GI Flashcards
What do the parotid glands secrete?
What percentage of the saliva is this?
serous saliva
enzymes and electrolytes
25%
What do the submandibular glands secrete?
What percentage of the saliva is this?
mucous
5%
What do the sublingual glands secrete?
What percentage of the saliva is this?
serous and mucous
70%
What do the acinar cells of salivary glands secrete?
isotonic fluid
enxymes
How is a hypotonic saliva created from an isotonic solution?
ductal cells in the salivary glands remove Na+ and Cl-. adding HCO3-
How many salts are removed depends on the flow rate
high flow = less salts removed = less hypotonic
How does the autonomic nervous system affect salivary gland secretion?
Para = increased production. increased addition of HCO3- Symp = decreased production
What are the boundaries of the oesophagus?
inferior border of the cricoid cartilage, C6
cardiac orifice of the stomach T11
What type of muscle is the external longitudinal layer of the oesophagus?
superior third = voluntary striated
middle third = voluntary striated and smooth
inferior third = smooth
Describe the muscular layers of the oesophagus
external longitudinal layer
internal circular
How is the upper oesophageal sphincter created?
this is an anatomical striated muscle sphincter
produced by cricopharyngeus
How is the lower oesophageal sphincter created?
physiological sphincter
angle of His = oesophagus entering stomach at an acute angle
positive intra-abdominal pressure causes compression of the walls of the intra-abdominal section of the oesophagus
right crus of the diaphragm
folds of the mucosa occlude the lumen
At what vertebral level is the lower oesophageal sphincter found?
T11
What are the three phases of swallowing?
voluntary
pharyngeal
oesophageal
What happens in the voluntary phase of swallowing?
the tongue moves the bolus into the pharynx
What happens in the pharyngeal phase of swallowing?
breathing inhibited
larynx raised
glottis closes
upper oesophageal sphincter opens
What happens in the oesophageal phase of swallowing?
peristalsis sweeps down the oesophagus
lower oesophageal sphincter opens
define odynophagia
pain whilst swallowing
Why does dysphagia of solids happen?
oesophageal dysphagia
Why does dysphagia of fluids happen?
oropharyngeal dysphagia
What weakens the LOS?
being obese - increased P on stomach
fatty foods - stomach takes longer to dispose of acid
tobacco, alcohol, coffee, chocolate - relax LOS
pregnancy - increased P on stomach
hiatus hernia
stress
What are the consequences of a weakened LOS?
heart burn
acid reflux
dysphagia
What is Barrett’s Oesophagus?
metaplasia of the epithelial cells of the oesophagus
from non-keratinised stratified squamous to columnar with goblet cells
attempt to better resist the harmful acid of the stomach
What is a complication of Barrett’s Oesophagus?
adenocarcinoma
What are boundaries of the anterolateral abdominal wall?
cartilages of the 7th to 10th ribs and xiphoid process of sternum
inguinal ligaments
From superficial to deep, what are the layers of the anterolateral abdominal wall?
skin subcutaneous tissue external oblique internal oblique transversus abdominis extraperitoneal fat parietal peritoneum
At what spinal level is the umbilicus?
L3
Where is the linea alba found?
in the midline
aponeurosis of abdominal muscles, separating right and left rectus abdominis
extends from the xiphoid process to the pubic symphysis
Where are the semilunar lines found?
vertical lines either side of the rectus abdominis
Where are the tendinous intersections found?
horzontal lines between sections of the rectus abdominis
What is the rectus sheath?
aponeuroses of external oblique, internal oblique and transversus abdomis combine between the midclavicular line and the midline
surrounds the rectus abdominis
When does the posterior wall of the rectus sheath disappear?
the arcuate line
one third of the way between the umbilicus and the pubic symphysis
Where is MvBurney’s point?
1/3rd of the distance between the ASIS and the umbilicus
What is a patent urachus?
the allantois persists
communication between the bladder and umbilicus
What is a patent vitelline duct?
communication between midgut and umbilicus
What is Meckel’s diverticulum?
small portion of vitelline duct persists
outpocketing of ilium
can contain gastric or pancreatic tissue
What is the rule of twos is relation to Meckel’s diverticulum?
