Arbittier Digestion and Metabolism

deglutition

transport of bolus of food or liquid from the mouth to the stomach

phases of deglutition

voluntary and involuntary

voluntary swallowing

tongue pushed food bolus towards pharynx

involuntary swallowing

pharynx directs food towards digestive tract not airway

layers of esophagus

mucosa, submucosa, tunica muscularis and adventitia

mucosa epithelium

stratified squamous epithelium

parts of the mucosa

epithelium, lamina propria and muscularis mucosa

submucosa contains

vessels, lymphatics and nerves

describe the tunica muscularis

inner circular and outer longitudinal

adventitia

connective tissue

function of muscularis

to propel food

difference between the action of long and circular muscle

long contracts and circular relaxes

tunica muscularis: which species has primarily skeletal muscle with distal segments of smooth muscle?

cats, horses, pigs and humans

tunica muscularis: uniform skeletal muscle along entire length

dog and ruminant

tunica muscularis: smooth muscle along the entire length

avian

types of esophageal sphincters

upper and lower

upper sphincter

at the back/lower end of pharynx

lower sphincter

relaxes to allow food to pass into the stomach

what happens to the sphincters when swallowing does not occur?

both constricted

what cranial nerves coordinate swallowing?

trigeminal, facial glossopharyngeal, vagus and hypoglossal

what nerve provides motor control?

hypoglossal

what are the phases of phases

voluntary, involuntary and peristalsis

types of peristalsis

primary and secondary

primary peristalsis

initiated by the pharyngoesophageal action

secondary peristalsis

occurs when material remains in esophagus which is initiated by the receptive fields

how is peristalsis relaxed?

inhibition wave

esophageal innervation

enteric nervous system parasympathetic and sympathetic

how is the striated muscle innervated?

motor neurons from the medulla oblongata

somatic motor neurons in the vagus nerve

smooth muscle innervation

controlled by ENS and indirect control of ANS

myentreic plexus

responsible for generating and controlling peristaltic movements

where is the myenteric plexus?

between the two layers of the muscularis externa

submucosal plexus

controls GI secretions and local blood flow