Kuracloud

Question 1

What achieves food and air reaching the correct destinations in the body?

Answer 1

epiglottis and upper oesophageal sphincter

Question 2

What is the state of these components at rest?

Answer 2

epiglottis is upright and UOS is tonically active

Both structures move when swallowing so epiglottis cover trachea to ensure food bolus moves through pharynx . UOS relaxes to allow bolus to flow into oesophagus

Question 3

State of the oesophagus and trachea at rest?

Answer 3

Oesophagus is mostly collapsed and the trachea remains patent due to supporting cartilaginous discs.

Question 4

What 2 muscles make up the upper oesophageal sphincter?

Answer 4

Constrictor pharyngeal medius that is common with the circular muscle of the GI tract

Constrictor pharynges inferior in common with the longitudinal muscle layer

Question 5

Structure of the oesophagus?

Answer 5

25cm long in adult male and made of smooth and skeletal muscle. Upper oesophagus is skeletal muscle only and lower oesophagus is smooth muscle only. Middle third is a mixture of the two.
Skeletal muscle is not under voluntary control?

Question 6

Components of the lower oesophageal sphincter?

Answer 6

internal component (in circular smooth muscle of oesophageal wall)

external component (formed by right crus of diaphragm)

Question 7

What are the pressures of the oesophagus and stomach?

Answer 7

oesophagus - negative pressure

stomach - positive pressure

Question 8

What is the epithelial lining of the oesophagus like?

Answer 8

non-keratinised stratified squamous cells for wear and tear lining to protect against ingested foods, hot, cold, acidic, abrasive - extends to lower oesophageal sphincter

LOS - simple columnar epithelia as cells need to tolerate resistance against strong stomach acid

Question 9

Where does change in epithelia occur?

Answer 9

jagged line (Z line)

Question 10

Stage 0 of swallowing

Answer 10

oral phase - chewing and saliva to prepare bolus for swallowing

both sphincters are constricted

Question 11

Stage 1?

Answer 11

Pharyngeal phase - food bolus moves to back of pharynx and pharyngeal musculature guides it to oesophagus. Both sphincters open.

Question 12

Stage 2?

Answer 12

UO phase?

upper sphincter closes and superior rings of circular muscle contract as inferior rings dilate

sequential contractions of longitudinal muscle to guide food

Question 13

Stage3?

Answer 13

LO phase
food passes through LOS and that also closes

peristaltic wave pushes food into stomach

Question 14

Where is the oesophageal phase controlled?

Answer 14

centrally