal sac
22
Q
What is the greater omentum derived from? And the lesser omentum? And what do they connect?
A
Greater - dorsal mesentery. Greater curve to transverse colon
Lesser - ventral mesentery. Lesser curve to liver
23
Q
What does retroperitoneal mean and give an example of some organs which are
A
Never in the peritoneal cavity and never had a mesentery. Aorta, vena cava and kidney
24
What does secondary retroperitoneal mean and give an example of organs which are
Began development in the peritoneum but lost mesentery. Ascending and descending colon and duodenum
25
What are the three vertical muscles of the abdominal wall?
External oblique, internal oblique, transversalis
26
What are the two flat muscles of the abdominal wall?
Rectus abdominis and pyramidalis
27
What is the rectus sheath?
The aponeurosis of the vertical muscles combine at the linea alba and enclose the flat muscles
28
What are the layers of the abdominal wall from superficial to deep?
Skin
Superficial fascia
Muscles and their associated fascia
Peritoneum
29
What is the arcuate line?
The point where posterior wall of the rectus sheath disappears
30
What are the 3 main types of incision?
Midline - through linea alba
Transverse - through the oblique muscles
Grid iron - split the muscle fibres
31
What is a Meckel's diverticulum?
Remnant of the vitelline duct
| 2% of the population, 2" in length, 2:1 male/female ratio, found in under 2's
32
What are the following conditions: vitelline fistula, omphalocoele, gastroschisis?
Direct communication between umbilicus and GI resulting in faecal matter out of the umbilicus
Persistence of physiological herniation
Gut tube outside body with no covering
33
What is a hernia?
Abnormal protrusion of an organ or fascia through the walls of the cavity that contain it
34
What are the 3 main types of herniation?
Inguinal
Femoral
Umbilical
35
What are the borders of the inguinal canal and what does it normally contain?
Lateral - deep inguinal ring
Medial - superficial inguinal ring
Anterior and superior - aponeurosis of external oblique
Posterior - transversalis fascia
Inferior - inguinal ligament
Males - spermatic cord and ilioinguinal nerve
Females - round ligament and ilioinguinal nerve
36
What is the difference between a direct and indirect inguinal hernia
Direct goes through Hesselbachs triangle. Indirect goes through the deep ring
37
What are some complications of hernias?
Strangulation - poor blood supply
| Incarceration - not easily reversed
38
What are the functions of the stomach?
Store food
Digest food
Break food down into chyme
39
What are the "attack" and "defence" secretions by the stomach?
HCl and proteolytic enzymes
| Mucus and HCO3-
40
What are the 4 cells in gastric pits and what do they produce?
Parietal - acid
Chief - enzymes
Endocrine - gastrin
Neck - mucus
41
Outline the method of acid production and secretion
The mitochondria produces H+ and OH- ions from water in the mitochondria. OH- becomes HCO3- and is secreted into the blood. H+ enters the stomach via a proton pump using ATP
42
What effects acid secretion?
Gastrin - increased by peptides, ACh. Decreased by acid
Histamine - increased by gastrin and ACh
ACh - increased by CNS and distention
43
Outline the 3 phases of control
Cephalic - detect and ingest food. Autonomic
Gastric - food reaches stomach and via pH rising, stomach distending and peptides being released more acid is produced
Intestinal - as stomach empties gastrin antagonists and pH lowering reduces acid secretion
44
How are the stomachs defences promoted?
Prostaglandins which are stimulated by the same mechanisms stimulating acid secretion thus matching attack and defence
45
What are some problems with stomach defences and what is the result?
Alcohol - dissolve mucus
H. pylori
NSAIDS - inhibit prostaglandins
Leads to peptic ulcers
46
How can you reduce acid secretion?
Proton pump inhibitors - omeprazole
| Histamine antagonists - cimetidine
47
What inhibits stomach emptying?
Fat, hypertonicity and low pH in the duodenum
48
Explain the primary intestinal loop and it's function
The midgut herniated into the umbilical cord to accommodate the growing liver and undergoes 3x 90 degree anticlockwise rotations around the SMA resulting in the final positions of the midgut.
49
What are some malformation problems?
Incomplete - left sided colon
Reverse - transverse colon posterior to duodenum
Volvulus - abnormally twisted bowel = blockage, strangulation and ischaemia
50
What is the purpose of recanalisation and what can its failure result in?
Gut cell growth is so rapid in the oesophagus, bile duct and small intestine the lumen can become obliterated
If it fails you can get atresia or stenosis
51
What is the difference between an umbilical hernia and omphalocoele?
Umbilical hernia has a skin covering
52
How is the anal canal and urogenital canal separated?
Urorectal septum separates them
53
What are the differences above and below the pectineal line?
Above - IMA, columnar epithelium, parasympathetic, internal inguinal nodes, stretch sensation only
Below - pudendal a, stratified squamous, sympathetic, superficial inguinal nodes, pain/touch/temperature sensation
54
Where is visceral foregut, midgut and hind gut pain felt?