2% of population affected 2 feet from ileocecal valve 2 inches long detected in inder 2's 2:1 male:female
What type of cancer is oesophageal cancer?
squamous cell carcinoma
adenocarcinoma
What are the risk factors for oesophageal carcinoma?
tobacco alcohol Barrett's oesophagus - AC chronic inflammation - SCC obesity - AC
Why do oesophageal carcinomas present late?
approximately 75% of the circumference of the oesophagus must be involved before symptoms of ‘food sticking’ are experienced.
What are the symptoms and signs of oesophageal carcinoma?
- Dysphagia
- Weight loss
- Loss of appetite
- Odynophagia
- Hoarseness
- Melaena
- Retrosternal pain
- Intractable hiccups
- Lymphadenopathy
Which region of the stomach do most gastric cancers involve?
pylorus - 50%
lesser curve - 25%
What are the risk factors for gastric cancer?
increasing age male low SE status H pylori poor diet smoking familial risk - E-cadherin gene mutations
What are the symptoms and signs of gastric cancer?
dysphagia dyspepsia weight loss anaemia vomiting
What are the macroscopic features of a gastric cancer?
Fungating
Ulcerating
Infiltrative
Where does gastric cancer spread to?
Through gastric wall into duodenum, transverse colon, pancreas
left supraclavicular lymph node
transcoelomic spread to peritoneum/ovaries
venous to liver
What is the progression of H pylori infection to gastric cancer?
acute gastritis chronic gastritis atrophic gastrisis intestinal metaplasia dysplasia gastric cancer
What type of cancer are most colorectal cancers?
adenocarcinomas
What are the most common sites of spread of colorectal cancers?
liver - most common
lungs
brain
bone
What are the risk factors of colorectal cancer?
family history of colorectal carcinoma past history of colorectal neoplasm IBD polyposis syndromes hormonal factors - nulliparity, late age at first pregnancy, early menopause diet rich in meat and fat sedentary lifestyle smoking obesity alcohol diabetes
Describe the presentation of a right colon cancer
weight loss
anaemia,
blood in stool but only detectable by testing,
mass in right iliac fossa
disease more likely to be advanced at presentation
Describe the presentation of a left colon cancer
often colicky pain, rectal bleeding, bowel obstruction, continual or recurrent inclination to evacuate the bowels mass in left iliac fossa, early change in bowel habit, less advanced disease at presentation.
What are the most common symptoms and signs of colorectal cancer?
rectal bleeding,
persisting change in bowel habit
anaemia
Describe the T staging of colorectal cancer
T0: no evidence of primary carcinoma in situ (Tis) - intraepithelial or lamina propria only.
T1: invades submucosa.
T2: invades muscularis propria.
T3: invades subserosa or non-peritonealised pericolic tissues.
T4: directly invades other tissues and/or penetrates visceral peritoneum
Describe the N staging of colorectal cancer
N0: no regional nodes involved.
N1: 1-3 regional nodes involved.
N2: 4 or more regional nodes involved.
Describe the M staging of colorectal cancer
M0: no distant metastasis.
M1: distant metastasis present (may be transcoelomic spread).
Which lymph nodes does colorectal cancer spread to?
mesenteric
Which organ does colorectal cancer most commonly spread to?
liver
What type of cancer are most pancreatic cancers?
ductal adenocarcinoma
where are most pancreatic cancers found?
head of the pancreas
What are the risk factors for pancreatic cancer?
smoking poor diet diabetes alcohol chronic pancreatitis family history IBD peptic disease
What are the early symptoms of pancreatic cancer
epigastric discomfort
dull backache
painless, progressive, obstructive jaundice
steeatorrhoea
What are the symptoms of advanced pancreatic cancer?
rapid weight loss, persistent back pain, ascites, an epigastric mass enlarged supraclavicular node
What type of cancer is most common for liver cancers?
hepatocellular carcinomas
What are the risk factors for hepatocellular carcinoma?
Hep B Hep C cirrhosis alcoholism aflatoxins produced by Aspergillus flavus and Aspergillus parasiticus diabetes smoking
What are the signs and symptoms of hepatocellular carcinoma?
Pruritus - severe itching of the skin Splenomegaly. Bleeding oesophageal varices. Weight loss. Jaundice. Confusion and hepatic encephalopathy. Abdominal distension due to ascites. Right upper quadrant abdominal pain. Hepatomegaly. Ascites. Spider naevi. Peripheral oedema. Anaemia. Periumbilical collateral veins. Flapping tremor.
