Digestive System: Ingestion, Stomach, and Liver

These flashcards cover key concepts about the digestive system, including ingestion, stomach functions, and the role of the liver.

What is the main purpose of the digestive system?

To process the food that an organism consumes.

What are the two main types of digestion?

Mechanical and chemical digestion.

What starts the mechanical digestion of food?

Chewing with teeth.

What components are involved in chemical digestion during eating?

Chemical processes that break food into simpler nutrients.

What are salivary enzymes responsible for?

Beginning the breakdown of starches.

What fluid is secreted during chewing?

Saliva.

What does gastric juice contain?

Enzymes and hydrochloric acid.

What is absorbed in the intestines?

Nutrients and water.

What organ is primarily responsible for digestion of fats and proteins?

The liver.

How are undigested wastes removed from the body?

Via the excretory system.

What is mechanical digestion primarily associated with in the mouth?

Chewing (mastication).

What are the three phases of swallowing?

Voluntary buccal phase and involuntary pharyngeal and esophageal phases.

What is peristalsis?

Involuntary propulsive process that moves food through the digestive tract.

What type of muscle tissue does the muscularis externa consist of?

Two layers of muscle tissue (three in the stomach).

What is the purpose of the esophagus?

To serve as a passageway for food.

What does the mucosa of the digestive tract do?

It is the innermost layer containing epithelium and secretory cells.

How long is the esophagus?

About 25 cm.

What happens during segmentation in the intestines?

Non-adjacent portions of the digestive tract contract and relax to move the chyme.

What are haustral contractions?

A form of segmentation moving chyme in the large intestine.

What does saliva contain that aids in breaking down bacteria?

Lysozyme and immunoglobulin A.

What are the major salivary glands?

Parotid, submandibular, and sublingual glands.

What is bolus?

A ball of food that is formed in the mouth after being chewed and mixed with saliva.

What does the stomach primarily store?

Food.

What does pyloric sphincter regulate?

The release of chyme into the small intestine.

What is chyme?

A creamy paste formed in the stomach as food is mixed with gastric juices.

What are the four types of cells found in gastric glands?

Mucous cells, parietal cells, chief cells, endocrine cells.

What do parietal cells secrete?

Hydrochloric acid and intrinsic factor.

What enzyme breaks down proteins in the stomach?

Pepsin.

What is the main function of the liver in digestion?

Synthesis of bile.

What is bile primarily responsible for?

Emulsifying fats.

How is bile stored?

In the gallbladder.

What hormone signals the gallbladder to contract?

Cholecystokinin (CCK).

What role does the liver play in glucose regulation?

Regulates blood glucose concentration.

What process occurs when blood sugar levels are too high?

Glycogenesis.

What is gluconeogenesis?

Production of glucose from non-carbohydrate sources.

What toxic substance does the liver convert to urea?

Ammonia.

What is the pH range of gastric juices?

1 to 3.

What does intrinsic factor assist in absorbing?

Vitamin B12.

How long does the stomach typically hold food?

About 1 liter, but can stretch to nearly four times that.

What structural feature of the stomach allows it to expand?

Rugae.

What is the primary digestive activity in the stomach?

Storage and mechanical breakdown of food.

What is the role of bicarbonate ions in saliva?

To help maintain optimal pH for salivary enzymes.

What type of digestion occurs mainly in the stomach and small intestine?

Chemical digestion.

What do the chief cells secrete besides pepsin?

Gastric lipase.

What system is the liver a crucial part of?

The gastrointestinal system.

What enhances the absorption of fat-soluble vitamins?

Bile.

What type of digestion starts in the mouth with enzymes and continues in the stomach?

Chemical digestion.

What is the muscularis externa responsible for?

Contracting to move food along the digestive tract.

What are gastric pits?

Pits in the stomach lining that lead to gastric glands.