16.3 Pharynx and Esophagus

Question 1

What is the common name for the glottis?

Answer 1

Vocal cords

Question 2

What is the pharynx?

Answer 2

It is the cavity at the rear of the throat

Question 3

What is the function of the pharynx?

Answer 3

It acts as a common passageway for both the digestive system and the respiratory system.This necessitates mechanisms to guide food and air into the proper passageways beyond the pharynx.

Question 4

What is the function of the pharynx in the digestive system?

Answer 4

It serves as the link between the mouth and the esophagus for food

Question 5

What is the function of the pharynx in the respiratory system?

Answer 5

It provides access between the nasal passages and trachea for air

Question 6

What two things does the pharynx house in its walls?

Answer 6

The tonsils and lymphoid tissue

Question 7

What is the function of the tonsils and lymphoid tissue in the pharynx?

Answer 7

They fight off pathogens that enter the body through the mouth and nose.

Question 8

What is the motility associated with the pharynx and esophagus?

Answer 8

Swallowing

Question 9

What is swallowing?

Answer 9

The entire process of moving food from the mouth through the esophagus into the stomach

Question 10

Swallowing is a sequentially programmed…………………reflex

Answer 10

all-or-none

Question 11

What initiates swallowing?

Answer 11

When a bolus is voluntarily forced by the tongue to the rear of the mouth and into the pharynx

Question 12

What is a bolus?

Answer 12

Ball of chewed or liquid food

Question 13

Explain the whole first step process of swallowing

Answer 13

After the bolus is pushed into the pharynx, the pressure of the bolus stimulates pharyngeal pressure receptors. This sends afferent impulses to the swallowing center in the medulla of the brain stem. The swallowing center then reflexly activates in the appropriate sequence of the muscles involved in swallowing.

Question 14

What is the most complex reflex in the body?

Answer 14

Swallowing

Question 15

Explain the oropharyngeal stage of swallowing(2)

Answer 15

This stage involves moving the bolus from the mouth, through the pharynx and into the esophagus.

Question 16

What 7 properties prevent the bolus from entering the respiratory airways and direct it into the esophagus?

Answer 16

1. Swallowing temporarily inhibits the respiratory center, closing off the airways meaning you cannot breath
2. The uvula is elevated and lodges against the back of the throat, sealing off the nasal passage from the pharynx, and preventing food from entering the nose.
3. The tongue’s position against the hard palate keeps food from reentering the mouth during swallowing.
4. Food is prevented from entering the trachea primarily by the elevation of the larynx and the tight closure of the glottis across the laryngeal opening.
5. The epiglottis folds backwards down over the closed glottis for additional protection.
6. Pharyngoesophageal sphincter
7. Peristalsis

Question 17

What causes the sealing of the glottis?

Answer 17

Contraction of laryngeal muscles aligns the vocal folds tightly to seal the glottis.

Question 18

What is the epiglottis?

Answer 18

A flap of cartilagenous tissue anterior to the glottis

Question 19

With the glottis closed pharyngeal muscles to force the _______________ into the esophagus

Answer 19

bolus

Question 20

What is the function of the pharyngoesophageal sphincter?

Answer 20

It prevents air from entering the digestive tract since it remains closed during breathing. (closed most of the time) only open during swallowing

Question 21

What is the esophagus?

Answer 21

A fairly straight muscular tube that extends between the pharynx and the stomach.

Question 22

Where is the esophagus mostly situated?

Answer 22

The thoracic cavity, it penetrates the diaphragm and joins the stomach in the abdominal cavity a few cms between the diaphragm

Question 23

what is a sphincter

Answer 23

It is a ring-like muscular structure that when closed, prevents passage through the tube it guards.

Question 24

What is the actualy same of the upper esophageal sphincter?

Answer 24

pharyngoesophageal sphincter

Question 25

What is the actually name of the lower esophageal sphincter?

Answer 25

gastroesophageal sphincter

Question 26

When is the pharyngoesophageal sphincter opened and closed?

Answer 26

open: during swallowing to allow bolus to pass into the esophagus
closed: Once the bolus has entered the esophagus (during breathing which is most of the time)

Question 27

What waves push food through the esophagus to the stomach

Answer 27

Peristaltic waves

Question 28

peristaltic waves are controlled by the __________________which undergoes innervation by means of the _________

Answer 28

swallowing center, vagus nerve

Question 29

Define peristalsis

Answer 29

It is the ring-like contraction of the circular smooth muscle that move progressively forward, pushing the bolus into a relaxed area ahead of the contraction

Question 30

When do secondary peristaltic waves come into action?

Answer 30

When we swallow a large or sticky bolus, the bolus distends the esophagus which activates the stretch receptors. In response, the intrinsic nerve plexus at the point of distension initiates additional waves to clear the lodged bolus. Distension of the esophagus also increases salivary secretion to lubricate it to prevent friction.

Question 31

the gastroesophageal sphincter prevents ____________of gastric contents

Answer 31

Reflux

Question 32

What keeps the smooth muscle gastroesophageal sphincter tonically contracted?

Answer 32

Myogenic activity

Question 33

Inspiration causes ………….

Answer 33

Subatmospheric intrapleural pressure

Question 34

What is the purpose of the contraction of the gastroesophageal sphincter increasing during inspiration?

Answer 34

To reduce the chance of reflux of acidic gastric contents into the esophageal when subatmospheric intrapleural pressure would favour backward movement of gastric contents.

Question 34

What is heartburn?

Answer 34

When gastric contents in the stomach flow backwards into the esophagus. This irritates the esophagus and causes discomfort due to the acidity.

Question 35

When is the gastroesophageal sphincter open and closed?

Answer 35

open: As the bolus is going down the esophagus by peristaltic waves
closed: After the bolus has entered the stomach.

Question 36

What is the only esophageal secretion and what is its function?

Answer 36

It is mucus which serves to lubricate the passage of food to lessen the possible damage to the esophageal by any sharp edges of food. Moreover, it protects the esophagus against damage caused by acid and enzymes in gastric juice should gastric reflux occur.

Question 37

True or false: The protective mucus of the esophageal is secreted throughout the length of the digestive tract?

Answer 37

True

Question 38

Does any digestion or absorption occur during swallowing?

Answer 38

No! the process is too short.