Session 1 Flashcards
what kind of surface is the lumen of the gut
external surface lined with epithelia
what is the enteric system
semi-autonomous, controlling motot functions of the gut, local blood flow, secretions and transport across the mucosa
where is the enteric system
contained within the submucosa- meissner’s plexus and between the external muscle layers- auerbach’s plexus
layers of the gut tube
mucosa
submucosa
external muscle layers- circular then longitudinal
serosa
how does the number of gobelt cells change from duodenum to colon
increase
what does the mucus in the gut do
protects from friction, chemical damagr, and bacteria
what folds are in the gut and what do they do
rugae in the stomach - temporary
plicae circularis- small intestine permanent forms
haustra in colon
increase SA
what are crypts
invaginations of the epithelial surface of the small intestine and are present in both small and large intestine
what are the 4 major muscle groups that form thne anterolateral abdominal wall
external oblique
internal oblique
transverse abdominus
Rectus abdominus
what is the peritoneal cavity
mesothelium lined cavity that contains nothing but a small amount of lubricating fluid. this cavity is a potential space formed by a continuous layer of peritoneum.
what is a mesentry
a double layer og peritoneum lying inbetween is blood and lymph vessels and fat
intraperitoneal structures
abdominal viscera\ that are enveloped in peritoneum
retroperitoneal structures
SAD PUCKER
abdominal viscers that lie behind the peritonium
Suprenal glands- adrenal Aorta Duodenum Pancreas Ureters Colon Kidney Eoesophagus Rectum
what is aponeurosis
thin sheet like tendon
origin, insertion and action of external oblique
5th and 12th rib
iliac crest, linea alba and inguinal ligameny
flex the trunk and rotate the core contralaterally
origin, insertion and action of internal oblique
thoracolumba fascia and iliac crest
lower 3/4 ribs linea alba via aponeurosis
rotation in the same direction, flex trunk, ipsilateral rotataer
origin, insertion and action of transverse abdominus
costal cartilages of lower ribs, thoracolumber fascia, medial lip of iliac crest and portion of inguinal ligament
linea alba and pubic crest via aponeurosis
compress abdominal contents
nerve supply of abdominal muscles
anterior rami- T7 - T12 - ALL
internal oblique and transverse abdominus are also innervated by L1
origin, insertion and action of rectus abdominus
origin: pubic crest, pubic tubercle and pubic symphysis
insertion: costal cartilages of ribs 5-7 and xiphoid process
action: Flexion of the trunk (flexion of thoracic and lumber spine), while it works by drawing pubic symphysis and sternum toward each other. Tense the anterior wall of the abdomen and assist in compressing the contents of the abdomen.
what is the rectus sheath
the aponeurosis of the lateral muscles surrounding the rectus abdominus
what is the arcuate line
lower limit of the posterior layer of rectus sheath
roughly halfway between umbilicus and pubic crest
what is gastrin
produced by G cells in the antrum of the stomach
increases gastric acid secreetion
what is cholecystokinin
i cells in duodenum and jejenum
increases pancreatic/ gall bladder secretions
stimulated by fat and protein
gall bladder contracts
pancreas stimulated
secretin secretion
secreted by s cells in duodenum
what stimulates secretin secretion
stimulated by H+ and fatty acids
secretin function
increases HCO3 from pancreas/ gallbladder
decreases gastric acid secretion
where is GIP secreted
cells in the duodenum and jejenum
what stimulates GIP secretion
sugars, amino acids and fatty acids
GIP Function
increases insulin
decreaed gastric acid secretion
what is GIP
gastric inhibitory peptide
what are enteroendocrine cells
predominantly located deeper in crypts and gastric glands
-secrete hormons that control the function of the gut
what are brunner glands
secrete an alkline mucoid material and put into the base of crypts to neutralse the acid chyme from stomach
where do lipids go whne theyre absorbed from the gut
lymph capillaries
what is chyme
a fluid that passes out from the stomach that consists of gastric secretions and partially digested food
broad function of mouth
physical breakdown of food
initiat digestive enzymes released
infectio conrol
Function of oesophagus
rapid transport of bolus to stomach through thorax
UOS
upper oesphageal sphincter- prvents air from entering GI tract
LOS
helps prevents reflex into oesophagus
stomach
storage facility
produce chyme
infection control.
secrete intrinsic factor
duodenum function
start of SI
neutralisaion of chyme
digestion
jejenum/ ileum function
final digestion nutrient absorption water/ electrolyte absorptiom- mainly ileum bile recirculation- ileum B12 absorption- terminal ileum
large bowel function
final water absorption
temporary storage
final electrolyte absorption
what type of epithelia ios present in the GI system
stratified sqamous in oesophagus and distal anus
everything in between is simple columnar
what divides the gut into its various areas
sphincters
what 2 abdominal viscera have gland like function with respect to the GI tract
liver and pancreas
how long is the duodenum
25cm
how does the jejunum differ from the ileum
wider
longer
more folds
at what point does the GI tract enter the pelvis
end of sigmoid colon going into rectum
why is it necessary for the small intestine to have a large surface area
nutrients are moving through fast so they need multiple areas within the intestine to be absorpbed which increases the time they are in contact with the epithelium
What is the enteric system that is contained in the submucosa called
Meissner’s plexus
What is the enteric system that is contained in the muscular layers called
Auerbach’s plexus
What is malrotation
When the midgut colon ends up on the left side as only one of the 90 degree rotations occur
