cavity within the abdomen and pelvis
epithelium that secretes a watery solution
epithelium layer with a layer of connective tissue at the basal surface
serous membrane arranged as a continuous sheet
lying againt the body wall (of the abdominal cavity)
serus membrane lying over an organ
cavity that lies between parietal and visceral membranes
double layer of peritoneal membrane- attaches organ to organ
double layer of peritoneal membrane- attaches organ to posterior wall
What are the organs in the abdominal cavity covered in?
peritoneal membrane- serous
Where does food move?
Through fauces, into oropharynx, into oesophagus
What closes the space between the mouth and nose (blocks the nasal cavity)?
What are the 3 salivary glands?
parotid- serous, submandibular-mixed, sublingual-mucous
Where does the oesophagus pierce the diaphragm?
esophageal hiatus (T10)
What does the tubular portion of the GI tract do?
mechanical digestion, chemical digestion, absorption, excretion
What are the 4 layers of the GI tract from outside to inside?
serosa (adventitia), muscularis, submucosa, mucosa
List the segments of the GI tract
Mouth, Oropharynx, Oesophagus, Stomach, SI (duodenum, jejunum, ilieum), LI (cecum, colon, rectum), anal canal
What are the accessory organs of the GI system?
salivary galnds, tongue, teeth, liver, gallbladder, pancreas, appendix
What kind of epithelium lines the oesophagus?
stratified squamous epithelium
What are the functions of the stomach?
storage, mechanical and chemical digestion, mixing
Describe the wall of the stomach
Adventitia (serosa over that), muscularis (longitudinal, circular, oblique- innermost) submucosa, mucosa
eosphagus enters stomach at
lower eosphageal sphincter
3 parts of stomach
Fundus, body and pylorus
What separates the stomach from the duodenum?
what are the 4 types of modified epithelia cells?
mucous cells, pariteal cells, chief cells, endocrine cells
What do paritetal cells do?
secrete HCl, membrane invaginations- caniliculi
To assist with digestion and absorption we need...
movement, large SA, enzymes
describe the wall of the small intestine
adventitia, muscularis (longitudinal and circular muscle), submucosa, mucosa
what is the inner surface of the SI like?
inside surface folded- pilcae circulares, contains villus- finger like extensions of lamina propria (capillary network, lymph vessels- lacteals), covered in epithelium
For digestion and absorption in the SI we need..
movement, large SA, enzymes, delivery of absorbed products
What is the volume of the stomach?
Where is the stomach found?
In the abdominal cavity, under the liver and diaphragm
Chief cells secrete
Parietal cells secrete
HCl and intrinsic factor
Endocrine cells secrete
Goblet cells secrete
What are the 3 divisions of the small intestine?
Duodenum, Jejunum, ilieum
How is the intestinal lining of the SI folded?
submucosa folded into circular pilcae that have tiny projections called villi, epithelial cells have a brushborded of microvilli where digestive enzymes are produced
How long is the Large intestine?
length= 1.5-1.8m, diameter= 6cm
How long is the small intestine?
length= 6m, diameter= 2.5cm
what are the divisions of the large intestine?
cecum, colon and rectum
What are the 4 parts of the colon?
ascending, descending, transverse and sigmoid colon
Where does the large intestine start?
at the cecum
what is the terminal arch of the rectum called?
The mucous lining of the rectum is arranged into numerous folds called...
anal columns each of which contains an artery and a vein
What glands does the wall of the large intestine contain?
intestinal mucous glands- produce mucus that coats the faeces as they are formed.
What epithelium lines the rectum?
What 2 sphicters does the rectum contain?
internal- smooth, and external-skeletal
internal sphicter relaxes, external sphincter contracts
In the large intestine, how are the muscles arranged?
longitudinal- tenae coli, circular- rings that produce pouch-like haustra between them
Where is the vermiform appendix found?
behind the cecum or over the pelvic ring. 8-10cm long
what does retroperitoneal mean?
Only have peritoneum on their anterior side. eg pancreas
Where is the pancreas found?
head in C-shaped duodenum, tail in spleen, behind the stomach
How long is the pancreas?
12-15cm long, 60g
What are the 2 secretory units of the pancreas?
endocrine (into blood) and exocrine (ducts)
How are secretory products delivered into the duodenum?
via the greater duodenal papillae (if in pancreas) or from gallbladder via cystic duct
What do exocrine cells secrete?
What do ducts secrete?
What is an acinus?
spherical cluster of cells, duct begins in centre (exocrine tissue)
Name 3 unicellular glands?
mucous, chief, parietal cells
Name 3 multicellular glands?
salivary glands, pancreas, mucous glands in submucosa
Why is there a large blood supply to the GI organs?
Supply nutrients (arterial), remove wastes (venous), remove nutrients for rest of body
What are the 3 branches of the abdominal aorta?
superior and inferior mesenteric, celiac trunk
Which organs does the Celiac trunk mostly innervate?
gastric organs- liver, stomach, spleen, pancreas, duodenum
What organs does the superior mesenteric mostly innervate?
SI and LI
What organs does the inferior mesenteric mostly innervate?
Describe hepatic portal circulation?
Capillaries, veins, capillaries, veins, inferior vena cava
What veins enter the liver?
What veins leave th liver?
hepatic portal vein
How is gut function regulated?
autonomic nervous system, enteric nervous system
What is the effect of sympathetic innervation?
fight or flight- constriction of blood vessels on viscera, decrease gastric motility, pancreatic secretion, salivation digestive tract sphincters contract,
What is the effect of parasympathetic innervation?
rest and digest- relaxation of sphicters, increase gastric motility, secretion of pancreatic enzymes, salivation
Where is the enteric nervous system found?
embedded in the lining of the small intestine, serosa, longitudinal muscle, myenteric plexus, circular muscle, submucosal plexus, submucosa, mucosa
How does the ENS communicate with the CNS through the parasympathetic?
via vagus nerve, plevic nerve
How does the ENS communicate with the CNS through the sympathetic?
via the sympathetic ganglia
What is the myenteric plexus?
Auerbach's plexus- between longitudinal and circular layer of muscle, has both parasympathetic and sympathetic input. Found in eosophagus, stomach and intestine
What is the meissner's plexus?
Submucosal plexus, found in submucosal coat of intestine, function is to innervate cells in the epithelial layer and the smooth muscle, only parasympathetic input
What are the receptors in the gut wall?
chemoreceptors, mechanoreceptors- stretch of gut wall, osmoreceptors
What is the role of the submuscosal plexus?
regulation of secretion
What is the role of the myenteric plexus?
regulation of motility
The parasympathetic system ______ motility and secretion
Sympathetic system ________ motility and secretion
What are 2 examples of long reflexes of the CNS?
gastroileal reflex and intestinal reflex
Compare CNS and ENS
CNS- long reflexes, doesn't directly innervate cells, ENS- short local reflexes, directly innervates muscle, secretory cells
made by gastric mucosa (stimulated by vagus nerve, or when stomach is stretched), stimulates secretion of gastric juice
Gastric inhibitory peptide (GIP)
formed by intestinal mucosa cells in presence of fat, inhibits gastric secretion and motility
formed by intestinal mucosa in presence of acid, protein, fat, inhibits gastric secretion, stimualtes secretion of pancreatic juices, bile into gall bladder
formed by intestinal mucosa in presence of fats, proteins, acids, stimulates ejection of bile into gall bladder, secretion of pancreatic juice, opposes action of gastrin