Oesophagus

Question 1

What is the oral cavity bound by anatomically?

Answer 1

Teeth to the front and the sides, the tongue to the bottom and the hard and soft palates to the top and the oropharynx to the rear

Question 2

What is the massater muscle? What does it do and where is it found

Answer 2

Largest jaw muscle, responsible for biting action an lateral to the molars

Question 3

What digestive enzymes are found in the mouth?

Answer 3

Linguinal lipase and salivary amylase - first stage of fat and carb digestion respectively

Question 4

What are the two categories of muscles found in the tongue

Answer 4

Intrinsic and extrinsic

Question 5

What are intrinsic tongue muscles for?

Answer 5

fine motor control of the tongue, such as enunciating specific sounds, or for moving food from one part of the mouth to another

Question 6

What are extrinsic tongue muscles for?

Answer 6

gross movements of the tongue, such as in, out, up and down. This is especially useful to assist mechanical digestion, by pounding the food bolus against the hard palate at the roof of the mouth

Question 7

What are the key functions of the tongue?

Answer 7

speech, eating and taste (salt, sweet, bitter, sour, umami)

Question 8

What positions are the oesophageal sphincter and the epiglottis at at rest?

Answer 8

upper oesophageal sphincter. At rest, the oesophageal sphincter is tonically active and the epiglottis is in the upright position

Question 9

What happens to theoesophageal sphincter and the epiglottis during swallowing?

Answer 9

epiglottis coming down to cover the entrance to the trachea as the bolus of food moves through the pharynx, and the upper oesophageal sphincter relaxes allowing it to flow into the oesophagus

Question 10

What is the oesophagus?

Answer 10

conduit tube connecting the oral cavity and the stomach

Question 11

Where does the oesophagus pass through

Answer 11

the thorax places it in close proximity to key structures such as the heart, lungs and major blood vessels

Question 12

What are the two muscles that the upper oesophageal sphincter is made up of?

Answer 12

Constrictor pharynges medius and constrictor pharynges inferior

Question 13

What does the constrictor pharyngeal medius have a commonality with

Answer 13

circular muscle layer of the GI tract

Question 14

What does the constrictor pharyngeal inferior have a commonality with

Answer 14

longitudinal muscle layer

Question 15

How long approx is the eoesophgus in a typical adult male?

Answer 15

25cm

Question 16

What muscles are the different parts of the oesophgus made out of

Answer 16

the upper oesophagus is composed of skeletal muscle only, and the lower oesophagus is smooth muscle only. The middle third is a mixture of the two as the proportion of skeletal muscle tapers along its length

Question 17

What two parts are the lower oesophageal sphincter made out of?

Answer 17

Internal and external component

Question 18

What is the internal component built into?

Answer 18

circular smooth muscle of the oesophageal wall

Question 19

What is the external component formed by?

Answer 19

the right crus of the diaphragm (voluntary control)

Question 20

What kind of pressure is the oesophagus and the stomach usually under

Answer 20

oesophagus is under negative pressure most of the time, whereas the stomach is under positive pressure.

Question 21

What epithelium makes up the lining of the oesophagus

Answer 21

non-keratinised stratified squamous cells

Question 22

What quality does the epithelia of the oesophagus need to have

Answer 22

robust wear-and-tear lining to protect the oesophagus from a variety of ingested foods, ranging from smooth to abrasive, hot, cold and acidic

Question 23

What kind of epithelial cells are found in the lower oesophageal sphincter?

Answer 23

Simple columnar epithelia bc different conditions - resist stomach acid

Question 24

How does the epithelial cell change in the oesophagus happen?

Answer 24

Within the sphincter along a jagged line called the z line

Question 25

What are the 4 stages of swallowing

Answer 25

Stage 0 - oral phase
Stage 1 - pharyngeal phase
Stage 2 - Upper oesophageal phase
Stage 3 - Lower oesophageal phase

Question 26

What happens in the oral phase?

Answer 26

Chewing and saliva help to prepare the bolus for swallowing. Both oesophageal sphincters are constricted.

Question 27

What happens in the pharyngeal phase?

Answer 27

As the food bolus moves to the back of the pharynx the pharyngeal musculature helps to guide it towards the oesophagus. Both oesophageal sphincters open.

Question 28

What happens in the upper oesophageal phase?

Answer 28

The upper sphincter closes, and superior rings of circular muscle contract as inferior rings dilate. Sequential contractions of longitudinal muscle help guide the food down the gullet.

Question 29

What happens in the lower oesophageal phase

Answer 29

As food passes through the lower sphincter that too closes, and the peristaltic wave continues to push food into the stomach.