Physio 2: motility

Question 1

What is trismus?

Answer 1

Inability to open the jaw.

Question 2

Explain the voluntary stage of swallowing.

Answer 2

1. Tongue pushes food to back of mouth.

2. Tactile sensors in tonsillar pillars (CN IX endings) sense food and send signal to the medulla

Question 3

Explain the pharyngeal phase of swallowing.

Answer 3

1. Efferents from the medulla send signals to CN V, IX, X, XII
2. Soft palate lifts to close nasopharynx
3. Trachea closed by vocal cords and epiglottis
4. Upper Esophageal Sphincter (UES) relaxes
5. Contraction of pharynx walls

Question 4

How can the enteric nervous system suffer an autoimmune attack?

Answer 4

Trypanosoma cruzi is a parasite that causes chagas disease. It has an epitope on its surface that is similar to epitopes on nerves in the enteric nervous system. When the immune system reacts to T. cruzi it can also react to the ENS.

Question 5

Neurotransmitter that relaxes the lower esophageal sphincter (LES).

Answer 5

Vasoactive Intestinal Peptide (VIP)

Question 6

What is receptive relaxation?

Answer 6

Once swallowing occurs, the stomach relaxes to allow the entrance of food.

Question 7

What is adaptive relaxation?

Answer 7

Once food enters the stomach, the stomach relaxes even more.

Question 8

What is feedback relaxation?

Answer 8

Once food reaches the duodenum and SI the stomach is told to relax to prevent any more food from entering.

Question 9

Most potent hormone that decreases Gastric Emptying.

Answer 9

Cholecystokinin (CCK)

Question 10

What does Gastrin do to gastric emptying?

Answer 10

Decreases it. Actually increases Stomach muscle contraction but also contracts the pyloric sphincter.

Question 11

What is dumping syndrome?

Answer 11

Hypertonic meals usually result in food that passes thru the stomach long before it is able to be digested. Patients have nausea, vomiting, or diarrhea.

Question 12

Hormone that controls the Migrating Myoelectric Complex (MMC).

Answer 12

Motilin
-released with vagal stimulation every 90 minutes without food to “clear” the GI tract. Presence of food stops its release.

Question 13

Describe the segmentation contractions of the small intestines.

Answer 13

A section of small intestine will contract pushing food in both directions up and down the GI tract. Then it relaxes allowing food back into the segment. This allows mixing without forward movement.

Question 14

What is peristaltic rush?

Answer 14

Strong contraction in the GI tract to remove food or contents that are irritating or causing extensive distension.

Question 15

What are mass movements?

Answer 15

Movement of fecal material through the colon by 10 - 12in. contractile rings.

Question 16

Name two muscles that, if innervation is lost, result in fecal incontinence.

Answer 16

1. Puborectalis m.

2. External Anal Sphincter