digestive system characteristics

process that breaks macromolecules into its polymers

hydrolysis

where are digestive enzymes confined to

lumen of GI tract

premature activation of digestive enzymes in the pancreas

pancreatitis

why are digestive enzymes confined to the lumen

to avoid digesting itself

the lumen is open at both ends

continuous with the environment

where does digestion occur

outside the body

what type of transport is the GI tract

one way

1st (innermost) layer of the GI tract

mucosa

function of the mucosa

protection, digestion, and absorption

what is the function of stratified squamous epithelial mucosa

protection against friction

what is the function of the simple columnar epithelial mucosa

secretes mucus and digestive enzymes

what is the lamina propria made of

connective tissue

what does the lamina propria mcontain

lymph nodes and capillaries

what is the muscularis mucosae made of

smooth muscle

what is the function of the muscularis mucosae

moves the mucosa to enhance contact

what are the 3 sublayers of the mucosa

epithelium, lamina propria, muscularis mucosae

what is the 2nd layer of the GI tract

submucosa

what is the submucosa made of

dense connective tissue

function of the submucosa

structure, flexibility, and vessel supply

what does the submucosa contain

submucosal plexusw

what does the submucosal plexus do

provides nerve supply to the muscularis mucosae

3rd layer of the GI tract

muscularis

what is the muscularis composed of

inner circular and outer longitudinal smooth muscle

function of the muscularis

segmental contractions and peristaltic movement

segmental contraction

pulverize

peristaltic movement

propel

what does the muscularis contain

myenteric plexuswh

what does the myenteric plexus do

provide nerve supply

4th (outermost) layer of the GI tract

serosa

what is the serosa composed of

connective tissue covered by a simple squamous epithelium

what is the function of the serosa

secretes fluid into the peritoneal cavity (lubrication)