Upper GI Tract Structure and Function

Question 1

why do we chew?

Answer 1

prolong taste experience

defence against respiratory failure

Question 2

how is chewing controlled?

Answer 2

somatic nerves –> skeletal muscles of mouth and jaw

reflex –> contraction of jaw muscles - pressure of food against gums, hard palate and tongue - mechanoreceptors - inhibition of jaw muscles - reduced pressure - contraction - …

Question 3

what are the salivary glands called?

Answer 3

sublingual, submandibular and parotid

Question 4

what is in saliva, and what are their roles?

Answer 4

water - softens moistens, dilutes particles
mucins - creates viscous solution, lubricant function
a-amylase - catalyses breakdown of polysaccharides into disaccharides and glucose
electrolytes - tonicity / pH
lysozymes - bacteriocidal