Epigastric, peri umbilical, suprapubically
55
How is gastric reflux normally prevented?
Lower oesophageal sphincter
Abdominal pressure>thoracic pressure
Right crus of diaphragm
Oblique entrance angle
56
What are the symptoms of acid reflux and when are they worse?
Dyspepsia - heart burn
| Lying down and hot drinks
57
How do is reflux managed?
Lifestyle - stop smoking, weight loss, reduce alcohol
| Medicate - antacids, PPIs, H2 antagonist
58
What is an ulcer?
Break in the superficial epithelial cells down to muscularis mucosa
59
Where are stomach ulcers and duodenal ulcers most likely to be found?
Lesser curve
| Duodenal cap
60
What can cause peptic ulcers and why?
NSAID - inhibit prostaglandins which produce the defences
61
What are the symptoms of peptic ulcers?
Recurrent burn in epigastric pain worse at night and when hungry
Nausea
Weight loss
62
How are ulcers managed?
PPI - omeprazole
H2 antagonist - cimetidine
Antibiotics - clarithromycin H. Pylori
Stop using NSAIDS
63
What type of bacteria is H. pylori? How is it able to survive in the stomach?
Gram negative aerobic
| It has urease which produces ammonia to neutralise the acid
64
How is H. pylori diagnosed?
IgG
Urea breath test
Biopsy
65
In what state does Chyme leave the stomach and how is that corrected?
Acidic - HCO3- added
Hypertonic - H2O added
Partly digested - enzymes and bile acids added
66
What do the exocrine glands of the pancreas produce? Which part produces which?
Alkaline juice - ducts
| Enzymes - acinar
67
What stimulates the release of enzymes and alkaline juice respectively?
CCK
| Secretin
68
What are the four main functions of the liver?
Energy metabolism, detoxification, plasma proteins and bile
69
Describe the blood and bile flow in the liver
Blood enters from the hepatic portal vein into sinusoids lined with hepatocytes into the central vein. Bile enter canaliculi and flows to the bile duct
70
What are the two components of bile?
Bile acid dependent - bile acids and pigments
| Bile acid independent - alkaline juice
71
What do bile acids do?
Help with fat digestion by emulsifying them to increase surface area
72
What does the gall bladder do?
Store recycled bile and concentrate it. When CCK is their the muscle contracts emptying it
73
What are the defences the GI has to toxins?
Innate - physical and cellular
| Adaptive
74
List the physical defences
Sight, smell, memory, saliva, gastric acid, mucus, anaerobic, small intestinal secretions, peristalsis/segmentation
75
What conditions can arise due to salivary problems?
Xerostomia - mucus and teeth degradation
| Parotitis - staph aureus
76
What can cause achlohydria and what conditions can then develop?
PPI, pernicious anaemia
| Shigellosis, cholera, salmonella, clostridium difficile
77
How is the small intestine protected?
Bile, enzymes, anaerobic environment, epithelial shedding and segmentation
78
What can survive gastric acid?
TB - resist acid
H. Pylori - protective ammonia
Hep A
Polio
79
What are the cellular defences?
Neutrophils, macrophages, natural killer cells, mast cells, eosinophils
80
What can cause liver failure?
```
Viral hepatitis
Alcohol
Drugs
Solvent
Mushrooms
```
81
What are the GIs adaptive defences?
B lymphocytes
T lymphocytes
Lymphatics - MALT/GALT
82
Explain mesenteric adenitis
Right iliac fossa pain - adenovirus
| Mistaken for appendicitis
83
Explain appendicitis
Obstruction of appendix leads to stasis and infection
| Usually due to lymphoid hyperplasia (chickenpox) or facecloth
84
What would you see in the blood for: hepatocellular damage, cholestasis, reduced synthetic function?
ALT, AST, gamma glutamyl transpeptidase
Bilirubin, alkaline phosphatase
Reduced albumin and increased clotting time (prothrombin)
85
What are the 3 classifications of jaundice?
Pre hepatic - haemolytic
Hepatic - parenchymal
Post hepatic - cholestatic
86
Explain pre hepatic causes of jaundice
Excess haemolysis - membrane defects, infections, Gilbert's syndrome
87
Explain hepatic jaundice
Decreased function - drugs, viruses, cirrhosis
88
Explain post hepatic jaundice
Obstruction - intrahepatic - hepatitis, cirrhosis, drugs
| Extra hepatic - gallstones, cancer
89
What would you see in the blood for acute and chronic hepatitis?
Raised AST/ALT and jaundice
| Reduced clotting and albumin
90
What are risk factors for gallstones?
Female
Old
Obese
91
What can gallstones be made of?
Cholesterol, calcium and bile
92
Explain pancreatitis
Inflammation of the pancreas due to released enzymes. A duct obstruction causes acinar damage and release of proteases, lipase sand elastase
93
What are some causes and clinical features of pancreatitis?
