oesophagus and stomach

Question 1

what is the oral cavity bound by

Answer 1

teeth to front and sides, tongue to bottom, hard and soft plates to top, oropharynx to rear

Question 2

how many teeth in an adult human

Answer 2

32

Question 3

what types of teeth are present and how many

Answer 3

8 incisors, 4 canines, 8 premolars, 12 molars

Question 4

function of incisors and canines

Answer 4

bite and rip food

Question 5

function of premolars and molars

Answer 5

grind food down

Question 6

what is the name for the jawbone

Answer 6

mandible

Question 7

what is the largest jaw muscle

Answer 7

massater muscle

Question 8

what is the massater muscle responsible for

Answer 8

biting action

Question 9

what two major digestive enzymes do salivary glands secrete

Answer 9

lingual lipase, salivary amylase

Question 10

what is lingual lipase involved with

Answer 10

fat digestion

Question 11

what is salivary amylase involved with

Answer 11

carbohydrate digestion

Question 12

what is the name given to the mixture of food and saliva

Answer 12

bollus

Question 13

what two types of muscles form the tongue

Answer 13

intrinsic, extrinsic

Question 14

what are intrinsic tongue muscles responsible for

Answer 14

fine motor control, including enunciating specific sounds or moving food around the mouth

Question 15

what are extrinsic muscles responsible for

Answer 15

groos movements of the tongue (in, out, up, down), aiding mechanical digestion

Question 16

key functions of the tongue

Answer 16

speech, eating, taste

Question 17

what two structures ensure food reaches the stomach and air reaches the lungs

Answer 17

epiglottis, upper oesophageal sphincter

Question 18

movements of epiglottis and upper oesophageal sphincter at rest and swallowing

Answer 18

at rest the oesophageal sphincter is tonically active (both sphincters shut) and the epiglottis is upright; during swallowing (centre in brain) the epiglottis comes down to cover the entrance to the trachea as the bolus of food moves through the pharynx, and the upper oesophageal sphincter relaxes to allow it to flow into the oesophagus (swallowing has a more powerful effect on upper oesophageal sphincter (skeletal) vs lower (smooth))

Question 19

what is the oesophagus

Answer 19

conduit tube connecting oral cavity and stomach

Question 20

what two muscles form the upper oesophagael sphincter

Answer 20

constrictor pharyngeal medius, constrictor pharyngeal inferior

Question 21

what does the constrictor pharyngeal medius have commonality with

Answer 21

circular muscle layer of GI tract

Question 22

what does the constrictor pharyngeal inferior have commonality with

Answer 22

longitudinal muscle layer

Question 23

how long is the oesophagus in a typical adult male

Answer 23

25cm

Question 24

what type of muscle makes up the upper oesophagus

Answer 24

skeletal

Question 25

what type of muscle makes up the lower oesophagus

Answer 25

smooth

Question 26

what type of muscle makes the middle third of the oesophagus

Answer 26

mixture of skeletal and smooth

Question 27

what control is the oesophagus under

Answer 27

involuntary despite skeletal muscle

Question 28

what pressure is the oesophagus under most of the time

Answer 28

negative

Question 29

epithelial lining of oesophagus to jagged z-line and reason

Answer 29

non-keratinised stratified squamous cells, to allow abrasive damage (temperature and texture) of bolus without loss of function; after z-line becomes simple columnar

Question 30

epithelial lining of lower oesophageal sphincter and reason

Answer 30

simple columnar epithelia to tolerate stomach conditions

Question 31

swallowing: stage 0 - oral phase

Answer 31

chewing and saliva prepare bolus for swallowing; both oesophageal sphincters constricted

Question 32

swallowing: stage 1 - pharyngeal phase

Answer 32

bolus moves to back of pharynx, pharyngeal musculature guides towards oesophagus; both oesophageal sphincters open

Question 33

swallowing: stage 2 - upper oesophageal phase

Answer 33

upper sphincter closes; local effect as superior rings of circular muscle contract as inferior rings dilate (peristalsis); sequential contractions of longitudinal muscle guide food down; if bolus is stuck, signal up to brain so release of second peristalitc wave

Question 34

swallowing: stage 3 - lower oesophageal phase

Answer 34

food passes through lower sphincter that then closes; peristaltic wave pushes food into stomach (able to work against gravity) - gastro-oesophageal junction; partly due to diaphagm (muscular contraction) and fold of stomach (empty so opening is narrow)

Question 35

what is the major plexus which innovates the gastrointestinal tract

Answer 35

myenteric plexus

Question 36

where does the myenteric plexus lie

Answer 36

immediately superficial to circular smooth muscle layer of gut wall and immediately deep to longitudinal smooth muscle

Question 37

does absorption of nutrients occur in the oesophagus

Answer 37

no

Question 38

structure of oesophagus when food is not pasing through

Answer 38

collapsed

Question 39

what is secreted into oesophagus

Answer 39

mucous; saliva lubricates also (but from mouth)

Question 40

colour of oesophageal epithelium

Answer 40

light pink

Question 41

define digestion

Answer 41

process of breaking down macromolecules to allow absorption

Question 42

define absorption

Answer 42

process of moving nutrients and water across a membrane

Question 43

oesophagus wall: mucosa layers

Answer 43

epithelium, lamina propria (loose connective tissue), muscularis mucosae

Question 44

oesophagus wall: submucosa layer

Answer 44

connective tissue containing nerve plexus, blood vessels and glands

Question 45

oesophagus wall: muscularis layer

Answer 45

smooth muscle containing nerve plexus, blood vessels

Question 46

oesophagus wall: serosa/adventitia layer

Answer 46

connective tissue +/- epithelium

Question 47

examples of secretory tissues outside of GIT

Answer 47

liver, pancreas

Question 48

what can oesophagus impact on

Answer 48

recurrent laryngeal nerves, pericardium

Question 49

where does oesophagus originate and terminate

Answer 49

originates around C5, through thorax into stomach (in abdomen)

Question 50

close structures to oesophagus

Answer 50

trachea, aorta, diaphragm, lungs, heart