GI Tract Anatomy

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What is the primary function of the muscularis mucosae?

To absorb the end products of digestion

To protect against infectious disease

To facilitate local movements of the mucosa (correct)

To secrete mucus

Which part of the alimentary canal is involved in ingestion?

Oral cavity or buccal cavity (correct)

Oropharynx

Esophagus

Pharynx

What is the function of the serosa in the GI tract?

To facilitate peristalsis

To secrete mucus

To absorb the end products of digestion

To protect the GI tract (correct)

What is the function of the epithelium of the gum and hard palate?

To protect against abrasion Signup and view all the answers

What is the function of the defensins released by the oral cavity?

To protect against infectious disease Signup and view all the answers

What is the function of the lips in the oral cavity?

To protect the anterior opening Signup and view all the answers

What is the function of the muscularis externa in the GI tract?

To facilitate segmentation and peristalsis Signup and view all the answers

What is the function of the submucosa in the GI tract?

To enable the stomach to regain its shape Signup and view all the answers

In which region of the abdomen does the cecum lie?

Right iliac fossa Signup and view all the answers

What is the main function of the large intestine in terms of digestion?

Absorption of water and electrolytes Signup and view all the answers

What is the characteristic of the mucosa in the large intestine?

It has a large number of goblet cells Signup and view all the answers

Which muscle layer is incomplete in the large intestine?

Longitudinal muscle layer Signup and view all the answers

What is the function of the internal anal sphincter?

Involuntary control of anal canal Signup and view all the answers

What is the characteristic of the anal canal?

It is the last 2 to 3 cm of the digestive tract Signup and view all the answers

How many major lobes does the liver have?

Two Signup and view all the answers

What is the characteristic of the external anal sphincter?

It is composed of skeletal muscle Signup and view all the answers

What is the function of the teniae coli in the large intestine?

To create pocket-like sacs called haustra Signup and view all the answers

What is unique about the mucosa of the large intestine compared to the small intestine?

It lacks villi and enzymes Signup and view all the answers

What is the role of the vermiform appendix?

To play a role in body immunity and host enteric bacteria Signup and view all the answers

What is the function of the rectal valves?

To prevent gas from being passed with feces Signup and view all the answers

What do enteric bacteria in the large intestine synthesize?

B complex vitamins and most of vitamin K Signup and view all the answers

What stimulates mucus secretion in the large intestine?

Tactile stimulation of the mucous cells Signup and view all the answers

What is the function of mucus in the large intestine?

To protect the wall against excoriation and bacterial activity Signup and view all the answers

Why is the colon not essential for life?

Because no food breakdown occurs except for that done by enteric bacteria Signup and view all the answers

What is the primary mechanism by which the stomach empties its contents into the duodenum?

Each strong antral peristaltic wave forcing several milliliters of chyme into the duodenum Signup and view all the answers

What is the main function of enterogastric nervous reflexes from the duodenum?

To inhibit antral propulsive contractions and increase the tone of the pyloric sphincter Signup and view all the answers

What is the primary factor that initiates enterogastric nervous reflexes from the duodenum?

The degree of distention of the duodenum Signup and view all the answers

How do fats in the duodenum affect gastric emptying?

They inhibit the activity of the pyloric pump and increase the tone of the pyloric sphincter Signup and view all the answers

What is the approximate length of the small intestine in a living body?

2-4 meters Signup and view all the answers

What type of movement in the small intestine is responsible for propelling chyme towards the large intestine?

Propulsive contractions Signup and view all the answers

What is the primary function of vitamin B12 in the body?

Maturation of RBCs Signup and view all the answers

What is the primary mechanism by which the stomach regulates the amount of chyme it empties into the duodenum?

Enterogastric nervous reflexes from the duodenum Signup and view all the answers

Which nerve type stimulates the secretory activity of the stomach?

Parasympathetic nerves Signup and view all the answers

What is the effect of increased food volume in the stomach on stomach emptying?

It increases stomach emptying by stretching of the stomach wall and inducing nervous reflexes Signup and view all the answers

What is the role of gastrin in the stomach?

Stimulation of HCl and enzyme secretion Signup and view all the answers

Which of the following is NOT a stimulator of parietal cells?

Insulin Signup and view all the answers

What is the effect of antihistamines on HCl secretion?

Decrease HCl secretion Signup and view all the answers

What is the mechanism of HCl formation in the stomach?

Active secretion of H+ in exchange with K+ and Na+ Signup and view all the answers

What is the primary stimulus for pepsinogen secretion?

Acetylcholine release Signup and view all the answers

What is the role of bicarbonate in the stomach?

Neutralization of acid in the stomach Signup and view all the answers