Lecture 32 Flashcards
Gastrointestinal Tract
How long is the GI tract?
4.5m from mouth to anus
What part of the GI tract is external environment and why?
The lumen because everything in there is leaving the body
What are the accessory glands and organs that are used in the GI tract BUT food does not pass through it?
- gallbladder
- pancreas
- liver
- salivary glands
The organs that food passes through?
- oral cavity
- esophagus
- stomach
- small intestine
- large intestine (colon & rectum)
what’s the function of the esophagus?
transport food to stomach
what’s the job of the small intestine
mostly chemical but mechanical as well in the duodenum
What are sphincters?
one way valves made from smooth muscles that closes and open to create compartments
What spinster separates the mouth an the esophagus
Upper esophageal sphincter
what spinster separates the esophagus and the stomach
low esophageal sphincter
what separates the stomach and the small intestine?
pyloric sphincter
what separates the small and large intestines?
ileocecal sphincter
What separates the rectum and the outside? which are do you have control of?
voluntary control of external sphincter
involuntary control of internal sphincter
what are the 4 tissues of the Gl Tract?
1) Mucosa- most inner layer
2) Submucosa
3) Muscularis Externa
4) Serosa
function of the mucosa
has a epithelium with
- stems cell to replace
- transporting cells
- secreting cells
lamina propria with lymph, blood vessels and nerves
function of submucosa
loose tissue contains blood vessels, lymph and nerves
- has the submucosal plexus (secretion function)
function of muscularis externa
layers of smooth muscle to
- constrict lumen (inner layer)
- shorten lumen (external layer)
contains the myenteric plexus for motility
function of the serosa
lubricates and protects using secretory epithelium and connective tissues
Which organ has 3 layers of muscularis externa
stomach and its the oblique layer to contract diagonally/transverse
what is the submucosal and myenteric plexus?
it is a part of the enteric nervous system which allows for secretion and motile of the GI. it is apart of the autonomic nervous system and doesn’t need input form the CNS and PNS
what are the 4 basic functions of the GI Process?
1) secretions
2) digestion
3) absorption
4) motility
what are the 2 types of motility?
peristaltic - pushing down like a empty toothpaste tube
segmental- move side to side to mix up food
After food leaves the mouth, when is it called?
bolus
after bolus enters the stomach, what is it called?
chyme
What is secreted into the GI Tract
saliva, bile, gastric , pancreatic and intestinal enzymes
how much fluid is absorbed?
7.5 in small and 1.5 in large
0.1 is excreted
long reflexes
integrated with the CNS to contribute feedback and emotional reflexes to digestion
short reflexes
no outside input
GI peptides
secreted by the long and short reflexes to alter motility and/or secrections
