Gastrointestinal Flashcards
six roles of the digestive system
ingestion, secretion, motility, digestion, absorption, defecation
the gut layer that has:
-epithelium
-lamina propria
-muscularis mucosae
mucosa
the gut layer containing vessels and glands
submucosa
the 2 muscularis externa layers on the intestine
longitudinal, circular
the 2 components of the enteric nervous system
submucosal plexus, myenteric plexus
what is the role of the serosa layer?
structure
what is the control center of the short reflex?
interneuron in ENS
what are the 2 outputs of the short reflex?
submucosal plexus, myenteric plexus
___ _____ is the major digestive enzyme in saliva that conducts startch breakdown
a-amylase
what does a-amylase’s function depend on?
how well food is chewed
why is the starch breakdown important to occur in the mouth?
a-amylase is deactivated in the stomach due to the acidic environment
what does taste depend on?
ability to detect chemicals in the food
dissolved chemicals diffuse into pores in the tongue and are sensed by taste hairs that ____ the membrane and activate the nervous system
depolarize
____ produce thick mucus to protect us against chewing sharp material
mucins
what are the 3 ways that saliva protect?
mucins producing mucus, alkaline pH buffer against food and stomach, antimicrobial secretions
absorption of ____ ___ ____ _____ occurs in the mouth
low molecular weight molecules
what kind of drugs can be absorbed in the mouth?
sublingual/under the tongue
molecules absorbed in the mouth bypass what process?
the first round of liver metabolism
mucins produce ____ that coat food so they can move around the mouth
mucins
what is the muscularis externa of the top third of the esophagus made of?
skeletal longitudinal and circular muscle
what is the muscularis externa of the bottom 2/3 of the esophagus made of?
smooth longitudinal and circular muscle
where in the brain is swallowing integrated?
medulla oblongata
the swallowing reflex requires activation of what two types of nerve?
sensory afferent, somatic motor
once the food touches the ___ ____, the swallowing reflex is triggered (AKA stimulus)
soft palate