Chapter 3

Question 1

Digestive System

Answer 1

Digestive System: Includes all organs and glands involved in ingestion and digestion of food. It works with the circulatory, nervous, and hormonal systems.

Question 2

Challenges of Digestion

Answer 2

Challenges of Digestion: Involves multiple tasks like mouth functions, passage through the diaphragm, steady movement, lubrication, enzyme function, GI tract cell protection, and waste excretion.

Question 3

Digestion

Answer 3

Digestion: Breakdown of food into absorbable nutrients, later used for energy.

Question 4

Absorption

Answer 4

Absorption: Nutrients taken up by cells in the small intestine (SI) for transport into the blood or lymphatic system.

Question 5

Organs

Digestive Tract Anatomy

Answer 5

Organs: Mouth, esophagus, stomach, small intestine, large intestine, rectum, and anus. Connected by the lumen (inner space from mouth to anus).

Question 6

Mouth

Answer 6

Function: Digestion begins with chewing and saliva production. Saliva helps in swallowing and begins carbohydrate digestion via salivary amylase. The bolus (mass of food) is swallowed and enters the stomach.

Question 7

Esophagus

Esophagus & Stomach

Answer 7

Esophagus: Contains two sphincters (upper and lower) that control food movement. The bolus moves into the stomach, which churns food and adds digestive juices to form chyme.

Question 8

Stomach

Esophagus & Stomach

Answer 8

Stomach: The pyloric sphincter releases chyme into the small intestine.

Question 9

Small Intestine

Intestines

Answer 9

Small Intestine: About 10 feet long, consisting of the duodenum, jejunum, and ileum. The common bile duct drips fluids from the pancreas and gallbladder.

Question 10

Large Intestine (colon)

Intestines

Answer 10

Large Intestine: Water is withdrawn to form semi-solid waste, which is passed into the rectum. Defecation occurs when the rectal muscles relax, and the 2 anal sphincters open.

Question 11

ileocecal valve

Intestines

Answer 11

The ileocecal valve is a sphincter muscle situated at the junction of the ileum (last portion of your small intestine) and the colon (first portion of your large intestine).

Question 12

GI Motility

Muscular Action of Digestion

Answer 12

GI Motility: Spontaneous movements aiding digestion.

Segmentation: Circular muscles contract to mix chyme with digestive juices.
Peristalsis: Longitudinal muscles push the chyme forward.
Sphincter Contractions: Control the pace of GI tract contents.

Question 13

Segmentation

Muscular Action of Digestion

Answer 13

Segmentation: Circular muscles contract to mix chyme with digestive juices.

Question 14

Peristalsis

Muscular Action of Digestion

Answer 14

Peristalsis: Longitudinal muscles push the chyme forward.

Question 15

Sphincter Contractions

Muscular Action of Digestion

Answer 15

Sphincter Contractions: Control the pace of GI tract contents.

Question 16

Saliva

Answer 16

Saliva: Moistens food for swallowing and begins carbohydrate digestion.

Question 17

Gastric Juice

Answer 17

Gastric Juice: Produced in the stomach, primarily aiding protein digestion with enzymes and hydrochloric acid (HCl).

Question 18

Pancreatic Juice

Answer 18

Pancreatic Juice: Released into the duodenum, contains enzymes for all energy nutrients and sodium bicarbonate to neutralize acidic chyme.

Question 19

Bile

Answer 19

Bile: Produced by the liver, stored in the gallbladder, and released into the duodenum to emulsify fats.

Question 20

Villi & Microvilli

Absorption in the Small Intestine

Answer 20

Villi & Microvilli: Increase the surface area for absorption.

Villi move constantly to absorb nutrients, while microvilli contain enzymes for nutrient breakdown.

Question 21

Absorption Methods:

Answer 21

Simple Diffusion
Facilitated Diffusion
Active Transport

Question 22

Vascular System

Answer 22

Vascular System: Nutrients (like water-soluble nutrients and small fats) enter the bloodstream via the hepatic portal vein to the liver.

Question 23

Lymphatic System

Answer 23

Lymphatic System: Larger fats and fat-soluble vitamins are absorbed into the lymphatic system before entering the bloodstream.

Question 24

GI Microbes

Answer 24

Healthy GI tract microbes aid in digestion and may influence disease. Prebiotics support microbial growth, and probiotics are live beneficial microbes.

Question 25

Homeostasis

GI Hormones & Nerve Pathways

Answer 25

Homeostasis: The digestive process is regulated by feedback mechanisms involving hormones:

Question 26

Gastrin

GI Hormones & Nerve Pathways

Answer 26

Gastrin: Secreted by the stomach to maintain acidic pH.

Question 27

Secretin

GI Hormones & Nerve Pathways

Answer 27

Secretin: Stimulates the pancreas to release bicarbonate to neutralize acidic chyme.

Question 28

Cholecystokinin

GI Hormones & Nerve Pathways

Answer 28

Cholecystokinin (CCK): Released in response to fat/protein in the small intestine, stimulating the gallbladder to release bile and slowing GI motility.

Question 29

Choking

Common Digestive Problems & Solutions

Answer 29

Choking: Caused by food blocking the trachea, prevented by eating slowly and chewing well.

Question 30

Vomiting & Diarrhea

Common Digestive Problems & Solutions

Answer 30

Vomiting & Diarrhea: Vomiting leads to dehydration; diarrhea can be caused by fast-moving intestinal contents. Both require rehydration.

Question 31

Constipation

Common Digestive Problems & Solutions

Answer 31

Constipation: Prevented with a high-fiber diet, fluids, and exercise.

Question 32

Gastroesophageal Reflux

Common Digestive Problems & Solutions

Answer 32

Gastroesophageal Reflux: Heartburn caused by stomach acid entering the esophagus. Prevention includes small meals, proper posture, and avoiding irritant foods.

Question 33

Ulcers

Common Digestive Problems & Solutions

Answer 33

Ulcers: Caused by bacterial infections, anti-inflammatory drugs, or excess acid, treated with medication and diet changes.