Upper GIT (swallowing etc)

Question 1

define mastication

Answer 1

mastication is the voluntary action of mechanical breakdown and the mixing with salivary enzymes

Question 2

what is the correct order or phases in swallowing from start to finish

Answer 2

voluntary phase
pharyngeal phase
oropharengeal phase

Question 3

what occurs in the voluntary phase

Answer 3

bolus formation, tongue moves to the back of the mouth pushing the bolus with it
salivary enzymes mixed into the bolus

Question 4

what occurs in the pharyngeal phase

Answer 4

soft palate moves up and tongue moves bolus into the pharynx
constriction of the epiglottis and the windpipe is closed off - halting respiration
relaxation of the upper oesophageal sphincter

Question 5

how fast is phase 2 of swallowing

Answer 5

less than second

Question 6

what occurs in the oropharyngeal phase

Answer 6

bolus travels down oesophagus in peristaltic waves - constriction of the upper oesophageal sphincter
relaxation of the glottis for respiration to occur

Question 7

how long does it take for food to travel down the oesophagus

Answer 7

about 9 seconds

Question 8

what process is phase 3 of swallowing

Answer 8

autonomic

Question 9

what is the top 1/3 of the oesophagus controlled by

Answer 9

direct vagus nerve input to longitudinal and circular smooth muscle

Question 10

what is the lower 2/3 of the oesophagus controlled by

Answer 10

indirect input from nerve plexus between the circular muscle layers

Question 11

what occurs to swallowing if vagus is cut

Answer 11

loss of direct input to top half but peristalsis still occurs in the bottom 3rd

Question 12

what are the three regulatory mechanisms of the lower 2/3 of the oesophagus

Answer 12

increase in nerual activity to increase tone
decrease in neural activity to decrease tone
activate relaxation

Question 13

where in the stomach is food stored and why

Answer 13

food is stored in the fundus as there is little muscle and high distensibility

Question 14

which part of the stomach do peristaltic waves occur

Answer 14

body

Question 15

what happens in the body of the stomach

Answer 15

mixing of food with acid producing chyme

Question 16

what is the resting volume of the stomach and what can it expand to

Answer 16

500ml to 6L

Question 17

what is receptive relaxation

Answer 17

increases in volume of the stomach without increases in pressure

Question 18

what is the order of movement and mechanisms of chyme in the stomach

Answer 18

progressive contractions from proximal to distal parts of the stomach, post prandial contraction to retropulsion (causing mixing) to antral contraction with pyloric sphincter relaxation allowing 1.5 ml of chyme into the small intestine and the rest mixed back into the body