Introduction to Digestion

Questions and Answers

Which hormone is NOT secreted by the pancreas?

Glucagon

Cortisol (correct)

Somatostatin

Insulin

What is the primary function of trypsin and chymotrypsin secreted by the pancreas?

Digests carbohydrates

Digests proteins (correct)

Neutralizes acidic chyme

Digests fats

Which procedure is commonly used to diagnose pancreatitis?

Ultrasound (correct)

MRI scan

Blood test

X-ray

What pH level do pancreatic enzymes have when secreted into the duodenum?

8 Signup and view all the answers

Which factor is NOT a known cause of pancreatitis?

Heavy exercise Signup and view all the answers

What is a common treatment for pancreatitis?

IV fluids and pain medications Signup and view all the answers

What is digestion primarily responsible for?

Breaking down large food molecules for absorption Signup and view all the answers

Which of the following nutrients is NOT broken down into smaller units during digestion?

Minerals Signup and view all the answers

What role do bacteria play in the gastrointestinal (GI) tract?

They help with food digestion Signup and view all the answers

Which of the following describes mechanical digestion?

Physical movement of food in the digestive tract Signup and view all the answers

What is the function of digestive enzymes?

To decompose macromolecules into smaller units Signup and view all the answers

Which major nutrient is broken down into amino acids during digestion?

Proteins Signup and view all the answers

What does absorption in the digestive system involve?

Transport of nutrients into blood or lymph fluid Signup and view all the answers

Which of the following is a product of fat digestion?

Fatty acids and glycerol Signup and view all the answers

What is the primary function of hydrochloric acid (HCl) in the stomach?

To activate pepsinogen and provide suitable pH for enzyme action Signup and view all the answers

Which cell type is responsible for producing the hormone gastrin?

G-cells Signup and view all the answers

What is the pH range of gastric juice, making it the lowest in the body?

0.9 to 1.5 Signup and view all the answers

Which component is primarily responsible for neutralizing acid in the mucus layer of the stomach?

HCO3- Signup and view all the answers

Pepsin is most effective at breaking down proteins at what pH level?

pH 2.0 Signup and view all the answers

What is the role of somatostatin in the stomach?

Inhibit gastric acid and hormone secretion Signup and view all the answers

Which statement about pepsinogen is true?

It is activated by hydrochloric acid. Signup and view all the answers

What is the volume range of gastric juice produced per day?

1.5 to 2.5 L Signup and view all the answers

What is the primary role of pancreatic amylase in digestion?

To convert starch to maltose and glucose Signup and view all the answers

Which hormone inhibits gastric secretion and gastrointestinal motility?

Gastrin Inhibitory Polypeptide Signup and view all the answers

How does bile facilitate digestion?

By promoting fat digestion and absorption Signup and view all the answers

What is the main source of bicarbonates in the small intestine?

Pancreatic juice Signup and view all the answers

What does enterohepatic cycling mainly involve?

Absorption of bile salts by the small intestine and reuse by the liver Signup and view all the answers

Which enzyme is responsible for fat digestion in pancreatic juice?

Lipase Signup and view all the answers

What is the primary nutrient absorbed through bile?

Fats and fat-soluble vitamins Signup and view all the answers

Which of the following compounds helps to protect the intestinal mucosa from gastric acid erosion?

Water and bicarbonates Signup and view all the answers

What is a common sensation associated with constipation?

Feeling that not all stool has passed Signup and view all the answers

Which autonomic nervous system primarily exerts an inhibitory effect on the GI muscle?

Sympathetic nervous system Signup and view all the answers

What do the submucous and mucosal nerve plexus primarily regulate?

Secretion of digestive juices and blood vessels Signup and view all the answers

What might be recommended if constipation is caused by a blockade?

Surgery Signup and view all the answers

Which nerves control the oral cavity and the external anal sphincter?

Somatic nerves Signup and view all the answers

How do enteric nerves respond when food stretches the walls of the GIT?

They release substances to regulate bowel movement Signup and view all the answers

What type of effect does the parasympathetic nervous system have on gastric and intestinal tone?

Both excitatory and inhibitory control Signup and view all the answers

What lifestyle change can help alleviate constipation?

Increasing liquid intake Signup and view all the answers

Study Notes

Digestion Overview

Digestion: The breakdown of large insoluble food molecules in the digestive tract for absorption.
Absorption: Nutrients from digested food cross the mucosa of the alimentary tract to enter blood or lymph fluids.

Importance of Digestion

Microbiome/Gut Flora: Bacteria in the GI tract aid in digestion.
Essential for absorbing nutrients from daily food and beverages for bodily functions.

Nutrient Breakdown

Major nutrients include proteins, carbohydrates, fats, vitamins, minerals, and water.
Proteins: Broken down into amino acids.
Fats: Decomposed into fatty acids and glycerol.
Carbohydrates: Converted into simple sugars.

Types of Digestion

Mechanical Digestion: Involves grinding, agitating, and pushing food through the digestive tract.
Chemical Digestion: Decomposes macromolecules into micromolecules using digestive enzymes, bile, and stomach acid.

Mouth Functionality

Tongue assists in pushing food to the throat.
Cell Types:
- Parietal Cells: Produce hydrochloric acid (HCl).
- Chief Cells: Produce pepsinogen.
- G Cells: Secrete gastrin hormone.
- D Cells: Secretes somatostatin.

Stomach Acidity and Components

Gastric Juice: Colorless liquid, pH 0.9-1.5, volume 1.5-2.5L/D.
Components: Hydrochloric acid, pepsinogen, mucus, intrinsic factor, and bicarbonate.

Function of Hydrochloric Acid (HCl)

Activates pepsinogen and aids in protein digestion (proteolysis).
Promotes secretion of pancreatic juice, bile, and small intestinal juice.
Facilitates absorption of iron and calcium by intestinal mucosal cells.

Pepsin and Mucus Function

Pepsin: Breaks down proteins; inactive when secreted, requires activation.
Mucus: Contains glycoprotein; neutral pH protects mucosa by neutralizing acid.

Digestion in the Small Intestine

Water & Bicarbonates: Neutralize gastric acid, protect the intestinal mucosa.
Pancreatic Enzymes:
- Amylase: Converts starch to maltose and glucose.
- Lipase: Digests fats.
- Trypsin and Chymotrypsin: Aid in protein digestion.

Role of Bile

Secreted by the gallbladder to promote fat digestion and absorption of fat-soluble vitamins.

Enterohepatic Circulation

Over 90% of bile salts absorbed in the terminal ileum; recycled to the liver.
New bile formed and secreted back into the intestine.

GI Tract Innervation

Autonomic Nervous System: Supplies the GI tract, regulates movement and secretion.
Enteric Nervous System: Controls local functions within the GI wall.
Sympathetic System: Primarily inhibitory, regulates blood flow.
Parasympathetic System: Controls gastric and intestinal tone and motility.

Pancreatic Function

Produces 1-1.5L of digestive juice daily.
Pancreatic Juice: Contains enzymes (amylase, lipase, trypsin, chymotrypsin) for digesting carbohydrates, fats, and proteins.

Clinical Relevance: Pancreatitis

Inflammation of the pancreas due to digestive enzymes attacking it.
Causes include alcohol abuse, gallstones, and abdominal injury.
Diagnosed via ultrasound or CT; treatment involves IV fluids, pain management, and potential surgery for gallstones or tumors.

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Description

This quiz focuses on the processes of digestion and absorption within the digestive system. It covers how large food molecules are broken down and absorbed into the body through the alimentary tract. Test your knowledge of these fundamental biological processes.