Upper GIT Structure & Function Flashcards
why do you need to chew
Prolong taste experience
prevents against respiratory failure
is chewing under voluntary or involuntary control
voluntary
Somatic nerves ⇒ skeletal muscles of mouth/jaw
what is the voluntary control of chewing
Somatic nerves ⇒ skeletal muscles of mouth/jaw
what makes up the chewing reflex
Contraction of jaw muscles
what does contraction of jaw muscles result in
pressure of food against gums, hard palate and tongue ⇒ mechanoreceptors
inhibition of jaw muscles ⇒ reduced pressure ⇒ contraction
what makes up saliva
water
mucins
alpha amylase
electrolytes
lysozyme
water
99% of secreted fluid. Softens, moistens, dilutes particles. Solvent
mucins
Major glycoprotein component. Mucins + water = mucus. Viscous solution - lubricant function in GI tract
alpha amylase
Catalyses breakdown of polysaccharide (starch, glycogen) into disaccharide (maltose) + glucose
electrolytes
Tonicity/pH
lysozyme
Bacteriocidal - cleaves polysaccharide component of bacterial cell wall
what does mucous cells secrete
mucin
what do serous cells secrete
ezymes such as lipase
what controls salivary secretion
Controlled by parasympathetic and sympathetic NS
Both stimulatory
what controls the parasympathetic aspect of salivary secretion
Cranial nerves VII (facial) & IX (glossopharyngeal)
what does parasympathetic stimulate
profuse watery salivary secretion