Digestive System Flashcards

Questions and Answers

What are the 4 layers of the digestive tract?

Mucosa, submucosa, muscularis externa, serosa

Define peristalsis and segmentation.

Peristalsis: a wavelike muscle contraction that moves food bolus along esophagus; Segmentation: occurs in the small intestine, involving contraction of circular muscles to break up food and move it along the gastrointestinal tract.

Briefly describe the 6 gastrointestinal activities.

1-Ingestion, 2- Propulsion, 3- Mechanical breakdown, 4- Digestion, 5- Absorption, 6- Defecation.

What are the 3 pairs of salivary glands?

Parotid, sublingual, submandibular Signup and view all the answers

What is the function of saliva?

To moisten food as it is mechanically digested and begin chemical digestion using enzymes. Signup and view all the answers

What enzymes are found in saliva?

Salivary amylase, lingual lipase Signup and view all the answers

Briefly describe the structure of a tooth.

From top to bottom: crown, neck, root; from inside out: nerves and blood vessels, pulp/root canal, dentin and dentinal tubules, enamel. Signup and view all the answers

What are the 4 major regions of the stomach?

1- Cardial part, 2- Fundus, 3- Body/mid portion, 4- Pyloric part. Signup and view all the answers

What are the four different types of cells found in the stomach wall, and what does each produce?

Mucus neck cells: unknown purpose, Parietal cells: secrete intrinsic factor and HCl, Chief cells: produce pepsinogen, Enteroendocrine cells: release chemical messengers. Signup and view all the answers

Summarize the digestive processes that occur in the stomach.

Churning or mechanical digestion, storage of food, breakdown by pepsin. Signup and view all the answers

What is protein allergy and what causes it?

An allergic reaction when a whole protein is absorbed and acts as an antigen, most common in newborns due to immaturity of their intestinal mucosa. Signup and view all the answers

What are the 3 sections of the small intestine?

Duodenum, jejunum, ileum Signup and view all the answers

How does the structure of the small intestine contribute to the efficiency of absorption?

The folds and villi maximize surface area available for absorption. Signup and view all the answers

What are the 3 general categories of functions of the liver?

Bile production and excretion, metabolism of fats, proteins, and carbohydrates. Signup and view all the answers

What are the gastric glands of the fundus and body of the stomach? What do they produce?

Fundic glands: HCl and intrinsic factor; Cardiac glands: mucus; Pyloric glands: gastrin. Signup and view all the answers

What is the function of bile?

To emulsify lipids for ease of absorption. Signup and view all the answers

Know the following hormones and their digestive action: gastrin, somatostatin, intestinal gastrin, secretin, CCK, GIP, and VIP.

Gastrin: increases HCl, stimulates gastric emptying; Somatostatin: inhibits gastric secretion; Secretin: inhibits gastric secretions, increases bile output; CCK: stimulates enzyme-rich pancreatic juice; GIP: inhibits HCl production. Signup and view all the answers

What are the digestive roles of the pancreas, liver, and gall bladder?

Pancreas: produces bicarbonate and digestive enzymes; Gall bladder: stores bile; Liver: produces bile. Signup and view all the answers

What is produced in the large intestine during the process of absorption?

Feces, gas Signup and view all the answers

What is the bacterial flora of the large intestine? What does it do?

Friendly bacteria that play a role in breaking down hard to digest food and in immunity. Signup and view all the answers

What are micelles, chylomicrons, and lipoproteins?

Vessels for the transport of lipids; Micelles transport fats, Chylomicrons transport triglycerides, Lipoproteins transport fat in blood plasma. Signup and view all the answers

Know the process of emulsification, digestion, and absorption of fats.

Lingual lipase in the mouth, gastric lipase in the stomach, emulsification by bile salts, pancreatic lipases. Signup and view all the answers

Study Notes

Layers of the Digestive Tract

Four layers: Mucosa, Submucosa, Muscularis Externa, Serosa

Peristalsis and Segmentation

Peristalsis: Wavelike muscle contraction that moves food bolus in the esophagus.
Segmentation: Circular muscle contractions in the small intestine that further break down food and aid in movement through the gastrointestinal tract.

