PBL week 2 wrap up Flashcards
describe the location of the oesophagus
long fibromuscular tube
pharynx to stomach, C6 to C11
cross-sectional anatomy of the oesophagus
adventitia
muscularis externa
submucosa
mucosa
adventitia
outer layer of connective tissue (very distal and intraperitoneal portion of oesophagus has an outer covering of serosa instead)
muscularis externa
external layer of longitudinal muscle and inner layer of circular muscle
in superior third: voluntary striated muscle
middle third: voluntary striated and Smooth muscle
inferior third: smooth muscle
how is food transported through the oesophagus
peristalsis
rhythmic contractions of the muscles which propagate down the oesophagus, coordinated by the myenteric plexus
hardening of the muscles can interfere and cause dysphagia
dysphagia
difficulty swallowing
upper oesophageal sphincter
anatomical, striated muscle sphincter
junction between the pharynx and oesophagus
produced by cricopharyngeus
lower oesophageal sphincter
located at the gastro-oesophageal junction
between the stomach and oesophagus
left of the T11 vertebra and marked by change from oesophageal and gastric mucosa
relaxed in peristalsis
layers of the muscularis externa
from superficial to deep
longitudinal muscle
circular muscle
oblique muscle
which region of abdomen is the stomach located
epigastric
partly in the left hypochondriac and umbilical
4 regions of the stomach
cardia: surrounds opening of oesophagus into stomach
fundus: area above the cardia orifice
body: largest region
pylorus: connects stomach to duodenum, divided into the pyloric antrum and pyloric canal and is the distal end of the stomach
2 sphincters of the stomach
inferior oesophageal sphincter: marks transition between oesophagus and stomach at T11, food passes from oesophagus through cardiac orifice into the body of the stomach
pyloric sphincter: lies between pylorus and the start of the duodenum and controls exit of chyme
histology of the oesophagus
mucosa is comprised of 3 different layers
stratified squamous non-keratinised epithelium
lamina propria
muscularis mucosa
stratified squamous non-keratinised epithelium
mucous production
(for lubrication and neutralisation of acid)
protection
lamina propria
absorption via capillaries and also contains MALT for immunological response
muscularis mucosa
for localised movement using muscle contractions to move food down the oesophagus
submucosa
has a large network of blood vessels to increase surface area for nutrient absorption
contains mucus glands for lubrication of bolus
contains Meissen nerve cells which control the effectors
histology of the stomach
simple columnar epithelium
the mucosa and submucosal layer are folded in on themselves which allows them to unfold when the stomach expands
what do gastric pits of the stomach contain
surface lining cells
regenerative cells
mucous neck cells
parietal cells
chief cells
regenerative cells
replace any of the other cells
mucous neck cells
secret mucous and neutralise acid
parietal cells
release hydrochloride acid which is an intrinsic factor for protein digestion
chief cells
secrete pepsinogen and HCl converts pepsinogen to pepsin (active form)
parietal cells
secrets gastrin
stimulates parietal cells
what is GERD
gastro-oesophageal reflux disease
when stomach acid flows back up the oesophagus, backwash is called acid reflux
irritate lining of the oesophagus, damages the cells
impaired lower oesophageal sphincter mechanism (may be due to intragastric pressure or delayed gastric emptying)
symptoms and presentation of GERD
heartburn (may present as a heart attack)
sour taste in mouth
upper GI pain
cough
hiccups
halitosis
bloating
nausea/vomiting
dysphagia
odynophagia (pain on swallowing)
when may GERD symptoms be worse
when lying down
bending over
after eating
difference between dyspepsia and GORD
dyspepsia is a collection of symptoms of upper GI pain, heartburn, reflux, nausea and vomiting
may lead to diagnosis of GERD
what is the drug often prescribed to manage GERD
lansoprazole
definition of Barrett’s oesophagus
the replacement of normal stratified squamous epithelium with metaplastic, premalignant intestinal columnar epithelium in the distal oesophagus
definition of oesophageal cancer
a malignancy that develops in tissues of the hollow muscular canal along which food and liquid travel from the throat to the stomach
what is the difference between Barrett’s oesophagus and oesophageal cancer
Barrett’s oesophagus has stratified squamous epithelium
then in oesophageal cancer there is specialised intestinal metaplasia which is metaplastic intestinal columnar epithelium
2 main types of oesophageal cancer
adenocarcinoma
squamous cell carcinoma
adenocarcinoma
begins in the glandular tissue in the lower part of the oesophagus
squamous cell carcinoma
starts in the squamous cells that line the oesophagus
usually develop in the upper and middle part of the oesophagus
risk factors of GERD
overweight
pregnancy
smoking
drugs
hiatus hernia
stress
certain foods and drinks
overweight
increased pressure
lower oesophageal sphincter relaxes
acid travels up the oesophagus
body is less efficient at emptying the stomach contents, increases acid secretion, gastroesophageal pressure gradient potential refluxate
pregnancy
increased weight and growth of the foetus increases the pressure on the stomach, acid travels up the oesophagus
hormones such as plasma progesterone weakens the lower oesophagus and stomach acid pushes through easily
smoking
nicotine relaxes the smooth muscle and lower oesophageal sphincter, acid and stomach contents travel up the oesophagus
redues salvation, saliva contains acid-neutralising bicarbonate, less acid neutralisation
increases acid secretion from the stomach
drugs
mucosal damage, relaxes the LES due to the pressure reduction/oesophageal inflammation/delay gastric emptying
non-steroidal anti-inflammatory drugs, inhibit Cyclooxygenase enzymes, increase acid secretion
short term implications of GERD
heartburn
dry cough
difficulty swallowing
asthma like symptoms
sore throat
bad breath
nausea
long term implications of GERD
esophagitis: inflammation of oesophagus
oesophageal ulcers
oesophageal bleeding
oesophageal stricture
Barrett’s oesophagus
oesophageal cancer
age as a risk factor for GERD
increases with age
peaking at age 75-79 for both sexes
large 95% confidence interval for both sexes
methods used in GERD diagnosis
endoscopy
barium swallow
pH monitoring
nonmetry
endoscopy
camera down oesophagus to the stomach
barium swallow
chalky drink followed with an x-ray to look at the shape and size of the pharynx and oesophagus
monitors how you swallow
pH monitoring
for acid levels
24 hour long helps to determine how well the oesophageal sphincter is working to prevent acid reflux
manometry
shows how well the oesophagus is able to move food down the oesophagus by measuring the changes in pressure
management of GERD
maintain healthy weight
stop smoking
eat smaller and more frequent meals
avoid food and drink
avoid fatty food
don’t wear tight clothing
raise head of the bed by up to 20cm
try to relax to reduce stress
examples of short term GERD management
antacids and alginates
antacids
drugs that neutralise the hydrochloric acid in your stomach
calcium carbonate, magnesium hydroxide and/or sodium bicarbonate
alginate
derived from seaweed and form a physical protective barrier on top of the stomach
combo products
contain an antacid and a raft-forming alginate
purchased over the counter
Gaviscon, Rennie Duo
biomarkers associated with various stages of oesophageal adenocarcinoma
DNA content abnormalities and loss of heterozygosity
DNA content abnormalities
tumour suppressor loci
p53 loss of heterozygosity
p53 staining
epigenetics
p16 methylation
proliferation
cell cycle markers
cyclin A
cyclin D1
