Gastrointestinal Tract Anatomy Flashcards
what are the 5 standard layers of the GI tract and their sublayers
mucosa
- epithelium
- lamina propria
- muscularis mucosae
submucosa
muscularis
- circular muscle
- longitudinal muscle
serosa
- areolar connective tissue
- epithelium
mesentery
what are the salivary glands called and what do they secrete
submandibular
parotid
sublingual
salivary amylase
3 parts of pharynx
naso
oro
laryngo
3 parts of pharynx
naso
oro
laryngo
oesophagus or trachea more posterior
oesophagus
what cell type lines the oesophagus
squamous epithelium until last cm where is becomes columnar epithelium
what type of muscle is the oesophagus
1st third - voluntary - striated
2nd third - mixed
3rd third - involuntary - smooth
what are the sphincters of the oesophagus
lower and upper oesophageal
what muscle forms the majority of the upper oesophageal sphincter
cricopharyngeus
function of upper oesophageal sphincter
stops air getting into the gut
function of lower oesophageal sphincter
prevents acid and food reflux
what makes up the lower oesophageal sphincter
thickened muscular layer of the cardia of the stomach intrinsically and the diaphragm extrinsically
where does the stomach move in a sliding hiatal hernia
above diaphragm but within oesophagus
where does the stomach move in a paraoesophageal hiatal hernia
outside of the oesophagus and above diaphragm
4 parts of the stomach
cardia
fundus
body
antrum
where does food exit the stomach
pylorus/pyloric sphincter
what adaptation to the standard 4 layers does the stomach have
the mucosa is folded into rugae and between these are gastric pits
which direction do muscle layers lie in the stomach
oblique
what is the function of the glands found in the gastric mucosa
they secrete mucous which protects the mucosa from the acid
what do chief cells secrete
pepsin
what do parietal cells secrete
HCl acid
instrinsic factor
what is the function of intrinsic factor
it is important for B12 absorption
what do endocrine cells secrete in the stomach
grelin and gastrin
what does grelin do
hormone which promotes appetite
what is gastrin
a digestive hormone
what is absorbed in the stomach
B12
water
alcohol
some drugs
where does the duodenum become the jejunum
at the duodenojejunal flexure (where it abruptly turns downwards)
how many sections is the duodenum split into and what are the sections
4
1. pylorus - superior duodenal flexure
2. descending part
3. horizontal part
4. ascending part
where does the ileum end
the ileo-caecal valve
what is different about the small intestine mucosa
it is folded into villi
what is contained in each vili
blood vessels
lymph vessel
what cells are found on the surface of villi and what are they characterised by
enterocytes
they have microvilli
which cells secrete mucus in the small intestine
goblet cells
what cell type is found in the deep crypts of the small intestine
stem cells
what are the sections and subsections of the large intestine
caecum
colon
- ascending
- transverse
- descending
- sigmoid
rectum
anal canal
what cell type do cells transition to at the anal canal
squamous mucosa
what makes up the anal sphincter
an internal smooth muscle and external striated muscle
describe the mucosa of the colon
there are crypts but not villi
how are the muscles of the colon grouped
grouped into dense strips called teaniae coli
these are shorter than the colon and mean haustra are formed
what are the two most common positions of the appendix
retrocaecal
pelvic
what are the two layers of the peritoneum and which layer cover the organs and which covers the abdo wall
visceral - lines organs
parietal - abdo wall
retroperitoneal organs
pancreas
kidneys
adrenal glands
urinary tract
parts of duodenum
parts of colon
parts of rectum
function of mesentary
prevents knotting of the small intestine
function of omentum
can wrap around perforation of inflammation and seal it
describe mucosa of gallbladder
rugae
what hormone triggers the gallbladder to empty
cholecystokinin
where does the common bile duct enter the duodenum
merges with pancreatic duct then enters at the ampulla of vater
how is the exocrine pancreas arranged
acinar arrangements
where are endocrine cells of pancreas
islets of langerhans