Gastrointestinal Activities

Ingestion: Taking food into the digestive system.
Propulsion: Involves swallowing and peristalsis.
Mechanical Breakdown: Includes chewing, mixing, churning, and segmentation.
Digestion: Enzymatic breakdown of complex food molecules into monomers.
Absorption: Nutrient passage into blood and lymph via transport mechanisms.
Defecation: Elimination of indigestible substances through the anus.

Salivary Glands

Three pairs of salivary glands: Parotid (near ears), Sublingual (under tongue), Submandibular (under mandible).

Function of Saliva

Moistens food during digestion and initiates chemical digestion using enzymes.

Enzymes in Saliva

Salivary Amylase: Breaks down carbohydrates.
Lingual Lipase: Aids in fat digestion.

Tooth Structure

Top to bottom: Crown, Neck, Root.
Inside out: Nerves and Blood Vessels, Pulp/Root Canal, Dentin with Dentinal Tubules, Enamel.

Major Regions of the Stomach

Cardial Part: Entry area from esophagus.
Fundus: Dome-shaped section.
Body: Middle section of the stomach.
Pyloric Part: Funnel-shaped, includes Pyloric Antrum, Canal, and Sphincter.

Stomach Wall Cells

Mucus Neck Cells: Function is not fully understood.
Parietal Cells: Secrete intrinsic factor and components of hydrochloric acid (HCl).
Chief Cells: Produce pepsinogen, which activates to pepsin.
Enteroendocrine Cells: Release hormones like histamine and gastrin.

Digestive Processes in the Stomach

Mechanical digestion through churning.
Food storage capacity of up to 1 gallon.
Breakdown of food facilitated by pepsin, activated by HCl.

Regulation of Gastric Juice

Neural: ACh release stimulates gastric juice secretion.
Hormonal: Gastrin stimulates HCl secretion.

Mechanism of HCl Secretion

Generation of H+ and HCO3- from carbonic acid dissociation.
H+ is pumped into lumen, K+ into cells.
Cl- exchanged with HCO3-.
Cl- then diffuses into the lumen.

Bile Function

Emulsifies lipids for absorption.

Digestive Hormones

Gastrin: Increases HCl secretion, stimulates gastric emptying.
Somatostatin: Inhibits gastric secretions and absorption.
Secretin: Inhibits gastric activity, increases pancreatic juice output.
CCK: Triggers bile release and stimulates pancreatic enzyme secretion.
GIP: Inhibits HCl production, promotes insulin release.
VIP: Increases secretions, dilates intestinal vessels.

Digestive Role of Pancreas, Liver, and Gallbladder

Pancreas: Produces bicarbonate and digestive enzymes.
Gallbladder: Stores bile for fat breakdown.
Liver: Produces bile for fat emulsification.

Mechanism for Bile and Pancreatic Juice Secretion

CCK and secretin are released in response to fatty and acidic chyme.
CCK induces enzymes from acinar cells, while secretin stimulates bicarbonate-rich juice from duct cells.
Bile salts prompt liver secretion, while CCK causes gallbladder contraction.

Products of Large Intestine Absorption

Formation of feces and gas.

Bacterial Flora in the Large Intestine

"Friendly" bacteria aid in digestion and immunity.

Lipid Transport Mechanisms

Micelles: Transport lipids from digestion.
Chylomicrons: Carry dietary triglycerides, made water-soluble by protein surface.
Lipoproteins: Transport fat and lipids in blood plasma.

Processes Involved with Fats

Lingual lipase initiates fat digestion in the mouth.
Gastric lipase continues in the stomach.
Bile salts emulsify fats to facilitate pancreatic lipase action.

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Description

Test your knowledge of the digestive system with these flashcards! This quiz covers the four layers of the digestive tract and important processes such as peristalsis and segmentation. Perfect for students studying human anatomy and physiology.