What is a vitelline fistula?
direct communication between the umbilicus and the intestinal tract
What is an omaphalocoele?
persistence of physiological herniation.
part of the gut tube fails to return to the abdominal cavity
covered by a reflection of the amnion
What is gastroschisis?
protrusion of the abdominal contents through the body wall directly into the amniotic cavity
due to the failure of closure of the abdominal wall
There is no covering over the gut tube
The bowel may be damaged by exposure to the amniotic fluid
What is referred pain?
pain perceived at a site distant from the site causing the pain
How is visceral pain perceived to be coming from a somatic portion of the body?
visceral sensory nerve joins sensory spinal nerve before spinal cord
pain is perceived as being from the somatic areas that are supplied by the same spinal segment
If pain is felt in the epigastric region, which region of the gut is causing the pain?
foregut
If pain is felt in the periumbilical region, which region of the gut is causing the pain?
midgut
If pain is felt in the suprapubic region, which region of the gut is causing the pain?
hindgut
Where does pain in the liver refer to?
right hypochondrium
right middle back
Where does pain in pancreas and abdominal aorta refer to?
periumbilical region
through to back
Where does pain in the gall bladder refer to?
right back below shoulder
epigastric
right hypochondrium
Where does pain in the spleen refer to?
left hypochondrium and behind
Where does pain in the stomach/duodenum refer to?
epigastric
Where does pain in the oesophageal pain refer to?
retrosternal
Where does pain in the appendix pain refer to?
periumbilical (midgut)
Where does pain in the uterus/ovary pain refer to?
suprapubic
lower back
Where does pain in the bladder pain refer to?
suprapubic
Why does the presence of fluid in the peritoneum cause pain in the left shoulder?
referred pain from diaphragm = C345
liver in way of right diaphragm
Where does pain in the Kidney refer to?
groin
lower back
Where is the rectovesical pouch found?
between the rectum and the bladder in males
Where is the rectouterine pouch found?
between the rectum and the posterior wall of the uterus
Where is the vesicouterine pouch found?
between the anterior surface of the uterus and the bladder.
State the boundaries of the inguinal canal
anterior wall = aponeurosis of the external oblique. reinforced by the internal oblique muscle laterally.
posterior wall = transversalis fascia.
roof = transversalis fascia, internal oblique and transversus abdominis.
floor = inguinal ligament. thickened medially by the lacunar ligament.
opening = deep inguinal ring
exit = superficial inguinal ring
Describe the anatomical relations of the deep inguinal ring
above the midpoint of the inguinal ligament,
lateral to the epigastric vessels
Describe the anatomical relations of the superficial inguinal ring
lies just superior to the pubic tubercle
How does a direct inguinal hernia form?
the peritoneal sac enters the inguinal canal though the posterior wall of the inguinal canal, the transveralis fascia
= Hesselbach’s tirangle
medial to epigastric vessels
What are the boundaries of Hesselbach’s triangle?
anterior = inguinal ligament lateral = inferior epigastric vessels medial = rectus abdominis
How does an indirect inguinal hernia form?
due to the failure of the processus vaginalis to regress.
The peritoneal sac enters the inguinal canal via the deep inguinal ring.
As the sac moves through the inguinal canal, it acquires the same three coverings as the contents of the canal.
lateral to epigastric vessels
Name some bacteria present in the mouth
Streptococcus mutans Staph aureus Candida albicans Enterococcus Lactobacillus
Name pathogens present in the throat
Strep viridans Strep pyogenes Strep pneumoniae Neisseria meningitidis H influenzae Lactobacillus Candida albicans
Which bacteria travels from the throat to cause surface infections?
Streptococcus viridans
Which bacteria are always present in the colon?
Bacteroides fragilis Bacteroides oralis Bacteroides melaninogenicus E. coli Enterococcus faecalis
Describe the flora of the vagina
Lactobacillus - converts glycogen to lactic acid, creating acidic environment
Name bacteria present on the perineal skin
E. coli
Enterococcus faecalis
Lactobacillus
NOT bacteroides as cannot survive oxygen
Which organisms cause gastroenteritis?
Salmonella
Campylobacter
Listeria
Toxins from staphylococcus and clostridium
What are the symptoms of cholera?
Rice water diarrhoea
Sever dehydration
