Gastrointestinal System Flashcards
what is the opening and terminal of the alimentary system?
opening - mouth
terminal - anal canal
what are the 2 roles of the digestion system?
digestion - processing food
absorption - nutrient transfer to circulation
what are the 2 groups of organs in the digestive system?
digestive tract
accessory organs - salivary glands, gallbladder, liver pancreas
what are the different organs in the GI tract?
oral cavity, pharynx, oesophagus, stomach, small intestine, large intestine
what are the 3 parts of the small intestine?
duodenum, jejunum, ileum
what are the 4 parts of the large intestine?
caecum
ascending/transverse/descending colon
rectum
anus
what is the pharynx responsible for?
food and air passing through (muscular tube)
what is the function of the stomach?
secretes enzymes/acids that digest food following the small amount of amylase digesting in the mouth
what is the function of the parts of the small intestine?
duodenum - pancreas secretions and bile (digestion of fat/protein)
towards ileum - more absorption of nutrients
what does the pancreas secrete into the small intestine?
bile
bicarbonate rich fluid to maintain alkaline pH
what is the function of the large intestine?
absorb any unabsorbed nutrients and expel waste as faeces
where are the mucosa membranes found?
lines body cavities and internal organ surfaces
what 3 types of epithelium are found in the GI tract?
squamous, columnar, cuboidal
what is the lamina propria and what is its function?
thin layer of loose CT beneath epithelium
contains inflammatory cells and provides support to epithelium
what is the muscularis mucosae?
smooth muscle lining the GI tract
what is the submucosa and what does it contain?
composed of dense, irregular CT
contains nerves, vessels and lymphatic tissues
what does the muscularis propria do?
inner-circular layer and outer longitudinal layer of smooth muscle
resonsible for food movement
what is the function of the serosa/adventilia?
outer layer of fibrous CT in GI tract, reduction of friction
where are the meissners and auerbachs nerve plexus located?
meissners - stomach
auerbachs - between circular/longitudinal muscle
what is the function of peyers patches?
lymphoid follicles, forms part of immune system preventing harmful bacteria growth
where are the nasopharynx, oropharynx and laryngopharynx located?
nasopharynx - base of skull to soft palate
oropharynx - soft palate to epiglottis
laryngopharynx - epiglottis to splitting of trachea/oesophagus
what 4 GI structures are present in the oesophagus?
mucosa (stratified squamous non-keratinised epithelium)
submucosa (glands and lymphoid follicles)
muscularis mucosae (circular/CM, longitudinal/LM)
serosa
what muscle is present in the oesophagus?
top third - skeletal
middle third - mixed
lower third - smooth
what are the 9 areas of abdomen layout?
- R hypochondrium
- epigastric
- L hypochondrium
- R lumbar
- umbilical
- L lumbar
- R iliac fossa
- suprapubic (hypogastrium)
- L iliac fossa
what would be found in abdomen section 1?
liver
what would be found in abdomen section 2?
duodenum, liver, gallbladder, pancreas, stomach
what would be found in abdomen section 3?
spleen/stomach
what would be found in abdomen area 4?
ascending colon, right kidney
what would be found in abdomen area 5?
stomach, pancreas head, duodenum, transverse colon, lower L/R kidneys
what would be found in abdomen area 6?
descending colon, left kidney
what would be found in abdomen area 7?
caecum, appendix, part of ascending colon
what would be found in abdomen area 8?
bladder, uterus, small intestine parts (ileum)
what would be found in abdomen area 9?
sigmoid colon, descending colon
where is the stomach?
left hypochondrium, epigastric region
what is the function of the fundus in the stomach?
air collection
what is the 5 components of the stomach?
fundus, cardia, body, pylorus, pyloric sphincter
what is the function of the pyloric sphincter?
controls secretions from stomach to duodenum
what is the function of rugae in the stomach body?
folds of the organ, increase stomach surface area
what 3 types of muscle are in the stomach and what is their function?
muscularis propria/externa, LM, oblique muscle layer
help with stomach content (chyme) mixing
what cells exist in the stomach mucosa and what are their functions?
endocrine cells - produce gastrin
parietal cells - HCl secretion (gastrin stimulated)
chief cells - produces pepsinogen (degredated to pepsin by HCL)
mucous neck cells - secrete mucous to protect lining
what are villi and what is their function?
projections in SI to increase surface area for digestion/absorption
what 3 things does the duodenum receive?
chyme from stomach (through pyloric sphincter)
pancreatic fluid (through oddi sphincter at duodenal papilla)
bile from common bile duct
what is the function of brunner’s glands in the duodenum?
alkaline secretion
what are the folds in the small intestine called?
plicae
what is in each singular villi?
microvilli, lacteal (lymph capillary), blood vessels, epithelium, mucosa
what is the function of the exocrine and endocrine glands of the pancreas?
exocrine - secretes digestive enzymes and bicarbonate ions
endocrine - secretes hormones (insulin, glucagon, somatostatin)
what do insulin and glucagon do?
insulin - promotes glucose absorption of blood into liver, muscle and fat
glucagon - promotes glycogen returning into bloodstream
what does somatostatin do?
reduces acid secretion and reduces digestion
what are some of the functions of the liver?
produces bile (through cystic duct)
detoxification of absorptions from GI tract
synthesises proteins (clotting factors/platelet regulation)
regulates blood glucose
inactivates hormones/drugs
where does the liver get its blood supply?
hepatic artery and hepatic portal vein
what do the common/left/right hepatic ducts do?
transport bile to gallbladder
what is the purpose of the caecum?
chyme resevoir
what does the ilial/caecal valve do?
prevents reflux of chyme
what flexures connect the different aspects of the colon?
ascending -> transverse - hepatic (right colic)
transverse -> descending - splenic (left colic)
what are taenia coli? what is their function?
3 longitudinal bands of smooth muscle from appendix to sigmoid colon
they facilitate circular muscle contraction
what are haustrations?
ring-like circular muscle in the large intestine
what are appendices epiploicae?
pouches of peritoneum filled with fat
what do goblet cells do in the large intestine?
mucous production
what are the main vessels of blood supply in the GI tract?
coeliac trunk (stomach/liver/spleen/duodenum)
superior mesentric artery (jejunum, ilium, caecum, ascending colon)
inferior mesentric artery (transverse/descending/sigmoid colon, rectum)
what blood vessels allow for GI tract venous drainage?
inferior mesenteric vein (hind gut)
superior mesenteric vein (mid gut)
portal vein (unpaired abdominal organs)
hepatic vein (to heart)