Gall stones, ethanol, trauma
Acute - Increased amylase, ALP, pain, vomiting, SIRS
Chronic - pain, steatorrhea, reduced albumin and jaundice
94
What is the structure of the small intestine?
```
Mucosa folded into villi separated by crypts. Cells multiply and then migrate and mature on the way to villi tips
Micro villi (brush border) to increase surface area
```
95
In broad terms how is absorption done in the small intestine?
Villi cells secrete enzymes forming an unstirred layer. Nutrients diffuse into it and the enzymes digest them
96
What enzymes does the body have to digest carbohydrates?
Alpha amylase in saliva and pancreas
| Isomaltase, maltase, sucrose and lactase in the unstirred layer
97
Explain how glucose is absorbed
Sodium pumps generate a sodium gradient and then glucose enters from the lumen along with sodium using SGLT1. Glucose then diffuses into the ECF via GLUT2
98
What is oral rehydration therapy?
Consuming glucose and salt allows for greater Na+ intake and therefore a greater osmotic gradient
99
How are amino acids absorbed?
Protein --> oligopeptide via pepsin from the stomachs chief cells and peptidases from the pancreas
Oligopeptide --> amino acids using enzymes in the brush border
Up taken in same manner as glucose
100
Explain pernicious anaemia
Vit B12 is absorbed in the terminal ileum using intrinsic factor produced in the stomach
Vit B12 deficiency due to stomach damage or ileum removal
101
Explain segmentation
The intestine is divided into segments which mixes the contents. The pacemakers fire more rapidly at the cephalic end (12-->8) so the gradient moves contents down
102
What movement mechanisms are in the large intestine?
Haustral shuttling - same as segmentation
| Mass movement - once or twice a day a peristaltic propulsion
103
What factors control defaecation?
Internal anal sphincter - smooth muscle - parasympathetic - relax
External anal sphincter - striated - voluntary - relax
104
What are the types of inflammatory bowel disease?
Ulcerative colitis - mucosal ulceration in rectum and colon
Crohn's disease - transmutation inflammation of entire GIT
Microscopic, diversion, diverticular colitis
105
Contrast Crohn's disease and ulcerative colitis
Crohn's - small bowl and colon, skip lesions, peri anal disease, fistulas, granulomas and fibrosis
Ulcerative - only in colon, continuous lesions, rectal involvement and bleeding
106
What are the roles of normal microbiological flora?
```
Synthesise vitamins - K, B12
Prevent colonisation by pathogens
Kill non-indigenous bacteria
Stimulate GALT development
Stimulate antibody production
```
107
What are the types of bacteria (oxygen) and give an example of each?
Obligate aerobes - need O2 - TB
Obligate anaerobes - die in O2 presence - clostridium (produce spores for protection)
Facultative anaerobes - prefer O2 - E. Coli, staphylococcus
108
Where are the anaerobic areas of the body?
Mouth, small bowel, colon
109
Name some microbes found in the mouth and a condition it can cause
Staph aureus - parotitis
Candida albicans - oral thrush
110
Name some microbes in the throat
Strep viridans/pyogenes/pneumoniae
Staphylococci
Neiserria meningitidis
Haemophilus influenza
111
Why is abdominal surgery risky? What conditions can occur? And what is done to reduce the risk?
Lots of bacteria in the colon so high risk of wound infection
Faecal peritonitis and perianal abscessw
Prophylactic metronidazole and gentamicin
112
What microbes are normally in the vagina and what is their physiological function?
Lactobacillus (gram positive)
| Produce lactic acid to stop other bacteria colonising
113
What is the difference between bacteraemia and septicaemia?
Bacteraemia - bacteria are cleared rapidly
| Septicaemia - bacteria aren't cleared and multiply. Cause sepsis
114
What are the symptoms of oesophageal carcinoma? What is the 5 year survival rate? What investigations are done?
Dysphagia and weight loss
5%
Endoscopy, biopsy, barium
115
What are the symptoms of gastric cancer? What is the 5 year survival rate? What investigations are done?
Epigastric pain, vomiting, weight loss
20%
Endoscope, biopsy, barium
116
What are some ways of imaging the GI tract?
```
X ray
Barium swallow/enema/meal follow through
Ultrasound
CT
MRI
Angiography
```
117
What could cause a small bowel obstruction and what would the symptoms be?
Hernia, adhesion, tumour, inflammation
Vomit, mild distension, absolute constipation, colick pain
118
What can cause large bowel obstruction and what would the symptoms be?
Colorectal carcinoma, diverticular stricture, hernia, volvulas, pseudobstruction
Pain, distention, constipation, colick pain
119
Why might an erect chest x ray have to be done for an abdominal problem?
See if diaphragm is elevated due to
| Perforated bowl - ulcer, tumour, obstruction, trauma, iatrogenic, diverticular disease
