Gastro 1

Question 1

What is the digestive system (DS) and what does it include?

Answer 1

The digestive system, also known as the gastrointestinal or alimentary canal, is a long, hollow, muscular tube that extends from the oral cavity to the anus. It comprises the primary organs—oral cavity, pharynx, esophagus, stomach, small intestine, and large intestine—and is supported by accessory organs and glands (teeth, tongue, salivary glands, liver, gallbladder, and pancreas).

Question 2

What are the six primary digestive processes, and why are they essential?

Answer 2

The six primary digestive processes are ingestion, propulsion, mechanical digestion, chemical digestion, secretion, and absorption (followed by defecation). These processes break down complex macromolecules (proteins, carbohydrates, lipids) into their absorbable subunits, enabling energy production, cell repair, and overall nutrient assimilation.

Question 3

How is mechanical digestion different in the oral cavity compared to the stomach and small intestine?

Answer 3

In the oral cavity, mechanical digestion involves mastication (chewing) by the teeth and mixing with saliva by the tongue to form a food bolus, which increases the surface area for enzyme action. In the stomach, mechanical digestion involves churning to mix food with gastric juices, and in the small intestine, segmentation movements further mix food with digestive enzymes for optimal absorption.

Question 4

What roles do accessory organs play in digestion?

Answer 4

Accessory organs such as the salivary glands, liver, gallbladder, and pancreas secrete enzymes, bile, and other fluids that facilitate chemical digestion, emulsification of fats, and neutralization of stomach acid. They are vital for efficient breakdown of complex food molecules.

Question 5

How does the structure of the gut wall relate to its digestive function?

Answer 5

The gut wall is multilayered and highly specialized. Its mucosal layer, with its villi and microvilli, maximizes surface area for absorption. The muscularis layer drives peristalsis and segmentation, moving and mixing food to enhance digestion and absorption, while the submucosa contains blood vessels and nerves that support these functions.

Question 6

The DS is a long hollow muscular tube extending from

Answer 6

the mouth to the anus.

Question 7

Primary organs include the

Answer 7

oral cavity, pharynx, esophagus, stomach, small intestine, and large intestine.

Question 8

Accessory organs (teeth, tongue, salivary glands, liver, gallbladder, pancreas) support

Answer 8

digestion.

Question 9

The DS integrates

Answer 9

ingestion, propulsion, mechanical and chemical digestion, secretion, absorption, and defecation.

Question 10

Mechanical digestion increases

Answer 10

food surface area, facilitating chemical digestion.

Question 11

The mucosal layer of the gut wall contains

Answer 11

villi and microvilli to optimize nutrient absorption.

Question 12

The liver is part of the alimentary canal.

Answer 12

False – The liver is an accessory organ.

Question 13

Chemical digestion transforms macromolecules into absorbable subunits.

Answer 13

True

Question 14

Peristalsis and segmentation are both types of propulsion in the DS.

Answer 14

True

Question 15

Mechanical digestion only occurs in the oral cavity.

Answer 15

False – It also occurs in the stomach and, to a lesser extent, in the intestines.

Question 16

Defecation is the process that eliminates only indigestible waste materials.

Answer 16

True

Question 17

______ is the process of taking food and liquid into the digestive tract through the oral cavity.

Answer 17

Ingestion

Question 18

The muscular contractions that move food along the DS are known as ______.

Answer 18

Peristalsis

Question 19

______ digestion involves the physical breakdown of food into smaller particles without chemical change.

Answer 19

Mechanical

Question 20

The enzyme-rich secretions from accessory glands assist in ______ digestion by chemically breaking down food.

Answer 20

Chemical

Question 21

The inner lining of the small intestine, with its villi and microvilli, is specialized for ______.

Answer 21

Absorption

Question 22

Which of the following is NOT a component of the primary digestive organs?
A) Stomach
B) Small intestine
C) Gallbladder
D) Esophagus

Answer 22

C) Gallbladder (It is an accessory organ.)

Question 23

What is the primary purpose of mastication in the oral cavity?
A) To chemically digest proteins
B) To mix food with gastric acid
C) To reduce food particle size and increase surface area
D) To neutralize stomach acid

Answer 23

C) To reduce food particle size and increase surface area

Question 24

Which digestive process involves the mixing of food with enzymes and other secretions?
A) Ingestion
B) Propulsion
C) Secretion
D) Absorption

Answer 24

C) Secretion (It aids chemical digestion.)

Question 25

The villi in the small intestine serve primarily to: A) Produce digestive enzymes B) Increase the surface area for nutrient absorption C) Generate peristaltic waves D) Store bile

Answer 25

B) Increase the surface area for nutrient absorption

Question 26

What is the role of segmentation in the digestive tract? A) To propel food rapidly from the stomach B) To mix and break down food mechanically C) To facilitate the initial breakdown of food in the mouth D) To contract the esophagus during swallowing

Answer 26

B) To mix and break down food mechanically

Question 27

A patient complains of chronic indigestion and bloating. Endoscopic examination reveals reduced villi density in the small intestine. Question: How might this finding affect nutrient absorption, and what could be a potential diagnosis?

Answer 27

A: Reduced villi density decreases the absorptive surface area, leading to malabsorption of nutrients. This could be indicative of conditions such as celiac disease.

Question 28

An individual presents with difficulty swallowing and frequent regurgitation. Imaging studies show abnormalities in the pharyngeal phase of deglutition. Question: Which digestive process is primarily affected, and what therapeutic strategies might be considered?

Answer 28

A: The process of ingestion and initial propulsion (deglutition) is impaired. Therapeutic strategies may include swallowing therapy, dietary modifications, or interventions to correct the structural abnormality.

Question 29

A patient with gallstones reports severe postprandial pain and fatty food intolerance. Question: Explain how the accessory organs of the DS are involved in this clinical presentation.

Answer 29

A: Gallstones can obstruct the bile ducts, impairing bile secretion from the liver and storage in the gallbladder. Bile is essential for emulsifying fats; its deficiency leads to poor fat digestion and the associated symptoms.

Question 30

A malnourished patient is found to have significantly reduced mechanical breakdown of food due to poor dentition. Question: What is the potential impact on chemical digestion and nutrient absorption?

Answer 30

A: Inadequate mastication reduces the surface area of food, hindering effective chemical digestion by enzymes. This leads to inefficient nutrient extraction and subsequent malabsorption, worsening the patient's nutritional status.

Question 31

Ingestion:

Answer 31

The process of taking food and liquids into the mouth.

Question 32

Propulsion:

Answer 32

The movement of food along the digestive tract, primarily via peristalsis.

Question 33

Mechanical Digestion:

Answer 33

Physical breakdown of food (e.g., chewing, churning in the stomach) that increases surface area.

Question 34

Chemical Digestion:

Answer 34

Enzymatic breakdown of complex macromolecules into simpler absorbable units.

Question 35

Secretion:

Answer 35

The release of fluids (enzymes, acids, bile) by glands and the gut epithelium to aid digestion.

Question 36

Absorption:

Answer 36

The process by which digested nutrients are taken up by the intestinal epithelium and transported into the bloodstream or lymph.

Question 37

Defecation:

Answer 37

The elimination of indigestible waste material from the body.